matter.js

/**
* matter-js 0.14.2 by @liabru 2018-06-11
* http://brm.io/matter-js/
* License MIT
*/

/**
 * The MIT License (MIT)
 * 
 * Copyright (c) Liam Brummitt and contributors.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.Matter = f()}})(function(){var define,module,exports;return (function(){function r(e,n,t){function o(i,f){if(!n[i]){if(!e[i]){var c="function"==typeof require&&require;if(!f&&c)return c(i,!0);if(u)return u(i,!0);var a=new Error("Cannot find module '"+i+"'");throw a.code="MODULE_NOT_FOUND",a}var p=n[i]={exports:{}};e[i][0].call(p.exports,function(r){var n=e[i][1][r];return o(n||r)},p,p.exports,r,e,n,t)}return n[i].exports}for(var u="function"==typeof require&&require,i=0;i<t.length;i++)o(t[i]);return o}return r})()({1:[function(_dereq_,module,exports){
    /**
    * The `Matter.Body` module contains methods for creating and manipulating body models.
    * A `Matter.Body` is a rigid body that can be simulated by a `Matter.Engine`.
    * Factories for commonly used body configurations (such as rectangles, circles and other polygons) can be found in the module `Matter.Bodies`.
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    
    * @class Body
    */
    
    var Body = {};
    
    module.exports = Body;
    
    var Vertices = _dereq_('../geometry/Vertices');
    var Vector = _dereq_('../geometry/Vector');
    var Sleeping = _dereq_('../core/Sleeping');
    var Render = _dereq_('../render/Render');
    var Common = _dereq_('../core/Common');
    var Bounds = _dereq_('../geometry/Bounds');
    var Axes = _dereq_('../geometry/Axes');
    
    (function() {
    
        Body._inertiaScale = 4;
        Body._nextCollidingGroupId = 1;
        Body._nextNonCollidingGroupId = -1;
        Body._nextCategory = 0x0001;
    
        /**
         * Creates a new rigid body model. The options parameter is an object that specifies any properties you wish to override the defaults.
         * All properties have default values, and many are pre-calculated automatically based on other properties.
         * Vertices must be specified in clockwise order.
         * See the properties section below for detailed information on what you can pass via the `options` object.
         * @method create
         * @param {} options
         * @return {body} body
         */
        Body.create = function(options) {
            var defaults = {
                id: Common.nextId(),
                type: 'body',
                label: 'Body',
                parts: [],
                plugin: {},
                angle: 0,
                vertices: Vertices.fromPath('L 0 0 L 40 0 L 40 40 L 0 40'),
                position: { x: 0, y: 0 },
                force: { x: 0, y: 0 },
                torque: 0,
                positionImpulse: { x: 0, y: 0 },
                constraintImpulse: { x: 0, y: 0, angle: 0 },
                totalContacts: 0,
                speed: 0,
                angularSpeed: 0,
                velocity: { x: 0, y: 0 },
                angularVelocity: 0,
                isSensor: false,
                isStatic: false,
                isSleeping: false,
                motion: 0,
                sleepThreshold: 60,
                density: 0.001,
                restitution: 0,
                friction: 0.1,
                frictionStatic: 0.5,
                frictionAir: 0.01,
                collisionFilter: {
                    category: 0x0001,
                    mask: 0xFFFFFFFF,
                    group: 0
                },
                slop: 0.05,
                timeScale: 1,
                render: {
                    visible: true,
                    opacity: 1,
                    sprite: {
                        xScale: 1,
                        yScale: 1,
                        xOffset: 0,
                        yOffset: 0
                    },
                    lineWidth: 0
                }
            };
    
            var body = Common.extend(defaults, options);
    
            _initProperties(body, options);
    
            return body;
        };
    
        /**
         * Returns the next unique group index for which bodies will collide.
         * If `isNonColliding` is `true`, returns the next unique group index for which bodies will _not_ collide.
         * See `body.collisionFilter` for more information.
         * @method nextGroup
         * @param {bool} [isNonColliding=false]
         * @return {Number} Unique group index
         */
        Body.nextGroup = function(isNonColliding) {
            if (isNonColliding)
                return Body._nextNonCollidingGroupId--;
    
            return Body._nextCollidingGroupId++;
        };
    
        /**
         * Returns the next unique category bitfield (starting after the initial default category `0x0001`).
         * There are 32 available. See `body.collisionFilter` for more information.
         * @method nextCategory
         * @return {Number} Unique category bitfield
         */
        Body.nextCategory = function() {
            Body._nextCategory = Body._nextCategory << 1;
            return Body._nextCategory;
        };
    
        /**
         * Initialises body properties.
         * @method _initProperties
         * @private
         * @param {body} body
         * @param {} [options]
         */
        var _initProperties = function(body, options) {
            options = options || {};
    
            // init required properties (order is important)
            Body.set(body, {
                bounds: body.bounds || Bounds.create(body.vertices),
                positionPrev: body.positionPrev || Vector.clone(body.position),
                anglePrev: body.anglePrev || body.angle,
                vertices: body.vertices,
                parts: body.parts || [body],
                isStatic: body.isStatic,
                isSleeping: body.isSleeping,
                parent: body.parent || body
            });
    
            Vertices.rotate(body.vertices, body.angle, body.position);
            Axes.rotate(body.axes, body.angle);
            Bounds.update(body.bounds, body.vertices, body.velocity);
    
            // allow options to override the automatically calculated properties
            Body.set(body, {
                axes: options.axes || body.axes,
                area: options.area || body.area,
                mass: options.mass || body.mass,
                inertia: options.inertia || body.inertia
            });
    
            // render properties
            var defaultFillStyle = (body.isStatic ? '#2e2b44' : Common.choose(['#006BA6', '#0496FF', '#FFBC42', '#D81159', '#8F2D56'])),
                defaultStrokeStyle = '#000';
            body.render.fillStyle = body.render.fillStyle || defaultFillStyle;
            body.render.strokeStyle = body.render.strokeStyle || defaultStrokeStyle;
            body.render.sprite.xOffset += -(body.bounds.min.x - body.position.x) / (body.bounds.max.x - body.bounds.min.x);
            body.render.sprite.yOffset += -(body.bounds.min.y - body.position.y) / (body.bounds.max.y - body.bounds.min.y);
        };
    
        /**
         * Given a property and a value (or map of), sets the property(s) on the body, using the appropriate setter functions if they exist.
         * Prefer to use the actual setter functions in performance critical situations.
         * @method set
         * @param {body} body
         * @param {} settings A property name (or map of properties and values) to set on the body.
         * @param {} value The value to set if `settings` is a single property name.
         */
        Body.set = function(body, settings, value) {
            var property;
    
            if (typeof settings === 'string') {
                property = settings;
                settings = {};
                settings[property] = value;
            }
    
            for (property in settings) {
                value = settings[property];
    
                if (!settings.hasOwnProperty(property))
                    continue;
    
                switch (property) {
    
                case 'isStatic':
                    Body.setStatic(body, value);
                    break;
                case 'isSleeping':
                    Sleeping.set(body, value);
                    break;
                case 'mass':
                    Body.setMass(body, value);
                    break;
                case 'density':
                    Body.setDensity(body, value);
                    break;
                case 'inertia':
                    Body.setInertia(body, value);
                    break;
                case 'vertices':
                    Body.setVertices(body, value);
                    break;
                case 'position':
                    Body.setPosition(body, value);
                    break;
                case 'angle':
                    Body.setAngle(body, value);
                    break;
                case 'velocity':
                    Body.setVelocity(body, value);
                    break;
                case 'angularVelocity':
                    Body.setAngularVelocity(body, value);
                    break;
                case 'parts':
                    Body.setParts(body, value);
                    break;
                default:
                    body[property] = value;
    
                }
            }
        };
    
        /**
         * Sets the body as static, including isStatic flag and setting mass and inertia to Infinity.
         * @method setStatic
         * @param {body} body
         * @param {bool} isStatic
         */
        Body.setStatic = function(body, isStatic) {
            for (var i = 0; i < body.parts.length; i++) {
                var part = body.parts[i];
                part.isStatic = isStatic;
    
                if (isStatic) {
                    part._original = {
                        restitution: part.restitution,
                        friction: part.friction,
                        mass: part.mass,
                        inertia: part.inertia,
                        density: part.density,
                        inverseMass: part.inverseMass,
                        inverseInertia: part.inverseInertia
                    };
    
                    part.restitution = 0;
                    part.friction = 1;
                    part.mass = part.inertia = part.density = Infinity;
                    part.inverseMass = part.inverseInertia = 0;
    
                    part.positionPrev.x = part.position.x;
                    part.positionPrev.y = part.position.y;
                    part.anglePrev = part.angle;
                    part.angularVelocity = 0;
                    part.speed = 0;
                    part.angularSpeed = 0;
                    part.motion = 0;
                } else if (part._original) {
                    part.restitution = part._original.restitution;
                    part.friction = part._original.friction;
                    part.mass = part._original.mass;
                    part.inertia = part._original.inertia;
                    part.density = part._original.density;
                    part.inverseMass = part._original.inverseMass;
                    part.inverseInertia = part._original.inverseInertia;
    
                    delete part._original;
                }
            }
        };
    
        /**
         * Sets the mass of the body. Inverse mass, density and inertia are automatically updated to reflect the change.
         * @method setMass
         * @param {body} body
         * @param {number} mass
         */
        Body.setMass = function(body, mass) {
            var moment = body.inertia / (body.mass / 6);
            body.inertia = moment * (mass / 6);
            body.inverseInertia = 1 / body.inertia;
    
            body.mass = mass;
            body.inverseMass = 1 / body.mass;
            body.density = body.mass / body.area;
        };
    
        /**
         * Sets the density of the body. Mass and inertia are automatically updated to reflect the change.
         * @method setDensity
         * @param {body} body
         * @param {number} density
         */
        Body.setDensity = function(body, density) {
            Body.setMass(body, density * body.area);
            body.density = density;
        };
    
        /**
         * Sets the moment of inertia (i.e. second moment of area) of the body of the body. 
         * Inverse inertia is automatically updated to reflect the change. Mass is not changed.
         * @method setInertia
         * @param {body} body
         * @param {number} inertia
         */
        Body.setInertia = function(body, inertia) {
            body.inertia = inertia;
            body.inverseInertia = 1 / body.inertia;
        };
    
        /**
         * Sets the body's vertices and updates body properties accordingly, including inertia, area and mass (with respect to `body.density`).
         * Vertices will be automatically transformed to be orientated around their centre of mass as the origin.
         * They are then automatically translated to world space based on `body.position`.
         *
         * The `vertices` argument should be passed as an array of `Matter.Vector` points (or a `Matter.Vertices` array).
         * Vertices must form a convex hull, concave hulls are not supported.
         *
         * @method setVertices
         * @param {body} body
         * @param {vector[]} vertices
         */
        Body.setVertices = function(body, vertices) {
            // change vertices
            if (vertices[0].body === body) {
                body.vertices = vertices;
            } else {
                body.vertices = Vertices.create(vertices, body);
            }
    
            // update properties
            body.axes = Axes.fromVertices(body.vertices);
            body.area = Vertices.area(body.vertices);
            Body.setMass(body, body.density * body.area);
    
            // orient vertices around the centre of mass at origin (0, 0)
            var centre = Vertices.centre(body.vertices);
            Vertices.translate(body.vertices, centre, -1);
    
            // update inertia while vertices are at origin (0, 0)
            Body.setInertia(body, Body._inertiaScale * Vertices.inertia(body.vertices, body.mass));
    
            // update geometry
            Vertices.translate(body.vertices, body.position);
            Bounds.update(body.bounds, body.vertices, body.velocity);
        };
    
        /**
         * Sets the parts of the `body` and updates mass, inertia and centroid.
         * Each part will have its parent set to `body`.
         * By default the convex hull will be automatically computed and set on `body`, unless `autoHull` is set to `false.`
         * Note that this method will ensure that the first part in `body.parts` will always be the `body`.
         * @method setParts
         * @param {body} body
         * @param [body] parts
         * @param {bool} [autoHull=true]
         */
        Body.setParts = function(body, parts, autoHull) {
            var i;
    
            // add all the parts, ensuring that the first part is always the parent body
            parts = parts.slice(0);
            body.parts.length = 0;
            body.parts.push(body);
            body.parent = body;
    
            for (i = 0; i < parts.length; i++) {
                var part = parts[i];
                if (part !== body) {
                    part.parent = body;
                    body.parts.push(part);
                }
            }
    
            if (body.parts.length === 1)
                return;
    
            autoHull = typeof autoHull !== 'undefined' ? autoHull : true;
    
            // find the convex hull of all parts to set on the parent body
            if (autoHull) {
                var vertices = [];
                for (i = 0; i < parts.length; i++) {
                    vertices = vertices.concat(parts[i].vertices);
                }
    
                Vertices.clockwiseSort(vertices);
    
                var hull = Vertices.hull(vertices),
                    hullCentre = Vertices.centre(hull);
    
                Body.setVertices(body, hull);
                Vertices.translate(body.vertices, hullCentre);
            }
    
            // sum the properties of all compound parts of the parent body
            var total = Body._totalProperties(body);
    
            body.area = total.area;
            body.parent = body;
            body.position.x = total.centre.x;
            body.position.y = total.centre.y;
            body.positionPrev.x = total.centre.x;
            body.positionPrev.y = total.centre.y;
    
            Body.setMass(body, total.mass);
            Body.setInertia(body, total.inertia);
            Body.setPosition(body, total.centre);
        };
    
        /**
         * Sets the position of the body instantly. Velocity, angle, force etc. are unchanged.
         * @method setPosition
         * @param {body} body
         * @param {vector} position
         */
        Body.setPosition = function(body, position) {
            var delta = Vector.sub(position, body.position);
            body.positionPrev.x += delta.x;
            body.positionPrev.y += delta.y;
    
            for (var i = 0; i < body.parts.length; i++) {
                var part = body.parts[i];
                part.position.x += delta.x;
                part.position.y += delta.y;
                Vertices.translate(part.vertices, delta);
                Bounds.update(part.bounds, part.vertices, body.velocity);
            }
        };
    
        /**
         * Sets the angle of the body instantly. Angular velocity, position, force etc. are unchanged.
         * @method setAngle
         * @param {body} body
         * @param {number} angle
         */
        Body.setAngle = function(body, angle) {
            var delta = angle - body.angle;
            body.anglePrev += delta;
    
            for (var i = 0; i < body.parts.length; i++) {
                var part = body.parts[i];
                part.angle += delta;
                Vertices.rotate(part.vertices, delta, body.position);
                Axes.rotate(part.axes, delta);
                Bounds.update(part.bounds, part.vertices, body.velocity);
                if (i > 0) {
                    Vector.rotateAbout(part.position, delta, body.position, part.position);
                }
            }
        };
    
        /**
         * Sets the linear velocity of the body instantly. Position, angle, force etc. are unchanged. See also `Body.applyForce`.
         * @method setVelocity
         * @param {body} body
         * @param {vector} velocity
         */
        Body.setVelocity = function(body, velocity) {
            body.positionPrev.x = body.position.x - velocity.x;
            body.positionPrev.y = body.position.y - velocity.y;
            body.velocity.x = velocity.x;
            body.velocity.y = velocity.y;
            body.speed = Vector.magnitude(body.velocity);
        };
    
        /**
         * Sets the angular velocity of the body instantly. Position, angle, force etc. are unchanged. See also `Body.applyForce`.
         * @method setAngularVelocity
         * @param {body} body
         * @param {number} velocity
         */
        Body.setAngularVelocity = function(body, velocity) {
            body.anglePrev = body.angle - velocity;
            body.angularVelocity = velocity;
            body.angularSpeed = Math.abs(body.angularVelocity);
        };
    
        /**
         * Moves a body by a given vector relative to its current position, without imparting any velocity.
         * @method translate
         * @param {body} body
         * @param {vector} translation
         */
        Body.translate = function(body, translation) {
            Body.setPosition(body, Vector.add(body.position, translation));
        };
    
        /**
         * Rotates a body by a given angle relative to its current angle, without imparting any angular velocity.
         * @method rotate
         * @param {body} body
         * @param {number} rotation
         * @param {vector} [point]
         */
        Body.rotate = function(body, rotation, point) {
            if (!point) {
                Body.setAngle(body, body.angle + rotation);
            } else {
                var cos = Math.cos(rotation),
                    sin = Math.sin(rotation),
                    dx = body.position.x - point.x,
                    dy = body.position.y - point.y;
                    
                Body.setPosition(body, {
                    x: point.x + (dx * cos - dy * sin),
                    y: point.y + (dx * sin + dy * cos)
                });
    
                Body.setAngle(body, body.angle + rotation);
            }
        };
    
        /**
         * Scales the body, including updating physical properties (mass, area, axes, inertia), from a world-space point (default is body centre).
         * @method scale
         * @param {body} body
         * @param {number} scaleX
         * @param {number} scaleY
         * @param {vector} [point]
         */
        Body.scale = function(body, scaleX, scaleY, point) {
            var totalArea = 0,
                totalInertia = 0;
    
            point = point || body.position;
    
            for (var i = 0; i < body.parts.length; i++) {
                var part = body.parts[i];
    
                // scale vertices
                Vertices.scale(part.vertices, scaleX, scaleY, point);
    
                // update properties
                part.axes = Axes.fromVertices(part.vertices);
                part.area = Vertices.area(part.vertices);
                Body.setMass(part, body.density * part.area);
    
                // update inertia (requires vertices to be at origin)
                Vertices.translate(part.vertices, { x: -part.position.x, y: -part.position.y });
                Body.setInertia(part, Body._inertiaScale * Vertices.inertia(part.vertices, part.mass));
                Vertices.translate(part.vertices, { x: part.position.x, y: part.position.y });
    
                if (i > 0) {
                    totalArea += part.area;
                    totalInertia += part.inertia;
                }
    
                // scale position
                part.position.x = point.x + (part.position.x - point.x) * scaleX;
                part.position.y = point.y + (part.position.y - point.y) * scaleY;
    
                // update bounds
                Bounds.update(part.bounds, part.vertices, body.velocity);
            }
    
            // handle parent body
            if (body.parts.length > 1) {
                body.area = totalArea;
    
                if (!body.isStatic) {
                    Body.setMass(body, body.density * totalArea);
                    Body.setInertia(body, totalInertia);
                }
            }
    
            // handle circles
            if (body.circleRadius) { 
                if (scaleX === scaleY) {
                    body.circleRadius *= scaleX;
                } else {
                    // body is no longer a circle
                    body.circleRadius = null;
                }
            }
        };
    
        /**
         * Performs a simulation step for the given `body`, including updating position and angle using Verlet integration.
         * @method update
         * @param {body} body
         * @param {number} deltaTime
         * @param {number} timeScale
         * @param {number} correction
         */
        Body.update = function(body, deltaTime, timeScale, correction) {
            var deltaTimeSquared = Math.pow(deltaTime * timeScale * body.timeScale, 2);
    
            // from the previous step
            var frictionAir = 1 - body.frictionAir * timeScale * body.timeScale,
                velocityPrevX = body.position.x - body.positionPrev.x,
                velocityPrevY = body.position.y - body.positionPrev.y;
    
            // update velocity with Verlet integration
            body.velocity.x = (velocityPrevX * frictionAir * correction) + (body.force.x / body.mass) * deltaTimeSquared;
            body.velocity.y = (velocityPrevY * frictionAir * correction) + (body.force.y / body.mass) * deltaTimeSquared;
    
            body.positionPrev.x = body.position.x;
            body.positionPrev.y = body.position.y;
            body.position.x += body.velocity.x;
            body.position.y += body.velocity.y;
    
            // update angular velocity with Verlet integration
            body.angularVelocity = ((body.angle - body.anglePrev) * frictionAir * correction) + (body.torque / body.inertia) * deltaTimeSquared;
            body.anglePrev = body.angle;
            body.angle += body.angularVelocity;
    
            // track speed and acceleration
            body.speed = Vector.magnitude(body.velocity);
            body.angularSpeed = Math.abs(body.angularVelocity);
    
            // transform the body geometry
            for (var i = 0; i < body.parts.length; i++) {
                var part = body.parts[i];
    
                Vertices.translate(part.vertices, body.velocity);
                
                if (i > 0) {
                    part.position.x += body.velocity.x;
                    part.position.y += body.velocity.y;
                }
    
                if (body.angularVelocity !== 0) {
                    Vertices.rotate(part.vertices, body.angularVelocity, body.position);
                    Axes.rotate(part.axes, body.angularVelocity);
                    if (i > 0) {
                        Vector.rotateAbout(part.position, body.angularVelocity, body.position, part.position);
                    }
                }
    
                Bounds.update(part.bounds, part.vertices, body.velocity);
            }
        };
    
        /**
         * Applies a force to a body from a given world-space position, including resulting torque.
         * @method applyForce
         * @param {body} body
         * @param {vector} position
         * @param {vector} force
         */
        Body.applyForce = function(body, position, force) {
            body.force.x += force.x;
            body.force.y += force.y;
            var offset = { x: position.x - body.position.x, y: position.y - body.position.y };
            body.torque += offset.x * force.y - offset.y * force.x;
        };
    
        /**
         * Returns the sums of the properties of all compound parts of the parent body.
         * @method _totalProperties
         * @private
         * @param {body} body
         * @return {}
         */
        Body._totalProperties = function(body) {
            // from equations at:
            // https://ecourses.ou.edu/cgi-bin/ebook.cgi?doc=&topic=st&chap_sec=07.2&page=theory
            // http://output.to/sideway/default.asp?qno=121100087
    
            var properties = {
                mass: 0,
                area: 0,
                inertia: 0,
                centre: { x: 0, y: 0 }
            };
    
            // sum the properties of all compound parts of the parent body
            for (var i = body.parts.length === 1 ? 0 : 1; i < body.parts.length; i++) {
                var part = body.parts[i],
                    mass = part.mass !== Infinity ? part.mass : 1;
    
                properties.mass += mass;
                properties.area += part.area;
                properties.inertia += part.inertia;
                properties.centre = Vector.add(properties.centre, Vector.mult(part.position, mass));
            }
    
            properties.centre = Vector.div(properties.centre, properties.mass);
    
            return properties;
        };
    
        /*
        *
        *  Events Documentation
        *
        */
    
        /**
        * Fired when a body starts sleeping (where `this` is the body).
        *
        * @event sleepStart
        * @this {body} The body that has started sleeping
        * @param {} event An event object
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired when a body ends sleeping (where `this` is the body).
        *
        * @event sleepEnd
        * @this {body} The body that has ended sleeping
        * @param {} event An event object
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /*
        *
        *  Properties Documentation
        *
        */
    
        /**
         * An integer `Number` uniquely identifying number generated in `Body.create` by `Common.nextId`.
         *
         * @property id
         * @type number
         */
    
        /**
         * A `String` denoting the type of object.
         *
         * @property type
         * @type string
         * @default "body"
         * @readOnly
         */
    
        /**
         * An arbitrary `String` name to help the user identify and manage bodies.
         *
         * @property label
         * @type string
         * @default "Body"
         */
    
        /**
         * An array of bodies that make up this body. 
         * The first body in the array must always be a self reference to the current body instance.
         * All bodies in the `parts` array together form a single rigid compound body.
         * Parts are allowed to overlap, have gaps or holes or even form concave bodies.
         * Parts themselves should never be added to a `World`, only the parent body should be.
         * Use `Body.setParts` when setting parts to ensure correct updates of all properties.
         *
         * @property parts
         * @type body[]
         */
    
        /**
         * An object reserved for storing plugin-specific properties.
         *
         * @property plugin
         * @type {}
         */
    
        /**
         * A self reference if the body is _not_ a part of another body.
         * Otherwise this is a reference to the body that this is a part of.
         * See `body.parts`.
         *
         * @property parent
         * @type body
         */
    
        /**
         * A `Number` specifying the angle of the body, in radians.
         *
         * @property angle
         * @type number
         * @default 0
         */
    
        /**
         * An array of `Vector` objects that specify the convex hull of the rigid body.
         * These should be provided about the origin `(0, 0)`. E.g.
         *
         *     [{ x: 0, y: 0 }, { x: 25, y: 50 }, { x: 50, y: 0 }]
         *
         * When passed via `Body.create`, the vertices are translated relative to `body.position` (i.e. world-space, and constantly updated by `Body.update` during simulation).
         * The `Vector` objects are also augmented with additional properties required for efficient collision detection. 
         *
         * Other properties such as `inertia` and `bounds` are automatically calculated from the passed vertices (unless provided via `options`).
         * Concave hulls are not currently supported. The module `Matter.Vertices` contains useful methods for working with vertices.
         *
         * @property vertices
         * @type vector[]
         */
    
        /**
         * A `Vector` that specifies the current world-space position of the body.
         *
         * @property position
         * @type vector
         * @default { x: 0, y: 0 }
         */
    
        /**
         * A `Vector` that specifies the force to apply in the current step. It is zeroed after every `Body.update`. See also `Body.applyForce`.
         *
         * @property force
         * @type vector
         * @default { x: 0, y: 0 }
         */
    
        /**
         * A `Number` that specifies the torque (turning force) to apply in the current step. It is zeroed after every `Body.update`.
         *
         * @property torque
         * @type number
         * @default 0
         */
    
        /**
         * A `Number` that _measures_ the current speed of the body after the last `Body.update`. It is read-only and always positive (it's the magnitude of `body.velocity`).
         *
         * @readOnly
         * @property speed
         * @type number
         * @default 0
         */
    
        /**
         * A `Number` that _measures_ the current angular speed of the body after the last `Body.update`. It is read-only and always positive (it's the magnitude of `body.angularVelocity`).
         *
         * @readOnly
         * @property angularSpeed
         * @type number
         * @default 0
         */
    
        /**
         * A `Vector` that _measures_ the current velocity of the body after the last `Body.update`. It is read-only. 
         * If you need to modify a body's velocity directly, you should either apply a force or simply change the body's `position` (as the engine uses position-Verlet integration).
         *
         * @readOnly
         * @property velocity
         * @type vector
         * @default { x: 0, y: 0 }
         */
    
        /**
         * A `Number` that _measures_ the current angular velocity of the body after the last `Body.update`. It is read-only. 
         * If you need to modify a body's angular velocity directly, you should apply a torque or simply change the body's `angle` (as the engine uses position-Verlet integration).
         *
         * @readOnly
         * @property angularVelocity
         * @type number
         * @default 0
         */
    
        /**
         * A flag that indicates whether a body is considered static. A static body can never change position or angle and is completely fixed.
         * If you need to set a body as static after its creation, you should use `Body.setStatic` as this requires more than just setting this flag.
         *
         * @property isStatic
         * @type boolean
         * @default false
         */
    
        /**
         * A flag that indicates whether a body is a sensor. Sensor triggers collision events, but doesn't react with colliding body physically.
         *
         * @property isSensor
         * @type boolean
         * @default false
         */
    
        /**
         * A flag that indicates whether the body is considered sleeping. A sleeping body acts similar to a static body, except it is only temporary and can be awoken.
         * If you need to set a body as sleeping, you should use `Sleeping.set` as this requires more than just setting this flag.
         *
         * @property isSleeping
         * @type boolean
         * @default false
         */
    
        /**
         * A `Number` that _measures_ the amount of movement a body currently has (a combination of `speed` and `angularSpeed`). It is read-only and always positive.
         * It is used and updated by the `Matter.Sleeping` module during simulation to decide if a body has come to rest.
         *
         * @readOnly
         * @property motion
         * @type number
         * @default 0
         */
    
        /**
         * A `Number` that defines the number of updates in which this body must have near-zero velocity before it is set as sleeping by the `Matter.Sleeping` module (if sleeping is enabled by the engine).
         *
         * @property sleepThreshold
         * @type number
         * @default 60
         */
    
        /**
         * A `Number` that defines the density of the body, that is its mass per unit area.
         * If you pass the density via `Body.create` the `mass` property is automatically calculated for you based on the size (area) of the object.
         * This is generally preferable to simply setting mass and allows for more intuitive definition of materials (e.g. rock has a higher density than wood).
         *
         * @property density
         * @type number
         * @default 0.001
         */
    
        /**
         * A `Number` that defines the mass of the body, although it may be more appropriate to specify the `density` property instead.
         * If you modify this value, you must also modify the `body.inverseMass` property (`1 / mass`).
         *
         * @property mass
         * @type number
         */
    
        /**
         * A `Number` that defines the inverse mass of the body (`1 / mass`).
         * If you modify this value, you must also modify the `body.mass` property.
         *
         * @property inverseMass
         * @type number
         */
    
        /**
         * A `Number` that defines the moment of inertia (i.e. second moment of area) of the body.
         * It is automatically calculated from the given convex hull (`vertices` array) and density in `Body.create`.
         * If you modify this value, you must also modify the `body.inverseInertia` property (`1 / inertia`).
         *
         * @property inertia
         * @type number
         */
    
        /**
         * A `Number` that defines the inverse moment of inertia of the body (`1 / inertia`).
         * If you modify this value, you must also modify the `body.inertia` property.
         *
         * @property inverseInertia
         * @type number
         */
    
        /**
         * A `Number` that defines the restitution (elasticity) of the body. The value is always positive and is in the range `(0, 1)`.
         * A value of `0` means collisions may be perfectly inelastic and no bouncing may occur. 
         * A value of `0.8` means the body may bounce back with approximately 80% of its kinetic energy.
         * Note that collision response is based on _pairs_ of bodies, and that `restitution` values are _combined_ with the following formula:
         *
         *     Math.max(bodyA.restitution, bodyB.restitution)
         *
         * @property restitution
         * @type number
         * @default 0
         */
    
        /**
         * A `Number` that defines the friction of the body. The value is always positive and is in the range `(0, 1)`.
         * A value of `0` means that the body may slide indefinitely.
         * A value of `1` means the body may come to a stop almost instantly after a force is applied.
         *
         * The effects of the value may be non-linear. 
         * High values may be unstable depending on the body.
         * The engine uses a Coulomb friction model including static and kinetic friction.
         * Note that collision response is based on _pairs_ of bodies, and that `friction` values are _combined_ with the following formula:
         *
         *     Math.min(bodyA.friction, bodyB.friction)
         *
         * @property friction
         * @type number
         * @default 0.1
         */
    
        /**
         * A `Number` that defines the static friction of the body (in the Coulomb friction model). 
         * A value of `0` means the body will never 'stick' when it is nearly stationary and only dynamic `friction` is used.
         * The higher the value (e.g. `10`), the more force it will take to initially get the body moving when nearly stationary.
         * This value is multiplied with the `friction` property to make it easier to change `friction` and maintain an appropriate amount of static friction.
         *
         * @property frictionStatic
         * @type number
         * @default 0.5
         */
    
        /**
         * A `Number` that defines the air friction of the body (air resistance). 
         * A value of `0` means the body will never slow as it moves through space.
         * The higher the value, the faster a body slows when moving through space.
         * The effects of the value are non-linear. 
         *
         * @property frictionAir
         * @type number
         * @default 0.01
         */
    
        /**
         * An `Object` that specifies the collision filtering properties of this body.
         *
         * Collisions between two bodies will obey the following rules:
         * - If the two bodies have the same non-zero value of `collisionFilter.group`,
         *   they will always collide if the value is positive, and they will never collide
         *   if the value is negative.
         * - If the two bodies have different values of `collisionFilter.group` or if one
         *   (or both) of the bodies has a value of 0, then the category/mask rules apply as follows:
         *
         * Each body belongs to a collision category, given by `collisionFilter.category`. This
         * value is used as a bit field and the category should have only one bit set, meaning that
         * the value of this property is a power of two in the range [1, 2^31]. Thus, there are 32
         * different collision categories available.
         *
         * Each body also defines a collision bitmask, given by `collisionFilter.mask` which specifies
         * the categories it collides with (the value is the bitwise AND value of all these categories).
         *
         * Using the category/mask rules, two bodies `A` and `B` collide if each includes the other's
         * category in its mask, i.e. `(categoryA & maskB) !== 0` and `(categoryB & maskA) !== 0`
         * are both true.
         *
         * @property collisionFilter
         * @type object
         */
    
        /**
         * An Integer `Number`, that specifies the collision group this body belongs to.
         * See `body.collisionFilter` for more information.
         *
         * @property collisionFilter.group
         * @type object
         * @default 0
         */
    
        /**
         * A bit field that specifies the collision category this body belongs to.
         * The category value should have only one bit set, for example `0x0001`.
         * This means there are up to 32 unique collision categories available.
         * See `body.collisionFilter` for more information.
         *
         * @property collisionFilter.category
         * @type object
         * @default 1
         */
    
        /**
         * A bit mask that specifies the collision categories this body may collide with.
         * See `body.collisionFilter` for more information.
         *
         * @property collisionFilter.mask
         * @type object
         * @default -1
         */
    
        /**
         * A `Number` that specifies a tolerance on how far a body is allowed to 'sink' or rotate into other bodies.
         * Avoid changing this value unless you understand the purpose of `slop` in physics engines.
         * The default should generally suffice, although very large bodies may require larger values for stable stacking.
         *
         * @property slop
         * @type number
         * @default 0.05
         */
    
        /**
         * A `Number` that allows per-body time scaling, e.g. a force-field where bodies inside are in slow-motion, while others are at full speed.
         *
         * @property timeScale
         * @type number
         * @default 1
         */
    
        /**
         * An `Object` that defines the rendering properties to be consumed by the module `Matter.Render`.
         *
         * @property render
         * @type object
         */
    
        /**
         * A flag that indicates if the body should be rendered.
         *
         * @property render.visible
         * @type boolean
         * @default true
         */
    
        /**
         * Sets the opacity to use when rendering.
         *
         * @property render.opacity
         * @type number
         * @default 1
        */
    
        /**
         * An `Object` that defines the sprite properties to use when rendering, if any.
         *
         * @property render.sprite
         * @type object
         */
    
        /**
         * An `String` that defines the path to the image to use as the sprite texture, if any.
         *
         * @property render.sprite.texture
         * @type string
         */
         
        /**
         * A `Number` that defines the scaling in the x-axis for the sprite, if any.
         *
         * @property render.sprite.xScale
         * @type number
         * @default 1
         */
    
        /**
         * A `Number` that defines the scaling in the y-axis for the sprite, if any.
         *
         * @property render.sprite.yScale
         * @type number
         * @default 1
         */
    
         /**
          * A `Number` that defines the offset in the x-axis for the sprite (normalised by texture width).
          *
          * @property render.sprite.xOffset
          * @type number
          * @default 0
          */
    
         /**
          * A `Number` that defines the offset in the y-axis for the sprite (normalised by texture height).
          *
          * @property render.sprite.yOffset
          * @type number
          * @default 0
          */
    
        /**
         * A `Number` that defines the line width to use when rendering the body outline (if a sprite is not defined).
         * A value of `0` means no outline will be rendered.
         *
         * @property render.lineWidth
         * @type number
         * @default 0
         */
    
        /**
         * A `String` that defines the fill style to use when rendering the body (if a sprite is not defined).
         * It is the same as when using a canvas, so it accepts CSS style property values.
         *
         * @property render.fillStyle
         * @type string
         * @default a random colour
         */
    
        /**
         * A `String` that defines the stroke style to use when rendering the body outline (if a sprite is not defined).
         * It is the same as when using a canvas, so it accepts CSS style property values.
         *
         * @property render.strokeStyle
         * @type string
         * @default a random colour
         */
    
        /**
         * An array of unique axis vectors (edge normals) used for collision detection.
         * These are automatically calculated from the given convex hull (`vertices` array) in `Body.create`.
         * They are constantly updated by `Body.update` during the simulation.
         *
         * @property axes
         * @type vector[]
         */
         
        /**
         * A `Number` that _measures_ the area of the body's convex hull, calculated at creation by `Body.create`.
         *
         * @property area
         * @type string
         * @default 
         */
    
        /**
         * A `Bounds` object that defines the AABB region for the body.
         * It is automatically calculated from the given convex hull (`vertices` array) in `Body.create` and constantly updated by `Body.update` during simulation.
         *
         * @property bounds
         * @type bounds
         */
    
    })();
    
    },{"../core/Common":14,"../core/Sleeping":22,"../geometry/Axes":25,"../geometry/Bounds":26,"../geometry/Vector":28,"../geometry/Vertices":29,"../render/Render":31}],2:[function(_dereq_,module,exports){
    /**
    * The `Matter.Composite` module contains methods for creating and manipulating composite bodies.
    * A composite body is a collection of `Matter.Body`, `Matter.Constraint` and other `Matter.Composite`, therefore composites form a tree structure.
    * It is important to use the functions in this module to modify composites, rather than directly modifying their properties.
    * Note that the `Matter.World` object is also a type of `Matter.Composite` and as such all composite methods here can also operate on a `Matter.World`.
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class Composite
    */
    
    var Composite = {};
    
    module.exports = Composite;
    
    var Events = _dereq_('../core/Events');
    var Common = _dereq_('../core/Common');
    var Bounds = _dereq_('../geometry/Bounds');
    var Body = _dereq_('./Body');
    
    (function() {
    
        /**
         * Creates a new composite. The options parameter is an object that specifies any properties you wish to override the defaults.
         * See the properites section below for detailed information on what you can pass via the `options` object.
         * @method create
         * @param {} [options]
         * @return {composite} A new composite
         */
        Composite.create = function(options) {
            return Common.extend({ 
                id: Common.nextId(),
                type: 'composite',
                parent: null,
                isModified: false,
                bodies: [], 
                constraints: [], 
                composites: [],
                label: 'Composite',
                plugin: {}
            }, options);
        };
    
        /**
         * Sets the composite's `isModified` flag. 
         * If `updateParents` is true, all parents will be set (default: false).
         * If `updateChildren` is true, all children will be set (default: false).
         * @method setModified
         * @param {composite} composite
         * @param {boolean} isModified
         * @param {boolean} [updateParents=false]
         * @param {boolean} [updateChildren=false]
         */
        Composite.setModified = function(composite, isModified, updateParents, updateChildren) {
            composite.isModified = isModified;
    
            if (updateParents && composite.parent) {
                Composite.setModified(composite.parent, isModified, updateParents, updateChildren);
            }
    
            if (updateChildren) {
                for(var i = 0; i < composite.composites.length; i++) {
                    var childComposite = composite.composites[i];
                    Composite.setModified(childComposite, isModified, updateParents, updateChildren);
                }
            }
        };
    
        /**
         * Generic add function. Adds one or many body(s), constraint(s) or a composite(s) to the given composite.
         * Triggers `beforeAdd` and `afterAdd` events on the `composite`.
         * @method add
         * @param {composite} composite
         * @param {} object
         * @return {composite} The original composite with the objects added
         */
        Composite.add = function(composite, object) {
            var objects = [].concat(object);
    
            Events.trigger(composite, 'beforeAdd', { object: object });
    
            for (var i = 0; i < objects.length; i++) {
                var obj = objects[i];
    
                switch (obj.type) {
    
                case 'body':
                    // skip adding compound parts
                    if (obj.parent !== obj) {
                        Common.warn('Composite.add: skipped adding a compound body part (you must add its parent instead)');
                        break;
                    }
    
                    Composite.addBody(composite, obj);
                    break;
                case 'constraint':
                    Composite.addConstraint(composite, obj);
                    break;
                case 'composite':
                    Composite.addComposite(composite, obj);
                    break;
                case 'mouseConstraint':
                    Composite.addConstraint(composite, obj.constraint);
                    break;
    
                }
            }
    
            Events.trigger(composite, 'afterAdd', { object: object });
    
            return composite;
        };
    
        /**
         * Generic remove function. Removes one or many body(s), constraint(s) or a composite(s) to the given composite.
         * Optionally searching its children recursively.
         * Triggers `beforeRemove` and `afterRemove` events on the `composite`.
         * @method remove
         * @param {composite} composite
         * @param {} object
         * @param {boolean} [deep=false]
         * @return {composite} The original composite with the objects removed
         */
        Composite.remove = function(composite, object, deep) {
            var objects = [].concat(object);
    
            Events.trigger(composite, 'beforeRemove', { object: object });
    
            for (var i = 0; i < objects.length; i++) {
                var obj = objects[i];
    
                switch (obj.type) {
    
                case 'body':
                    Composite.removeBody(composite, obj, deep);
                    break;
                case 'constraint':
                    Composite.removeConstraint(composite, obj, deep);
                    break;
                case 'composite':
                    Composite.removeComposite(composite, obj, deep);
                    break;
                case 'mouseConstraint':
                    Composite.removeConstraint(composite, obj.constraint);
                    break;
    
                }
            }
    
            Events.trigger(composite, 'afterRemove', { object: object });
    
            return composite;
        };
    
        /**
         * Adds a composite to the given composite.
         * @private
         * @method addComposite
         * @param {composite} compositeA
         * @param {composite} compositeB
         * @return {composite} The original compositeA with the objects from compositeB added
         */
        Composite.addComposite = function(compositeA, compositeB) {
            compositeA.composites.push(compositeB);
            compositeB.parent = compositeA;
            Composite.setModified(compositeA, true, true, false);
            return compositeA;
        };
    
        /**
         * Removes a composite from the given composite, and optionally searching its children recursively.
         * @private
         * @method removeComposite
         * @param {composite} compositeA
         * @param {composite} compositeB
         * @param {boolean} [deep=false]
         * @return {composite} The original compositeA with the composite removed
         */
        Composite.removeComposite = function(compositeA, compositeB, deep) {
            var position = Common.indexOf(compositeA.composites, compositeB);
            if (position !== -1) {
                Composite.removeCompositeAt(compositeA, position);
                Composite.setModified(compositeA, true, true, false);
            }
    
            if (deep) {
                for (var i = 0; i < compositeA.composites.length; i++){
                    Composite.removeComposite(compositeA.composites[i], compositeB, true);
                }
            }
    
            return compositeA;
        };
    
        /**
         * Removes a composite from the given composite.
         * @private
         * @method removeCompositeAt
         * @param {composite} composite
         * @param {number} position
         * @return {composite} The original composite with the composite removed
         */
        Composite.removeCompositeAt = function(composite, position) {
            composite.composites.splice(position, 1);
            Composite.setModified(composite, true, true, false);
            return composite;
        };
    
        /**
         * Adds a body to the given composite.
         * @private
         * @method addBody
         * @param {composite} composite
         * @param {body} body
         * @return {composite} The original composite with the body added
         */
        Composite.addBody = function(composite, body) {
            composite.bodies.push(body);
            Composite.setModified(composite, true, true, false);
            return composite;
        };
    
        /**
         * Removes a body from the given composite, and optionally searching its children recursively.
         * @private
         * @method removeBody
         * @param {composite} composite
         * @param {body} body
         * @param {boolean} [deep=false]
         * @return {composite} The original composite with the body removed
         */
        Composite.removeBody = function(composite, body, deep) {
            var position = Common.indexOf(composite.bodies, body);
            if (position !== -1) {
                Composite.removeBodyAt(composite, position);
                Composite.setModified(composite, true, true, false);
            }
    
            if (deep) {
                for (var i = 0; i < composite.composites.length; i++){
                    Composite.removeBody(composite.composites[i], body, true);
                }
            }
    
            return composite;
        };
    
        /**
         * Removes a body from the given composite.
         * @private
         * @method removeBodyAt
         * @param {composite} composite
         * @param {number} position
         * @return {composite} The original composite with the body removed
         */
        Composite.removeBodyAt = function(composite, position) {
            composite.bodies.splice(position, 1);
            Composite.setModified(composite, true, true, false);
            return composite;
        };
    
        /**
         * Adds a constraint to the given composite.
         * @private
         * @method addConstraint
         * @param {composite} composite
         * @param {constraint} constraint
         * @return {composite} The original composite with the constraint added
         */
        Composite.addConstraint = function(composite, constraint) {
            composite.constraints.push(constraint);
            Composite.setModified(composite, true, true, false);
            return composite;
        };
    
        /**
         * Removes a constraint from the given composite, and optionally searching its children recursively.
         * @private
         * @method removeConstraint
         * @param {composite} composite
         * @param {constraint} constraint
         * @param {boolean} [deep=false]
         * @return {composite} The original composite with the constraint removed
         */
        Composite.removeConstraint = function(composite, constraint, deep) {
            var position = Common.indexOf(composite.constraints, constraint);
            if (position !== -1) {
                Composite.removeConstraintAt(composite, position);
            }
    
            if (deep) {
                for (var i = 0; i < composite.composites.length; i++){
                    Composite.removeConstraint(composite.composites[i], constraint, true);
                }
            }
    
            return composite;
        };
    
        /**
         * Removes a body from the given composite.
         * @private
         * @method removeConstraintAt
         * @param {composite} composite
         * @param {number} position
         * @return {composite} The original composite with the constraint removed
         */
        Composite.removeConstraintAt = function(composite, position) {
            composite.constraints.splice(position, 1);
            Composite.setModified(composite, true, true, false);
            return composite;
        };
    
        /**
         * Removes all bodies, constraints and composites from the given composite.
         * Optionally clearing its children recursively.
         * @method clear
         * @param {composite} composite
         * @param {boolean} keepStatic
         * @param {boolean} [deep=false]
         */
        Composite.clear = function(composite, keepStatic, deep) {
            if (deep) {
                for (var i = 0; i < composite.composites.length; i++){
                    Composite.clear(composite.composites[i], keepStatic, true);
                }
            }
            
            if (keepStatic) {
                composite.bodies = composite.bodies.filter(function(body) { return body.isStatic; });
            } else {
                composite.bodies.length = 0;
            }
    
            composite.constraints.length = 0;
            composite.composites.length = 0;
            Composite.setModified(composite, true, true, false);
    
            return composite;
        };
    
        /**
         * Returns all bodies in the given composite, including all bodies in its children, recursively.
         * @method allBodies
         * @param {composite} composite
         * @return {body[]} All the bodies
         */
        Composite.allBodies = function(composite) {
            var bodies = [].concat(composite.bodies);
    
            for (var i = 0; i < composite.composites.length; i++)
                bodies = bodies.concat(Composite.allBodies(composite.composites[i]));
    
            return bodies;
        };
    
        /**
         * Returns all constraints in the given composite, including all constraints in its children, recursively.
         * @method allConstraints
         * @param {composite} composite
         * @return {constraint[]} All the constraints
         */
        Composite.allConstraints = function(composite) {
            var constraints = [].concat(composite.constraints);
    
            for (var i = 0; i < composite.composites.length; i++)
                constraints = constraints.concat(Composite.allConstraints(composite.composites[i]));
    
            return constraints;
        };
    
        /**
         * Returns all composites in the given composite, including all composites in its children, recursively.
         * @method allComposites
         * @param {composite} composite
         * @return {composite[]} All the composites
         */
        Composite.allComposites = function(composite) {
            var composites = [].concat(composite.composites);
    
            for (var i = 0; i < composite.composites.length; i++)
                composites = composites.concat(Composite.allComposites(composite.composites[i]));
    
            return composites;
        };
    
        /**
         * Searches the composite recursively for an object matching the type and id supplied, null if not found.
         * @method get
         * @param {composite} composite
         * @param {number} id
         * @param {string} type
         * @return {object} The requested object, if found
         */
        Composite.get = function(composite, id, type) {
            var objects,
                object;
    
            switch (type) {
            case 'body':
                objects = Composite.allBodies(composite);
                break;
            case 'constraint':
                objects = Composite.allConstraints(composite);
                break;
            case 'composite':
                objects = Composite.allComposites(composite).concat(composite);
                break;
            }
    
            if (!objects)
                return null;
    
            object = objects.filter(function(object) { 
                return object.id.toString() === id.toString(); 
            });
    
            return object.length === 0 ? null : object[0];
        };
    
        /**
         * Moves the given object(s) from compositeA to compositeB (equal to a remove followed by an add).
         * @method move
         * @param {compositeA} compositeA
         * @param {object[]} objects
         * @param {compositeB} compositeB
         * @return {composite} Returns compositeA
         */
        Composite.move = function(compositeA, objects, compositeB) {
            Composite.remove(compositeA, objects);
            Composite.add(compositeB, objects);
            return compositeA;
        };
    
        /**
         * Assigns new ids for all objects in the composite, recursively.
         * @method rebase
         * @param {composite} composite
         * @return {composite} Returns composite
         */
        Composite.rebase = function(composite) {
            var objects = Composite.allBodies(composite)
                            .concat(Composite.allConstraints(composite))
                            .concat(Composite.allComposites(composite));
    
            for (var i = 0; i < objects.length; i++) {
                objects[i].id = Common.nextId();
            }
    
            Composite.setModified(composite, true, true, false);
    
            return composite;
        };
    
        /**
         * Translates all children in the composite by a given vector relative to their current positions, 
         * without imparting any velocity.
         * @method translate
         * @param {composite} composite
         * @param {vector} translation
         * @param {bool} [recursive=true]
         */
        Composite.translate = function(composite, translation, recursive) {
            var bodies = recursive ? Composite.allBodies(composite) : composite.bodies;
    
            for (var i = 0; i < bodies.length; i++) {
                Body.translate(bodies[i], translation);
            }
    
            Composite.setModified(composite, true, true, false);
    
            return composite;
        };
    
        /**
         * Rotates all children in the composite by a given angle about the given point, without imparting any angular velocity.
         * @method rotate
         * @param {composite} composite
         * @param {number} rotation
         * @param {vector} point
         * @param {bool} [recursive=true]
         */
        Composite.rotate = function(composite, rotation, point, recursive) {
            var cos = Math.cos(rotation),
                sin = Math.sin(rotation),
                bodies = recursive ? Composite.allBodies(composite) : composite.bodies;
    
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i],
                    dx = body.position.x - point.x,
                    dy = body.position.y - point.y;
                    
                Body.setPosition(body, {
                    x: point.x + (dx * cos - dy * sin),
                    y: point.y + (dx * sin + dy * cos)
                });
    
                Body.rotate(body, rotation);
            }
    
            Composite.setModified(composite, true, true, false);
    
            return composite;
        };
    
        /**
         * Scales all children in the composite, including updating physical properties (mass, area, axes, inertia), from a world-space point.
         * @method scale
         * @param {composite} composite
         * @param {number} scaleX
         * @param {number} scaleY
         * @param {vector} point
         * @param {bool} [recursive=true]
         */
        Composite.scale = function(composite, scaleX, scaleY, point, recursive) {
            var bodies = recursive ? Composite.allBodies(composite) : composite.bodies;
    
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i],
                    dx = body.position.x - point.x,
                    dy = body.position.y - point.y;
                    
                Body.setPosition(body, {
                    x: point.x + dx * scaleX,
                    y: point.y + dy * scaleY
                });
    
                Body.scale(body, scaleX, scaleY);
            }
    
            Composite.setModified(composite, true, true, false);
    
            return composite;
        };
    
        /**
         * Returns the union of the bounds of all of the composite's bodies.
         * @method bounds
         * @param {composite} composite The composite.
         * @returns {bounds} The composite bounds.
         */
        Composite.bounds = function(composite) {
            var bodies = Composite.allBodies(composite),
                vertices = [];
    
            for (var i = 0; i < bodies.length; i += 1) {
                var body = bodies[i];
                vertices.push(body.bounds.min, body.bounds.max);
            }
    
            return Bounds.create(vertices);
        };
    
        /*
        *
        *  Events Documentation
        *
        */
    
        /**
        * Fired when a call to `Composite.add` is made, before objects have been added.
        *
        * @event beforeAdd
        * @param {} event An event object
        * @param {} event.object The object(s) to be added (may be a single body, constraint, composite or a mixed array of these)
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired when a call to `Composite.add` is made, after objects have been added.
        *
        * @event afterAdd
        * @param {} event An event object
        * @param {} event.object The object(s) that have been added (may be a single body, constraint, composite or a mixed array of these)
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired when a call to `Composite.remove` is made, before objects have been removed.
        *
        * @event beforeRemove
        * @param {} event An event object
        * @param {} event.object The object(s) to be removed (may be a single body, constraint, composite or a mixed array of these)
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired when a call to `Composite.remove` is made, after objects have been removed.
        *
        * @event afterRemove
        * @param {} event An event object
        * @param {} event.object The object(s) that have been removed (may be a single body, constraint, composite or a mixed array of these)
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /*
        *
        *  Properties Documentation
        *
        */
    
        /**
         * An integer `Number` uniquely identifying number generated in `Composite.create` by `Common.nextId`.
         *
         * @property id
         * @type number
         */
    
        /**
         * A `String` denoting the type of object.
         *
         * @property type
         * @type string
         * @default "composite"
         * @readOnly
         */
    
        /**
         * An arbitrary `String` name to help the user identify and manage composites.
         *
         * @property label
         * @type string
         * @default "Composite"
         */
    
        /**
         * A flag that specifies whether the composite has been modified during the current step.
         * Most `Matter.Composite` methods will automatically set this flag to `true` to inform the engine of changes to be handled.
         * If you need to change it manually, you should use the `Composite.setModified` method.
         *
         * @property isModified
         * @type boolean
         * @default false
         */
    
        /**
         * The `Composite` that is the parent of this composite. It is automatically managed by the `Matter.Composite` methods.
         *
         * @property parent
         * @type composite
         * @default null
         */
    
        /**
         * An array of `Body` that are _direct_ children of this composite.
         * To add or remove bodies you should use `Composite.add` and `Composite.remove` methods rather than directly modifying this property.
         * If you wish to recursively find all descendants, you should use the `Composite.allBodies` method.
         *
         * @property bodies
         * @type body[]
         * @default []
         */
    
        /**
         * An array of `Constraint` that are _direct_ children of this composite.
         * To add or remove constraints you should use `Composite.add` and `Composite.remove` methods rather than directly modifying this property.
         * If you wish to recursively find all descendants, you should use the `Composite.allConstraints` method.
         *
         * @property constraints
         * @type constraint[]
         * @default []
         */
    
        /**
         * An array of `Composite` that are _direct_ children of this composite.
         * To add or remove composites you should use `Composite.add` and `Composite.remove` methods rather than directly modifying this property.
         * If you wish to recursively find all descendants, you should use the `Composite.allComposites` method.
         *
         * @property composites
         * @type composite[]
         * @default []
         */
    
        /**
         * An object reserved for storing plugin-specific properties.
         *
         * @property plugin
         * @type {}
         */
    
    })();
    
    },{"../core/Common":14,"../core/Events":16,"../geometry/Bounds":26,"./Body":1}],3:[function(_dereq_,module,exports){
    /**
    * The `Matter.World` module contains methods for creating and manipulating the world composite.
    * A `Matter.World` is a `Matter.Composite` body, which is a collection of `Matter.Body`, `Matter.Constraint` and other `Matter.Composite`.
    * A `Matter.World` has a few additional properties including `gravity` and `bounds`.
    * It is important to use the functions in the `Matter.Composite` module to modify the world composite, rather than directly modifying its properties.
    * There are also a few methods here that alias those in `Matter.Composite` for easier readability.
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class World
    * @extends Composite
    */
    
    var World = {};
    
    module.exports = World;
    
    var Composite = _dereq_('./Composite');
    var Constraint = _dereq_('../constraint/Constraint');
    var Common = _dereq_('../core/Common');
    
    (function() {
    
        /**
         * Creates a new world composite. The options parameter is an object that specifies any properties you wish to override the defaults.
         * See the properties section below for detailed information on what you can pass via the `options` object.
         * @method create
         * @constructor
         * @param {} options
         * @return {world} A new world
         */
        World.create = function(options) {
            var composite = Composite.create();
    
            var defaults = {
                label: 'World',
                gravity: {
                    x: 0,
                    y: 1,
                    scale: 0.001
                },
                bounds: { 
                    min: { x: -Infinity, y: -Infinity }, 
                    max: { x: Infinity, y: Infinity } 
                }
            };
            
            return Common.extend(composite, defaults, options);
        };
    
        /*
        *
        *  Properties Documentation
        *
        */
    
        /**
         * The gravity to apply on the world.
         *
         * @property gravity
         * @type object
         */
    
        /**
         * The gravity x component.
         *
         * @property gravity.x
         * @type object
         * @default 0
         */
    
        /**
         * The gravity y component.
         *
         * @property gravity.y
         * @type object
         * @default 1
         */
    
        /**
         * The gravity scale factor.
         *
         * @property gravity.scale
         * @type object
         * @default 0.001
         */
    
        /**
         * A `Bounds` object that defines the world bounds for collision detection.
         *
         * @property bounds
         * @type bounds
         * @default { min: { x: -Infinity, y: -Infinity }, max: { x: Infinity, y: Infinity } }
         */
    
        // World is a Composite body
        // see src/module/Outro.js for these aliases:
        
        /**
         * An alias for Composite.add
         * @method add
         * @param {world} world
         * @param {} object
         * @return {composite} The original world with the objects added
         */
    
        /**
         * An alias for Composite.remove
         * @method remove
         * @param {world} world
         * @param {} object
         * @param {boolean} [deep=false]
         * @return {composite} The original world with the objects removed
         */
    
        /**
         * An alias for Composite.clear
         * @method clear
         * @param {world} world
         * @param {boolean} keepStatic
         */
    
        /**
         * An alias for Composite.addComposite
         * @method addComposite
         * @param {world} world
         * @param {composite} composite
         * @return {world} The original world with the objects from composite added
         */
        
         /**
          * An alias for Composite.addBody
          * @method addBody
          * @param {world} world
          * @param {body} body
          * @return {world} The original world with the body added
          */
    
         /**
          * An alias for Composite.addConstraint
          * @method addConstraint
          * @param {world} world
          * @param {constraint} constraint
          * @return {world} The original world with the constraint added
          */
    
    })();
    
    },{"../constraint/Constraint":12,"../core/Common":14,"./Composite":2}],4:[function(_dereq_,module,exports){
    /**
    * The `Matter.Contact` module contains methods for creating and manipulating collision contacts.
    *
    * @class Contact
    */
    
    var Contact = {};
    
    module.exports = Contact;
    
    (function() {
    
        /**
         * Creates a new contact.
         * @method create
         * @param {vertex} vertex
         * @return {contact} A new contact
         */
        Contact.create = function(vertex) {
            return {
                id: Contact.id(vertex),
                vertex: vertex,
                normalImpulse: 0,
                tangentImpulse: 0
            };
        };
        
        /**
         * Generates a contact id.
         * @method id
         * @param {vertex} vertex
         * @return {string} Unique contactID
         */
        Contact.id = function(vertex) {
            return vertex.body.id + '_' + vertex.index;
        };
    
    })();
    
    },{}],5:[function(_dereq_,module,exports){
    /**
    * The `Matter.Detector` module contains methods for detecting collisions given a set of pairs.
    *
    * @class Detector
    */
    
    // TODO: speculative contacts
    
    var Detector = {};
    
    module.exports = Detector;
    
    var SAT = _dereq_('./SAT');
    var Pair = _dereq_('./Pair');
    var Bounds = _dereq_('../geometry/Bounds');
    
    (function() {
    
        /**
         * Finds all collisions given a list of pairs.
         * @method collisions
         * @param {pair[]} broadphasePairs
         * @param {engine} engine
         * @return {array} collisions
         */
        Detector.collisions = function(broadphasePairs, engine) {
            var collisions = [],
                pairsTable = engine.pairs.table;
    
            
            for (var i = 0; i < broadphasePairs.length; i++) {
                var bodyA = broadphasePairs[i][0], 
                    bodyB = broadphasePairs[i][1];
    
                if ((bodyA.isStatic || bodyA.isSleeping) && (bodyB.isStatic || bodyB.isSleeping))
                    continue;
                
                if (!Detector.canCollide(bodyA.collisionFilter, bodyB.collisionFilter))
                    continue;
    
    
                // mid phase
                if (Bounds.overlaps(bodyA.bounds, bodyB.bounds)) {
                    for (var j = bodyA.parts.length > 1 ? 1 : 0; j < bodyA.parts.length; j++) {
                        var partA = bodyA.parts[j];
    
                        for (var k = bodyB.parts.length > 1 ? 1 : 0; k < bodyB.parts.length; k++) {
                            var partB = bodyB.parts[k];
    
                            if ((partA === bodyA && partB === bodyB) || Bounds.overlaps(partA.bounds, partB.bounds)) {
                                // find a previous collision we could reuse
                                var pairId = Pair.id(partA, partB),
                                    pair = pairsTable[pairId],
                                    previousCollision;
    
                                if (pair && pair.isActive) {
                                    previousCollision = pair.collision;
                                } else {
                                    previousCollision = null;
                                }
    
                                // narrow phase
                                var collision = SAT.collides(partA, partB, previousCollision);
    
    
                                if (collision.collided) {
                                    collisions.push(collision);
                                }
                            }
                        }
                    }
                }
            }
    
            return collisions;
        };
    
        /**
         * Returns `true` if both supplied collision filters will allow a collision to occur.
         * See `body.collisionFilter` for more information.
         * @method canCollide
         * @param {} filterA
         * @param {} filterB
         * @return {bool} `true` if collision can occur
         */
        Detector.canCollide = function(filterA, filterB) {
            if (filterA.group === filterB.group && filterA.group !== 0)
                return filterA.group > 0;
    
            return (filterA.mask & filterB.category) !== 0 && (filterB.mask & filterA.category) !== 0;
        };
    
    })();
    
    },{"../geometry/Bounds":26,"./Pair":7,"./SAT":11}],6:[function(_dereq_,module,exports){
    /**
    * The `Matter.Grid` module contains methods for creating and manipulating collision broadphase grid structures.
    *
    * @class Grid
    */
    
    var Grid = {};
    
    module.exports = Grid;
    
    var Pair = _dereq_('./Pair');
    var Detector = _dereq_('./Detector');
    var Common = _dereq_('../core/Common');
    
    (function() {
    
        /**
         * Creates a new grid.
         * @method create
         * @param {} options
         * @return {grid} A new grid
         */
        Grid.create = function(options) {
            var defaults = {
                controller: Grid,
                detector: Detector.collisions,
                buckets: {},
                pairs: {},
                pairsList: [],
                bucketWidth: 48,
                bucketHeight: 48
            };
    
            return Common.extend(defaults, options);
        };
    
        /**
         * The width of a single grid bucket.
         *
         * @property bucketWidth
         * @type number
         * @default 48
         */
    
        /**
         * The height of a single grid bucket.
         *
         * @property bucketHeight
         * @type number
         * @default 48
         */
    
        /**
         * Updates the grid.
         * @method update
         * @param {grid} grid
         * @param {body[]} bodies
         * @param {engine} engine
         * @param {boolean} forceUpdate
         */
        Grid.update = function(grid, bodies, engine, forceUpdate) {
            var i, col, row,
                world = engine.world,
                buckets = grid.buckets,
                bucket,
                bucketId,
                gridChanged = false;
    
    
            for (i = 0; i < bodies.length; i++) {
                var body = bodies[i];
    
                if (body.isSleeping && !forceUpdate)
                    continue;
    
                // don't update out of world bodies
                if (body.bounds.max.x < world.bounds.min.x || body.bounds.min.x > world.bounds.max.x
                    || body.bounds.max.y < world.bounds.min.y || body.bounds.min.y > world.bounds.max.y)
                    continue;
    
                var newRegion = Grid._getRegion(grid, body);
    
                // if the body has changed grid region
                if (!body.region || newRegion.id !== body.region.id || forceUpdate) {
    
    
                    if (!body.region || forceUpdate)
                        body.region = newRegion;
    
                    var union = Grid._regionUnion(newRegion, body.region);
    
                    // update grid buckets affected by region change
                    // iterate over the union of both regions
                    for (col = union.startCol; col <= union.endCol; col++) {
                        for (row = union.startRow; row <= union.endRow; row++) {
                            bucketId = Grid._getBucketId(col, row);
                            bucket = buckets[bucketId];
    
                            var isInsideNewRegion = (col >= newRegion.startCol && col <= newRegion.endCol
                                                    && row >= newRegion.startRow && row <= newRegion.endRow);
    
                            var isInsideOldRegion = (col >= body.region.startCol && col <= body.region.endCol
                                                    && row >= body.region.startRow && row <= body.region.endRow);
    
                            // remove from old region buckets
                            if (!isInsideNewRegion && isInsideOldRegion) {
                                if (isInsideOldRegion) {
                                    if (bucket)
                                        Grid._bucketRemoveBody(grid, bucket, body);
                                }
                            }
    
                            // add to new region buckets
                            if (body.region === newRegion || (isInsideNewRegion && !isInsideOldRegion) || forceUpdate) {
                                if (!bucket)
                                    bucket = Grid._createBucket(buckets, bucketId);
                                Grid._bucketAddBody(grid, bucket, body);
                            }
                        }
                    }
    
                    // set the new region
                    body.region = newRegion;
    
                    // flag changes so we can update pairs
                    gridChanged = true;
                }
            }
    
            // update pairs list only if pairs changed (i.e. a body changed region)
            if (gridChanged)
                grid.pairsList = Grid._createActivePairsList(grid);
        };
    
        /**
         * Clears the grid.
         * @method clear
         * @param {grid} grid
         */
        Grid.clear = function(grid) {
            grid.buckets = {};
            grid.pairs = {};
            grid.pairsList = [];
        };
    
        /**
         * Finds the union of two regions.
         * @method _regionUnion
         * @private
         * @param {} regionA
         * @param {} regionB
         * @return {} region
         */
        Grid._regionUnion = function(regionA, regionB) {
            var startCol = Math.min(regionA.startCol, regionB.startCol),
                endCol = Math.max(regionA.endCol, regionB.endCol),
                startRow = Math.min(regionA.startRow, regionB.startRow),
                endRow = Math.max(regionA.endRow, regionB.endRow);
    
            return Grid._createRegion(startCol, endCol, startRow, endRow);
        };
    
        /**
         * Gets the region a given body falls in for a given grid.
         * @method _getRegion
         * @private
         * @param {} grid
         * @param {} body
         * @return {} region
         */
        Grid._getRegion = function(grid, body) {
            var bounds = body.bounds,
                startCol = Math.floor(bounds.min.x / grid.bucketWidth),
                endCol = Math.floor(bounds.max.x / grid.bucketWidth),
                startRow = Math.floor(bounds.min.y / grid.bucketHeight),
                endRow = Math.floor(bounds.max.y / grid.bucketHeight);
    
            return Grid._createRegion(startCol, endCol, startRow, endRow);
        };
    
        /**
         * Creates a region.
         * @method _createRegion
         * @private
         * @param {} startCol
         * @param {} endCol
         * @param {} startRow
         * @param {} endRow
         * @return {} region
         */
        Grid._createRegion = function(startCol, endCol, startRow, endRow) {
            return { 
                id: startCol + ',' + endCol + ',' + startRow + ',' + endRow,
                startCol: startCol, 
                endCol: endCol, 
                startRow: startRow, 
                endRow: endRow 
            };
        };
    
        /**
         * Gets the bucket id at the given position.
         * @method _getBucketId
         * @private
         * @param {} column
         * @param {} row
         * @return {string} bucket id
         */
        Grid._getBucketId = function(column, row) {
            return 'C' + column + 'R' + row;
        };
    
        /**
         * Creates a bucket.
         * @method _createBucket
         * @private
         * @param {} buckets
         * @param {} bucketId
         * @return {} bucket
         */
        Grid._createBucket = function(buckets, bucketId) {
            var bucket = buckets[bucketId] = [];
            return bucket;
        };
    
        /**
         * Adds a body to a bucket.
         * @method _bucketAddBody
         * @private
         * @param {} grid
         * @param {} bucket
         * @param {} body
         */
        Grid._bucketAddBody = function(grid, bucket, body) {
            // add new pairs
            for (var i = 0; i < bucket.length; i++) {
                var bodyB = bucket[i];
    
                if (body.id === bodyB.id || (body.isStatic && bodyB.isStatic))
                    continue;
    
                // keep track of the number of buckets the pair exists in
                // important for Grid.update to work
                var pairId = Pair.id(body, bodyB),
                    pair = grid.pairs[pairId];
    
                if (pair) {
                    pair[2] += 1;
                } else {
                    grid.pairs[pairId] = [body, bodyB, 1];
                }
            }
    
            // add to bodies (after pairs, otherwise pairs with self)
            bucket.push(body);
        };
    
        /**
         * Removes a body from a bucket.
         * @method _bucketRemoveBody
         * @private
         * @param {} grid
         * @param {} bucket
         * @param {} body
         */
        Grid._bucketRemoveBody = function(grid, bucket, body) {
            // remove from bucket
            bucket.splice(Common.indexOf(bucket, body), 1);
    
            // update pair counts
            for (var i = 0; i < bucket.length; i++) {
                // keep track of the number of buckets the pair exists in
                // important for _createActivePairsList to work
                var bodyB = bucket[i],
                    pairId = Pair.id(body, bodyB),
                    pair = grid.pairs[pairId];
    
                if (pair)
                    pair[2] -= 1;
            }
        };
    
        /**
         * Generates a list of the active pairs in the grid.
         * @method _createActivePairsList
         * @private
         * @param {} grid
         * @return [] pairs
         */
        Grid._createActivePairsList = function(grid) {
            var pairKeys,
                pair,
                pairs = [];
    
            // grid.pairs is used as a hashmap
            pairKeys = Common.keys(grid.pairs);
    
            // iterate over grid.pairs
            for (var k = 0; k < pairKeys.length; k++) {
                pair = grid.pairs[pairKeys[k]];
    
                // if pair exists in at least one bucket
                // it is a pair that needs further collision testing so push it
                if (pair[2] > 0) {
                    pairs.push(pair);
                } else {
                    delete grid.pairs[pairKeys[k]];
                }
            }
    
            return pairs;
        };
        
    })();
    
    },{"../core/Common":14,"./Detector":5,"./Pair":7}],7:[function(_dereq_,module,exports){
    /**
    * The `Matter.Pair` module contains methods for creating and manipulating collision pairs.
    *
    * @class Pair
    */
    
    var Pair = {};
    
    module.exports = Pair;
    
    var Contact = _dereq_('./Contact');
    
    (function() {
        
        /**
         * Creates a pair.
         * @method create
         * @param {collision} collision
         * @param {number} timestamp
         * @return {pair} A new pair
         */
        Pair.create = function(collision, timestamp) {
            var bodyA = collision.bodyA,
                bodyB = collision.bodyB,
                parentA = collision.parentA,
                parentB = collision.parentB;
    
            var pair = {
                id: Pair.id(bodyA, bodyB),
                bodyA: bodyA,
                bodyB: bodyB,
                contacts: {},
                activeContacts: [],
                separation: 0,
                isActive: true,
                isSensor: bodyA.isSensor || bodyB.isSensor,
                timeCreated: timestamp,
                timeUpdated: timestamp,
                inverseMass: parentA.inverseMass + parentB.inverseMass,
                friction: Math.min(parentA.friction, parentB.friction),
                frictionStatic: Math.max(parentA.frictionStatic, parentB.frictionStatic),
                restitution: Math.max(parentA.restitution, parentB.restitution),
                slop: Math.max(parentA.slop, parentB.slop)
            };
    
            Pair.update(pair, collision, timestamp);
    
            return pair;
        };
    
        /**
         * Updates a pair given a collision.
         * @method update
         * @param {pair} pair
         * @param {collision} collision
         * @param {number} timestamp
         */
        Pair.update = function(pair, collision, timestamp) {
            var contacts = pair.contacts,
                supports = collision.supports,
                activeContacts = pair.activeContacts,
                parentA = collision.parentA,
                parentB = collision.parentB;
            
            pair.collision = collision;
            pair.inverseMass = parentA.inverseMass + parentB.inverseMass;
            pair.friction = Math.min(parentA.friction, parentB.friction);
            pair.frictionStatic = Math.max(parentA.frictionStatic, parentB.frictionStatic);
            pair.restitution = Math.max(parentA.restitution, parentB.restitution);
            pair.slop = Math.max(parentA.slop, parentB.slop);
            activeContacts.length = 0;
            
            if (collision.collided) {
                for (var i = 0; i < supports.length; i++) {
                    var support = supports[i],
                        contactId = Contact.id(support),
                        contact = contacts[contactId];
    
                    if (contact) {
                        activeContacts.push(contact);
                    } else {
                        activeContacts.push(contacts[contactId] = Contact.create(support));
                    }
                }
    
                pair.separation = collision.depth;
                Pair.setActive(pair, true, timestamp);
            } else {
                if (pair.isActive === true)
                    Pair.setActive(pair, false, timestamp);
            }
        };
        
        /**
         * Set a pair as active or inactive.
         * @method setActive
         * @param {pair} pair
         * @param {bool} isActive
         * @param {number} timestamp
         */
        Pair.setActive = function(pair, isActive, timestamp) {
            if (isActive) {
                pair.isActive = true;
                pair.timeUpdated = timestamp;
            } else {
                pair.isActive = false;
                pair.activeContacts.length = 0;
            }
        };
    
        /**
         * Get the id for the given pair.
         * @method id
         * @param {body} bodyA
         * @param {body} bodyB
         * @return {string} Unique pairId
         */
        Pair.id = function(bodyA, bodyB) {
            if (bodyA.id < bodyB.id) {
                return 'A' + bodyA.id + 'B' + bodyB.id;
            } else {
                return 'A' + bodyB.id + 'B' + bodyA.id;
            }
        };
    
    })();
    
    },{"./Contact":4}],8:[function(_dereq_,module,exports){
    /**
    * The `Matter.Pairs` module contains methods for creating and manipulating collision pair sets.
    *
    * @class Pairs
    */
    
    var Pairs = {};
    
    module.exports = Pairs;
    
    var Pair = _dereq_('./Pair');
    var Common = _dereq_('../core/Common');
    
    (function() {
        
        Pairs._pairMaxIdleLife = 1000;
    
        /**
         * Creates a new pairs structure.
         * @method create
         * @param {object} options
         * @return {pairs} A new pairs structure
         */
        Pairs.create = function(options) {
            return Common.extend({ 
                table: {},
                list: [],
                collisionStart: [],
                collisionActive: [],
                collisionEnd: []
            }, options);
        };
    
        /**
         * Updates pairs given a list of collisions.
         * @method update
         * @param {object} pairs
         * @param {collision[]} collisions
         * @param {number} timestamp
         */
        Pairs.update = function(pairs, collisions, timestamp) {
            var pairsList = pairs.list,
                pairsTable = pairs.table,
                collisionStart = pairs.collisionStart,
                collisionEnd = pairs.collisionEnd,
                collisionActive = pairs.collisionActive,
                activePairIds = [],
                collision,
                pairId,
                pair,
                i;
    
            // clear collision state arrays, but maintain old reference
            collisionStart.length = 0;
            collisionEnd.length = 0;
            collisionActive.length = 0;
    
            for (i = 0; i < collisions.length; i++) {
                collision = collisions[i];
    
                if (collision.collided) {
                    pairId = Pair.id(collision.bodyA, collision.bodyB);
                    activePairIds.push(pairId);
    
                    pair = pairsTable[pairId];
                    
                    if (pair) {
                        // pair already exists (but may or may not be active)
                        if (pair.isActive) {
                            // pair exists and is active
                            collisionActive.push(pair);
                        } else {
                            // pair exists but was inactive, so a collision has just started again
                            collisionStart.push(pair);
                        }
    
                        // update the pair
                        Pair.update(pair, collision, timestamp);
                    } else {
                        // pair did not exist, create a new pair
                        pair = Pair.create(collision, timestamp);
                        pairsTable[pairId] = pair;
    
                        // push the new pair
                        collisionStart.push(pair);
                        pairsList.push(pair);
                    }
                }
            }
    
            // deactivate previously active pairs that are now inactive
            for (i = 0; i < pairsList.length; i++) {
                pair = pairsList[i];
                if (pair.isActive && Common.indexOf(activePairIds, pair.id) === -1) {
                    Pair.setActive(pair, false, timestamp);
                    collisionEnd.push(pair);
                }
            }
        };
        
        /**
         * Finds and removes pairs that have been inactive for a set amount of time.
         * @method removeOld
         * @param {object} pairs
         * @param {number} timestamp
         */
        Pairs.removeOld = function(pairs, timestamp) {
            var pairsList = pairs.list,
                pairsTable = pairs.table,
                indexesToRemove = [],
                pair,
                collision,
                pairIndex,
                i;
    
            for (i = 0; i < pairsList.length; i++) {
                pair = pairsList[i];
                collision = pair.collision;
                
                // never remove sleeping pairs
                if (collision.bodyA.isSleeping || collision.bodyB.isSleeping) {
                    pair.timeUpdated = timestamp;
                    continue;
                }
    
                // if pair is inactive for too long, mark it to be removed
                if (timestamp - pair.timeUpdated > Pairs._pairMaxIdleLife) {
                    indexesToRemove.push(i);
                }
            }
    
            // remove marked pairs
            for (i = 0; i < indexesToRemove.length; i++) {
                pairIndex = indexesToRemove[i] - i;
                pair = pairsList[pairIndex];
                delete pairsTable[pair.id];
                pairsList.splice(pairIndex, 1);
            }
        };
    
        /**
         * Clears the given pairs structure.
         * @method clear
         * @param {pairs} pairs
         * @return {pairs} pairs
         */
        Pairs.clear = function(pairs) {
            pairs.table = {};
            pairs.list.length = 0;
            pairs.collisionStart.length = 0;
            pairs.collisionActive.length = 0;
            pairs.collisionEnd.length = 0;
            return pairs;
        };
    
    })();
    
    },{"../core/Common":14,"./Pair":7}],9:[function(_dereq_,module,exports){
    /**
    * The `Matter.Query` module contains methods for performing collision queries.
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class Query
    */
    
    var Query = {};
    
    module.exports = Query;
    
    var Vector = _dereq_('../geometry/Vector');
    var SAT = _dereq_('./SAT');
    var Bounds = _dereq_('../geometry/Bounds');
    var Bodies = _dereq_('../factory/Bodies');
    var Vertices = _dereq_('../geometry/Vertices');
    
    (function() {
    
        /**
         * Returns a list of collisions between `body` and `bodies`.
         * @method collides
         * @param {body} body
         * @param {body[]} bodies
         * @return {object[]} Collisions
         */
        Query.collides = function(body, bodies) {
            var collisions = [];
    
            for (var i = 0; i < bodies.length; i++) {
                var bodyA = bodies[i];
                
                if (Bounds.overlaps(bodyA.bounds, body.bounds)) {
                    for (var j = bodyA.parts.length === 1 ? 0 : 1; j < bodyA.parts.length; j++) {
                        var part = bodyA.parts[j];
    
                        if (Bounds.overlaps(part.bounds, body.bounds)) {
                            var collision = SAT.collides(part, body);
    
                            if (collision.collided) {
                                collisions.push(collision);
                                break;
                            }
                        }
                    }
                }
            }
    
            return collisions;
        };
    
        /**
         * Casts a ray segment against a set of bodies and returns all collisions, ray width is optional. Intersection points are not provided.
         * @method ray
         * @param {body[]} bodies
         * @param {vector} startPoint
         * @param {vector} endPoint
         * @param {number} [rayWidth]
         * @return {object[]} Collisions
         */
        Query.ray = function(bodies, startPoint, endPoint, rayWidth) {
            rayWidth = rayWidth || 1e-100;
    
            var rayAngle = Vector.angle(startPoint, endPoint),
                rayLength = Vector.magnitude(Vector.sub(startPoint, endPoint)),
                rayX = (endPoint.x + startPoint.x) * 0.5,
                rayY = (endPoint.y + startPoint.y) * 0.5,
                ray = Bodies.rectangle(rayX, rayY, rayLength, rayWidth, { angle: rayAngle }),
                collisions = Query.collides(ray, bodies);
    
            for (var i = 0; i < collisions.length; i += 1) {
                var collision = collisions[i];
                collision.body = collision.bodyB = collision.bodyA;            
            }
    
            return collisions;
        };
    
        /**
         * Returns all bodies whose bounds are inside (or outside if set) the given set of bounds, from the given set of bodies.
         * @method region
         * @param {body[]} bodies
         * @param {bounds} bounds
         * @param {bool} [outside=false]
         * @return {body[]} The bodies matching the query
         */
        Query.region = function(bodies, bounds, outside) {
            var result = [];
    
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i],
                    overlaps = Bounds.overlaps(body.bounds, bounds);
                if ((overlaps && !outside) || (!overlaps && outside))
                    result.push(body);
            }
    
            return result;
        };
    
        /**
         * Returns all bodies whose vertices contain the given point, from the given set of bodies.
         * @method point
         * @param {body[]} bodies
         * @param {vector} point
         * @return {body[]} The bodies matching the query
         */
        Query.point = function(bodies, point) {
            var result = [];
    
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i];
                
                if (Bounds.contains(body.bounds, point)) {
                    for (var j = body.parts.length === 1 ? 0 : 1; j < body.parts.length; j++) {
                        var part = body.parts[j];
    
                        if (Bounds.contains(part.bounds, point)
                            && Vertices.contains(part.vertices, point)) {
                            result.push(body);
                            break;
                        }
                    }
                }
            }
    
            return result;
        };
    
    })();
    
    },{"../factory/Bodies":23,"../geometry/Bounds":26,"../geometry/Vector":28,"../geometry/Vertices":29,"./SAT":11}],10:[function(_dereq_,module,exports){
    /**
    * The `Matter.Resolver` module contains methods for resolving collision pairs.
    *
    * @class Resolver
    */
    
    var Resolver = {};
    
    module.exports = Resolver;
    
    var Vertices = _dereq_('../geometry/Vertices');
    var Vector = _dereq_('../geometry/Vector');
    var Common = _dereq_('../core/Common');
    var Bounds = _dereq_('../geometry/Bounds');
    
    (function() {
    
        Resolver._restingThresh = 4;
        Resolver._restingThreshTangent = 6;
        Resolver._positionDampen = 0.9;
        Resolver._positionWarming = 0.8;
        Resolver._frictionNormalMultiplier = 5;
    
        /**
         * Prepare pairs for position solving.
         * @method preSolvePosition
         * @param {pair[]} pairs
         */
        Resolver.preSolvePosition = function(pairs) {
            var i,
                pair,
                activeCount;
    
            // find total contacts on each body
            for (i = 0; i < pairs.length; i++) {
                pair = pairs[i];
                
                if (!pair.isActive)
                    continue;
                
                activeCount = pair.activeContacts.length;
                pair.collision.parentA.totalContacts += activeCount;
                pair.collision.parentB.totalContacts += activeCount;
            }
        };
    
        /**
         * Find a solution for pair positions.
         * @method solvePosition
         * @param {pair[]} pairs
         * @param {number} timeScale
         */
        Resolver.solvePosition = function(pairs, timeScale) {
            var i,
                pair,
                collision,
                bodyA,
                bodyB,
                normal,
                bodyBtoA,
                contactShare,
                positionImpulse,
                contactCount = {},
                tempA = Vector._temp[0],
                tempB = Vector._temp[1],
                tempC = Vector._temp[2],
                tempD = Vector._temp[3];
    
            // find impulses required to resolve penetration
            for (i = 0; i < pairs.length; i++) {
                pair = pairs[i];
                
                if (!pair.isActive || pair.isSensor)
                    continue;
    
                collision = pair.collision;
                bodyA = collision.parentA;
                bodyB = collision.parentB;
                normal = collision.normal;
    
                // get current separation between body edges involved in collision
                bodyBtoA = Vector.sub(Vector.add(bodyB.positionImpulse, bodyB.position, tempA), 
                                        Vector.add(bodyA.positionImpulse, 
                                            Vector.sub(bodyB.position, collision.penetration, tempB), tempC), tempD);
    
                pair.separation = Vector.dot(normal, bodyBtoA);
            }
            
            for (i = 0; i < pairs.length; i++) {
                pair = pairs[i];
    
                if (!pair.isActive || pair.isSensor)
                    continue;
                
                collision = pair.collision;
                bodyA = collision.parentA;
                bodyB = collision.parentB;
                normal = collision.normal;
                positionImpulse = (pair.separation - pair.slop) * timeScale;
    
                if (bodyA.isStatic || bodyB.isStatic)
                    positionImpulse *= 2;
                
                if (!(bodyA.isStatic || bodyA.isSleeping)) {
                    contactShare = Resolver._positionDampen / bodyA.totalContacts;
                    bodyA.positionImpulse.x += normal.x * positionImpulse * contactShare;
                    bodyA.positionImpulse.y += normal.y * positionImpulse * contactShare;
                }
    
                if (!(bodyB.isStatic || bodyB.isSleeping)) {
                    contactShare = Resolver._positionDampen / bodyB.totalContacts;
                    bodyB.positionImpulse.x -= normal.x * positionImpulse * contactShare;
                    bodyB.positionImpulse.y -= normal.y * positionImpulse * contactShare;
                }
            }
        };
    
        /**
         * Apply position resolution.
         * @method postSolvePosition
         * @param {body[]} bodies
         */
        Resolver.postSolvePosition = function(bodies) {
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i];
    
                // reset contact count
                body.totalContacts = 0;
    
                if (body.positionImpulse.x !== 0 || body.positionImpulse.y !== 0) {
                    // update body geometry
                    for (var j = 0; j < body.parts.length; j++) {
                        var part = body.parts[j];
                        Vertices.translate(part.vertices, body.positionImpulse);
                        Bounds.update(part.bounds, part.vertices, body.velocity);
                        part.position.x += body.positionImpulse.x;
                        part.position.y += body.positionImpulse.y;
                    }
    
                    // move the body without changing velocity
                    body.positionPrev.x += body.positionImpulse.x;
                    body.positionPrev.y += body.positionImpulse.y;
    
                    if (Vector.dot(body.positionImpulse, body.velocity) < 0) {
                        // reset cached impulse if the body has velocity along it
                        body.positionImpulse.x = 0;
                        body.positionImpulse.y = 0;
                    } else {
                        // warm the next iteration
                        body.positionImpulse.x *= Resolver._positionWarming;
                        body.positionImpulse.y *= Resolver._positionWarming;
                    }
                }
            }
        };
    
        /**
         * Prepare pairs for velocity solving.
         * @method preSolveVelocity
         * @param {pair[]} pairs
         */
        Resolver.preSolveVelocity = function(pairs) {
            var i,
                j,
                pair,
                contacts,
                collision,
                bodyA,
                bodyB,
                normal,
                tangent,
                contact,
                contactVertex,
                normalImpulse,
                tangentImpulse,
                offset,
                impulse = Vector._temp[0],
                tempA = Vector._temp[1];
            
            for (i = 0; i < pairs.length; i++) {
                pair = pairs[i];
                
                if (!pair.isActive || pair.isSensor)
                    continue;
                
                contacts = pair.activeContacts;
                collision = pair.collision;
                bodyA = collision.parentA;
                bodyB = collision.parentB;
                normal = collision.normal;
                tangent = collision.tangent;
    
                // resolve each contact
                for (j = 0; j < contacts.length; j++) {
                    contact = contacts[j];
                    contactVertex = contact.vertex;
                    normalImpulse = contact.normalImpulse;
                    tangentImpulse = contact.tangentImpulse;
    
                    if (normalImpulse !== 0 || tangentImpulse !== 0) {
                        // total impulse from contact
                        impulse.x = (normal.x * normalImpulse) + (tangent.x * tangentImpulse);
                        impulse.y = (normal.y * normalImpulse) + (tangent.y * tangentImpulse);
                        
                        // apply impulse from contact
                        if (!(bodyA.isStatic || bodyA.isSleeping)) {
                            offset = Vector.sub(contactVertex, bodyA.position, tempA);
                            bodyA.positionPrev.x += impulse.x * bodyA.inverseMass;
                            bodyA.positionPrev.y += impulse.y * bodyA.inverseMass;
                            bodyA.anglePrev += Vector.cross(offset, impulse) * bodyA.inverseInertia;
                        }
    
                        if (!(bodyB.isStatic || bodyB.isSleeping)) {
                            offset = Vector.sub(contactVertex, bodyB.position, tempA);
                            bodyB.positionPrev.x -= impulse.x * bodyB.inverseMass;
                            bodyB.positionPrev.y -= impulse.y * bodyB.inverseMass;
                            bodyB.anglePrev -= Vector.cross(offset, impulse) * bodyB.inverseInertia;
                        }
                    }
                }
            }
        };
    
        /**
         * Find a solution for pair velocities.
         * @method solveVelocity
         * @param {pair[]} pairs
         * @param {number} timeScale
         */
        Resolver.solveVelocity = function(pairs, timeScale) {
            var timeScaleSquared = timeScale * timeScale,
                impulse = Vector._temp[0],
                tempA = Vector._temp[1],
                tempB = Vector._temp[2],
                tempC = Vector._temp[3],
                tempD = Vector._temp[4],
                tempE = Vector._temp[5];
            
            for (var i = 0; i < pairs.length; i++) {
                var pair = pairs[i];
                
                if (!pair.isActive || pair.isSensor)
                    continue;
                
                var collision = pair.collision,
                    bodyA = collision.parentA,
                    bodyB = collision.parentB,
                    normal = collision.normal,
                    tangent = collision.tangent,
                    contacts = pair.activeContacts,
                    contactShare = 1 / contacts.length;
    
                // update body velocities
                bodyA.velocity.x = bodyA.position.x - bodyA.positionPrev.x;
                bodyA.velocity.y = bodyA.position.y - bodyA.positionPrev.y;
                bodyB.velocity.x = bodyB.position.x - bodyB.positionPrev.x;
                bodyB.velocity.y = bodyB.position.y - bodyB.positionPrev.y;
                bodyA.angularVelocity = bodyA.angle - bodyA.anglePrev;
                bodyB.angularVelocity = bodyB.angle - bodyB.anglePrev;
    
                // resolve each contact
                for (var j = 0; j < contacts.length; j++) {
                    var contact = contacts[j],
                        contactVertex = contact.vertex,
                        offsetA = Vector.sub(contactVertex, bodyA.position, tempA),
                        offsetB = Vector.sub(contactVertex, bodyB.position, tempB),
                        velocityPointA = Vector.add(bodyA.velocity, Vector.mult(Vector.perp(offsetA), bodyA.angularVelocity), tempC),
                        velocityPointB = Vector.add(bodyB.velocity, Vector.mult(Vector.perp(offsetB), bodyB.angularVelocity), tempD), 
                        relativeVelocity = Vector.sub(velocityPointA, velocityPointB, tempE),
                        normalVelocity = Vector.dot(normal, relativeVelocity);
    
                    var tangentVelocity = Vector.dot(tangent, relativeVelocity),
                        tangentSpeed = Math.abs(tangentVelocity),
                        tangentVelocityDirection = Common.sign(tangentVelocity);
    
                    // raw impulses
                    var normalImpulse = (1 + pair.restitution) * normalVelocity,
                        normalForce = Common.clamp(pair.separation + normalVelocity, 0, 1) * Resolver._frictionNormalMultiplier;
    
                    // coulomb friction
                    var tangentImpulse = tangentVelocity,
                        maxFriction = Infinity;
    
                    if (tangentSpeed > pair.friction * pair.frictionStatic * normalForce * timeScaleSquared) {
                        maxFriction = tangentSpeed;
                        tangentImpulse = Common.clamp(
                            pair.friction * tangentVelocityDirection * timeScaleSquared,
                            -maxFriction, maxFriction
                        );
                    }
    
                    // modify impulses accounting for mass, inertia and offset
                    var oAcN = Vector.cross(offsetA, normal),
                        oBcN = Vector.cross(offsetB, normal),
                        share = contactShare / (bodyA.inverseMass + bodyB.inverseMass + bodyA.inverseInertia * oAcN * oAcN  + bodyB.inverseInertia * oBcN * oBcN);
    
                    normalImpulse *= share;
                    tangentImpulse *= share;
    
                    // handle high velocity and resting collisions separately
                    if (normalVelocity < 0 && normalVelocity * normalVelocity > Resolver._restingThresh * timeScaleSquared) {
                        // high normal velocity so clear cached contact normal impulse
                        contact.normalImpulse = 0;
                    } else {
                        // solve resting collision constraints using Erin Catto's method (GDC08)
                        // impulse constraint tends to 0
                        var contactNormalImpulse = contact.normalImpulse;
                        contact.normalImpulse = Math.min(contact.normalImpulse + normalImpulse, 0);
                        normalImpulse = contact.normalImpulse - contactNormalImpulse;
                    }
    
                    // handle high velocity and resting collisions separately
                    if (tangentVelocity * tangentVelocity > Resolver._restingThreshTangent * timeScaleSquared) {
                        // high tangent velocity so clear cached contact tangent impulse
                        contact.tangentImpulse = 0;
                    } else {
                        // solve resting collision constraints using Erin Catto's method (GDC08)
                        // tangent impulse tends to -tangentSpeed or +tangentSpeed
                        var contactTangentImpulse = contact.tangentImpulse;
                        contact.tangentImpulse = Common.clamp(contact.tangentImpulse + tangentImpulse, -maxFriction, maxFriction);
                        tangentImpulse = contact.tangentImpulse - contactTangentImpulse;
                    }
    
                    // total impulse from contact
                    impulse.x = (normal.x * normalImpulse) + (tangent.x * tangentImpulse);
                    impulse.y = (normal.y * normalImpulse) + (tangent.y * tangentImpulse);
                    
                    // apply impulse from contact
                    if (!(bodyA.isStatic || bodyA.isSleeping)) {
                        bodyA.positionPrev.x += impulse.x * bodyA.inverseMass;
                        bodyA.positionPrev.y += impulse.y * bodyA.inverseMass;
                        bodyA.anglePrev += Vector.cross(offsetA, impulse) * bodyA.inverseInertia;
                    }
    
                    if (!(bodyB.isStatic || bodyB.isSleeping)) {
                        bodyB.positionPrev.x -= impulse.x * bodyB.inverseMass;
                        bodyB.positionPrev.y -= impulse.y * bodyB.inverseMass;
                        bodyB.anglePrev -= Vector.cross(offsetB, impulse) * bodyB.inverseInertia;
                    }
                }
            }
        };
    
    })();
    
    },{"../core/Common":14,"../geometry/Bounds":26,"../geometry/Vector":28,"../geometry/Vertices":29}],11:[function(_dereq_,module,exports){
    /**
    * The `Matter.SAT` module contains methods for detecting collisions using the Separating Axis Theorem.
    *
    * @class SAT
    */
    
    // TODO: true circles and curves
    
    var SAT = {};
    
    module.exports = SAT;
    
    var Vertices = _dereq_('../geometry/Vertices');
    var Vector = _dereq_('../geometry/Vector');
    
    (function() {
    
        /**
         * Detect collision between two bodies using the Separating Axis Theorem.
         * @method collides
         * @param {body} bodyA
         * @param {body} bodyB
         * @param {collision} previousCollision
         * @return {collision} collision
         */
        SAT.collides = function(bodyA, bodyB, previousCollision) {
            var overlapAB,
                overlapBA, 
                minOverlap,
                collision,
                canReusePrevCol = false;
    
            if (previousCollision) {
                // estimate total motion
                var parentA = bodyA.parent,
                    parentB = bodyB.parent,
                    motion = parentA.speed * parentA.speed + parentA.angularSpeed * parentA.angularSpeed
                           + parentB.speed * parentB.speed + parentB.angularSpeed * parentB.angularSpeed;
    
                // we may be able to (partially) reuse collision result 
                // but only safe if collision was resting
                canReusePrevCol = previousCollision && previousCollision.collided && motion < 0.2;
    
                // reuse collision object
                collision = previousCollision;
            } else {
                collision = { collided: false, bodyA: bodyA, bodyB: bodyB };
            }
    
            if (previousCollision && canReusePrevCol) {
                // if we can reuse the collision result
                // we only need to test the previously found axis
                var axisBodyA = collision.axisBody,
                    axisBodyB = axisBodyA === bodyA ? bodyB : bodyA,
                    axes = [axisBodyA.axes[previousCollision.axisNumber]];
    
                minOverlap = SAT._overlapAxes(axisBodyA.vertices, axisBodyB.vertices, axes);
                collision.reused = true;
    
                if (minOverlap.overlap <= 0) {
                    collision.collided = false;
                    return collision;
                }
            } else {
                // if we can't reuse a result, perform a full SAT test
    
                overlapAB = SAT._overlapAxes(bodyA.vertices, bodyB.vertices, bodyA.axes);
    
                if (overlapAB.overlap <= 0) {
                    collision.collided = false;
                    return collision;
                }
    
                overlapBA = SAT._overlapAxes(bodyB.vertices, bodyA.vertices, bodyB.axes);
    
                if (overlapBA.overlap <= 0) {
                    collision.collided = false;
                    return collision;
                }
    
                if (overlapAB.overlap < overlapBA.overlap) {
                    minOverlap = overlapAB;
                    collision.axisBody = bodyA;
                } else {
                    minOverlap = overlapBA;
                    collision.axisBody = bodyB;
                }
    
                // important for reuse later
                collision.axisNumber = minOverlap.axisNumber;
            }
    
            collision.bodyA = bodyA.id < bodyB.id ? bodyA : bodyB;
            collision.bodyB = bodyA.id < bodyB.id ? bodyB : bodyA;
            collision.collided = true;
            collision.depth = minOverlap.overlap;
            collision.parentA = collision.bodyA.parent;
            collision.parentB = collision.bodyB.parent;
            
            bodyA = collision.bodyA;
            bodyB = collision.bodyB;
    
            // ensure normal is facing away from bodyA
            if (Vector.dot(minOverlap.axis, Vector.sub(bodyB.position, bodyA.position)) < 0) {
                collision.normal = {
                    x: minOverlap.axis.x,
                    y: minOverlap.axis.y
                };
            } else {
                collision.normal = {
                    x: -minOverlap.axis.x,
                    y: -minOverlap.axis.y
                };
            }
    
            collision.tangent = Vector.perp(collision.normal);
    
            collision.penetration = collision.penetration || {};
            collision.penetration.x = collision.normal.x * collision.depth;
            collision.penetration.y = collision.normal.y * collision.depth; 
    
            // find support points, there is always either exactly one or two
            var verticesB = SAT._findSupports(bodyA, bodyB, collision.normal),
                supports = [];
    
            // find the supports from bodyB that are inside bodyA
            if (Vertices.contains(bodyA.vertices, verticesB[0]))
                supports.push(verticesB[0]);
    
            if (Vertices.contains(bodyA.vertices, verticesB[1]))
                supports.push(verticesB[1]);
    
            // find the supports from bodyA that are inside bodyB
            if (supports.length < 2) {
                var verticesA = SAT._findSupports(bodyB, bodyA, Vector.neg(collision.normal));
                    
                if (Vertices.contains(bodyB.vertices, verticesA[0]))
                    supports.push(verticesA[0]);
    
                if (supports.length < 2 && Vertices.contains(bodyB.vertices, verticesA[1]))
                    supports.push(verticesA[1]);
            }
    
            // account for the edge case of overlapping but no vertex containment
            if (supports.length < 1)
                supports = [verticesB[0]];
            
            collision.supports = supports;
    
            return collision;
        };
    
        /**
         * Find the overlap between two sets of vertices.
         * @method _overlapAxes
         * @private
         * @param {} verticesA
         * @param {} verticesB
         * @param {} axes
         * @return result
         */
        SAT._overlapAxes = function(verticesA, verticesB, axes) {
            var projectionA = Vector._temp[0], 
                projectionB = Vector._temp[1],
                result = { overlap: Number.MAX_VALUE },
                overlap,
                axis;
    
            for (var i = 0; i < axes.length; i++) {
                axis = axes[i];
    
                SAT._projectToAxis(projectionA, verticesA, axis);
                SAT._projectToAxis(projectionB, verticesB, axis);
    
                overlap = Math.min(projectionA.max - projectionB.min, projectionB.max - projectionA.min);
    
                if (overlap <= 0) {
                    result.overlap = overlap;
                    return result;
                }
    
                if (overlap < result.overlap) {
                    result.overlap = overlap;
                    result.axis = axis;
                    result.axisNumber = i;
                }
            }
    
            return result;
        };
    
        /**
         * Projects vertices on an axis and returns an interval.
         * @method _projectToAxis
         * @private
         * @param {} projection
         * @param {} vertices
         * @param {} axis
         */
        SAT._projectToAxis = function(projection, vertices, axis) {
            var min = Vector.dot(vertices[0], axis),
                max = min;
    
            for (var i = 1; i < vertices.length; i += 1) {
                var dot = Vector.dot(vertices[i], axis);
    
                if (dot > max) { 
                    max = dot; 
                } else if (dot < min) { 
                    min = dot; 
                }
            }
    
            projection.min = min;
            projection.max = max;
        };
        
        /**
         * Finds supporting vertices given two bodies along a given direction using hill-climbing.
         * @method _findSupports
         * @private
         * @param {} bodyA
         * @param {} bodyB
         * @param {} normal
         * @return [vector]
         */
        SAT._findSupports = function(bodyA, bodyB, normal) {
            var nearestDistance = Number.MAX_VALUE,
                vertexToBody = Vector._temp[0],
                vertices = bodyB.vertices,
                bodyAPosition = bodyA.position,
                distance,
                vertex,
                vertexA,
                vertexB;
    
            // find closest vertex on bodyB
            for (var i = 0; i < vertices.length; i++) {
                vertex = vertices[i];
                vertexToBody.x = vertex.x - bodyAPosition.x;
                vertexToBody.y = vertex.y - bodyAPosition.y;
                distance = -Vector.dot(normal, vertexToBody);
    
                if (distance < nearestDistance) {
                    nearestDistance = distance;
                    vertexA = vertex;
                }
            }
    
            // find next closest vertex using the two connected to it
            var prevIndex = vertexA.index - 1 >= 0 ? vertexA.index - 1 : vertices.length - 1;
            vertex = vertices[prevIndex];
            vertexToBody.x = vertex.x - bodyAPosition.x;
            vertexToBody.y = vertex.y - bodyAPosition.y;
            nearestDistance = -Vector.dot(normal, vertexToBody);
            vertexB = vertex;
    
            var nextIndex = (vertexA.index + 1) % vertices.length;
            vertex = vertices[nextIndex];
            vertexToBody.x = vertex.x - bodyAPosition.x;
            vertexToBody.y = vertex.y - bodyAPosition.y;
            distance = -Vector.dot(normal, vertexToBody);
            if (distance < nearestDistance) {
                vertexB = vertex;
            }
    
            return [vertexA, vertexB];
        };
    
    })();
    
    },{"../geometry/Vector":28,"../geometry/Vertices":29}],12:[function(_dereq_,module,exports){
    /**
    * The `Matter.Constraint` module contains methods for creating and manipulating constraints.
    * Constraints are used for specifying that a fixed distance must be maintained between two bodies (or a body and a fixed world-space position).
    * The stiffness of constraints can be modified to create springs or elastic.
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class Constraint
    */
    
    var Constraint = {};
    
    module.exports = Constraint;
    
    var Vertices = _dereq_('../geometry/Vertices');
    var Vector = _dereq_('../geometry/Vector');
    var Sleeping = _dereq_('../core/Sleeping');
    var Bounds = _dereq_('../geometry/Bounds');
    var Axes = _dereq_('../geometry/Axes');
    var Common = _dereq_('../core/Common');
    
    (function() {
    
        Constraint._warming = 0.4;
        Constraint._torqueDampen = 1;
        Constraint._minLength = 0.000001;
    
        /**
         * Creates a new constraint.
         * All properties have default values, and many are pre-calculated automatically based on other properties.
         * To simulate a revolute constraint (or pin joint) set `length: 0` and a high `stiffness` value (e.g. `0.7` or above).
         * If the constraint is unstable, try lowering the `stiffness` value and / or increasing `engine.constraintIterations`.
         * For compound bodies, constraints must be applied to the parent body (not one of its parts).
         * See the properties section below for detailed information on what you can pass via the `options` object.
         * @method create
         * @param {} options
         * @return {constraint} constraint
         */
        Constraint.create = function(options) {
            var constraint = options;
    
            // if bodies defined but no points, use body centre
            if (constraint.bodyA && !constraint.pointA)
                constraint.pointA = { x: 0, y: 0 };
            if (constraint.bodyB && !constraint.pointB)
                constraint.pointB = { x: 0, y: 0 };
    
            // calculate static length using initial world space points
            var initialPointA = constraint.bodyA ? Vector.add(constraint.bodyA.position, constraint.pointA) : constraint.pointA,
                initialPointB = constraint.bodyB ? Vector.add(constraint.bodyB.position, constraint.pointB) : constraint.pointB,
                length = Vector.magnitude(Vector.sub(initialPointA, initialPointB));
        
            constraint.length = typeof constraint.length !== 'undefined' ? constraint.length : length;
    
            // option defaults
            constraint.id = constraint.id || Common.nextId();
            constraint.label = constraint.label || 'Constraint';
            constraint.type = 'constraint';
            constraint.stiffness = constraint.stiffness || (constraint.length > 0 ? 1 : 0.7);
            constraint.damping = constraint.damping || 0;
            constraint.angularStiffness = constraint.angularStiffness || 0;
            constraint.angleA = constraint.bodyA ? constraint.bodyA.angle : constraint.angleA;
            constraint.angleB = constraint.bodyB ? constraint.bodyB.angle : constraint.angleB;
            constraint.plugin = {};
    
            // render
            var render = {
                visible: true,
                lineWidth: 2,
                strokeStyle: '#ffffff',
                type: 'line',
                anchors: true
            };
    
            if (constraint.length === 0 && constraint.stiffness > 0.1) {
                render.type = 'pin';
                render.anchors = false;
            } else if (constraint.stiffness < 0.9) {
                render.type = 'spring';
            }
    
            constraint.render = Common.extend(render, constraint.render);
    
            return constraint;
        };
    
        /**
         * Prepares for solving by constraint warming.
         * @private
         * @method preSolveAll
         * @param {body[]} bodies
         */
        Constraint.preSolveAll = function(bodies) {
            for (var i = 0; i < bodies.length; i += 1) {
                var body = bodies[i],
                    impulse = body.constraintImpulse;
    
                if (body.isStatic || (impulse.x === 0 && impulse.y === 0 && impulse.angle === 0)) {
                    continue;
                }
    
                body.position.x += impulse.x;
                body.position.y += impulse.y;
                body.angle += impulse.angle;
            }
        };
    
        /**
         * Solves all constraints in a list of collisions.
         * @private
         * @method solveAll
         * @param {constraint[]} constraints
         * @param {number} timeScale
         */
        Constraint.solveAll = function(constraints, timeScale) {
            // Solve fixed constraints first.
            for (var i = 0; i < constraints.length; i += 1) {
                var constraint = constraints[i],
                    fixedA = !constraint.bodyA || (constraint.bodyA && constraint.bodyA.isStatic),
                    fixedB = !constraint.bodyB || (constraint.bodyB && constraint.bodyB.isStatic);
    
                if (fixedA || fixedB) {
                    Constraint.solve(constraints[i], timeScale);
                }
            }
    
            // Solve free constraints last.
            for (i = 0; i < constraints.length; i += 1) {
                constraint = constraints[i];
                fixedA = !constraint.bodyA || (constraint.bodyA && constraint.bodyA.isStatic);
                fixedB = !constraint.bodyB || (constraint.bodyB && constraint.bodyB.isStatic);
    
                if (!fixedA && !fixedB) {
                    Constraint.solve(constraints[i], timeScale);
                }
            }
        };
    
        /**
         * Solves a distance constraint with Gauss-Siedel method.
         * @private
         * @method solve
         * @param {constraint} constraint
         * @param {number} timeScale
         */
        Constraint.solve = function(constraint, timeScale) {
            var bodyA = constraint.bodyA,
                bodyB = constraint.bodyB,
                pointA = constraint.pointA,
                pointB = constraint.pointB;
    
            if (!bodyA && !bodyB)
                return;
    
            // update reference angle
            if (bodyA && !bodyA.isStatic) {
                Vector.rotate(pointA, bodyA.angle - constraint.angleA, pointA);
                constraint.angleA = bodyA.angle;
            }
            
            // update reference angle
            if (bodyB && !bodyB.isStatic) {
                Vector.rotate(pointB, bodyB.angle - constraint.angleB, pointB);
                constraint.angleB = bodyB.angle;
            }
    
            var pointAWorld = pointA,
                pointBWorld = pointB;
    
            if (bodyA) pointAWorld = Vector.add(bodyA.position, pointA);
            if (bodyB) pointBWorld = Vector.add(bodyB.position, pointB);
    
            if (!pointAWorld || !pointBWorld)
                return;
    
            var delta = Vector.sub(pointAWorld, pointBWorld),
                currentLength = Vector.magnitude(delta);
    
            // prevent singularity
            if (currentLength < Constraint._minLength) {
                currentLength = Constraint._minLength;
            }
    
            // solve distance constraint with Gauss-Siedel method
            var difference = (currentLength - constraint.length) / currentLength,
                stiffness = constraint.stiffness < 1 ? constraint.stiffness * timeScale : constraint.stiffness,
                force = Vector.mult(delta, difference * stiffness),
                massTotal = (bodyA ? bodyA.inverseMass : 0) + (bodyB ? bodyB.inverseMass : 0),
                inertiaTotal = (bodyA ? bodyA.inverseInertia : 0) + (bodyB ? bodyB.inverseInertia : 0),
                resistanceTotal = massTotal + inertiaTotal,
                torque,
                share,
                normal,
                normalVelocity,
                relativeVelocity;
    
            if (constraint.damping) {
                var zero = Vector.create();
                normal = Vector.div(delta, currentLength);
    
                relativeVelocity = Vector.sub(
                    bodyB && Vector.sub(bodyB.position, bodyB.positionPrev) || zero,
                    bodyA && Vector.sub(bodyA.position, bodyA.positionPrev) || zero
                );
    
                normalVelocity = Vector.dot(normal, relativeVelocity);
            }
    
            if (bodyA && !bodyA.isStatic) {
                share = bodyA.inverseMass / massTotal;
    
                // keep track of applied impulses for post solving
                bodyA.constraintImpulse.x -= force.x * share;
                bodyA.constraintImpulse.y -= force.y * share;
    
                // apply forces
                bodyA.position.x -= force.x * share;
                bodyA.position.y -= force.y * share;
    
                // apply damping
                if (constraint.damping) {
                    bodyA.positionPrev.x -= constraint.damping * normal.x * normalVelocity * share;
                    bodyA.positionPrev.y -= constraint.damping * normal.y * normalVelocity * share;
                }
    
                // apply torque
                torque = (Vector.cross(pointA, force) / resistanceTotal) * Constraint._torqueDampen * bodyA.inverseInertia * (1 - constraint.angularStiffness);
                bodyA.constraintImpulse.angle -= torque;
                bodyA.angle -= torque;
            }
    
            if (bodyB && !bodyB.isStatic) {
                share = bodyB.inverseMass / massTotal;
    
                // keep track of applied impulses for post solving
                bodyB.constraintImpulse.x += force.x * share;
                bodyB.constraintImpulse.y += force.y * share;
                
                // apply forces
                bodyB.position.x += force.x * share;
                bodyB.position.y += force.y * share;
    
                // apply damping
                if (constraint.damping) {
                    bodyB.positionPrev.x += constraint.damping * normal.x * normalVelocity * share;
                    bodyB.positionPrev.y += constraint.damping * normal.y * normalVelocity * share;
                }
    
                // apply torque
                torque = (Vector.cross(pointB, force) / resistanceTotal) * Constraint._torqueDampen * bodyB.inverseInertia * (1 - constraint.angularStiffness);
                bodyB.constraintImpulse.angle += torque;
                bodyB.angle += torque;
            }
    
        };
    
        /**
         * Performs body updates required after solving constraints.
         * @private
         * @method postSolveAll
         * @param {body[]} bodies
         */
        Constraint.postSolveAll = function(bodies) {
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i],
                    impulse = body.constraintImpulse;
    
                if (body.isStatic || (impulse.x === 0 && impulse.y === 0 && impulse.angle === 0)) {
                    continue;
                }
    
                Sleeping.set(body, false);
    
                // update geometry and reset
                for (var j = 0; j < body.parts.length; j++) {
                    var part = body.parts[j];
                    
                    Vertices.translate(part.vertices, impulse);
    
                    if (j > 0) {
                        part.position.x += impulse.x;
                        part.position.y += impulse.y;
                    }
    
                    if (impulse.angle !== 0) {
                        Vertices.rotate(part.vertices, impulse.angle, body.position);
                        Axes.rotate(part.axes, impulse.angle);
                        if (j > 0) {
                            Vector.rotateAbout(part.position, impulse.angle, body.position, part.position);
                        }
                    }
    
                    Bounds.update(part.bounds, part.vertices, body.velocity);
                }
    
                // dampen the cached impulse for warming next step
                impulse.angle *= Constraint._warming;
                impulse.x *= Constraint._warming;
                impulse.y *= Constraint._warming;
            }
        };
    
        /*
        *
        *  Properties Documentation
        *
        */
    
        /**
         * An integer `Number` uniquely identifying number generated in `Composite.create` by `Common.nextId`.
         *
         * @property id
         * @type number
         */
    
        /**
         * A `String` denoting the type of object.
         *
         * @property type
         * @type string
         * @default "constraint"
         * @readOnly
         */
    
        /**
         * An arbitrary `String` name to help the user identify and manage bodies.
         *
         * @property label
         * @type string
         * @default "Constraint"
         */
    
        /**
         * An `Object` that defines the rendering properties to be consumed by the module `Matter.Render`.
         *
         * @property render
         * @type object
         */
    
        /**
         * A flag that indicates if the constraint should be rendered.
         *
         * @property render.visible
         * @type boolean
         * @default true
         */
    
        /**
         * A `Number` that defines the line width to use when rendering the constraint outline.
         * A value of `0` means no outline will be rendered.
         *
         * @property render.lineWidth
         * @type number
         * @default 2
         */
    
        /**
         * A `String` that defines the stroke style to use when rendering the constraint outline.
         * It is the same as when using a canvas, so it accepts CSS style property values.
         *
         * @property render.strokeStyle
         * @type string
         * @default a random colour
         */
    
        /**
         * A `String` that defines the constraint rendering type. 
         * The possible values are 'line', 'pin', 'spring'.
         * An appropriate render type will be automatically chosen unless one is given in options.
         *
         * @property render.type
         * @type string
         * @default 'line'
         */
    
        /**
         * A `Boolean` that defines if the constraint's anchor points should be rendered.
         *
         * @property render.anchors
         * @type boolean
         * @default true
         */
    
        /**
         * The first possible `Body` that this constraint is attached to.
         *
         * @property bodyA
         * @type body
         * @default null
         */
    
        /**
         * The second possible `Body` that this constraint is attached to.
         *
         * @property bodyB
         * @type body
         * @default null
         */
    
        /**
         * A `Vector` that specifies the offset of the constraint from center of the `constraint.bodyA` if defined, otherwise a world-space position.
         *
         * @property pointA
         * @type vector
         * @default { x: 0, y: 0 }
         */
    
        /**
         * A `Vector` that specifies the offset of the constraint from center of the `constraint.bodyB` if defined, otherwise a world-space position.
         *
         * @property pointB
         * @type vector
         * @default { x: 0, y: 0 }
         */
    
        /**
         * A `Number` that specifies the stiffness of the constraint, i.e. the rate at which it returns to its resting `constraint.length`.
         * A value of `1` means the constraint should be very stiff.
         * A value of `0.2` means the constraint acts like a soft spring.
         *
         * @property stiffness
         * @type number
         * @default 1
         */
    
        /**
         * A `Number` that specifies the damping of the constraint, 
         * i.e. the amount of resistance applied to each body based on their velocities to limit the amount of oscillation.
         * Damping will only be apparent when the constraint also has a very low `stiffness`.
         * A value of `0.1` means the constraint will apply heavy damping, resulting in little to no oscillation.
         * A value of `0` means the constraint will apply no damping.
         *
         * @property damping
         * @type number
         * @default 0
         */
    
        /**
         * A `Number` that specifies the target resting length of the constraint. 
         * It is calculated automatically in `Constraint.create` from initial positions of the `constraint.bodyA` and `constraint.bodyB`.
         *
         * @property length
         * @type number
         */
    
        /**
         * An object reserved for storing plugin-specific properties.
         *
         * @property plugin
         * @type {}
         */
    
    })();
    
    },{"../core/Common":14,"../core/Sleeping":22,"../geometry/Axes":25,"../geometry/Bounds":26,"../geometry/Vector":28,"../geometry/Vertices":29}],13:[function(_dereq_,module,exports){
    /**
    * The `Matter.MouseConstraint` module contains methods for creating mouse constraints.
    * Mouse constraints are used for allowing user interaction, providing the ability to move bodies via the mouse or touch.
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class MouseConstraint
    */
    
    var MouseConstraint = {};
    
    module.exports = MouseConstraint;
    
    var Vertices = _dereq_('../geometry/Vertices');
    var Sleeping = _dereq_('../core/Sleeping');
    var Mouse = _dereq_('../core/Mouse');
    var Events = _dereq_('../core/Events');
    var Detector = _dereq_('../collision/Detector');
    var Constraint = _dereq_('./Constraint');
    var Composite = _dereq_('../body/Composite');
    var Common = _dereq_('../core/Common');
    var Bounds = _dereq_('../geometry/Bounds');
    
    (function() {
    
        /**
         * Creates a new mouse constraint.
         * All properties have default values, and many are pre-calculated automatically based on other properties.
         * See the properties section below for detailed information on what you can pass via the `options` object.
         * @method create
         * @param {engine} engine
         * @param {} options
         * @return {MouseConstraint} A new MouseConstraint
         */
        MouseConstraint.create = function(engine, options) {
            var mouse = (engine ? engine.mouse : null) || (options ? options.mouse : null);
    
            if (!mouse) {
                if (engine && engine.render && engine.render.canvas) {
                    mouse = Mouse.create(engine.render.canvas);
                } else if (options && options.element) {
                    mouse = Mouse.create(options.element);
                } else {
                    mouse = Mouse.create();
                    Common.warn('MouseConstraint.create: options.mouse was undefined, options.element was undefined, may not function as expected');
                }
            }
    
            var constraint = Constraint.create({ 
                label: 'Mouse Constraint',
                pointA: mouse.position,
                pointB: { x: 0, y: 0 },
                length: 0.01, 
                stiffness: 0.1,
                angularStiffness: 1,
                render: {
                    strokeStyle: '#90EE90',
                    lineWidth: 3
                }
            });
    
            var defaults = {
                type: 'mouseConstraint',
                mouse: mouse,
                element: null,
                body: null,
                constraint: constraint,
                collisionFilter: {
                    category: 0x0001,
                    mask: 0xFFFFFFFF,
                    group: 0
                }
            };
    
            var mouseConstraint = Common.extend(defaults, options);
    
            Events.on(engine, 'beforeUpdate', function() {
                var allBodies = Composite.allBodies(engine.world);
                MouseConstraint.update(mouseConstraint, allBodies);
                MouseConstraint._triggerEvents(mouseConstraint);
            });
    
            return mouseConstraint;
        };
    
        /**
         * Updates the given mouse constraint.
         * @private
         * @method update
         * @param {MouseConstraint} mouseConstraint
         * @param {body[]} bodies
         */
        MouseConstraint.update = function(mouseConstraint, bodies) {
            var mouse = mouseConstraint.mouse,
                constraint = mouseConstraint.constraint,
                body = mouseConstraint.body;
    
            if (mouse.button === 0) {
                if (!constraint.bodyB) {
                    for (var i = 0; i < bodies.length; i++) {
                        body = bodies[i];
                        if (Bounds.contains(body.bounds, mouse.position) 
                                && Detector.canCollide(body.collisionFilter, mouseConstraint.collisionFilter)) {
                            for (var j = body.parts.length > 1 ? 1 : 0; j < body.parts.length; j++) {
                                var part = body.parts[j];
                                if (Vertices.contains(part.vertices, mouse.position)) {
                                    constraint.pointA = mouse.position;
                                    constraint.bodyB = mouseConstraint.body = body;
                                    constraint.pointB = { x: mouse.position.x - body.position.x, y: mouse.position.y - body.position.y };
                                    constraint.angleB = body.angle;
    
                                    Sleeping.set(body, false);
                                    Events.trigger(mouseConstraint, 'startdrag', { mouse: mouse, body: body });
    
                                    break;
                                }
                            }
                        }
                    }
                } else {
                    Sleeping.set(constraint.bodyB, false);
                    constraint.pointA = mouse.position;
                }
            } else {
                constraint.bodyB = mouseConstraint.body = null;
                constraint.pointB = null;
    
                if (body)
                    Events.trigger(mouseConstraint, 'enddrag', { mouse: mouse, body: body });
            }
        };
    
        /**
         * Triggers mouse constraint events.
         * @method _triggerEvents
         * @private
         * @param {mouse} mouseConstraint
         */
        MouseConstraint._triggerEvents = function(mouseConstraint) {
            var mouse = mouseConstraint.mouse,
                mouseEvents = mouse.sourceEvents;
    
            if (mouseEvents.mousemove)
                Events.trigger(mouseConstraint, 'mousemove', { mouse: mouse });
    
            if (mouseEvents.mousedown)
                Events.trigger(mouseConstraint, 'mousedown', { mouse: mouse });
    
            if (mouseEvents.mouseup)
                Events.trigger(mouseConstraint, 'mouseup', { mouse: mouse });
    
            // reset the mouse state ready for the next step
            Mouse.clearSourceEvents(mouse);
        };
    
        /*
        *
        *  Events Documentation
        *
        */
    
        /**
        * Fired when the mouse has moved (or a touch moves) during the last step
        *
        * @event mousemove
        * @param {} event An event object
        * @param {mouse} event.mouse The engine's mouse instance
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired when the mouse is down (or a touch has started) during the last step
        *
        * @event mousedown
        * @param {} event An event object
        * @param {mouse} event.mouse The engine's mouse instance
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired when the mouse is up (or a touch has ended) during the last step
        *
        * @event mouseup
        * @param {} event An event object
        * @param {mouse} event.mouse The engine's mouse instance
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired when the user starts dragging a body
        *
        * @event startdrag
        * @param {} event An event object
        * @param {mouse} event.mouse The engine's mouse instance
        * @param {body} event.body The body being dragged
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired when the user ends dragging a body
        *
        * @event enddrag
        * @param {} event An event object
        * @param {mouse} event.mouse The engine's mouse instance
        * @param {body} event.body The body that has stopped being dragged
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /*
        *
        *  Properties Documentation
        *
        */
    
        /**
         * A `String` denoting the type of object.
         *
         * @property type
         * @type string
         * @default "constraint"
         * @readOnly
         */
    
        /**
         * The `Mouse` instance in use. If not supplied in `MouseConstraint.create`, one will be created.
         *
         * @property mouse
         * @type mouse
         * @default mouse
         */
    
        /**
         * The `Body` that is currently being moved by the user, or `null` if no body.
         *
         * @property body
         * @type body
         * @default null
         */
    
        /**
         * The `Constraint` object that is used to move the body during interaction.
         *
         * @property constraint
         * @type constraint
         */
    
        /**
         * An `Object` that specifies the collision filter properties.
         * The collision filter allows the user to define which types of body this mouse constraint can interact with.
         * See `body.collisionFilter` for more information.
         *
         * @property collisionFilter
         * @type object
         */
    
    })();
    
    },{"../body/Composite":2,"../collision/Detector":5,"../core/Common":14,"../core/Events":16,"../core/Mouse":19,"../core/Sleeping":22,"../geometry/Bounds":26,"../geometry/Vertices":29,"./Constraint":12}],14:[function(_dereq_,module,exports){
    (function (global){
    /**
    * The `Matter.Common` module contains utility functions that are common to all modules.
    *
    * @class Common
    */
    
    var Common = {};
    
    module.exports = Common;
    
    (function() {
    
        Common._nextId = 0;
        Common._seed = 0;
        Common._nowStartTime = +(new Date());
    
        /**
         * Extends the object in the first argument using the object in the second argument.
         * @method extend
         * @param {} obj
         * @param {boolean} deep
         * @return {} obj extended
         */
        Common.extend = function(obj, deep) {
            var argsStart,
                args,
                deepClone;
    
            if (typeof deep === 'boolean') {
                argsStart = 2;
                deepClone = deep;
            } else {
                argsStart = 1;
                deepClone = true;
            }
    
            for (var i = argsStart; i < arguments.length; i++) {
                var source = arguments[i];
    
                if (source) {
                    for (var prop in source) {
                        if (deepClone && source[prop] && source[prop].constructor === Object) {
                            if (!obj[prop] || obj[prop].constructor === Object) {
                                obj[prop] = obj[prop] || {};
                                Common.extend(obj[prop], deepClone, source[prop]);
                            } else {
                                obj[prop] = source[prop];
                            }
                        } else {
                            obj[prop] = source[prop];
                        }
                    }
                }
            }
            
            return obj;
        };
    
        /**
         * Creates a new clone of the object, if deep is true references will also be cloned.
         * @method clone
         * @param {} obj
         * @param {bool} deep
         * @return {} obj cloned
         */
        Common.clone = function(obj, deep) {
            return Common.extend({}, deep, obj);
        };
    
        /**
         * Returns the list of keys for the given object.
         * @method keys
         * @param {} obj
         * @return {string[]} keys
         */
        Common.keys = function(obj) {
            if (Object.keys)
                return Object.keys(obj);
    
            // avoid hasOwnProperty for performance
            var keys = [];
            for (var key in obj)
                keys.push(key);
            return keys;
        };
    
        /**
         * Returns the list of values for the given object.
         * @method values
         * @param {} obj
         * @return {array} Array of the objects property values
         */
        Common.values = function(obj) {
            var values = [];
            
            if (Object.keys) {
                var keys = Object.keys(obj);
                for (var i = 0; i < keys.length; i++) {
                    values.push(obj[keys[i]]);
                }
                return values;
            }
            
            // avoid hasOwnProperty for performance
            for (var key in obj)
                values.push(obj[key]);
            return values;
        };
    
        /**
         * Gets a value from `base` relative to the `path` string.
         * @method get
         * @param {} obj The base object
         * @param {string} path The path relative to `base`, e.g. 'Foo.Bar.baz'
         * @param {number} [begin] Path slice begin
         * @param {number} [end] Path slice end
         * @return {} The object at the given path
         */
        Common.get = function(obj, path, begin, end) {
            path = path.split('.').slice(begin, end);
    
            for (var i = 0; i < path.length; i += 1) {
                obj = obj[path[i]];
            }
    
            return obj;
        };
    
        /**
         * Sets a value on `base` relative to the given `path` string.
         * @method set
         * @param {} obj The base object
         * @param {string} path The path relative to `base`, e.g. 'Foo.Bar.baz'
         * @param {} val The value to set
         * @param {number} [begin] Path slice begin
         * @param {number} [end] Path slice end
         * @return {} Pass through `val` for chaining
         */
        Common.set = function(obj, path, val, begin, end) {
            var parts = path.split('.').slice(begin, end);
            Common.get(obj, path, 0, -1)[parts[parts.length - 1]] = val;
            return val;
        };
    
        /**
         * Shuffles the given array in-place.
         * The function uses a seeded random generator.
         * @method shuffle
         * @param {array} array
         * @return {array} array shuffled randomly
         */
        Common.shuffle = function(array) {
            for (var i = array.length - 1; i > 0; i--) {
                var j = Math.floor(Common.random() * (i + 1));
                var temp = array[i];
                array[i] = array[j];
                array[j] = temp;
            }
            return array;
        };
    
        /**
         * Randomly chooses a value from a list with equal probability.
         * The function uses a seeded random generator.
         * @method choose
         * @param {array} choices
         * @return {object} A random choice object from the array
         */
        Common.choose = function(choices) {
            return choices[Math.floor(Common.random() * choices.length)];
        };
    
        /**
         * Returns true if the object is a HTMLElement, otherwise false.
         * @method isElement
         * @param {object} obj
         * @return {boolean} True if the object is a HTMLElement, otherwise false
         */
        Common.isElement = function(obj) {
            if (typeof HTMLElement !== 'undefined') {
                return obj instanceof HTMLElement;
            }
    
            return !!(obj && obj.nodeType && obj.nodeName);
        };
    
        /**
         * Returns true if the object is an array.
         * @method isArray
         * @param {object} obj
         * @return {boolean} True if the object is an array, otherwise false
         */
        Common.isArray = function(obj) {
            return Object.prototype.toString.call(obj) === '[object Array]';
        };
    
        /**
         * Returns true if the object is a function.
         * @method isFunction
         * @param {object} obj
         * @return {boolean} True if the object is a function, otherwise false
         */
        Common.isFunction = function(obj) {
            return typeof obj === "function";
        };
    
        /**
         * Returns true if the object is a plain object.
         * @method isPlainObject
         * @param {object} obj
         * @return {boolean} True if the object is a plain object, otherwise false
         */
        Common.isPlainObject = function(obj) {
            return typeof obj === 'object' && obj.constructor === Object;
        };
    
        /**
         * Returns true if the object is a string.
         * @method isString
         * @param {object} obj
         * @return {boolean} True if the object is a string, otherwise false
         */
        Common.isString = function(obj) {
            return toString.call(obj) === '[object String]';
        };
        
        /**
         * Returns the given value clamped between a minimum and maximum value.
         * @method clamp
         * @param {number} value
         * @param {number} min
         * @param {number} max
         * @return {number} The value clamped between min and max inclusive
         */
        Common.clamp = function(value, min, max) {
            if (value < min)
                return min;
            if (value > max)
                return max;
            return value;
        };
        
        /**
         * Returns the sign of the given value.
         * @method sign
         * @param {number} value
         * @return {number} -1 if negative, +1 if 0 or positive
         */
        Common.sign = function(value) {
            return value < 0 ? -1 : 1;
        };
        
        /**
         * Returns the current timestamp since the time origin (e.g. from page load).
         * The result will be high-resolution including decimal places if available.
         * @method now
         * @return {number} the current timestamp
         */
        Common.now = function() {
            if (window.performance) {
                if (window.performance.now) {
                    return window.performance.now();
                } else if (window.performance.webkitNow) {
                    return window.performance.webkitNow();
                }
            }
    
            return (new Date()) - Common._nowStartTime;
        };
        
        /**
         * Returns a random value between a minimum and a maximum value inclusive.
         * The function uses a seeded random generator.
         * @method random
         * @param {number} min
         * @param {number} max
         * @return {number} A random number between min and max inclusive
         */
        Common.random = function(min, max) {
            min = (typeof min !== "undefined") ? min : 0;
            max = (typeof max !== "undefined") ? max : 1;
            return min + _seededRandom() * (max - min);
        };
    
        var _seededRandom = function() {
            // https://en.wikipedia.org/wiki/Linear_congruential_generator
            Common._seed = (Common._seed * 9301 + 49297) % 233280;
            return Common._seed / 233280;
        };
    
        /**
         * Converts a CSS hex colour string into an integer.
         * @method colorToNumber
         * @param {string} colorString
         * @return {number} An integer representing the CSS hex string
         */
        Common.colorToNumber = function(colorString) {
            colorString = colorString.replace('#','');
    
            if (colorString.length == 3) {
                colorString = colorString.charAt(0) + colorString.charAt(0)
                            + colorString.charAt(1) + colorString.charAt(1)
                            + colorString.charAt(2) + colorString.charAt(2);
            }
    
            return parseInt(colorString, 16);
        };
    
        /**
         * The console logging level to use, where each level includes all levels above and excludes the levels below.
         * The default level is 'debug' which shows all console messages.  
         *
         * Possible level values are:
         * - 0 = None
         * - 1 = Debug
         * - 2 = Info
         * - 3 = Warn
         * - 4 = Error
         * @property Common.logLevel
         * @type {Number}
         * @default 1
         */
        Common.logLevel = 1;
    
        /**
         * Shows a `console.log` message only if the current `Common.logLevel` allows it.
         * The message will be prefixed with 'matter-js' to make it easily identifiable.
         * @method log
         * @param ...objs {} The objects to log.
         */
        Common.log = function() {
            if (console && Common.logLevel > 0 && Common.logLevel <= 3) {
                console.log.apply(console, ['matter-js:'].concat(Array.prototype.slice.call(arguments)));
            }
        };
    
        /**
         * Shows a `console.info` message only if the current `Common.logLevel` allows it.
         * The message will be prefixed with 'matter-js' to make it easily identifiable.
         * @method info
         * @param ...objs {} The objects to log.
         */
        Common.info = function() {
            if (console && Common.logLevel > 0 && Common.logLevel <= 2) {
                console.info.apply(console, ['matter-js:'].concat(Array.prototype.slice.call(arguments)));
            }
        };
    
        /**
         * Shows a `console.warn` message only if the current `Common.logLevel` allows it.
         * The message will be prefixed with 'matter-js' to make it easily identifiable.
         * @method warn
         * @param ...objs {} The objects to log.
         */
        Common.warn = function() {
            if (console && Common.logLevel > 0 && Common.logLevel <= 3) {
                console.warn.apply(console, ['matter-js:'].concat(Array.prototype.slice.call(arguments)));
            }
        };
    
        /**
         * Returns the next unique sequential ID.
         * @method nextId
         * @return {Number} Unique sequential ID
         */
        Common.nextId = function() {
            return Common._nextId++;
        };
    
        /**
         * A cross browser compatible indexOf implementation.
         * @method indexOf
         * @param {array} haystack
         * @param {object} needle
         * @return {number} The position of needle in haystack, otherwise -1.
         */
        Common.indexOf = function(haystack, needle) {
            if (haystack.indexOf)
                return haystack.indexOf(needle);
    
            for (var i = 0; i < haystack.length; i++) {
                if (haystack[i] === needle)
                    return i;
            }
    
            return -1;
        };
    
        /**
         * A cross browser compatible array map implementation.
         * @method map
         * @param {array} list
         * @param {function} func
         * @return {array} Values from list transformed by func.
         */
        Common.map = function(list, func) {
            if (list.map) {
                return list.map(func);
            }
    
            var mapped = [];
    
            for (var i = 0; i < list.length; i += 1) {
                mapped.push(func(list[i]));
            }
    
            return mapped;
        };
    
        /**
         * Takes a directed graph and returns the partially ordered set of vertices in topological order.
         * Circular dependencies are allowed.
         * @method topologicalSort
         * @param {object} graph
         * @return {array} Partially ordered set of vertices in topological order.
         */
        Common.topologicalSort = function(graph) {
            // https://github.com/mgechev/javascript-algorithms
            // Copyright (c) Minko Gechev (MIT license)
            // Modifications: tidy formatting and naming
            var result = [],
                visited = [],
                temp = [];
    
            for (var node in graph) {
                if (!visited[node] && !temp[node]) {
                    Common._topologicalSort(node, visited, temp, graph, result);
                }
            }
    
            return result;
        };
    
        Common._topologicalSort = function(node, visited, temp, graph, result) {
            var neighbors = graph[node] || [];
            temp[node] = true;
    
            for (var i = 0; i < neighbors.length; i += 1) {
                var neighbor = neighbors[i];
    
                if (temp[neighbor]) {
                    // skip circular dependencies
                    continue;
                }
    
                if (!visited[neighbor]) {
                    Common._topologicalSort(neighbor, visited, temp, graph, result);
                }
            }
    
            temp[node] = false;
            visited[node] = true;
    
            result.push(node);
        };
    
        /**
         * Takes _n_ functions as arguments and returns a new function that calls them in order.
         * The arguments applied when calling the new function will also be applied to every function passed.
         * The value of `this` refers to the last value returned in the chain that was not `undefined`.
         * Therefore if a passed function does not return a value, the previously returned value is maintained.
         * After all passed functions have been called the new function returns the last returned value (if any).
         * If any of the passed functions are a chain, then the chain will be flattened.
         * @method chain
         * @param ...funcs {function} The functions to chain.
         * @return {function} A new function that calls the passed functions in order.
         */
        Common.chain = function() {
            var funcs = [];
    
            for (var i = 0; i < arguments.length; i += 1) {
                var func = arguments[i];
    
                if (func._chained) {
                    // flatten already chained functions
                    funcs.push.apply(funcs, func._chained);
                } else {
                    funcs.push(func);
                }
            }
    
            var chain = function() {
                // https://github.com/GoogleChrome/devtools-docs/issues/53#issuecomment-51941358
                var lastResult,
                    args = new Array(arguments.length);
    
                for (var i = 0, l = arguments.length; i < l; i++) {
                    args[i] = arguments[i];
                }
    
                for (i = 0; i < funcs.length; i += 1) {
                    var result = funcs[i].apply(lastResult, args);
    
                    if (typeof result !== 'undefined') {
                        lastResult = result;
                    }
                }
    
                return lastResult;
            };
    
            chain._chained = funcs;
    
            return chain;
        };
    
        /**
         * Chains a function to excute before the original function on the given `path` relative to `base`.
         * See also docs for `Common.chain`.
         * @method chainPathBefore
         * @param {} base The base object
         * @param {string} path The path relative to `base`
         * @param {function} func The function to chain before the original
         * @return {function} The chained function that replaced the original
         */
        Common.chainPathBefore = function(base, path, func) {
            return Common.set(base, path, Common.chain(
                func,
                Common.get(base, path)
            ));
        };
    
        /**
         * Chains a function to excute after the original function on the given `path` relative to `base`.
         * See also docs for `Common.chain`.
         * @method chainPathAfter
         * @param {} base The base object
         * @param {string} path The path relative to `base`
         * @param {function} func The function to chain after the original
         * @return {function} The chained function that replaced the original
         */
        Common.chainPathAfter = function(base, path, func) {
            return Common.set(base, path, Common.chain(
                Common.get(base, path),
                func
            ));
        };
    
        /**
         * Used to require external libraries outside of the bundle.
         * It first looks for the `globalName` on the environment's global namespace.
         * If the global is not found, it will fall back to using the standard `require` using the `moduleName`.
         * @private
         * @method _requireGlobal
         * @param {string} globalName The global module name
         * @param {string} moduleName The fallback CommonJS module name
         * @return {} The loaded module
         */
        Common._requireGlobal = function(globalName, moduleName) {
            var obj = (typeof window !== 'undefined' ? window[globalName] : typeof global !== 'undefined' ? global[globalName] : null);
            return obj || _dereq_(moduleName);
        };
    })();
    
    }).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
    },{}],15:[function(_dereq_,module,exports){
    /**
    * The `Matter.Engine` module contains methods for creating and manipulating engines.
    * An engine is a controller that manages updating the simulation of the world.
    * See `Matter.Runner` for an optional game loop utility.
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class Engine
    */
    
    var Engine = {};
    
    module.exports = Engine;
    
    var World = _dereq_('../body/World');
    var Sleeping = _dereq_('./Sleeping');
    var Resolver = _dereq_('../collision/Resolver');
    var Render = _dereq_('../render/Render');
    var Pairs = _dereq_('../collision/Pairs');
    var Metrics = _dereq_('./Metrics');
    var Grid = _dereq_('../collision/Grid');
    var Events = _dereq_('./Events');
    var Composite = _dereq_('../body/Composite');
    var Constraint = _dereq_('../constraint/Constraint');
    var Common = _dereq_('./Common');
    var Body = _dereq_('../body/Body');
    
    (function() {
    
        /**
         * Creates a new engine. The options parameter is an object that specifies any properties you wish to override the defaults.
         * All properties have default values, and many are pre-calculated automatically based on other properties.
         * See the properties section below for detailed information on what you can pass via the `options` object.
         * @method create
         * @param {object} [options]
         * @return {engine} engine
         */
        Engine.create = function(element, options) {
            // options may be passed as the first (and only) argument
            options = Common.isElement(element) ? options : element;
            element = Common.isElement(element) ? element : null;
            options = options || {};
    
            if (element || options.render) {
                Common.warn('Engine.create: engine.render is deprecated (see docs)');
            }
    
            var defaults = {
                positionIterations: 6,
                velocityIterations: 4,
                constraintIterations: 2,
                enableSleeping: false,
                events: [],
                plugin: {},
                timing: {
                    timestamp: 0,
                    timeScale: 1
                },
                broadphase: {
                    controller: Grid
                }
            };
    
            var engine = Common.extend(defaults, options);
    
            // @deprecated
            if (element || engine.render) {
                var renderDefaults = {
                    element: element,
                    controller: Render
                };
                
                engine.render = Common.extend(renderDefaults, engine.render);
            }
    
            // @deprecated
            if (engine.render && engine.render.controller) {
                engine.render = engine.render.controller.create(engine.render);
            }
    
            // @deprecated
            if (engine.render) {
                engine.render.engine = engine;
            }
    
            engine.world = options.world || World.create(engine.world);
            engine.pairs = Pairs.create();
            engine.broadphase = engine.broadphase.controller.create(engine.broadphase);
            engine.metrics = engine.metrics || { extended: false };
    
    
            return engine;
        };
    
        /**
         * Moves the simulation forward in time by `delta` ms.
         * The `correction` argument is an optional `Number` that specifies the time correction factor to apply to the update.
         * This can help improve the accuracy of the simulation in cases where `delta` is changing between updates.
         * The value of `correction` is defined as `delta / lastDelta`, i.e. the percentage change of `delta` over the last step.
         * Therefore the value is always `1` (no correction) when `delta` constant (or when no correction is desired, which is the default).
         * See the paper on <a href="http://lonesock.net/article/verlet.html">Time Corrected Verlet</a> for more information.
         *
         * Triggers `beforeUpdate` and `afterUpdate` events.
         * Triggers `collisionStart`, `collisionActive` and `collisionEnd` events.
         * @method update
         * @param {engine} engine
         * @param {number} [delta=16.666]
         * @param {number} [correction=1]
         */
        Engine.update = function(engine, delta, correction) {
            delta = delta || 1000 / 60;
            correction = correction || 1;
    
            var world = engine.world,
                timing = engine.timing,
                broadphase = engine.broadphase,
                broadphasePairs = [],
                i;
    
            // increment timestamp
            timing.timestamp += delta * timing.timeScale;
    
            // create an event object
            var event = {
                timestamp: timing.timestamp
            };
    
            Events.trigger(engine, 'beforeUpdate', event);
    
            // get lists of all bodies and constraints, no matter what composites they are in
            var allBodies = Composite.allBodies(world),
                allConstraints = Composite.allConstraints(world);
    
    
            // if sleeping enabled, call the sleeping controller
            if (engine.enableSleeping)
                Sleeping.update(allBodies, timing.timeScale);
    
            // applies gravity to all bodies
            Engine._bodiesApplyGravity(allBodies, world.gravity);
    
            // update all body position and rotation by integration
            Engine._bodiesUpdate(allBodies, delta, timing.timeScale, correction, world.bounds);
    
            // update all constraints (first pass)
            Constraint.preSolveAll(allBodies);
            for (i = 0; i < engine.constraintIterations; i++) {
                Constraint.solveAll(allConstraints, timing.timeScale);
            }
            Constraint.postSolveAll(allBodies);
    
            // broadphase pass: find potential collision pairs
            if (broadphase.controller) {
                // if world is dirty, we must flush the whole grid
                if (world.isModified)
                    broadphase.controller.clear(broadphase);
    
                // update the grid buckets based on current bodies
                broadphase.controller.update(broadphase, allBodies, engine, world.isModified);
                broadphasePairs = broadphase.pairsList;
            } else {
                // if no broadphase set, we just pass all bodies
                broadphasePairs = allBodies;
            }
    
            // clear all composite modified flags
            if (world.isModified) {
                Composite.setModified(world, false, false, true);
            }
    
            // narrowphase pass: find actual collisions, then create or update collision pairs
            var collisions = broadphase.detector(broadphasePairs, engine);
    
            // update collision pairs
            var pairs = engine.pairs,
                timestamp = timing.timestamp;
            Pairs.update(pairs, collisions, timestamp);
            Pairs.removeOld(pairs, timestamp);
    
            // wake up bodies involved in collisions
            if (engine.enableSleeping)
                Sleeping.afterCollisions(pairs.list, timing.timeScale);
    
            // trigger collision events
            if (pairs.collisionStart.length > 0)
                Events.trigger(engine, 'collisionStart', { pairs: pairs.collisionStart });
    
            // iteratively resolve position between collisions
            Resolver.preSolvePosition(pairs.list);
            for (i = 0; i < engine.positionIterations; i++) {
                Resolver.solvePosition(pairs.list, timing.timeScale);
            }
            Resolver.postSolvePosition(allBodies);
    
            // update all constraints (second pass)
            Constraint.preSolveAll(allBodies);
            for (i = 0; i < engine.constraintIterations; i++) {
                Constraint.solveAll(allConstraints, timing.timeScale);
            }
            Constraint.postSolveAll(allBodies);
    
            // iteratively resolve velocity between collisions
            Resolver.preSolveVelocity(pairs.list);
            for (i = 0; i < engine.velocityIterations; i++) {
                Resolver.solveVelocity(pairs.list, timing.timeScale);
            }
    
            // trigger collision events
            if (pairs.collisionActive.length > 0)
                Events.trigger(engine, 'collisionActive', { pairs: pairs.collisionActive });
    
            if (pairs.collisionEnd.length > 0)
                Events.trigger(engine, 'collisionEnd', { pairs: pairs.collisionEnd });
    
    
            // clear force buffers
            Engine._bodiesClearForces(allBodies);
    
            Events.trigger(engine, 'afterUpdate', event);
    
            return engine;
        };
        
        /**
         * Merges two engines by keeping the configuration of `engineA` but replacing the world with the one from `engineB`.
         * @method merge
         * @param {engine} engineA
         * @param {engine} engineB
         */
        Engine.merge = function(engineA, engineB) {
            Common.extend(engineA, engineB);
            
            if (engineB.world) {
                engineA.world = engineB.world;
    
                Engine.clear(engineA);
    
                var bodies = Composite.allBodies(engineA.world);
    
                for (var i = 0; i < bodies.length; i++) {
                    var body = bodies[i];
                    Sleeping.set(body, false);
                    body.id = Common.nextId();
                }
            }
        };
    
        /**
         * Clears the engine including the world, pairs and broadphase.
         * @method clear
         * @param {engine} engine
         */
        Engine.clear = function(engine) {
            var world = engine.world;
            
            Pairs.clear(engine.pairs);
    
            var broadphase = engine.broadphase;
            if (broadphase.controller) {
                var bodies = Composite.allBodies(world);
                broadphase.controller.clear(broadphase);
                broadphase.controller.update(broadphase, bodies, engine, true);
            }
        };
    
        /**
         * Zeroes the `body.force` and `body.torque` force buffers.
         * @method _bodiesClearForces
         * @private
         * @param {body[]} bodies
         */
        Engine._bodiesClearForces = function(bodies) {
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i];
    
                // reset force buffers
                body.force.x = 0;
                body.force.y = 0;
                body.torque = 0;
            }
        };
    
        /**
         * Applys a mass dependant force to all given bodies.
         * @method _bodiesApplyGravity
         * @private
         * @param {body[]} bodies
         * @param {vector} gravity
         */
        Engine._bodiesApplyGravity = function(bodies, gravity) {
            var gravityScale = typeof gravity.scale !== 'undefined' ? gravity.scale : 0.001;
    
            if ((gravity.x === 0 && gravity.y === 0) || gravityScale === 0) {
                return;
            }
            
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i];
    
                if (body.isStatic || body.isSleeping)
                    continue;
    
                // apply gravity
                body.force.y += body.mass * gravity.y * gravityScale;
                body.force.x += body.mass * gravity.x * gravityScale;
            }
        };
    
        /**
         * Applys `Body.update` to all given `bodies`.
         * @method _bodiesUpdate
         * @private
         * @param {body[]} bodies
         * @param {number} deltaTime 
         * The amount of time elapsed between updates
         * @param {number} timeScale
         * @param {number} correction 
         * The Verlet correction factor (deltaTime / lastDeltaTime)
         * @param {bounds} worldBounds
         */
        Engine._bodiesUpdate = function(bodies, deltaTime, timeScale, correction, worldBounds) {
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i];
    
                if (body.isStatic || body.isSleeping)
                    continue;
    
                Body.update(body, deltaTime, timeScale, correction);
            }
        };
    
        /**
         * An alias for `Runner.run`, see `Matter.Runner` for more information.
         * @method run
         * @param {engine} engine
         */
    
        /**
        * Fired just before an update
        *
        * @event beforeUpdate
        * @param {} event An event object
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired after engine update and all collision events
        *
        * @event afterUpdate
        * @param {} event An event object
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired after engine update, provides a list of all pairs that have started to collide in the current tick (if any)
        *
        * @event collisionStart
        * @param {} event An event object
        * @param {} event.pairs List of affected pairs
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired after engine update, provides a list of all pairs that are colliding in the current tick (if any)
        *
        * @event collisionActive
        * @param {} event An event object
        * @param {} event.pairs List of affected pairs
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired after engine update, provides a list of all pairs that have ended collision in the current tick (if any)
        *
        * @event collisionEnd
        * @param {} event An event object
        * @param {} event.pairs List of affected pairs
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /*
        *
        *  Properties Documentation
        *
        */
    
        /**
         * An integer `Number` that specifies the number of position iterations to perform each update.
         * The higher the value, the higher quality the simulation will be at the expense of performance.
         *
         * @property positionIterations
         * @type number
         * @default 6
         */
    
        /**
         * An integer `Number` that specifies the number of velocity iterations to perform each update.
         * The higher the value, the higher quality the simulation will be at the expense of performance.
         *
         * @property velocityIterations
         * @type number
         * @default 4
         */
    
        /**
         * An integer `Number` that specifies the number of constraint iterations to perform each update.
         * The higher the value, the higher quality the simulation will be at the expense of performance.
         * The default value of `2` is usually very adequate.
         *
         * @property constraintIterations
         * @type number
         * @default 2
         */
    
        /**
         * A flag that specifies whether the engine should allow sleeping via the `Matter.Sleeping` module.
         * Sleeping can improve stability and performance, but often at the expense of accuracy.
         *
         * @property enableSleeping
         * @type boolean
         * @default false
         */
    
        /**
         * An `Object` containing properties regarding the timing systems of the engine. 
         *
         * @property timing
         * @type object
         */
    
        /**
         * A `Number` that specifies the global scaling factor of time for all bodies.
         * A value of `0` freezes the simulation.
         * A value of `0.1` gives a slow-motion effect.
         * A value of `1.2` gives a speed-up effect.
         *
         * @property timing.timeScale
         * @type number
         * @default 1
         */
    
        /**
         * A `Number` that specifies the current simulation-time in milliseconds starting from `0`. 
         * It is incremented on every `Engine.update` by the given `delta` argument. 
         *
         * @property timing.timestamp
         * @type number
         * @default 0
         */
    
        /**
         * An instance of a `Render` controller. The default value is a `Matter.Render` instance created by `Engine.create`.
         * One may also develop a custom renderer module based on `Matter.Render` and pass an instance of it to `Engine.create` via `options.render`.
         *
         * A minimal custom renderer object must define at least three functions: `create`, `clear` and `world` (see `Matter.Render`).
         * It is also possible to instead pass the _module_ reference via `options.render.controller` and `Engine.create` will instantiate one for you.
         *
         * @property render
         * @type render
         * @deprecated see Demo.js for an example of creating a renderer
         * @default a Matter.Render instance
         */
    
        /**
         * An instance of a broadphase controller. The default value is a `Matter.Grid` instance created by `Engine.create`.
         *
         * @property broadphase
         * @type grid
         * @default a Matter.Grid instance
         */
    
        /**
         * A `World` composite object that will contain all simulated bodies and constraints.
         *
         * @property world
         * @type world
         * @default a Matter.World instance
         */
    
        /**
         * An object reserved for storing plugin-specific properties.
         *
         * @property plugin
         * @type {}
         */
    
    })();
    
    },{"../body/Body":1,"../body/Composite":2,"../body/World":3,"../collision/Grid":6,"../collision/Pairs":8,"../collision/Resolver":10,"../constraint/Constraint":12,"../render/Render":31,"./Common":14,"./Events":16,"./Metrics":18,"./Sleeping":22}],16:[function(_dereq_,module,exports){
    /**
    * The `Matter.Events` module contains methods to fire and listen to events on other objects.
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class Events
    */
    
    var Events = {};
    
    module.exports = Events;
    
    var Common = _dereq_('./Common');
    
    (function() {
    
        /**
         * Subscribes a callback function to the given object's `eventName`.
         * @method on
         * @param {} object
         * @param {string} eventNames
         * @param {function} callback
         */
        Events.on = function(object, eventNames, callback) {
            var names = eventNames.split(' '),
                name;
    
            for (var i = 0; i < names.length; i++) {
                name = names[i];
                object.events = object.events || {};
                object.events[name] = object.events[name] || [];
                object.events[name].push(callback);
            }
    
            return callback;
        };
    
        /**
         * Removes the given event callback. If no callback, clears all callbacks in `eventNames`. If no `eventNames`, clears all events.
         * @method off
         * @param {} object
         * @param {string} eventNames
         * @param {function} callback
         */
        Events.off = function(object, eventNames, callback) {
            if (!eventNames) {
                object.events = {};
                return;
            }
    
            // handle Events.off(object, callback)
            if (typeof eventNames === 'function') {
                callback = eventNames;
                eventNames = Common.keys(object.events).join(' ');
            }
    
            var names = eventNames.split(' ');
    
            for (var i = 0; i < names.length; i++) {
                var callbacks = object.events[names[i]],
                    newCallbacks = [];
    
                if (callback && callbacks) {
                    for (var j = 0; j < callbacks.length; j++) {
                        if (callbacks[j] !== callback)
                            newCallbacks.push(callbacks[j]);
                    }
                }
    
                object.events[names[i]] = newCallbacks;
            }
        };
    
        /**
         * Fires all the callbacks subscribed to the given object's `eventName`, in the order they subscribed, if any.
         * @method trigger
         * @param {} object
         * @param {string} eventNames
         * @param {} event
         */
        Events.trigger = function(object, eventNames, event) {
            var names,
                name,
                callbacks,
                eventClone;
    
            if (object.events) {
                if (!event)
                    event = {};
    
                names = eventNames.split(' ');
    
                for (var i = 0; i < names.length; i++) {
                    name = names[i];
                    callbacks = object.events[name];
    
                    if (callbacks) {
                        eventClone = Common.clone(event, false);
                        eventClone.name = name;
                        eventClone.source = object;
    
                        for (var j = 0; j < callbacks.length; j++) {
                            callbacks[j].apply(object, [eventClone]);
                        }
                    }
                }
            }
        };
    
    })();
    
    },{"./Common":14}],17:[function(_dereq_,module,exports){
    /**
    * The `Matter` module is the top level namespace. It also includes a function for installing plugins on top of the library.
    *
    * @class Matter
    */
    
    var Matter = {};
    
    module.exports = Matter;
    
    var Plugin = _dereq_('./Plugin');
    var Common = _dereq_('./Common');
    
    (function() {
    
        /**
         * The library name.
         * @property name
         * @readOnly
         * @type {String}
         */
        Matter.name = 'matter-js';
    
        /**
         * The library version.
         * @property version
         * @readOnly
         * @type {String}
         */
        Matter.version = '0.14.2';
    
        /**
         * A list of plugin dependencies to be installed. These are normally set and installed through `Matter.use`.
         * Alternatively you may set `Matter.uses` manually and install them by calling `Plugin.use(Matter)`.
         * @property uses
         * @type {Array}
         */
        Matter.uses = [];
    
        /**
         * The plugins that have been installed through `Matter.Plugin.install`. Read only.
         * @property used
         * @readOnly
         * @type {Array}
         */
        Matter.used = [];
    
        /**
         * Installs the given plugins on the `Matter` namespace.
         * This is a short-hand for `Plugin.use`, see it for more information.
         * Call this function once at the start of your code, with all of the plugins you wish to install as arguments.
         * Avoid calling this function multiple times unless you intend to manually control installation order.
         * @method use
         * @param ...plugin {Function} The plugin(s) to install on `base` (multi-argument).
         */
        Matter.use = function() {
            Plugin.use(Matter, Array.prototype.slice.call(arguments));
        };
    
        /**
         * Chains a function to excute before the original function on the given `path` relative to `Matter`.
         * See also docs for `Common.chain`.
         * @method before
         * @param {string} path The path relative to `Matter`
         * @param {function} func The function to chain before the original
         * @return {function} The chained function that replaced the original
         */
        Matter.before = function(path, func) {
            path = path.replace(/^Matter./, '');
            return Common.chainPathBefore(Matter, path, func);
        };
    
        /**
         * Chains a function to excute after the original function on the given `path` relative to `Matter`.
         * See also docs for `Common.chain`.
         * @method after
         * @param {string} path The path relative to `Matter`
         * @param {function} func The function to chain after the original
         * @return {function} The chained function that replaced the original
         */
        Matter.after = function(path, func) {
            path = path.replace(/^Matter./, '');
            return Common.chainPathAfter(Matter, path, func);
        };
    
    })();
    
    },{"./Common":14,"./Plugin":20}],18:[function(_dereq_,module,exports){
    
    },{"../body/Composite":2,"./Common":14}],19:[function(_dereq_,module,exports){
    /**
    * The `Matter.Mouse` module contains methods for creating and manipulating mouse inputs.
    *
    * @class Mouse
    */
    
    var Mouse = {};
    
    module.exports = Mouse;
    
    var Common = _dereq_('../core/Common');
    
    (function() {
    
        /**
         * Creates a mouse input.
         * @method create
         * @param {HTMLElement} element
         * @return {mouse} A new mouse
         */
        Mouse.create = function(element) {
            var mouse = {};
    
            if (!element) {
                Common.log('Mouse.create: element was undefined, defaulting to document.body', 'warn');
            }
            
            mouse.element = element || document.body;
            mouse.absolute = { x: 0, y: 0 };
            mouse.position = { x: 0, y: 0 };
            mouse.mousedownPosition = { x: 0, y: 0 };
            mouse.mouseupPosition = { x: 0, y: 0 };
            mouse.offset = { x: 0, y: 0 };
            mouse.scale = { x: 1, y: 1 };
            mouse.wheelDelta = 0;
            mouse.button = -1;
            mouse.pixelRatio = mouse.element.getAttribute('data-pixel-ratio') || 1;
    
            mouse.sourceEvents = {
                mousemove: null,
                mousedown: null,
                mouseup: null,
                mousewheel: null
            };
            
            mouse.mousemove = function(event) { 
                var position = Mouse._getRelativeMousePosition(event, mouse.element, mouse.pixelRatio),
                    touches = event.changedTouches;
    
                if (touches) {
                    mouse.button = 0;
                    event.preventDefault();
                }
    
                mouse.absolute.x = position.x;
                mouse.absolute.y = position.y;
                mouse.position.x = mouse.absolute.x * mouse.scale.x + mouse.offset.x;
                mouse.position.y = mouse.absolute.y * mouse.scale.y + mouse.offset.y;
                mouse.sourceEvents.mousemove = event;
            };
            
            mouse.mousedown = function(event) {
                var position = Mouse._getRelativeMousePosition(event, mouse.element, mouse.pixelRatio),
                    touches = event.changedTouches;
    
                if (touches) {
                    mouse.button = 0;
                    event.preventDefault();
                } else {
                    mouse.button = event.button;
                }
    
                mouse.absolute.x = position.x;
                mouse.absolute.y = position.y;
                mouse.position.x = mouse.absolute.x * mouse.scale.x + mouse.offset.x;
                mouse.position.y = mouse.absolute.y * mouse.scale.y + mouse.offset.y;
                mouse.mousedownPosition.x = mouse.position.x;
                mouse.mousedownPosition.y = mouse.position.y;
                mouse.sourceEvents.mousedown = event;
            };
            
            mouse.mouseup = function(event) {
                var position = Mouse._getRelativeMousePosition(event, mouse.element, mouse.pixelRatio),
                    touches = event.changedTouches;
    
                if (touches) {
                    event.preventDefault();
                }
                
                mouse.button = -1;
                mouse.absolute.x = position.x;
                mouse.absolute.y = position.y;
                mouse.position.x = mouse.absolute.x * mouse.scale.x + mouse.offset.x;
                mouse.position.y = mouse.absolute.y * mouse.scale.y + mouse.offset.y;
                mouse.mouseupPosition.x = mouse.position.x;
                mouse.mouseupPosition.y = mouse.position.y;
                mouse.sourceEvents.mouseup = event;
            };
    
            mouse.mousewheel = function(event) {
                mouse.wheelDelta = Math.max(-1, Math.min(1, event.wheelDelta || -event.detail));
                event.preventDefault();
            };
    
            Mouse.setElement(mouse, mouse.element);
    
            return mouse;
        };
    
        /**
         * Sets the element the mouse is bound to (and relative to).
         * @method setElement
         * @param {mouse} mouse
         * @param {HTMLElement} element
         */
        Mouse.setElement = function(mouse, element) {
            mouse.element = element;
    
            element.addEventListener('mousemove', mouse.mousemove);
            element.addEventListener('mousedown', mouse.mousedown);
            element.addEventListener('mouseup', mouse.mouseup);
            
            element.addEventListener('mousewheel', mouse.mousewheel);
            element.addEventListener('DOMMouseScroll', mouse.mousewheel);
    
            element.addEventListener('touchmove', mouse.mousemove);
            element.addEventListener('touchstart', mouse.mousedown);
            element.addEventListener('touchend', mouse.mouseup);
        };
    
        /**
         * Clears all captured source events.
         * @method clearSourceEvents
         * @param {mouse} mouse
         */
        Mouse.clearSourceEvents = function(mouse) {
            mouse.sourceEvents.mousemove = null;
            mouse.sourceEvents.mousedown = null;
            mouse.sourceEvents.mouseup = null;
            mouse.sourceEvents.mousewheel = null;
            mouse.wheelDelta = 0;
        };
    
        /**
         * Sets the mouse position offset.
         * @method setOffset
         * @param {mouse} mouse
         * @param {vector} offset
         */
        Mouse.setOffset = function(mouse, offset) {
            mouse.offset.x = offset.x;
            mouse.offset.y = offset.y;
            mouse.position.x = mouse.absolute.x * mouse.scale.x + mouse.offset.x;
            mouse.position.y = mouse.absolute.y * mouse.scale.y + mouse.offset.y;
        };
    
        /**
         * Sets the mouse position scale.
         * @method setScale
         * @param {mouse} mouse
         * @param {vector} scale
         */
        Mouse.setScale = function(mouse, scale) {
            mouse.scale.x = scale.x;
            mouse.scale.y = scale.y;
            mouse.position.x = mouse.absolute.x * mouse.scale.x + mouse.offset.x;
            mouse.position.y = mouse.absolute.y * mouse.scale.y + mouse.offset.y;
        };
        
        /**
         * Gets the mouse position relative to an element given a screen pixel ratio.
         * @method _getRelativeMousePosition
         * @private
         * @param {} event
         * @param {} element
         * @param {number} pixelRatio
         * @return {}
         */
        Mouse._getRelativeMousePosition = function(event, element, pixelRatio) {
            var elementBounds = element.getBoundingClientRect(),
                rootNode = (document.documentElement || document.body.parentNode || document.body),
                scrollX = (window.pageXOffset !== undefined) ? window.pageXOffset : rootNode.scrollLeft,
                scrollY = (window.pageYOffset !== undefined) ? window.pageYOffset : rootNode.scrollTop,
                touches = event.changedTouches,
                x, y;
            
            if (touches) {
                x = touches[0].pageX - elementBounds.left - scrollX;
                y = touches[0].pageY - elementBounds.top - scrollY;
            } else {
                x = event.pageX - elementBounds.left - scrollX;
                y = event.pageY - elementBounds.top - scrollY;
            }
    
            return { 
                x: x / (element.clientWidth / (element.width || element.clientWidth) * pixelRatio),
                y: y / (element.clientHeight / (element.height || element.clientHeight) * pixelRatio)
            };
        };
    
    })();
    
    },{"../core/Common":14}],20:[function(_dereq_,module,exports){
    /**
    * The `Matter.Plugin` module contains functions for registering and installing plugins on modules.
    *
    * @class Plugin
    */
    
    var Plugin = {};
    
    module.exports = Plugin;
    
    var Common = _dereq_('./Common');
    
    (function() {
    
        Plugin._registry = {};
    
        /**
         * Registers a plugin object so it can be resolved later by name.
         * @method register
         * @param plugin {} The plugin to register.
         * @return {object} The plugin.
         */
        Plugin.register = function(plugin) {
            if (!Plugin.isPlugin(plugin)) {
                Common.warn('Plugin.register:', Plugin.toString(plugin), 'does not implement all required fields.');
            }
    
            if (plugin.name in Plugin._registry) {
                var registered = Plugin._registry[plugin.name],
                    pluginVersion = Plugin.versionParse(plugin.version).number,
                    registeredVersion = Plugin.versionParse(registered.version).number;
    
                if (pluginVersion > registeredVersion) {
                    Common.warn('Plugin.register:', Plugin.toString(registered), 'was upgraded to', Plugin.toString(plugin));
                    Plugin._registry[plugin.name] = plugin;
                } else if (pluginVersion < registeredVersion) {
                    Common.warn('Plugin.register:', Plugin.toString(registered), 'can not be downgraded to', Plugin.toString(plugin));
                } else if (plugin !== registered) {
                    Common.warn('Plugin.register:', Plugin.toString(plugin), 'is already registered to different plugin object');
                }
            } else {
                Plugin._registry[plugin.name] = plugin;
            }
    
            return plugin;
        };
    
        /**
         * Resolves a dependency to a plugin object from the registry if it exists. 
         * The `dependency` may contain a version, but only the name matters when resolving.
         * @method resolve
         * @param dependency {string} The dependency.
         * @return {object} The plugin if resolved, otherwise `undefined`.
         */
        Plugin.resolve = function(dependency) {
            return Plugin._registry[Plugin.dependencyParse(dependency).name];
        };
    
        /**
         * Returns a pretty printed plugin name and version.
         * @method toString
         * @param plugin {} The plugin.
         * @return {string} Pretty printed plugin name and version.
         */
        Plugin.toString = function(plugin) {
            return typeof plugin === 'string' ? plugin : (plugin.name || 'anonymous') + '@' + (plugin.version || plugin.range || '0.0.0');
        };
    
        /**
         * Returns `true` if the object meets the minimum standard to be considered a plugin.
         * This means it must define the following properties:
         * - `name`
         * - `version`
         * - `install`
         * @method isPlugin
         * @param obj {} The obj to test.
         * @return {boolean} `true` if the object can be considered a plugin otherwise `false`.
         */
        Plugin.isPlugin = function(obj) {
            return obj && obj.name && obj.version && obj.install;
        };
    
        /**
         * Returns `true` if a plugin with the given `name` been installed on `module`.
         * @method isUsed
         * @param module {} The module.
         * @param name {string} The plugin name.
         * @return {boolean} `true` if a plugin with the given `name` been installed on `module`, otherwise `false`.
         */
        Plugin.isUsed = function(module, name) {
            return module.used.indexOf(name) > -1;
        };
    
        /**
         * Returns `true` if `plugin.for` is applicable to `module` by comparing against `module.name` and `module.version`.
         * If `plugin.for` is not specified then it is assumed to be applicable.
         * The value of `plugin.for` is a string of the format `'module-name'` or `'module-name@version'`.
         * @method isFor
         * @param plugin {} The plugin.
         * @param module {} The module.
         * @return {boolean} `true` if `plugin.for` is applicable to `module`, otherwise `false`.
         */
        Plugin.isFor = function(plugin, module) {
            var parsed = plugin.for && Plugin.dependencyParse(plugin.for);
            return !plugin.for || (module.name === parsed.name && Plugin.versionSatisfies(module.version, parsed.range));
        };
    
        /**
         * Installs the plugins by calling `plugin.install` on each plugin specified in `plugins` if passed, otherwise `module.uses`.
         * For installing plugins on `Matter` see the convenience function `Matter.use`.
         * Plugins may be specified either by their name or a reference to the plugin object.
         * Plugins themselves may specify further dependencies, but each plugin is installed only once.
         * Order is important, a topological sort is performed to find the best resulting order of installation.
         * This sorting attempts to satisfy every dependency's requested ordering, but may not be exact in all cases.
         * This function logs the resulting status of each dependency in the console, along with any warnings.
         * - A green tick ✅ indicates a dependency was resolved and installed.
         * - An orange diamond 🔶 indicates a dependency was resolved but a warning was thrown for it or one if its dependencies.
         * - A red cross ❌ indicates a dependency could not be resolved.
         * Avoid calling this function multiple times on the same module unless you intend to manually control installation order.
         * @method use
         * @param module {} The module install plugins on.
         * @param [plugins=module.uses] {} The plugins to install on module (optional, defaults to `module.uses`).
         */
        Plugin.use = function(module, plugins) {
            module.uses = (module.uses || []).concat(plugins || []);
    
            if (module.uses.length === 0) {
                Common.warn('Plugin.use:', Plugin.toString(module), 'does not specify any dependencies to install.');
                return;
            }
    
            var dependencies = Plugin.dependencies(module),
                sortedDependencies = Common.topologicalSort(dependencies),
                status = [];
    
            for (var i = 0; i < sortedDependencies.length; i += 1) {
                if (sortedDependencies[i] === module.name) {
                    continue;
                }
    
                var plugin = Plugin.resolve(sortedDependencies[i]);
    
                if (!plugin) {
                    status.push('❌ ' + sortedDependencies[i]);
                    continue;
                }
    
                if (Plugin.isUsed(module, plugin.name)) {
                    continue;
                }
    
                if (!Plugin.isFor(plugin, module)) {
                    Common.warn('Plugin.use:', Plugin.toString(plugin), 'is for', plugin.for, 'but installed on', Plugin.toString(module) + '.');
                    plugin._warned = true;
                }
    
                if (plugin.install) {
                    plugin.install(module);
                } else {
                    Common.warn('Plugin.use:', Plugin.toString(plugin), 'does not specify an install function.');
                    plugin._warned = true;
                }
    
                if (plugin._warned) {
                    status.push('🔶 ' + Plugin.toString(plugin));
                    delete plugin._warned;
                } else {
                    status.push('✅ ' + Plugin.toString(plugin));
                }
    
                module.used.push(plugin.name);
            }
    
            if (status.length > 0) {
                Common.info(status.join('  '));
            }
        };
    
        /**
         * Recursively finds all of a module's dependencies and returns a flat dependency graph.
         * @method dependencies
         * @param module {} The module.
         * @return {object} A dependency graph.
         */
        Plugin.dependencies = function(module, tracked) {
            var parsedBase = Plugin.dependencyParse(module),
                name = parsedBase.name;
    
            tracked = tracked || {};
    
            if (name in tracked) {
                return;
            }
    
            module = Plugin.resolve(module) || module;
    
            tracked[name] = Common.map(module.uses || [], function(dependency) {
                if (Plugin.isPlugin(dependency)) {
                    Plugin.register(dependency);
                }
    
                var parsed = Plugin.dependencyParse(dependency),
                    resolved = Plugin.resolve(dependency);
    
                if (resolved && !Plugin.versionSatisfies(resolved.version, parsed.range)) {
                    Common.warn(
                        'Plugin.dependencies:', Plugin.toString(resolved), 'does not satisfy',
                        Plugin.toString(parsed), 'used by', Plugin.toString(parsedBase) + '.'
                    );
    
                    resolved._warned = true;
                    module._warned = true;
                } else if (!resolved) {
                    Common.warn(
                        'Plugin.dependencies:', Plugin.toString(dependency), 'used by',
                        Plugin.toString(parsedBase), 'could not be resolved.'
                    );
    
                    module._warned = true;
                }
    
                return parsed.name;
            });
    
            for (var i = 0; i < tracked[name].length; i += 1) {
                Plugin.dependencies(tracked[name][i], tracked);
            }
    
            return tracked;
        };
    
        /**
         * Parses a dependency string into its components.
         * The `dependency` is a string of the format `'module-name'` or `'module-name@version'`.
         * See documentation for `Plugin.versionParse` for a description of the format.
         * This function can also handle dependencies that are already resolved (e.g. a module object).
         * @method dependencyParse
         * @param dependency {string} The dependency of the format `'module-name'` or `'module-name@version'`.
         * @return {object} The dependency parsed into its components.
         */
        Plugin.dependencyParse = function(dependency) {
            if (Common.isString(dependency)) {
                var pattern = /^[\w-]+(@(\*|[\^~]?\d+\.\d+\.\d+(-[0-9A-Za-z-]+)?))?$/;
    
                if (!pattern.test(dependency)) {
                    Common.warn('Plugin.dependencyParse:', dependency, 'is not a valid dependency string.');
                }
    
                return {
                    name: dependency.split('@')[0],
                    range: dependency.split('@')[1] || '*'
                };
            }
    
            return {
                name: dependency.name,
                range: dependency.range || dependency.version
            };
        };
    
        /**
         * Parses a version string into its components.  
         * Versions are strictly of the format `x.y.z` (as in [semver](http://semver.org/)).
         * Versions may optionally have a prerelease tag in the format `x.y.z-alpha`.
         * Ranges are a strict subset of [npm ranges](https://docs.npmjs.com/misc/semver#advanced-range-syntax).
         * Only the following range types are supported:
         * - Tilde ranges e.g. `~1.2.3`
         * - Caret ranges e.g. `^1.2.3`
         * - Exact version e.g. `1.2.3`
         * - Any version `*`
         * @method versionParse
         * @param range {string} The version string.
         * @return {object} The version range parsed into its components.
         */
        Plugin.versionParse = function(range) {
            var pattern = /^\*|[\^~]?\d+\.\d+\.\d+(-[0-9A-Za-z-]+)?$/;
    
            if (!pattern.test(range)) {
                Common.warn('Plugin.versionParse:', range, 'is not a valid version or range.');
            }
    
            var identifiers = range.split('-');
            range = identifiers[0];
    
            var isRange = isNaN(Number(range[0])),
                version = isRange ? range.substr(1) : range,
                parts = Common.map(version.split('.'), function(part) {
                    return Number(part);
                });
    
            return {
                isRange: isRange,
                version: version,
                range: range,
                operator: isRange ? range[0] : '',
                parts: parts,
                prerelease: identifiers[1],
                number: parts[0] * 1e8 + parts[1] * 1e4 + parts[2]
            };
        };
    
        /**
         * Returns `true` if `version` satisfies the given `range`.
         * See documentation for `Plugin.versionParse` for a description of the format.
         * If a version or range is not specified, then any version (`*`) is assumed to satisfy.
         * @method versionSatisfies
         * @param version {string} The version string.
         * @param range {string} The range string.
         * @return {boolean} `true` if `version` satisfies `range`, otherwise `false`.
         */
        Plugin.versionSatisfies = function(version, range) {
            range = range || '*';
    
            var rangeParsed = Plugin.versionParse(range),
                rangeParts = rangeParsed.parts,
                versionParsed = Plugin.versionParse(version),
                versionParts = versionParsed.parts;
    
            if (rangeParsed.isRange) {
                if (rangeParsed.operator === '*' || version === '*') {
                    return true;
                }
    
                if (rangeParsed.operator === '~') {
                    return versionParts[0] === rangeParts[0] && versionParts[1] === rangeParts[1] && versionParts[2] >= rangeParts[2];
                }
    
                if (rangeParsed.operator === '^') {
                    if (rangeParts[0] > 0) {
                        return versionParts[0] === rangeParts[0] && versionParsed.number >= rangeParsed.number;
                    }
    
                    if (rangeParts[1] > 0) {
                        return versionParts[1] === rangeParts[1] && versionParts[2] >= rangeParts[2];
                    }
    
                    return versionParts[2] === rangeParts[2];
                }
            }
    
            return version === range || version === '*';
        };
    
    })();
    
    },{"./Common":14}],21:[function(_dereq_,module,exports){
    /**
    * The `Matter.Runner` module is an optional utility which provides a game loop, 
    * that handles continuously updating a `Matter.Engine` for you within a browser.
    * It is intended for development and debugging purposes, but may also be suitable for simple games.
    * If you are using your own game loop instead, then you do not need the `Matter.Runner` module.
    * Instead just call `Engine.update(engine, delta)` in your own loop.
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class Runner
    */
    
    var Runner = {};
    
    module.exports = Runner;
    
    var Events = _dereq_('./Events');
    var Engine = _dereq_('./Engine');
    var Common = _dereq_('./Common');
    
    (function() {
    
        var _requestAnimationFrame,
            _cancelAnimationFrame;
    
        if (typeof window !== 'undefined') {
            _requestAnimationFrame = window.requestAnimationFrame || window.webkitRequestAnimationFrame
                                          || window.mozRequestAnimationFrame || window.msRequestAnimationFrame;
       
            _cancelAnimationFrame = window.cancelAnimationFrame || window.mozCancelAnimationFrame 
                                          || window.webkitCancelAnimationFrame || window.msCancelAnimationFrame;
        }
    
        if (!_requestAnimationFrame) {
            var _frameTimeout;
    
            _requestAnimationFrame = function(callback){ 
                _frameTimeout = setTimeout(function() { 
                    callback(Common.now()); 
                }, 1000 / 60);
            };
    
            _cancelAnimationFrame = function() {
                clearTimeout(_frameTimeout);
            };
        }
    
        /**
         * Creates a new Runner. The options parameter is an object that specifies any properties you wish to override the defaults.
         * @method create
         * @param {} options
         */
        Runner.create = function(options) {
            var defaults = {
                fps: 60,
                correction: 1,
                deltaSampleSize: 60,
                counterTimestamp: 0,
                frameCounter: 0,
                deltaHistory: [],
                timePrev: null,
                timeScalePrev: 1,
                frameRequestId: null,
                isFixed: false,
                enabled: true
            };
    
            var runner = Common.extend(defaults, options);
    
            runner.delta = runner.delta || 1000 / runner.fps;
            runner.deltaMin = runner.deltaMin || 1000 / runner.fps;
            runner.deltaMax = runner.deltaMax || 1000 / (runner.fps * 0.5);
            runner.fps = 1000 / runner.delta;
    
            return runner;
        };
    
        /**
         * Continuously ticks a `Matter.Engine` by calling `Runner.tick` on the `requestAnimationFrame` event.
         * @method run
         * @param {engine} engine
         */
        Runner.run = function(runner, engine) {
            // create runner if engine is first argument
            if (typeof runner.positionIterations !== 'undefined') {
                engine = runner;
                runner = Runner.create();
            }
    
            (function render(time){
                runner.frameRequestId = _requestAnimationFrame(render);
    
                if (time && runner.enabled) {
                    Runner.tick(runner, engine, time);
                }
            })();
    
            return runner;
        };
    
        /**
         * A game loop utility that updates the engine and renderer by one step (a 'tick').
         * Features delta smoothing, time correction and fixed or dynamic timing.
         * Triggers `beforeTick`, `tick` and `afterTick` events on the engine.
         * Consider just `Engine.update(engine, delta)` if you're using your own loop.
         * @method tick
         * @param {runner} runner
         * @param {engine} engine
         * @param {number} time
         */
        Runner.tick = function(runner, engine, time) {
            var timing = engine.timing,
                correction = 1,
                delta;
    
            // create an event object
            var event = {
                timestamp: timing.timestamp
            };
    
            Events.trigger(runner, 'beforeTick', event);
            Events.trigger(engine, 'beforeTick', event); // @deprecated
    
            if (runner.isFixed) {
                // fixed timestep
                delta = runner.delta;
            } else {
                // dynamic timestep based on wall clock between calls
                delta = (time - runner.timePrev) || runner.delta;
                runner.timePrev = time;
    
                // optimistically filter delta over a few frames, to improve stability
                runner.deltaHistory.push(delta);
                runner.deltaHistory = runner.deltaHistory.slice(-runner.deltaSampleSize);
                delta = Math.min.apply(null, runner.deltaHistory);
                
                // limit delta
                delta = delta < runner.deltaMin ? runner.deltaMin : delta;
                delta = delta > runner.deltaMax ? runner.deltaMax : delta;
    
                // correction for delta
                correction = delta / runner.delta;
    
                // update engine timing object
                runner.delta = delta;
            }
    
            // time correction for time scaling
            if (runner.timeScalePrev !== 0)
                correction *= timing.timeScale / runner.timeScalePrev;
    
            if (timing.timeScale === 0)
                correction = 0;
    
            runner.timeScalePrev = timing.timeScale;
            runner.correction = correction;
    
            // fps counter
            runner.frameCounter += 1;
            if (time - runner.counterTimestamp >= 1000) {
                runner.fps = runner.frameCounter * ((time - runner.counterTimestamp) / 1000);
                runner.counterTimestamp = time;
                runner.frameCounter = 0;
            }
    
            Events.trigger(runner, 'tick', event);
            Events.trigger(engine, 'tick', event); // @deprecated
    
            // if world has been modified, clear the render scene graph
            if (engine.world.isModified 
                && engine.render
                && engine.render.controller
                && engine.render.controller.clear) {
                engine.render.controller.clear(engine.render); // @deprecated
            }
    
            // update
            Events.trigger(runner, 'beforeUpdate', event);
            Engine.update(engine, delta, correction);
            Events.trigger(runner, 'afterUpdate', event);
    
            // render
            // @deprecated
            if (engine.render && engine.render.controller) {
                Events.trigger(runner, 'beforeRender', event);
                Events.trigger(engine, 'beforeRender', event); // @deprecated
    
                engine.render.controller.world(engine.render);
    
                Events.trigger(runner, 'afterRender', event);
                Events.trigger(engine, 'afterRender', event); // @deprecated
            }
    
            Events.trigger(runner, 'afterTick', event);
            Events.trigger(engine, 'afterTick', event); // @deprecated
        };
    
        /**
         * Ends execution of `Runner.run` on the given `runner`, by canceling the animation frame request event loop.
         * If you wish to only temporarily pause the engine, see `engine.enabled` instead.
         * @method stop
         * @param {runner} runner
         */
        Runner.stop = function(runner) {
            _cancelAnimationFrame(runner.frameRequestId);
        };
    
        /**
         * Alias for `Runner.run`.
         * @method start
         * @param {runner} runner
         * @param {engine} engine
         */
        Runner.start = function(runner, engine) {
            Runner.run(runner, engine);
        };
    
        /*
        *
        *  Events Documentation
        *
        */
    
        /**
        * Fired at the start of a tick, before any updates to the engine or timing
        *
        * @event beforeTick
        * @param {} event An event object
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired after engine timing updated, but just before update
        *
        * @event tick
        * @param {} event An event object
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired at the end of a tick, after engine update and after rendering
        *
        * @event afterTick
        * @param {} event An event object
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired before update
        *
        * @event beforeUpdate
        * @param {} event An event object
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired after update
        *
        * @event afterUpdate
        * @param {} event An event object
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired before rendering
        *
        * @event beforeRender
        * @param {} event An event object
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        * @deprecated
        */
    
        /**
        * Fired after rendering
        *
        * @event afterRender
        * @param {} event An event object
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        * @deprecated
        */
    
        /*
        *
        *  Properties Documentation
        *
        */
    
        /**
         * A flag that specifies whether the runner is running or not.
         *
         * @property enabled
         * @type boolean
         * @default true
         */
    
        /**
         * A `Boolean` that specifies if the runner should use a fixed timestep (otherwise it is variable).
         * If timing is fixed, then the apparent simulation speed will change depending on the frame rate (but behaviour will be deterministic).
         * If the timing is variable, then the apparent simulation speed will be constant (approximately, but at the cost of determininism).
         *
         * @property isFixed
         * @type boolean
         * @default false
         */
    
        /**
         * A `Number` that specifies the time step between updates in milliseconds.
         * If `engine.timing.isFixed` is set to `true`, then `delta` is fixed.
         * If it is `false`, then `delta` can dynamically change to maintain the correct apparent simulation speed.
         *
         * @property delta
         * @type number
         * @default 1000 / 60
         */
    
    })();
    
    },{"./Common":14,"./Engine":15,"./Events":16}],22:[function(_dereq_,module,exports){
    /**
    * The `Matter.Sleeping` module contains methods to manage the sleeping state of bodies.
    *
    * @class Sleeping
    */
    
    var Sleeping = {};
    
    module.exports = Sleeping;
    
    var Events = _dereq_('./Events');
    
    (function() {
    
        Sleeping._motionWakeThreshold = 0.18;
        Sleeping._motionSleepThreshold = 0.08;
        Sleeping._minBias = 0.9;
    
        /**
         * Puts bodies to sleep or wakes them up depending on their motion.
         * @method update
         * @param {body[]} bodies
         * @param {number} timeScale
         */
        Sleeping.update = function(bodies, timeScale) {
            var timeFactor = timeScale * timeScale * timeScale;
    
            // update bodies sleeping status
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i],
                    motion = body.speed * body.speed + body.angularSpeed * body.angularSpeed;
    
                // wake up bodies if they have a force applied
                if (body.force.x !== 0 || body.force.y !== 0) {
                    Sleeping.set(body, false);
                    continue;
                }
    
                var minMotion = Math.min(body.motion, motion),
                    maxMotion = Math.max(body.motion, motion);
            
                // biased average motion estimation between frames
                body.motion = Sleeping._minBias * minMotion + (1 - Sleeping._minBias) * maxMotion;
                
                if (body.sleepThreshold > 0 && body.motion < Sleeping._motionSleepThreshold * timeFactor) {
                    body.sleepCounter += 1;
                    
                    if (body.sleepCounter >= body.sleepThreshold)
                        Sleeping.set(body, true);
                } else if (body.sleepCounter > 0) {
                    body.sleepCounter -= 1;
                }
            }
        };
    
        /**
         * Given a set of colliding pairs, wakes the sleeping bodies involved.
         * @method afterCollisions
         * @param {pair[]} pairs
         * @param {number} timeScale
         */
        Sleeping.afterCollisions = function(pairs, timeScale) {
            var timeFactor = timeScale * timeScale * timeScale;
    
            // wake up bodies involved in collisions
            for (var i = 0; i < pairs.length; i++) {
                var pair = pairs[i];
                
                // don't wake inactive pairs
                if (!pair.isActive)
                    continue;
    
                var collision = pair.collision,
                    bodyA = collision.bodyA.parent, 
                    bodyB = collision.bodyB.parent;
            
                // don't wake if at least one body is static
                if ((bodyA.isSleeping && bodyB.isSleeping) || bodyA.isStatic || bodyB.isStatic)
                    continue;
            
                if (bodyA.isSleeping || bodyB.isSleeping) {
                    var sleepingBody = (bodyA.isSleeping && !bodyA.isStatic) ? bodyA : bodyB,
                        movingBody = sleepingBody === bodyA ? bodyB : bodyA;
    
                    if (!sleepingBody.isStatic && movingBody.motion > Sleeping._motionWakeThreshold * timeFactor) {
                        Sleeping.set(sleepingBody, false);
                    }
                }
            }
        };
      
        /**
         * Set a body as sleeping or awake.
         * @method set
         * @param {body} body
         * @param {boolean} isSleeping
         */
        Sleeping.set = function(body, isSleeping) {
            var wasSleeping = body.isSleeping;
    
            if (isSleeping) {
                body.isSleeping = true;
                body.sleepCounter = body.sleepThreshold;
    
                body.positionImpulse.x = 0;
                body.positionImpulse.y = 0;
    
                body.positionPrev.x = body.position.x;
                body.positionPrev.y = body.position.y;
    
                body.anglePrev = body.angle;
                body.speed = 0;
                body.angularSpeed = 0;
                body.motion = 0;
    
                if (!wasSleeping) {
                    Events.trigger(body, 'sleepStart');
                }
            } else {
                body.isSleeping = false;
                body.sleepCounter = 0;
    
                if (wasSleeping) {
                    Events.trigger(body, 'sleepEnd');
                }
            }
        };
    
    })();
    
    },{"./Events":16}],23:[function(_dereq_,module,exports){
    /**
    * The `Matter.Bodies` module contains factory methods for creating rigid body models 
    * with commonly used body configurations (such as rectangles, circles and other polygons).
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class Bodies
    */
    
    // TODO: true circle bodies
    
    var Bodies = {};
    
    module.exports = Bodies;
    
    var Vertices = _dereq_('../geometry/Vertices');
    var Common = _dereq_('../core/Common');
    var Body = _dereq_('../body/Body');
    var Bounds = _dereq_('../geometry/Bounds');
    var Vector = _dereq_('../geometry/Vector');
    var decomp;
    
    (function() {
    
        /**
         * Creates a new rigid body model with a rectangle hull. 
         * The options parameter is an object that specifies any properties you wish to override the defaults.
         * See the properties section of the `Matter.Body` module for detailed information on what you can pass via the `options` object.
         * @method rectangle
         * @param {number} x
         * @param {number} y
         * @param {number} width
         * @param {number} height
         * @param {object} [options]
         * @return {body} A new rectangle body
         */
        Bodies.rectangle = function(x, y, width, height, options) {
            options = options || {};
    
            var rectangle = { 
                label: 'Rectangle Body',
                position: { x: x, y: y },
                vertices: Vertices.fromPath('L 0 0 L ' + width + ' 0 L ' + width + ' ' + height + ' L 0 ' + height)
            };
    
            if (options.chamfer) {
                var chamfer = options.chamfer;
                rectangle.vertices = Vertices.chamfer(rectangle.vertices, chamfer.radius, 
                                        chamfer.quality, chamfer.qualityMin, chamfer.qualityMax);
                delete options.chamfer;
            }
    
            return Body.create(Common.extend({}, rectangle, options));
        };
        
        /**
         * Creates a new rigid body model with a trapezoid hull. 
         * The options parameter is an object that specifies any properties you wish to override the defaults.
         * See the properties section of the `Matter.Body` module for detailed information on what you can pass via the `options` object.
         * @method trapezoid
         * @param {number} x
         * @param {number} y
         * @param {number} width
         * @param {number} height
         * @param {number} slope
         * @param {object} [options]
         * @return {body} A new trapezoid body
         */
        Bodies.trapezoid = function(x, y, width, height, slope, options) {
            options = options || {};
    
            slope *= 0.5;
            var roof = (1 - (slope * 2)) * width;
            
            var x1 = width * slope,
                x2 = x1 + roof,
                x3 = x2 + x1,
                verticesPath;
    
            if (slope < 0.5) {
                verticesPath = 'L 0 0 L ' + x1 + ' ' + (-height) + ' L ' + x2 + ' ' + (-height) + ' L ' + x3 + ' 0';
            } else {
                verticesPath = 'L 0 0 L ' + x2 + ' ' + (-height) + ' L ' + x3 + ' 0';
            }
    
            var trapezoid = { 
                label: 'Trapezoid Body',
                position: { x: x, y: y },
                vertices: Vertices.fromPath(verticesPath)
            };
    
            if (options.chamfer) {
                var chamfer = options.chamfer;
                trapezoid.vertices = Vertices.chamfer(trapezoid.vertices, chamfer.radius, 
                                        chamfer.quality, chamfer.qualityMin, chamfer.qualityMax);
                delete options.chamfer;
            }
    
            return Body.create(Common.extend({}, trapezoid, options));
        };
    
        /**
         * Creates a new rigid body model with a circle hull. 
         * The options parameter is an object that specifies any properties you wish to override the defaults.
         * See the properties section of the `Matter.Body` module for detailed information on what you can pass via the `options` object.
         * @method circle
         * @param {number} x
         * @param {number} y
         * @param {number} radius
         * @param {object} [options]
         * @param {number} [maxSides]
         * @return {body} A new circle body
         */
        Bodies.circle = function(x, y, radius, options, maxSides) {
            options = options || {};
    
            var circle = {
                label: 'Circle Body',
                circleRadius: radius
            };
            
            // approximate circles with polygons until true circles implemented in SAT
            maxSides = maxSides || 25;
            var sides = Math.ceil(Math.max(10, Math.min(maxSides, radius)));
    
            // optimisation: always use even number of sides (half the number of unique axes)
            if (sides % 2 === 1)
                sides += 1;
    
            return Bodies.polygon(x, y, sides, radius, Common.extend({}, circle, options));
        };
    
        /**
         * Creates a new rigid body model with a regular polygon hull with the given number of sides. 
         * The options parameter is an object that specifies any properties you wish to override the defaults.
         * See the properties section of the `Matter.Body` module for detailed information on what you can pass via the `options` object.
         * @method polygon
         * @param {number} x
         * @param {number} y
         * @param {number} sides
         * @param {number} radius
         * @param {object} [options]
         * @return {body} A new regular polygon body
         */
        Bodies.polygon = function(x, y, sides, radius, options) {
            options = options || {};
    
            if (sides < 3)
                return Bodies.circle(x, y, radius, options);
    
            var theta = 2 * Math.PI / sides,
                path = '',
                offset = theta * 0.5;
    
            for (var i = 0; i < sides; i += 1) {
                var angle = offset + (i * theta),
                    xx = Math.cos(angle) * radius,
                    yy = Math.sin(angle) * radius;
    
                path += 'L ' + xx.toFixed(3) + ' ' + yy.toFixed(3) + ' ';
            }
    
            var polygon = { 
                label: 'Polygon Body',
                position: { x: x, y: y },
                vertices: Vertices.fromPath(path)
            };
    
            if (options.chamfer) {
                var chamfer = options.chamfer;
                polygon.vertices = Vertices.chamfer(polygon.vertices, chamfer.radius, 
                                        chamfer.quality, chamfer.qualityMin, chamfer.qualityMax);
                delete options.chamfer;
            }
    
            return Body.create(Common.extend({}, polygon, options));
        };
    
        /**
         * Creates a body using the supplied vertices (or an array containing multiple sets of vertices).
         * If the vertices are convex, they will pass through as supplied.
         * Otherwise if the vertices are concave, they will be decomposed if [poly-decomp.js](https://github.com/schteppe/poly-decomp.js) is available.
         * Note that this process is not guaranteed to support complex sets of vertices (e.g. those with holes may fail).
         * By default the decomposition will discard collinear edges (to improve performance).
         * It can also optionally discard any parts that have an area less than `minimumArea`.
         * If the vertices can not be decomposed, the result will fall back to using the convex hull.
         * The options parameter is an object that specifies any `Matter.Body` properties you wish to override the defaults.
         * See the properties section of the `Matter.Body` module for detailed information on what you can pass via the `options` object.
         * @method fromVertices
         * @param {number} x
         * @param {number} y
         * @param [[vector]] vertexSets
         * @param {object} [options]
         * @param {bool} [flagInternal=false]
         * @param {number} [removeCollinear=0.01]
         * @param {number} [minimumArea=10]
         * @return {body}
         */
        Bodies.fromVertices = function(x, y, vertexSets, options, flagInternal, removeCollinear, minimumArea) {
            if (!decomp) {
                decomp = Common._requireGlobal('decomp', 'poly-decomp');
            }
    
            var body,
                parts,
                isConvex,
                vertices,
                i,
                j,
                k,
                v,
                z;
    
            options = options || {};
            parts = [];
    
            flagInternal = typeof flagInternal !== 'undefined' ? flagInternal : false;
            removeCollinear = typeof removeCollinear !== 'undefined' ? removeCollinear : 0.01;
            minimumArea = typeof minimumArea !== 'undefined' ? minimumArea : 10;
    
            if (!decomp) {
                Common.warn('Bodies.fromVertices: poly-decomp.js required. Could not decompose vertices. Fallback to convex hull.');
            }
    
            // ensure vertexSets is an array of arrays
            if (!Common.isArray(vertexSets[0])) {
                vertexSets = [vertexSets];
            }
    
            for (v = 0; v < vertexSets.length; v += 1) {
                vertices = vertexSets[v];
                isConvex = Vertices.isConvex(vertices);
    
                if (isConvex || !decomp) {
                    if (isConvex) {
                        vertices = Vertices.clockwiseSort(vertices);
                    } else {
                        // fallback to convex hull when decomposition is not possible
                        vertices = Vertices.hull(vertices);
                    }
    
                    parts.push({
                        position: { x: x, y: y },
                        vertices: vertices
                    });
                } else {
                    // initialise a decomposition
                    var concave = vertices.map(function(vertex) {
                        return [vertex.x, vertex.y];
                    });
    
                    // vertices are concave and simple, we can decompose into parts
                    decomp.makeCCW(concave);
                    if (removeCollinear !== false)
                        decomp.removeCollinearPoints(concave, removeCollinear);
    
                    // use the quick decomposition algorithm (Bayazit)
                    var decomposed = decomp.quickDecomp(concave);
    
                    // for each decomposed chunk
                    for (i = 0; i < decomposed.length; i++) {
                        var chunk = decomposed[i];
    
                        // convert vertices into the correct structure
                        var chunkVertices = chunk.map(function(vertices) {
                            return {
                                x: vertices[0],
                                y: vertices[1]
                            };
                        });
    
                        // skip small chunks
                        if (minimumArea > 0 && Vertices.area(chunkVertices) < minimumArea)
                            continue;
    
                        // create a compound part
                        parts.push({
                            position: Vertices.centre(chunkVertices),
                            vertices: chunkVertices
                        });
                    }
                }
            }
    
            // create body parts
            for (i = 0; i < parts.length; i++) {
                parts[i] = Body.create(Common.extend(parts[i], options));
            }
    
            // flag internal edges (coincident part edges)
            if (flagInternal) {
                var coincident_max_dist = 5;
    
                for (i = 0; i < parts.length; i++) {
                    var partA = parts[i];
    
                    for (j = i + 1; j < parts.length; j++) {
                        var partB = parts[j];
    
                        if (Bounds.overlaps(partA.bounds, partB.bounds)) {
                            var pav = partA.vertices,
                                pbv = partB.vertices;
    
                            // iterate vertices of both parts
                            for (k = 0; k < partA.vertices.length; k++) {
                                for (z = 0; z < partB.vertices.length; z++) {
                                    // find distances between the vertices
                                    var da = Vector.magnitudeSquared(Vector.sub(pav[(k + 1) % pav.length], pbv[z])),
                                        db = Vector.magnitudeSquared(Vector.sub(pav[k], pbv[(z + 1) % pbv.length]));
    
                                    // if both vertices are very close, consider the edge concident (internal)
                                    if (da < coincident_max_dist && db < coincident_max_dist) {
                                        pav[k].isInternal = true;
                                        pbv[z].isInternal = true;
                                    }
                                }
                            }
    
                        }
                    }
                }
            }
    
            if (parts.length > 1) {
                // create the parent body to be returned, that contains generated compound parts
                body = Body.create(Common.extend({ parts: parts.slice(0) }, options));
                Body.setPosition(body, { x: x, y: y });
    
                return body;
            } else {
                return parts[0];
            }
        };
    
    })();
    
    },{"../body/Body":1,"../core/Common":14,"../geometry/Bounds":26,"../geometry/Vector":28,"../geometry/Vertices":29}],24:[function(_dereq_,module,exports){
    /**
    * The `Matter.Composites` module contains factory methods for creating composite bodies
    * with commonly used configurations (such as stacks and chains).
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class Composites
    */
    
    var Composites = {};
    
    module.exports = Composites;
    
    var Composite = _dereq_('../body/Composite');
    var Constraint = _dereq_('../constraint/Constraint');
    var Common = _dereq_('../core/Common');
    var Body = _dereq_('../body/Body');
    var Bodies = _dereq_('./Bodies');
    
    (function() {
    
        /**
         * Create a new composite containing bodies created in the callback in a grid arrangement.
         * This function uses the body's bounds to prevent overlaps.
         * @method stack
         * @param {number} xx
         * @param {number} yy
         * @param {number} columns
         * @param {number} rows
         * @param {number} columnGap
         * @param {number} rowGap
         * @param {function} callback
         * @return {composite} A new composite containing objects created in the callback
         */
        Composites.stack = function(xx, yy, columns, rows, columnGap, rowGap, callback) {
            var stack = Composite.create({ label: 'Stack' }),
                x = xx,
                y = yy,
                lastBody,
                i = 0;
    
            for (var row = 0; row < rows; row++) {
                var maxHeight = 0;
                
                for (var column = 0; column < columns; column++) {
                    var body = callback(x, y, column, row, lastBody, i);
                        
                    if (body) {
                        var bodyHeight = body.bounds.max.y - body.bounds.min.y,
                            bodyWidth = body.bounds.max.x - body.bounds.min.x; 
    
                        if (bodyHeight > maxHeight)
                            maxHeight = bodyHeight;
                        
                        Body.translate(body, { x: bodyWidth * 0.5, y: bodyHeight * 0.5 });
    
                        x = body.bounds.max.x + columnGap;
    
                        Composite.addBody(stack, body);
                        
                        lastBody = body;
                        i += 1;
                    } else {
                        x += columnGap;
                    }
                }
                
                y += maxHeight + rowGap;
                x = xx;
            }
    
            return stack;
        };
        
        /**
         * Chains all bodies in the given composite together using constraints.
         * @method chain
         * @param {composite} composite
         * @param {number} xOffsetA
         * @param {number} yOffsetA
         * @param {number} xOffsetB
         * @param {number} yOffsetB
         * @param {object} options
         * @return {composite} A new composite containing objects chained together with constraints
         */
        Composites.chain = function(composite, xOffsetA, yOffsetA, xOffsetB, yOffsetB, options) {
            var bodies = composite.bodies;
            
            for (var i = 1; i < bodies.length; i++) {
                var bodyA = bodies[i - 1],
                    bodyB = bodies[i],
                    bodyAHeight = bodyA.bounds.max.y - bodyA.bounds.min.y,
                    bodyAWidth = bodyA.bounds.max.x - bodyA.bounds.min.x, 
                    bodyBHeight = bodyB.bounds.max.y - bodyB.bounds.min.y,
                    bodyBWidth = bodyB.bounds.max.x - bodyB.bounds.min.x;
            
                var defaults = {
                    bodyA: bodyA,
                    pointA: { x: bodyAWidth * xOffsetA, y: bodyAHeight * yOffsetA },
                    bodyB: bodyB,
                    pointB: { x: bodyBWidth * xOffsetB, y: bodyBHeight * yOffsetB }
                };
                
                var constraint = Common.extend(defaults, options);
            
                Composite.addConstraint(composite, Constraint.create(constraint));
            }
    
            composite.label += ' Chain';
            
            return composite;
        };
    
        /**
         * Connects bodies in the composite with constraints in a grid pattern, with optional cross braces.
         * @method mesh
         * @param {composite} composite
         * @param {number} columns
         * @param {number} rows
         * @param {boolean} crossBrace
         * @param {object} options
         * @return {composite} The composite containing objects meshed together with constraints
         */
        Composites.mesh = function(composite, columns, rows, crossBrace, options) {
            var bodies = composite.bodies,
                row,
                col,
                bodyA,
                bodyB,
                bodyC;
            
            for (row = 0; row < rows; row++) {
                for (col = 1; col < columns; col++) {
                    bodyA = bodies[(col - 1) + (row * columns)];
                    bodyB = bodies[col + (row * columns)];
                    Composite.addConstraint(composite, Constraint.create(Common.extend({ bodyA: bodyA, bodyB: bodyB }, options)));
                }
    
                if (row > 0) {
                    for (col = 0; col < columns; col++) {
                        bodyA = bodies[col + ((row - 1) * columns)];
                        bodyB = bodies[col + (row * columns)];
                        Composite.addConstraint(composite, Constraint.create(Common.extend({ bodyA: bodyA, bodyB: bodyB }, options)));
    
                        if (crossBrace && col > 0) {
                            bodyC = bodies[(col - 1) + ((row - 1) * columns)];
                            Composite.addConstraint(composite, Constraint.create(Common.extend({ bodyA: bodyC, bodyB: bodyB }, options)));
                        }
    
                        if (crossBrace && col < columns - 1) {
                            bodyC = bodies[(col + 1) + ((row - 1) * columns)];
                            Composite.addConstraint(composite, Constraint.create(Common.extend({ bodyA: bodyC, bodyB: bodyB }, options)));
                        }
                    }
                }
            }
    
            composite.label += ' Mesh';
            
            return composite;
        };
        
        /**
         * Create a new composite containing bodies created in the callback in a pyramid arrangement.
         * This function uses the body's bounds to prevent overlaps.
         * @method pyramid
         * @param {number} xx
         * @param {number} yy
         * @param {number} columns
         * @param {number} rows
         * @param {number} columnGap
         * @param {number} rowGap
         * @param {function} callback
         * @return {composite} A new composite containing objects created in the callback
         */
        Composites.pyramid = function(xx, yy, columns, rows, columnGap, rowGap, callback) {
            return Composites.stack(xx, yy, columns, rows, columnGap, rowGap, function(x, y, column, row, lastBody, i) {
                var actualRows = Math.min(rows, Math.ceil(columns / 2)),
                    lastBodyWidth = lastBody ? lastBody.bounds.max.x - lastBody.bounds.min.x : 0;
                
                if (row > actualRows)
                    return;
                
                // reverse row order
                row = actualRows - row;
                
                var start = row,
                    end = columns - 1 - row;
    
                if (column < start || column > end)
                    return;
                
                // retroactively fix the first body's position, since width was unknown
                if (i === 1) {
                    Body.translate(lastBody, { x: (column + (columns % 2 === 1 ? 1 : -1)) * lastBodyWidth, y: 0 });
                }
    
                var xOffset = lastBody ? column * lastBodyWidth : 0;
                
                return callback(xx + xOffset + column * columnGap, y, column, row, lastBody, i);
            });
        };
    
        /**
         * Creates a composite with a Newton's Cradle setup of bodies and constraints.
         * @method newtonsCradle
         * @param {number} xx
         * @param {number} yy
         * @param {number} number
         * @param {number} size
         * @param {number} length
         * @return {composite} A new composite newtonsCradle body
         */
        Composites.newtonsCradle = function(xx, yy, number, size, length) {
            var newtonsCradle = Composite.create({ label: 'Newtons Cradle' });
    
            for (var i = 0; i < number; i++) {
                var separation = 1.9,
                    circle = Bodies.circle(xx + i * (size * separation), yy + length, size, 
                                { inertia: Infinity, restitution: 1, friction: 0, frictionAir: 0.0001, slop: 1 }),
                    constraint = Constraint.create({ pointA: { x: xx + i * (size * separation), y: yy }, bodyB: circle });
    
                Composite.addBody(newtonsCradle, circle);
                Composite.addConstraint(newtonsCradle, constraint);
            }
    
            return newtonsCradle;
        };
        
        /**
         * Creates a composite with simple car setup of bodies and constraints.
         * @method car
         * @param {number} xx
         * @param {number} yy
         * @param {number} width
         * @param {number} height
         * @param {number} wheelSize
         * @return {composite} A new composite car body
         */
        Composites.car = function(xx, yy, width, height, wheelSize) {
            var group = Body.nextGroup(true),
                wheelBase = 20,
                wheelAOffset = -width * 0.5 + wheelBase,
                wheelBOffset = width * 0.5 - wheelBase,
                wheelYOffset = 0;
        
            var car = Composite.create({ label: 'Car' }),
                body = Bodies.rectangle(xx, yy, width, height, { 
                    collisionFilter: {
                        group: group
                    },
                    chamfer: {
                        radius: height * 0.5
                    },
                    density: 0.0002
                });
        
            var wheelA = Bodies.circle(xx + wheelAOffset, yy + wheelYOffset, wheelSize, { 
                collisionFilter: {
                    group: group
                },
                friction: 0.8
            });
                        
            var wheelB = Bodies.circle(xx + wheelBOffset, yy + wheelYOffset, wheelSize, { 
                collisionFilter: {
                    group: group
                },
                friction: 0.8
            });
                        
            var axelA = Constraint.create({
                bodyB: body,
                pointB: { x: wheelAOffset, y: wheelYOffset },
                bodyA: wheelA,
                stiffness: 1,
                length: 0
            });
                            
            var axelB = Constraint.create({
                bodyB: body,
                pointB: { x: wheelBOffset, y: wheelYOffset },
                bodyA: wheelB,
                stiffness: 1,
                length: 0
            });
            
            Composite.addBody(car, body);
            Composite.addBody(car, wheelA);
            Composite.addBody(car, wheelB);
            Composite.addConstraint(car, axelA);
            Composite.addConstraint(car, axelB);
    
            return car;
        };
    
        /**
         * Creates a simple soft body like object.
         * @method softBody
         * @param {number} xx
         * @param {number} yy
         * @param {number} columns
         * @param {number} rows
         * @param {number} columnGap
         * @param {number} rowGap
         * @param {boolean} crossBrace
         * @param {number} particleRadius
         * @param {} particleOptions
         * @param {} constraintOptions
         * @return {composite} A new composite softBody
         */
        Composites.softBody = function(xx, yy, columns, rows, columnGap, rowGap, crossBrace, particleRadius, particleOptions, constraintOptions) {
            particleOptions = Common.extend({ inertia: Infinity }, particleOptions);
            constraintOptions = Common.extend({ stiffness: 0.2, render: { type: 'line', anchors: false } }, constraintOptions);
    
            var softBody = Composites.stack(xx, yy, columns, rows, columnGap, rowGap, function(x, y) {
                return Bodies.circle(x, y, particleRadius, particleOptions);
            });
    
            Composites.mesh(softBody, columns, rows, crossBrace, constraintOptions);
    
            softBody.label = 'Soft Body';
    
            return softBody;
        };
    
    })();
    
    },{"../body/Body":1,"../body/Composite":2,"../constraint/Constraint":12,"../core/Common":14,"./Bodies":23}],25:[function(_dereq_,module,exports){
    /**
    * The `Matter.Axes` module contains methods for creating and manipulating sets of axes.
    *
    * @class Axes
    */
    
    var Axes = {};
    
    module.exports = Axes;
    
    var Vector = _dereq_('../geometry/Vector');
    var Common = _dereq_('../core/Common');
    
    (function() {
    
        /**
         * Creates a new set of axes from the given vertices.
         * @method fromVertices
         * @param {vertices} vertices
         * @return {axes} A new axes from the given vertices
         */
        Axes.fromVertices = function(vertices) {
            var axes = {};
    
            // find the unique axes, using edge normal gradients
            for (var i = 0; i < vertices.length; i++) {
                var j = (i + 1) % vertices.length, 
                    normal = Vector.normalise({ 
                        x: vertices[j].y - vertices[i].y, 
                        y: vertices[i].x - vertices[j].x
                    }),
                    gradient = (normal.y === 0) ? Infinity : (normal.x / normal.y);
                
                // limit precision
                gradient = gradient.toFixed(3).toString();
                axes[gradient] = normal;
            }
    
            return Common.values(axes);
        };
    
        /**
         * Rotates a set of axes by the given angle.
         * @method rotate
         * @param {axes} axes
         * @param {number} angle
         */
        Axes.rotate = function(axes, angle) {
            if (angle === 0)
                return;
            
            var cos = Math.cos(angle),
                sin = Math.sin(angle);
    
            for (var i = 0; i < axes.length; i++) {
                var axis = axes[i],
                    xx;
                xx = axis.x * cos - axis.y * sin;
                axis.y = axis.x * sin + axis.y * cos;
                axis.x = xx;
            }
        };
    
    })();
    
    },{"../core/Common":14,"../geometry/Vector":28}],26:[function(_dereq_,module,exports){
    /**
    * The `Matter.Bounds` module contains methods for creating and manipulating axis-aligned bounding boxes (AABB).
    *
    * @class Bounds
    */
    
    var Bounds = {};
    
    module.exports = Bounds;
    
    (function() {
    
        /**
         * Creates a new axis-aligned bounding box (AABB) for the given vertices.
         * @method create
         * @param {vertices} vertices
         * @return {bounds} A new bounds object
         */
        Bounds.create = function(vertices) {
            var bounds = { 
                min: { x: 0, y: 0 }, 
                max: { x: 0, y: 0 }
            };
    
            if (vertices)
                Bounds.update(bounds, vertices);
            
            return bounds;
        };
    
        /**
         * Updates bounds using the given vertices and extends the bounds given a velocity.
         * @method update
         * @param {bounds} bounds
         * @param {vertices} vertices
         * @param {vector} velocity
         */
        Bounds.update = function(bounds, vertices, velocity) {
            bounds.min.x = Infinity;
            bounds.max.x = -Infinity;
            bounds.min.y = Infinity;
            bounds.max.y = -Infinity;
    
            for (var i = 0; i < vertices.length; i++) {
                var vertex = vertices[i];
                if (vertex.x > bounds.max.x) bounds.max.x = vertex.x;
                if (vertex.x < bounds.min.x) bounds.min.x = vertex.x;
                if (vertex.y > bounds.max.y) bounds.max.y = vertex.y;
                if (vertex.y < bounds.min.y) bounds.min.y = vertex.y;
            }
            
            if (velocity) {
                if (velocity.x > 0) {
                    bounds.max.x += velocity.x;
                } else {
                    bounds.min.x += velocity.x;
                }
                
                if (velocity.y > 0) {
                    bounds.max.y += velocity.y;
                } else {
                    bounds.min.y += velocity.y;
                }
            }
        };
    
        /**
         * Returns true if the bounds contains the given point.
         * @method contains
         * @param {bounds} bounds
         * @param {vector} point
         * @return {boolean} True if the bounds contain the point, otherwise false
         */
        Bounds.contains = function(bounds, point) {
            return point.x >= bounds.min.x && point.x <= bounds.max.x 
                   && point.y >= bounds.min.y && point.y <= bounds.max.y;
        };
    
        /**
         * Returns true if the two bounds intersect.
         * @method overlaps
         * @param {bounds} boundsA
         * @param {bounds} boundsB
         * @return {boolean} True if the bounds overlap, otherwise false
         */
        Bounds.overlaps = function(boundsA, boundsB) {
            return (boundsA.min.x <= boundsB.max.x && boundsA.max.x >= boundsB.min.x
                    && boundsA.max.y >= boundsB.min.y && boundsA.min.y <= boundsB.max.y);
        };
    
        /**
         * Translates the bounds by the given vector.
         * @method translate
         * @param {bounds} bounds
         * @param {vector} vector
         */
        Bounds.translate = function(bounds, vector) {
            bounds.min.x += vector.x;
            bounds.max.x += vector.x;
            bounds.min.y += vector.y;
            bounds.max.y += vector.y;
        };
    
        /**
         * Shifts the bounds to the given position.
         * @method shift
         * @param {bounds} bounds
         * @param {vector} position
         */
        Bounds.shift = function(bounds, position) {
            var deltaX = bounds.max.x - bounds.min.x,
                deltaY = bounds.max.y - bounds.min.y;
                
            bounds.min.x = position.x;
            bounds.max.x = position.x + deltaX;
            bounds.min.y = position.y;
            bounds.max.y = position.y + deltaY;
        };
        
    })();
    
    },{}],27:[function(_dereq_,module,exports){
    /**
    * The `Matter.Svg` module contains methods for converting SVG images into an array of vector points.
    *
    * To use this module you also need the SVGPathSeg polyfill: https://github.com/progers/pathseg
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class Svg
    */
    
    var Svg = {};
    
    module.exports = Svg;
    
    var Bounds = _dereq_('../geometry/Bounds');
    var Common = _dereq_('../core/Common');
    
    (function() {
    
        /**
         * Converts an SVG path into an array of vector points.
         * If the input path forms a concave shape, you must decompose the result into convex parts before use.
         * See `Bodies.fromVertices` which provides support for this.
         * Note that this function is not guaranteed to support complex paths (such as those with holes).
         * You must load the `pathseg.js` polyfill on newer browsers.
         * @method pathToVertices
         * @param {SVGPathElement} path
         * @param {Number} [sampleLength=15]
         * @return {Vector[]} points
         */
        Svg.pathToVertices = function(path, sampleLength) {
            if (typeof window !== 'undefined' && !('SVGPathSeg' in window)) {
                Common.warn('Svg.pathToVertices: SVGPathSeg not defined, a polyfill is required.');
            }
    
            // https://github.com/wout/svg.topoly.js/blob/master/svg.topoly.js
            var i, il, total, point, segment, segments, 
                segmentsQueue, lastSegment, 
                lastPoint, segmentIndex, points = [],
                lx, ly, length = 0, x = 0, y = 0;
    
            sampleLength = sampleLength || 15;
    
            var addPoint = function(px, py, pathSegType) {
                // all odd-numbered path types are relative except PATHSEG_CLOSEPATH (1)
                var isRelative = pathSegType % 2 === 1 && pathSegType > 1;
    
                // when the last point doesn't equal the current point add the current point
                if (!lastPoint || px != lastPoint.x || py != lastPoint.y) {
                    if (lastPoint && isRelative) {
                        lx = lastPoint.x;
                        ly = lastPoint.y;
                    } else {
                        lx = 0;
                        ly = 0;
                    }
    
                    var point = {
                        x: lx + px,
                        y: ly + py
                    };
    
                    // set last point
                    if (isRelative || !lastPoint) {
                        lastPoint = point;
                    }
    
                    points.push(point);
    
                    x = lx + px;
                    y = ly + py;
                }
            };
    
            var addSegmentPoint = function(segment) {
                var segType = segment.pathSegTypeAsLetter.toUpperCase();
    
                // skip path ends
                if (segType === 'Z') 
                    return;
    
                // map segment to x and y
                switch (segType) {
    
                case 'M':
                case 'L':
                case 'T':
                case 'C':
                case 'S':
                case 'Q':
                    x = segment.x;
                    y = segment.y;
                    break;
                case 'H':
                    x = segment.x;
                    break;
                case 'V':
                    y = segment.y;
                    break;
                }
    
                addPoint(x, y, segment.pathSegType);
            };
    
            // ensure path is absolute
            Svg._svgPathToAbsolute(path);
    
            // get total length
            total = path.getTotalLength();
    
            // queue segments
            segments = [];
            for (i = 0; i < path.pathSegList.numberOfItems; i += 1)
                segments.push(path.pathSegList.getItem(i));
    
            segmentsQueue = segments.concat();
    
            // sample through path
            while (length < total) {
                // get segment at position
                segmentIndex = path.getPathSegAtLength(length);
                segment = segments[segmentIndex];
    
                // new segment
                if (segment != lastSegment) {
                    while (segmentsQueue.length && segmentsQueue[0] != segment)
                        addSegmentPoint(segmentsQueue.shift());
    
                    lastSegment = segment;
                }
    
                // add points in between when curving
                // TODO: adaptive sampling
                switch (segment.pathSegTypeAsLetter.toUpperCase()) {
    
                case 'C':
                case 'T':
                case 'S':
                case 'Q':
                case 'A':
                    point = path.getPointAtLength(length);
                    addPoint(point.x, point.y, 0);
                    break;
    
                }
    
                // increment by sample value
                length += sampleLength;
            }
    
            // add remaining segments not passed by sampling
            for (i = 0, il = segmentsQueue.length; i < il; ++i)
                addSegmentPoint(segmentsQueue[i]);
    
            return points;
        };
    
        Svg._svgPathToAbsolute = function(path) {
            // http://phrogz.net/convert-svg-path-to-all-absolute-commands
            // Copyright (c) Gavin Kistner
            // http://phrogz.net/js/_ReuseLicense.txt
            // Modifications: tidy formatting and naming
            var x0, y0, x1, y1, x2, y2, segs = path.pathSegList,
                x = 0, y = 0, len = segs.numberOfItems;
    
            for (var i = 0; i < len; ++i) {
                var seg = segs.getItem(i),
                    segType = seg.pathSegTypeAsLetter;
    
                if (/[MLHVCSQTA]/.test(segType)) {
                    if ('x' in seg) x = seg.x;
                    if ('y' in seg) y = seg.y;
                } else {
                    if ('x1' in seg) x1 = x + seg.x1;
                    if ('x2' in seg) x2 = x + seg.x2;
                    if ('y1' in seg) y1 = y + seg.y1;
                    if ('y2' in seg) y2 = y + seg.y2;
                    if ('x' in seg) x += seg.x;
                    if ('y' in seg) y += seg.y;
    
                    switch (segType) {
    
                    case 'm':
                        segs.replaceItem(path.createSVGPathSegMovetoAbs(x, y), i);
                        break;
                    case 'l':
                        segs.replaceItem(path.createSVGPathSegLinetoAbs(x, y), i);
                        break;
                    case 'h':
                        segs.replaceItem(path.createSVGPathSegLinetoHorizontalAbs(x), i);
                        break;
                    case 'v':
                        segs.replaceItem(path.createSVGPathSegLinetoVerticalAbs(y), i);
                        break;
                    case 'c':
                        segs.replaceItem(path.createSVGPathSegCurvetoCubicAbs(x, y, x1, y1, x2, y2), i);
                        break;
                    case 's':
                        segs.replaceItem(path.createSVGPathSegCurvetoCubicSmoothAbs(x, y, x2, y2), i);
                        break;
                    case 'q':
                        segs.replaceItem(path.createSVGPathSegCurvetoQuadraticAbs(x, y, x1, y1), i);
                        break;
                    case 't':
                        segs.replaceItem(path.createSVGPathSegCurvetoQuadraticSmoothAbs(x, y), i);
                        break;
                    case 'a':
                        segs.replaceItem(path.createSVGPathSegArcAbs(x, y, seg.r1, seg.r2, seg.angle, seg.largeArcFlag, seg.sweepFlag), i);
                        break;
                    case 'z':
                    case 'Z':
                        x = x0;
                        y = y0;
                        break;
    
                    }
                }
    
                if (segType == 'M' || segType == 'm') {
                    x0 = x;
                    y0 = y;
                }
            }
        };
    
    })();
    },{"../core/Common":14,"../geometry/Bounds":26}],28:[function(_dereq_,module,exports){
    /**
    * The `Matter.Vector` module contains methods for creating and manipulating vectors.
    * Vectors are the basis of all the geometry related operations in the engine.
    * A `Matter.Vector` object is of the form `{ x: 0, y: 0 }`.
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class Vector
    */
    
    // TODO: consider params for reusing vector objects
    
    var Vector = {};
    
    module.exports = Vector;
    
    (function() {
    
        /**
         * Creates a new vector.
         * @method create
         * @param {number} x
         * @param {number} y
         * @return {vector} A new vector
         */
        Vector.create = function(x, y) {
            return { x: x || 0, y: y || 0 };
        };
    
        /**
         * Returns a new vector with `x` and `y` copied from the given `vector`.
         * @method clone
         * @param {vector} vector
         * @return {vector} A new cloned vector
         */
        Vector.clone = function(vector) {
            return { x: vector.x, y: vector.y };
        };
    
        /**
         * Returns the magnitude (length) of a vector.
         * @method magnitude
         * @param {vector} vector
         * @return {number} The magnitude of the vector
         */
        Vector.magnitude = function(vector) {
            return Math.sqrt((vector.x * vector.x) + (vector.y * vector.y));
        };
    
        /**
         * Returns the magnitude (length) of a vector (therefore saving a `sqrt` operation).
         * @method magnitudeSquared
         * @param {vector} vector
         * @return {number} The squared magnitude of the vector
         */
        Vector.magnitudeSquared = function(vector) {
            return (vector.x * vector.x) + (vector.y * vector.y);
        };
    
        /**
         * Rotates the vector about (0, 0) by specified angle.
         * @method rotate
         * @param {vector} vector
         * @param {number} angle
         * @param {vector} [output]
         * @return {vector} The vector rotated about (0, 0)
         */
        Vector.rotate = function(vector, angle, output) {
            var cos = Math.cos(angle), sin = Math.sin(angle);
            if (!output) output = {};
            var x = vector.x * cos - vector.y * sin;
            output.y = vector.x * sin + vector.y * cos;
            output.x = x;
            return output;
        };
    
        /**
         * Rotates the vector about a specified point by specified angle.
         * @method rotateAbout
         * @param {vector} vector
         * @param {number} angle
         * @param {vector} point
         * @param {vector} [output]
         * @return {vector} A new vector rotated about the point
         */
        Vector.rotateAbout = function(vector, angle, point, output) {
            var cos = Math.cos(angle), sin = Math.sin(angle);
            if (!output) output = {};
            var x = point.x + ((vector.x - point.x) * cos - (vector.y - point.y) * sin);
            output.y = point.y + ((vector.x - point.x) * sin + (vector.y - point.y) * cos);
            output.x = x;
            return output;
        };
    
        /**
         * Normalises a vector (such that its magnitude is `1`).
         * @method normalise
         * @param {vector} vector
         * @return {vector} A new vector normalised
         */
        Vector.normalise = function(vector) {
            var magnitude = Vector.magnitude(vector);
            if (magnitude === 0)
                return { x: 0, y: 0 };
            return { x: vector.x / magnitude, y: vector.y / magnitude };
        };
    
        /**
         * Returns the dot-product of two vectors.
         * @method dot
         * @param {vector} vectorA
         * @param {vector} vectorB
         * @return {number} The dot product of the two vectors
         */
        Vector.dot = function(vectorA, vectorB) {
            return (vectorA.x * vectorB.x) + (vectorA.y * vectorB.y);
        };
    
        /**
         * Returns the cross-product of two vectors.
         * @method cross
         * @param {vector} vectorA
         * @param {vector} vectorB
         * @return {number} The cross product of the two vectors
         */
        Vector.cross = function(vectorA, vectorB) {
            return (vectorA.x * vectorB.y) - (vectorA.y * vectorB.x);
        };
    
        /**
         * Returns the cross-product of three vectors.
         * @method cross3
         * @param {vector} vectorA
         * @param {vector} vectorB
         * @param {vector} vectorC
         * @return {number} The cross product of the three vectors
         */
        Vector.cross3 = function(vectorA, vectorB, vectorC) {
            return (vectorB.x - vectorA.x) * (vectorC.y - vectorA.y) - (vectorB.y - vectorA.y) * (vectorC.x - vectorA.x);
        };
    
        /**
         * Adds the two vectors.
         * @method add
         * @param {vector} vectorA
         * @param {vector} vectorB
         * @param {vector} [output]
         * @return {vector} A new vector of vectorA and vectorB added
         */
        Vector.add = function(vectorA, vectorB, output) {
            if (!output) output = {};
            output.x = vectorA.x + vectorB.x;
            output.y = vectorA.y + vectorB.y;
            return output;
        };
    
        /**
         * Subtracts the two vectors.
         * @method sub
         * @param {vector} vectorA
         * @param {vector} vectorB
         * @param {vector} [output]
         * @return {vector} A new vector of vectorA and vectorB subtracted
         */
        Vector.sub = function(vectorA, vectorB, output) {
            if (!output) output = {};
            output.x = vectorA.x - vectorB.x;
            output.y = vectorA.y - vectorB.y;
            return output;
        };
    
        /**
         * Multiplies a vector and a scalar.
         * @method mult
         * @param {vector} vector
         * @param {number} scalar
         * @return {vector} A new vector multiplied by scalar
         */
        Vector.mult = function(vector, scalar) {
            return { x: vector.x * scalar, y: vector.y * scalar };
        };
    
        /**
         * Divides a vector and a scalar.
         * @method div
         * @param {vector} vector
         * @param {number} scalar
         * @return {vector} A new vector divided by scalar
         */
        Vector.div = function(vector, scalar) {
            return { x: vector.x / scalar, y: vector.y / scalar };
        };
    
        /**
         * Returns the perpendicular vector. Set `negate` to true for the perpendicular in the opposite direction.
         * @method perp
         * @param {vector} vector
         * @param {bool} [negate=false]
         * @return {vector} The perpendicular vector
         */
        Vector.perp = function(vector, negate) {
            negate = negate === true ? -1 : 1;
            return { x: negate * -vector.y, y: negate * vector.x };
        };
    
        /**
         * Negates both components of a vector such that it points in the opposite direction.
         * @method neg
         * @param {vector} vector
         * @return {vector} The negated vector
         */
        Vector.neg = function(vector) {
            return { x: -vector.x, y: -vector.y };
        };
    
        /**
         * Returns the angle between the vector `vectorB - vectorA` and the x-axis in radians.
         * @method angle
         * @param {vector} vectorA
         * @param {vector} vectorB
         * @return {number} The angle in radians
         */
        Vector.angle = function(vectorA, vectorB) {
            return Math.atan2(vectorB.y - vectorA.y, vectorB.x - vectorA.x);
        };
    
        /**
         * Temporary vector pool (not thread-safe).
         * @property _temp
         * @type {vector[]}
         * @private
         */
        Vector._temp = [
            Vector.create(), Vector.create(), 
            Vector.create(), Vector.create(), 
            Vector.create(), Vector.create()
        ];
    
    })();
    },{}],29:[function(_dereq_,module,exports){
    /**
    * The `Matter.Vertices` module contains methods for creating and manipulating sets of vertices.
    * A set of vertices is an array of `Matter.Vector` with additional indexing properties inserted by `Vertices.create`.
    * A `Matter.Body` maintains a set of vertices to represent the shape of the object (its convex hull).
    *
    * See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
    *
    * @class Vertices
    */
    
    var Vertices = {};
    
    module.exports = Vertices;
    
    var Vector = _dereq_('../geometry/Vector');
    var Common = _dereq_('../core/Common');
    
    (function() {
    
        /**
         * Creates a new set of `Matter.Body` compatible vertices.
         * The `points` argument accepts an array of `Matter.Vector` points orientated around the origin `(0, 0)`, for example:
         *
         *     [{ x: 0, y: 0 }, { x: 25, y: 50 }, { x: 50, y: 0 }]
         *
         * The `Vertices.create` method returns a new array of vertices, which are similar to Matter.Vector objects,
         * but with some additional references required for efficient collision detection routines.
         *
         * Vertices must be specified in clockwise order.
         *
         * Note that the `body` argument is not optional, a `Matter.Body` reference must be provided.
         *
         * @method create
         * @param {vector[]} points
         * @param {body} body
         */
        Vertices.create = function(points, body) {
            var vertices = [];
    
            for (var i = 0; i < points.length; i++) {
                var point = points[i],
                    vertex = {
                        x: point.x,
                        y: point.y,
                        index: i,
                        body: body,
                        isInternal: false
                    };
    
                vertices.push(vertex);
            }
    
            return vertices;
        };
    
        /**
         * Parses a string containing ordered x y pairs separated by spaces (and optionally commas), 
         * into a `Matter.Vertices` object for the given `Matter.Body`.
         * For parsing SVG paths, see `Svg.pathToVertices`.
         * @method fromPath
         * @param {string} path
         * @param {body} body
         * @return {vertices} vertices
         */
        Vertices.fromPath = function(path, body) {
            var pathPattern = /L?\s*([\-\d\.e]+)[\s,]*([\-\d\.e]+)*/ig,
                points = [];
    
            path.replace(pathPattern, function(match, x, y) {
                points.push({ x: parseFloat(x), y: parseFloat(y) });
            });
    
            return Vertices.create(points, body);
        };
    
        /**
         * Returns the centre (centroid) of the set of vertices.
         * @method centre
         * @param {vertices} vertices
         * @return {vector} The centre point
         */
        Vertices.centre = function(vertices) {
            var area = Vertices.area(vertices, true),
                centre = { x: 0, y: 0 },
                cross,
                temp,
                j;
    
            for (var i = 0; i < vertices.length; i++) {
                j = (i + 1) % vertices.length;
                cross = Vector.cross(vertices[i], vertices[j]);
                temp = Vector.mult(Vector.add(vertices[i], vertices[j]), cross);
                centre = Vector.add(centre, temp);
            }
    
            return Vector.div(centre, 6 * area);
        };
    
        /**
         * Returns the average (mean) of the set of vertices.
         * @method mean
         * @param {vertices} vertices
         * @return {vector} The average point
         */
        Vertices.mean = function(vertices) {
            var average = { x: 0, y: 0 };
    
            for (var i = 0; i < vertices.length; i++) {
                average.x += vertices[i].x;
                average.y += vertices[i].y;
            }
    
            return Vector.div(average, vertices.length);
        };
    
        /**
         * Returns the area of the set of vertices.
         * @method area
         * @param {vertices} vertices
         * @param {bool} signed
         * @return {number} The area
         */
        Vertices.area = function(vertices, signed) {
            var area = 0,
                j = vertices.length - 1;
    
            for (var i = 0; i < vertices.length; i++) {
                area += (vertices[j].x - vertices[i].x) * (vertices[j].y + vertices[i].y);
                j = i;
            }
    
            if (signed)
                return area / 2;
    
            return Math.abs(area) / 2;
        };
    
        /**
         * Returns the moment of inertia (second moment of area) of the set of vertices given the total mass.
         * @method inertia
         * @param {vertices} vertices
         * @param {number} mass
         * @return {number} The polygon's moment of inertia
         */
        Vertices.inertia = function(vertices, mass) {
            var numerator = 0,
                denominator = 0,
                v = vertices,
                cross,
                j;
    
            // find the polygon's moment of inertia, using second moment of area
            // from equations at http://www.physicsforums.com/showthread.php?t=25293
            for (var n = 0; n < v.length; n++) {
                j = (n + 1) % v.length;
                cross = Math.abs(Vector.cross(v[j], v[n]));
                numerator += cross * (Vector.dot(v[j], v[j]) + Vector.dot(v[j], v[n]) + Vector.dot(v[n], v[n]));
                denominator += cross;
            }
    
            return (mass / 6) * (numerator / denominator);
        };
    
        /**
         * Translates the set of vertices in-place.
         * @method translate
         * @param {vertices} vertices
         * @param {vector} vector
         * @param {number} scalar
         */
        Vertices.translate = function(vertices, vector, scalar) {
            var i;
            if (scalar) {
                for (i = 0; i < vertices.length; i++) {
                    vertices[i].x += vector.x * scalar;
                    vertices[i].y += vector.y * scalar;
                }
            } else {
                for (i = 0; i < vertices.length; i++) {
                    vertices[i].x += vector.x;
                    vertices[i].y += vector.y;
                }
            }
    
            return vertices;
        };
    
        /**
         * Rotates the set of vertices in-place.
         * @method rotate
         * @param {vertices} vertices
         * @param {number} angle
         * @param {vector} point
         */
        Vertices.rotate = function(vertices, angle, point) {
            if (angle === 0)
                return;
    
            var cos = Math.cos(angle),
                sin = Math.sin(angle);
    
            for (var i = 0; i < vertices.length; i++) {
                var vertice = vertices[i],
                    dx = vertice.x - point.x,
                    dy = vertice.y - point.y;
                    
                vertice.x = point.x + (dx * cos - dy * sin);
                vertice.y = point.y + (dx * sin + dy * cos);
            }
    
            return vertices;
        };
    
        /**
         * Returns `true` if the `point` is inside the set of `vertices`.
         * @method contains
         * @param {vertices} vertices
         * @param {vector} point
         * @return {boolean} True if the vertices contains point, otherwise false
         */
        Vertices.contains = function(vertices, point) {
            for (var i = 0; i < vertices.length; i++) {
                var vertice = vertices[i],
                    nextVertice = vertices[(i + 1) % vertices.length];
                if ((point.x - vertice.x) * (nextVertice.y - vertice.y) + (point.y - vertice.y) * (vertice.x - nextVertice.x) > 0) {
                    return false;
                }
            }
    
            return true;
        };
    
        /**
         * Scales the vertices from a point (default is centre) in-place.
         * @method scale
         * @param {vertices} vertices
         * @param {number} scaleX
         * @param {number} scaleY
         * @param {vector} point
         */
        Vertices.scale = function(vertices, scaleX, scaleY, point) {
            if (scaleX === 1 && scaleY === 1)
                return vertices;
    
            point = point || Vertices.centre(vertices);
    
            var vertex,
                delta;
    
            for (var i = 0; i < vertices.length; i++) {
                vertex = vertices[i];
                delta = Vector.sub(vertex, point);
                vertices[i].x = point.x + delta.x * scaleX;
                vertices[i].y = point.y + delta.y * scaleY;
            }
    
            return vertices;
        };
    
        /**
         * Chamfers a set of vertices by giving them rounded corners, returns a new set of vertices.
         * The radius parameter is a single number or an array to specify the radius for each vertex.
         * @method chamfer
         * @param {vertices} vertices
         * @param {number[]} radius
         * @param {number} quality
         * @param {number} qualityMin
         * @param {number} qualityMax
         */
        Vertices.chamfer = function(vertices, radius, quality, qualityMin, qualityMax) {
            if (typeof radius === 'number') {
                radius = [radius];
            } else {
                radius = radius || [8];
            }
    
            // quality defaults to -1, which is auto
            quality = (typeof quality !== 'undefined') ? quality : -1;
            qualityMin = qualityMin || 2;
            qualityMax = qualityMax || 14;
    
            var newVertices = [];
    
            for (var i = 0; i < vertices.length; i++) {
                var prevVertex = vertices[i - 1 >= 0 ? i - 1 : vertices.length - 1],
                    vertex = vertices[i],
                    nextVertex = vertices[(i + 1) % vertices.length],
                    currentRadius = radius[i < radius.length ? i : radius.length - 1];
    
                if (currentRadius === 0) {
                    newVertices.push(vertex);
                    continue;
                }
    
                var prevNormal = Vector.normalise({ 
                    x: vertex.y - prevVertex.y, 
                    y: prevVertex.x - vertex.x
                });
    
                var nextNormal = Vector.normalise({ 
                    x: nextVertex.y - vertex.y, 
                    y: vertex.x - nextVertex.x
                });
    
                var diagonalRadius = Math.sqrt(2 * Math.pow(currentRadius, 2)),
                    radiusVector = Vector.mult(Common.clone(prevNormal), currentRadius),
                    midNormal = Vector.normalise(Vector.mult(Vector.add(prevNormal, nextNormal), 0.5)),
                    scaledVertex = Vector.sub(vertex, Vector.mult(midNormal, diagonalRadius));
    
                var precision = quality;
    
                if (quality === -1) {
                    // automatically decide precision
                    precision = Math.pow(currentRadius, 0.32) * 1.75;
                }
    
                precision = Common.clamp(precision, qualityMin, qualityMax);
    
                // use an even value for precision, more likely to reduce axes by using symmetry
                if (precision % 2 === 1)
                    precision += 1;
    
                var alpha = Math.acos(Vector.dot(prevNormal, nextNormal)),
                    theta = alpha / precision;
    
                for (var j = 0; j < precision; j++) {
                    newVertices.push(Vector.add(Vector.rotate(radiusVector, theta * j), scaledVertex));
                }
            }
    
            return newVertices;
        };
    
        /**
         * Sorts the input vertices into clockwise order in place.
         * @method clockwiseSort
         * @param {vertices} vertices
         * @return {vertices} vertices
         */
        Vertices.clockwiseSort = function(vertices) {
            var centre = Vertices.mean(vertices);
    
            vertices.sort(function(vertexA, vertexB) {
                return Vector.angle(centre, vertexA) - Vector.angle(centre, vertexB);
            });
    
            return vertices;
        };
    
        /**
         * Returns true if the vertices form a convex shape (vertices must be in clockwise order).
         * @method isConvex
         * @param {vertices} vertices
         * @return {bool} `true` if the `vertices` are convex, `false` if not (or `null` if not computable).
         */
        Vertices.isConvex = function(vertices) {
            // http://paulbourke.net/geometry/polygonmesh/
            // Copyright (c) Paul Bourke (use permitted)
    
            var flag = 0,
                n = vertices.length,
                i,
                j,
                k,
                z;
    
            if (n < 3)
                return null;
    
            for (i = 0; i < n; i++) {
                j = (i + 1) % n;
                k = (i + 2) % n;
                z = (vertices[j].x - vertices[i].x) * (vertices[k].y - vertices[j].y);
                z -= (vertices[j].y - vertices[i].y) * (vertices[k].x - vertices[j].x);
    
                if (z < 0) {
                    flag |= 1;
                } else if (z > 0) {
                    flag |= 2;
                }
    
                if (flag === 3) {
                    return false;
                }
            }
    
            if (flag !== 0){
                return true;
            } else {
                return null;
            }
        };
    
        /**
         * Returns the convex hull of the input vertices as a new array of points.
         * @method hull
         * @param {vertices} vertices
         * @return [vertex] vertices
         */
        Vertices.hull = function(vertices) {
            // http://geomalgorithms.com/a10-_hull-1.html
    
            var upper = [],
                lower = [], 
                vertex,
                i;
    
            // sort vertices on x-axis (y-axis for ties)
            vertices = vertices.slice(0);
            vertices.sort(function(vertexA, vertexB) {
                var dx = vertexA.x - vertexB.x;
                return dx !== 0 ? dx : vertexA.y - vertexB.y;
            });
    
            // build lower hull
            for (i = 0; i < vertices.length; i += 1) {
                vertex = vertices[i];
    
                while (lower.length >= 2 
                       && Vector.cross3(lower[lower.length - 2], lower[lower.length - 1], vertex) <= 0) {
                    lower.pop();
                }
    
                lower.push(vertex);
            }
    
            // build upper hull
            for (i = vertices.length - 1; i >= 0; i -= 1) {
                vertex = vertices[i];
    
                while (upper.length >= 2 
                       && Vector.cross3(upper[upper.length - 2], upper[upper.length - 1], vertex) <= 0) {
                    upper.pop();
                }
    
                upper.push(vertex);
            }
    
            // concatenation of the lower and upper hulls gives the convex hull
            // omit last points because they are repeated at the beginning of the other list
            upper.pop();
            lower.pop();
    
            return upper.concat(lower);
        };
    
    })();
    
    },{"../core/Common":14,"../geometry/Vector":28}],30:[function(_dereq_,module,exports){
    var Matter = module.exports = _dereq_('../core/Matter');
    
    Matter.Body = _dereq_('../body/Body');
    Matter.Composite = _dereq_('../body/Composite');
    Matter.World = _dereq_('../body/World');
    
    Matter.Contact = _dereq_('../collision/Contact');
    Matter.Detector = _dereq_('../collision/Detector');
    Matter.Grid = _dereq_('../collision/Grid');
    Matter.Pairs = _dereq_('../collision/Pairs');
    Matter.Pair = _dereq_('../collision/Pair');
    Matter.Query = _dereq_('../collision/Query');
    Matter.Resolver = _dereq_('../collision/Resolver');
    Matter.SAT = _dereq_('../collision/SAT');
    
    Matter.Constraint = _dereq_('../constraint/Constraint');
    Matter.MouseConstraint = _dereq_('../constraint/MouseConstraint');
    
    Matter.Common = _dereq_('../core/Common');
    Matter.Engine = _dereq_('../core/Engine');
    Matter.Events = _dereq_('../core/Events');
    Matter.Mouse = _dereq_('../core/Mouse');
    Matter.Runner = _dereq_('../core/Runner');
    Matter.Sleeping = _dereq_('../core/Sleeping');
    Matter.Plugin = _dereq_('../core/Plugin');
    
    
    Matter.Bodies = _dereq_('../factory/Bodies');
    Matter.Composites = _dereq_('../factory/Composites');
    
    Matter.Axes = _dereq_('../geometry/Axes');
    Matter.Bounds = _dereq_('../geometry/Bounds');
    Matter.Svg = _dereq_('../geometry/Svg');
    Matter.Vector = _dereq_('../geometry/Vector');
    Matter.Vertices = _dereq_('../geometry/Vertices');
    
    Matter.Render = _dereq_('../render/Render');
    Matter.RenderPixi = _dereq_('../render/RenderPixi');
    
    // aliases
    
    Matter.World.add = Matter.Composite.add;
    Matter.World.remove = Matter.Composite.remove;
    Matter.World.addComposite = Matter.Composite.addComposite;
    Matter.World.addBody = Matter.Composite.addBody;
    Matter.World.addConstraint = Matter.Composite.addConstraint;
    Matter.World.clear = Matter.Composite.clear;
    Matter.Engine.run = Matter.Runner.run;
    
    },{"../body/Body":1,"../body/Composite":2,"../body/World":3,"../collision/Contact":4,"../collision/Detector":5,"../collision/Grid":6,"../collision/Pair":7,"../collision/Pairs":8,"../collision/Query":9,"../collision/Resolver":10,"../collision/SAT":11,"../constraint/Constraint":12,"../constraint/MouseConstraint":13,"../core/Common":14,"../core/Engine":15,"../core/Events":16,"../core/Matter":17,"../core/Metrics":18,"../core/Mouse":19,"../core/Plugin":20,"../core/Runner":21,"../core/Sleeping":22,"../factory/Bodies":23,"../factory/Composites":24,"../geometry/Axes":25,"../geometry/Bounds":26,"../geometry/Svg":27,"../geometry/Vector":28,"../geometry/Vertices":29,"../render/Render":31,"../render/RenderPixi":32}],31:[function(_dereq_,module,exports){
    /**
    * The `Matter.Render` module is a simple HTML5 canvas based renderer for visualising instances of `Matter.Engine`.
    * It is intended for development and debugging purposes, but may also be suitable for simple games.
    * It includes a number of drawing options including wireframe, vector with support for sprites and viewports.
    *
    * @class Render
    */
    
    var Render = {};
    
    module.exports = Render;
    
    var Common = _dereq_('../core/Common');
    var Composite = _dereq_('../body/Composite');
    var Bounds = _dereq_('../geometry/Bounds');
    var Events = _dereq_('../core/Events');
    var Grid = _dereq_('../collision/Grid');
    var Vector = _dereq_('../geometry/Vector');
    var Mouse = _dereq_('../core/Mouse');
    
    (function() {
    
        var _requestAnimationFrame,
            _cancelAnimationFrame;
    
        if (typeof window !== 'undefined') {
            _requestAnimationFrame = window.requestAnimationFrame || window.webkitRequestAnimationFrame
                                          || window.mozRequestAnimationFrame || window.msRequestAnimationFrame
                                          || function(callback){ window.setTimeout(function() { callback(Common.now()); }, 1000 / 60); };
    
            _cancelAnimationFrame = window.cancelAnimationFrame || window.mozCancelAnimationFrame
                                          || window.webkitCancelAnimationFrame || window.msCancelAnimationFrame;
        }
    
        /**
         * Creates a new renderer. The options parameter is an object that specifies any properties you wish to override the defaults.
         * All properties have default values, and many are pre-calculated automatically based on other properties.
         * See the properties section below for detailed information on what you can pass via the `options` object.
         * @method create
         * @param {object} [options]
         * @return {render} A new renderer
         */
        Render.create = function(options) {
            var defaults = {
                controller: Render,
                engine: null,
                element: null,
                canvas: null,
                mouse: null,
                frameRequestId: null,
                options: {
                    width: 800,
                    height: 600,
                    pixelRatio: 1,
                    background: '#18181d',
                    wireframeBackground: '#0f0f13',
                    hasBounds: !!options.bounds,
                    enabled: true,
                    wireframes: true,
                    showSleeping: true,
                    showDebug: false,
                    showBroadphase: false,
                    showBounds: false,
                    showVelocity: false,
                    showCollisions: false,
                    showSeparations: false,
                    showAxes: false,
                    showPositions: false,
                    showAngleIndicator: false,
                    showIds: false,
                    showShadows: false,
                    showVertexNumbers: false,
                    showConvexHulls: false,
                    showInternalEdges: false,
                    showMousePosition: false
                }
            };
    
            var render = Common.extend(defaults, options);
    
            if (render.canvas) {
                render.canvas.width = render.options.width || render.canvas.width;
                render.canvas.height = render.options.height || render.canvas.height;
            }
    
            render.mouse = options.mouse;
            render.engine = options.engine;
            render.canvas = render.canvas || _createCanvas(render.options.width, render.options.height);
            render.context = render.canvas.getContext('2d');
            render.textures = {};
    
            render.bounds = render.bounds || {
                min: {
                    x: 0,
                    y: 0
                },
                max: {
                    x: render.canvas.width,
                    y: render.canvas.height
                }
            };
    
            if (render.options.pixelRatio !== 1) {
                Render.setPixelRatio(render, render.options.pixelRatio);
            }
    
            if (Common.isElement(render.element)) {
                render.element.appendChild(render.canvas);
            } else if (!render.canvas.parentNode) {
                Common.log('Render.create: options.element was undefined, render.canvas was created but not appended', 'warn');
            }
    
            return render;
        };
    
        /**
         * Continuously updates the render canvas on the `requestAnimationFrame` event.
         * @method run
         * @param {render} render
         */
        Render.run = function(render) {
            (function loop(time){
                render.frameRequestId = _requestAnimationFrame(loop);
                Render.world(render);
            })();
        };
    
        /**
         * Ends execution of `Render.run` on the given `render`, by canceling the animation frame request event loop.
         * @method stop
         * @param {render} render
         */
        Render.stop = function(render) {
            _cancelAnimationFrame(render.frameRequestId);
        };
    
        /**
         * Sets the pixel ratio of the renderer and updates the canvas.
         * To automatically detect the correct ratio, pass the string `'auto'` for `pixelRatio`.
         * @method setPixelRatio
         * @param {render} render
         * @param {number} pixelRatio
         */
        Render.setPixelRatio = function(render, pixelRatio) {
            var options = render.options,
                canvas = render.canvas;
    
            if (pixelRatio === 'auto') {
                pixelRatio = _getPixelRatio(canvas);
            }
    
            options.pixelRatio = pixelRatio;
            canvas.setAttribute('data-pixel-ratio', pixelRatio);
            canvas.width = options.width * pixelRatio;
            canvas.height = options.height * pixelRatio;
            canvas.style.width = options.width + 'px';
            canvas.style.height = options.height + 'px';
            render.context.scale(pixelRatio, pixelRatio);
        };
    
        /**
         * Positions and sizes the viewport around the given object bounds.
         * Objects must have at least one of the following properties:
         * - `object.bounds`
         * - `object.position`
         * - `object.min` and `object.max`
         * - `object.x` and `object.y`
         * @method lookAt
         * @param {render} render
         * @param {object[]} objects
         * @param {vector} [padding]
         * @param {bool} [center=true]
         */
        Render.lookAt = function(render, objects, padding, center) {
            center = typeof center !== 'undefined' ? center : true;
            objects = Common.isArray(objects) ? objects : [objects];
            padding = padding || {
                x: 0,
                y: 0
            };
    
            // find bounds of all objects
            var bounds = {
                min: { x: Infinity, y: Infinity },
                max: { x: -Infinity, y: -Infinity }
            };
    
            for (var i = 0; i < objects.length; i += 1) {
                var object = objects[i],
                    min = object.bounds ? object.bounds.min : (object.min || object.position || object),
                    max = object.bounds ? object.bounds.max : (object.max || object.position || object);
    
                if (min && max) {
                    if (min.x < bounds.min.x)
                        bounds.min.x = min.x;
    
                    if (max.x > bounds.max.x)
                        bounds.max.x = max.x;
    
                    if (min.y < bounds.min.y)
                        bounds.min.y = min.y;
    
                    if (max.y > bounds.max.y)
                        bounds.max.y = max.y;
                }
            }
    
            // find ratios
            var width = (bounds.max.x - bounds.min.x) + 2 * padding.x,
                height = (bounds.max.y - bounds.min.y) + 2 * padding.y,
                viewHeight = render.canvas.height,
                viewWidth = render.canvas.width,
                outerRatio = viewWidth / viewHeight,
                innerRatio = width / height,
                scaleX = 1,
                scaleY = 1;
    
            // find scale factor
            if (innerRatio > outerRatio) {
                scaleY = innerRatio / outerRatio;
            } else {
                scaleX = outerRatio / innerRatio;
            }
    
            // enable bounds
            render.options.hasBounds = true;
    
            // position and size
            render.bounds.min.x = bounds.min.x;
            render.bounds.max.x = bounds.min.x + width * scaleX;
            render.bounds.min.y = bounds.min.y;
            render.bounds.max.y = bounds.min.y + height * scaleY;
    
            // center
            if (center) {
                render.bounds.min.x += width * 0.5 - (width * scaleX) * 0.5;
                render.bounds.max.x += width * 0.5 - (width * scaleX) * 0.5;
                render.bounds.min.y += height * 0.5 - (height * scaleY) * 0.5;
                render.bounds.max.y += height * 0.5 - (height * scaleY) * 0.5;
            }
    
            // padding
            render.bounds.min.x -= padding.x;
            render.bounds.max.x -= padding.x;
            render.bounds.min.y -= padding.y;
            render.bounds.max.y -= padding.y;
    
            // update mouse
            if (render.mouse) {
                Mouse.setScale(render.mouse, {
                    x: (render.bounds.max.x - render.bounds.min.x) / render.canvas.width,
                    y: (render.bounds.max.y - render.bounds.min.y) / render.canvas.height
                });
    
                Mouse.setOffset(render.mouse, render.bounds.min);
            }
        };
    
        /**
         * Applies viewport transforms based on `render.bounds` to a render context.
         * @method startViewTransform
         * @param {render} render
         */
        Render.startViewTransform = function(render) {
            var boundsWidth = render.bounds.max.x - render.bounds.min.x,
                boundsHeight = render.bounds.max.y - render.bounds.min.y,
                boundsScaleX = boundsWidth / render.options.width,
                boundsScaleY = boundsHeight / render.options.height;
    
            render.context.scale(1 / boundsScaleX, 1 / boundsScaleY);
            render.context.translate(-render.bounds.min.x, -render.bounds.min.y);
        };
    
        /**
         * Resets all transforms on the render context.
         * @method endViewTransform
         * @param {render} render
         */
        Render.endViewTransform = function(render) {
            render.context.setTransform(render.options.pixelRatio, 0, 0, render.options.pixelRatio, 0, 0);
        };
    
        /**
         * Renders the given `engine`'s `Matter.World` object.
         * This is the entry point for all rendering and should be called every time the scene changes.
         * @method world
         * @param {render} render
         */
        Render.world = function(render) {
            var engine = render.engine,
                world = engine.world,
                canvas = render.canvas,
                context = render.context,
                options = render.options,
                allBodies = Composite.allBodies(world),
                allConstraints = Composite.allConstraints(world),
                background = options.wireframes ? options.wireframeBackground : options.background,
                bodies = [],
                constraints = [],
                i;
    
            var event = {
                timestamp: engine.timing.timestamp
            };
    
            Events.trigger(render, 'beforeRender', event);
    
            // apply background if it has changed
            if (render.currentBackground !== background)
                _applyBackground(render, background);
    
            // clear the canvas with a transparent fill, to allow the canvas background to show
            context.globalCompositeOperation = 'source-in';
            context.fillStyle = "transparent";
            context.fillRect(0, 0, canvas.width, canvas.height);
            context.globalCompositeOperation = 'source-over';
    
            // handle bounds
            if (options.hasBounds) {
                // filter out bodies that are not in view
                for (i = 0; i < allBodies.length; i++) {
                    var body = allBodies[i];
                    if (Bounds.overlaps(body.bounds, render.bounds))
                        bodies.push(body);
                }
    
                // filter out constraints that are not in view
                for (i = 0; i < allConstraints.length; i++) {
                    var constraint = allConstraints[i],
                        bodyA = constraint.bodyA,
                        bodyB = constraint.bodyB,
                        pointAWorld = constraint.pointA,
                        pointBWorld = constraint.pointB;
    
                    if (bodyA) pointAWorld = Vector.add(bodyA.position, constraint.pointA);
                    if (bodyB) pointBWorld = Vector.add(bodyB.position, constraint.pointB);
    
                    if (!pointAWorld || !pointBWorld)
                        continue;
    
                    if (Bounds.contains(render.bounds, pointAWorld) || Bounds.contains(render.bounds, pointBWorld))
                        constraints.push(constraint);
                }
    
                // transform the view
                Render.startViewTransform(render);
    
                // update mouse
                if (render.mouse) {
                    Mouse.setScale(render.mouse, {
                        x: (render.bounds.max.x - render.bounds.min.x) / render.canvas.width,
                        y: (render.bounds.max.y - render.bounds.min.y) / render.canvas.height
                    });
    
                    Mouse.setOffset(render.mouse, render.bounds.min);
                }
            } else {
                constraints = allConstraints;
                bodies = allBodies;
            }
    
            if (!options.wireframes || (engine.enableSleeping && options.showSleeping)) {
                // fully featured rendering of bodies
                Render.bodies(render, bodies, context);
            } else {
                if (options.showConvexHulls)
                    Render.bodyConvexHulls(render, bodies, context);
    
                // optimised method for wireframes only
                Render.bodyWireframes(render, bodies, context);
            }
    
            if (options.showBounds)
                Render.bodyBounds(render, bodies, context);
    
            if (options.showAxes || options.showAngleIndicator)
                Render.bodyAxes(render, bodies, context);
    
            if (options.showPositions)
                Render.bodyPositions(render, bodies, context);
    
            if (options.showVelocity)
                Render.bodyVelocity(render, bodies, context);
    
            if (options.showIds)
                Render.bodyIds(render, bodies, context);
    
            if (options.showSeparations)
                Render.separations(render, engine.pairs.list, context);
    
            if (options.showCollisions)
                Render.collisions(render, engine.pairs.list, context);
    
            if (options.showVertexNumbers)
                Render.vertexNumbers(render, bodies, context);
    
            if (options.showMousePosition)
                Render.mousePosition(render, render.mouse, context);
    
            Render.constraints(constraints, context);
    
            if (options.showBroadphase && engine.broadphase.controller === Grid)
                Render.grid(render, engine.broadphase, context);
    
            if (options.showDebug)
                Render.debug(render, context);
    
            if (options.hasBounds) {
                // revert view transforms
                Render.endViewTransform(render);
            }
    
            Events.trigger(render, 'afterRender', event);
        };
    
        /**
         * Description
         * @private
         * @method debug
         * @param {render} render
         * @param {RenderingContext} context
         */
        Render.debug = function(render, context) {
            var c = context,
                engine = render.engine,
                world = engine.world,
                metrics = engine.metrics,
                options = render.options,
                bodies = Composite.allBodies(world),
                space = "    ";
    
            if (engine.timing.timestamp - (render.debugTimestamp || 0) >= 500) {
                var text = "";
    
                if (metrics.timing) {
                    text += "fps: " + Math.round(metrics.timing.fps) + space;
                }
    
    
                render.debugString = text;
                render.debugTimestamp = engine.timing.timestamp;
            }
    
            if (render.debugString) {
                c.font = "12px Arial";
    
                if (options.wireframes) {
                    c.fillStyle = 'rgba(255,255,255,0.5)';
                } else {
                    c.fillStyle = 'rgba(0,0,0,0.5)';
                }
    
                var split = render.debugString.split('\n');
    
                for (var i = 0; i < split.length; i++) {
                    c.fillText(split[i], 50, 50 + i * 18);
                }
            }
        };
    
        /**
         * Description
         * @private
         * @method constraints
         * @param {constraint[]} constraints
         * @param {RenderingContext} context
         */
        Render.constraints = function(constraints, context) {
            var c = context;
    
            for (var i = 0; i < constraints.length; i++) {
                var constraint = constraints[i];
    
                if (!constraint.render.visible || !constraint.pointA || !constraint.pointB)
                    continue;
    
                var bodyA = constraint.bodyA,
                    bodyB = constraint.bodyB,
                    start,
                    end;
    
                if (bodyA) {
                    start = Vector.add(bodyA.position, constraint.pointA);
                } else {
                    start = constraint.pointA;
                }
    
                if (constraint.render.type === 'pin') {
                    c.beginPath();
                    c.arc(start.x, start.y, 3, 0, 2 * Math.PI);
                    c.closePath();
                } else {
                    if (bodyB) {
                        end = Vector.add(bodyB.position, constraint.pointB);
                    } else {
                        end = constraint.pointB;
                    }
    
                    c.beginPath();
                    c.moveTo(start.x, start.y);
    
                    if (constraint.render.type === 'spring') {
                        var delta = Vector.sub(end, start),
                            normal = Vector.perp(Vector.normalise(delta)),
                            coils = Math.ceil(Common.clamp(constraint.length / 5, 12, 20)),
                            offset;
    
                        for (var j = 1; j < coils; j += 1) {
                            offset = j % 2 === 0 ? 1 : -1;
    
                            c.lineTo(
                                start.x + delta.x * (j / coils) + normal.x * offset * 4,
                                start.y + delta.y * (j / coils) + normal.y * offset * 4
                            );
                        }
                    }
    
                    c.lineTo(end.x, end.y);
                }
    
                if (constraint.render.lineWidth) {
                    c.lineWidth = constraint.render.lineWidth;
                    c.strokeStyle = constraint.render.strokeStyle;
                    c.stroke();
                }
    
                if (constraint.render.anchors) {
                    c.fillStyle = constraint.render.strokeStyle;
                    c.beginPath();
                    c.arc(start.x, start.y, 3, 0, 2 * Math.PI);
                    c.arc(end.x, end.y, 3, 0, 2 * Math.PI);
                    c.closePath();
                    c.fill();
                }
            }
        };
    
        /**
         * Description
         * @private
         * @method bodyShadows
         * @param {render} render
         * @param {body[]} bodies
         * @param {RenderingContext} context
         */
        Render.bodyShadows = function(render, bodies, context) {
            var c = context,
                engine = render.engine;
    
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i];
    
                if (!body.render.visible)
                    continue;
    
                if (body.circleRadius) {
                    c.beginPath();
                    c.arc(body.position.x, body.position.y, body.circleRadius, 0, 2 * Math.PI);
                    c.closePath();
                } else {
                    c.beginPath();
                    c.moveTo(body.vertices[0].x, body.vertices[0].y);
                    for (var j = 1; j < body.vertices.length; j++) {
                        c.lineTo(body.vertices[j].x, body.vertices[j].y);
                    }
                    c.closePath();
                }
    
                var distanceX = body.position.x - render.options.width * 0.5,
                    distanceY = body.position.y - render.options.height * 0.2,
                    distance = Math.abs(distanceX) + Math.abs(distanceY);
    
                c.shadowColor = 'rgba(0,0,0,0.15)';
                c.shadowOffsetX = 0.05 * distanceX;
                c.shadowOffsetY = 0.05 * distanceY;
                c.shadowBlur = 1 + 12 * Math.min(1, distance / 1000);
    
                c.fill();
    
                c.shadowColor = null;
                c.shadowOffsetX = null;
                c.shadowOffsetY = null;
                c.shadowBlur = null;
            }
        };
    
        /**
         * Description
         * @private
         * @method bodies
         * @param {render} render
         * @param {body[]} bodies
         * @param {RenderingContext} context
         */
        Render.bodies = function(render, bodies, context) {
            var c = context,
                engine = render.engine,
                options = render.options,
                showInternalEdges = options.showInternalEdges || !options.wireframes,
                body,
                part,
                i,
                k;
    
            for (i = 0; i < bodies.length; i++) {
                body = bodies[i];
    
                if (!body.render.visible)
                    continue;
    
                // handle compound parts
                for (k = body.parts.length > 1 ? 1 : 0; k < body.parts.length; k++) {
                    part = body.parts[k];
    
                    if (!part.render.visible)
                        continue;
    
                    if (options.showSleeping && body.isSleeping) {
                        c.globalAlpha = 0.5 * part.render.opacity;
                    } else if (part.render.opacity !== 1) {
                        c.globalAlpha = part.render.opacity;
                    }
    
                    if (part.render.sprite && part.render.sprite.texture && !options.wireframes) {
                        // part sprite
                        var sprite = part.render.sprite,
                            texture = _getTexture(render, sprite.texture);
    
                        c.translate(part.position.x, part.position.y);
                        c.rotate(part.angle);
    
                        c.drawImage(
                            texture,
                            texture.width * -sprite.xOffset * sprite.xScale,
                            texture.height * -sprite.yOffset * sprite.yScale,
                            texture.width * sprite.xScale,
                            texture.height * sprite.yScale
                        );
    
                        // revert translation, hopefully faster than save / restore
                        c.rotate(-part.angle);
                        c.translate(-part.position.x, -part.position.y);
                    } else {
                        // part polygon
                        if (part.circleRadius) {
                            c.beginPath();
                            c.arc(part.position.x, part.position.y, part.circleRadius, 0, 2 * Math.PI);
                        } else {
                            c.beginPath();
                            c.moveTo(part.vertices[0].x, part.vertices[0].y);
    
                            for (var j = 1; j < part.vertices.length; j++) {
                                if (!part.vertices[j - 1].isInternal || showInternalEdges) {
                                    c.lineTo(part.vertices[j].x, part.vertices[j].y);
                                } else {
                                    c.moveTo(part.vertices[j].x, part.vertices[j].y);
                                }
    
                                if (part.vertices[j].isInternal && !showInternalEdges) {
                                    c.moveTo(part.vertices[(j + 1) % part.vertices.length].x, part.vertices[(j + 1) % part.vertices.length].y);
                                }
                            }
    
                            c.lineTo(part.vertices[0].x, part.vertices[0].y);
                            c.closePath();
                        }
    
                        if (!options.wireframes) {
                            c.fillStyle = part.render.fillStyle;
    
                            if (part.render.lineWidth) {
                                c.lineWidth = part.render.lineWidth;
                                c.strokeStyle = part.render.strokeStyle;
                                c.stroke();
                            }
    
                            c.fill();
                        } else {
                            c.lineWidth = 1;
                            c.strokeStyle = '#bbb';
                            c.stroke();
                        }
                    }
    
                    c.globalAlpha = 1;
                }
            }
        };
    
        /**
         * Optimised method for drawing body wireframes in one pass
         * @private
         * @method bodyWireframes
         * @param {render} render
         * @param {body[]} bodies
         * @param {RenderingContext} context
         */
        Render.bodyWireframes = function(render, bodies, context) {
            var c = context,
                showInternalEdges = render.options.showInternalEdges,
                body,
                part,
                i,
                j,
                k;
    
            c.beginPath();
    
            // render all bodies
            for (i = 0; i < bodies.length; i++) {
                body = bodies[i];
    
                if (!body.render.visible)
                    continue;
    
                // handle compound parts
                for (k = body.parts.length > 1 ? 1 : 0; k < body.parts.length; k++) {
                    part = body.parts[k];
    
                    c.moveTo(part.vertices[0].x, part.vertices[0].y);
    
                    for (j = 1; j < part.vertices.length; j++) {
                        if (!part.vertices[j - 1].isInternal || showInternalEdges) {
                            c.lineTo(part.vertices[j].x, part.vertices[j].y);
                        } else {
                            c.moveTo(part.vertices[j].x, part.vertices[j].y);
                        }
    
                        if (part.vertices[j].isInternal && !showInternalEdges) {
                            c.moveTo(part.vertices[(j + 1) % part.vertices.length].x, part.vertices[(j + 1) % part.vertices.length].y);
                        }
                    }
    
                    c.lineTo(part.vertices[0].x, part.vertices[0].y);
                }
            }
    
            c.lineWidth = 1;
            c.strokeStyle = '#bbb';
            c.stroke();
        };
    
        /**
         * Optimised method for drawing body convex hull wireframes in one pass
         * @private
         * @method bodyConvexHulls
         * @param {render} render
         * @param {body[]} bodies
         * @param {RenderingContext} context
         */
        Render.bodyConvexHulls = function(render, bodies, context) {
            var c = context,
                body,
                part,
                i,
                j,
                k;
    
            c.beginPath();
    
            // render convex hulls
            for (i = 0; i < bodies.length; i++) {
                body = bodies[i];
    
                if (!body.render.visible || body.parts.length === 1)
                    continue;
    
                c.moveTo(body.vertices[0].x, body.vertices[0].y);
    
                for (j = 1; j < body.vertices.length; j++) {
                    c.lineTo(body.vertices[j].x, body.vertices[j].y);
                }
    
                c.lineTo(body.vertices[0].x, body.vertices[0].y);
            }
    
            c.lineWidth = 1;
            c.strokeStyle = 'rgba(255,255,255,0.2)';
            c.stroke();
        };
    
        /**
         * Renders body vertex numbers.
         * @private
         * @method vertexNumbers
         * @param {render} render
         * @param {body[]} bodies
         * @param {RenderingContext} context
         */
        Render.vertexNumbers = function(render, bodies, context) {
            var c = context,
                i,
                j,
                k;
    
            for (i = 0; i < bodies.length; i++) {
                var parts = bodies[i].parts;
                for (k = parts.length > 1 ? 1 : 0; k < parts.length; k++) {
                    var part = parts[k];
                    for (j = 0; j < part.vertices.length; j++) {
                        c.fillStyle = 'rgba(255,255,255,0.2)';
                        c.fillText(i + '_' + j, part.position.x + (part.vertices[j].x - part.position.x) * 0.8, part.position.y + (part.vertices[j].y - part.position.y) * 0.8);
                    }
                }
            }
        };
    
        /**
         * Renders mouse position.
         * @private
         * @method mousePosition
         * @param {render} render
         * @param {mouse} mouse
         * @param {RenderingContext} context
         */
        Render.mousePosition = function(render, mouse, context) {
            var c = context;
            c.fillStyle = 'rgba(255,255,255,0.8)';
            c.fillText(mouse.position.x + '  ' + mouse.position.y, mouse.position.x + 5, mouse.position.y - 5);
        };
    
        /**
         * Draws body bounds
         * @private
         * @method bodyBounds
         * @param {render} render
         * @param {body[]} bodies
         * @param {RenderingContext} context
         */
        Render.bodyBounds = function(render, bodies, context) {
            var c = context,
                engine = render.engine,
                options = render.options;
    
            c.beginPath();
    
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i];
    
                if (body.render.visible) {
                    var parts = bodies[i].parts;
                    for (var j = parts.length > 1 ? 1 : 0; j < parts.length; j++) {
                        var part = parts[j];
                        c.rect(part.bounds.min.x, part.bounds.min.y, part.bounds.max.x - part.bounds.min.x, part.bounds.max.y - part.bounds.min.y);
                    }
                }
            }
    
            if (options.wireframes) {
                c.strokeStyle = 'rgba(255,255,255,0.08)';
            } else {
                c.strokeStyle = 'rgba(0,0,0,0.1)';
            }
    
            c.lineWidth = 1;
            c.stroke();
        };
    
        /**
         * Draws body angle indicators and axes
         * @private
         * @method bodyAxes
         * @param {render} render
         * @param {body[]} bodies
         * @param {RenderingContext} context
         */
        Render.bodyAxes = function(render, bodies, context) {
            var c = context,
                engine = render.engine,
                options = render.options,
                part,
                i,
                j,
                k;
    
            c.beginPath();
    
            for (i = 0; i < bodies.length; i++) {
                var body = bodies[i],
                    parts = body.parts;
    
                if (!body.render.visible)
                    continue;
    
                if (options.showAxes) {
                    // render all axes
                    for (j = parts.length > 1 ? 1 : 0; j < parts.length; j++) {
                        part = parts[j];
                        for (k = 0; k < part.axes.length; k++) {
                            var axis = part.axes[k];
                            c.moveTo(part.position.x, part.position.y);
                            c.lineTo(part.position.x + axis.x * 20, part.position.y + axis.y * 20);
                        }
                    }
                } else {
                    for (j = parts.length > 1 ? 1 : 0; j < parts.length; j++) {
                        part = parts[j];
                        for (k = 0; k < part.axes.length; k++) {
                            // render a single axis indicator
                            c.moveTo(part.position.x, part.position.y);
                            c.lineTo((part.vertices[0].x + part.vertices[part.vertices.length-1].x) / 2,
                                     (part.vertices[0].y + part.vertices[part.vertices.length-1].y) / 2);
                        }
                    }
                }
            }
    
            if (options.wireframes) {
                c.strokeStyle = 'indianred';
                c.lineWidth = 1;
            } else {
                c.strokeStyle = 'rgba(255, 255, 255, 0.4)';
                c.globalCompositeOperation = 'overlay';
                c.lineWidth = 2;
            }
    
            c.stroke();
            c.globalCompositeOperation = 'source-over';
        };
    
        /**
         * Draws body positions
         * @private
         * @method bodyPositions
         * @param {render} render
         * @param {body[]} bodies
         * @param {RenderingContext} context
         */
        Render.bodyPositions = function(render, bodies, context) {
            var c = context,
                engine = render.engine,
                options = render.options,
                body,
                part,
                i,
                k;
    
            c.beginPath();
    
            // render current positions
            for (i = 0; i < bodies.length; i++) {
                body = bodies[i];
    
                if (!body.render.visible)
                    continue;
    
                // handle compound parts
                for (k = 0; k < body.parts.length; k++) {
                    part = body.parts[k];
                    c.arc(part.position.x, part.position.y, 3, 0, 2 * Math.PI, false);
                    c.closePath();
                }
            }
    
            if (options.wireframes) {
                c.fillStyle = 'indianred';
            } else {
                c.fillStyle = 'rgba(0,0,0,0.5)';
            }
            c.fill();
    
            c.beginPath();
    
            // render previous positions
            for (i = 0; i < bodies.length; i++) {
                body = bodies[i];
                if (body.render.visible) {
                    c.arc(body.positionPrev.x, body.positionPrev.y, 2, 0, 2 * Math.PI, false);
                    c.closePath();
                }
            }
    
            c.fillStyle = 'rgba(255,165,0,0.8)';
            c.fill();
        };
    
        /**
         * Draws body velocity
         * @private
         * @method bodyVelocity
         * @param {render} render
         * @param {body[]} bodies
         * @param {RenderingContext} context
         */
        Render.bodyVelocity = function(render, bodies, context) {
            var c = context;
    
            c.beginPath();
    
            for (var i = 0; i < bodies.length; i++) {
                var body = bodies[i];
    
                if (!body.render.visible)
                    continue;
    
                c.moveTo(body.position.x, body.position.y);
                c.lineTo(body.position.x + (body.position.x - body.positionPrev.x) * 2, body.position.y + (body.position.y - body.positionPrev.y) * 2);
            }
    
            c.lineWidth = 3;
            c.strokeStyle = 'cornflowerblue';
            c.stroke();
        };
    
        /**
         * Draws body ids
         * @private
         * @method bodyIds
         * @param {render} render
         * @param {body[]} bodies
         * @param {RenderingContext} context
         */
        Render.bodyIds = function(render, bodies, context) {
            var c = context,
                i,
                j;
    
            for (i = 0; i < bodies.length; i++) {
                if (!bodies[i].render.visible)
                    continue;
    
                var parts = bodies[i].parts;
                for (j = parts.length > 1 ? 1 : 0; j < parts.length; j++) {
                    var part = parts[j];
                    c.font = "12px Arial";
                    c.fillStyle = 'rgba(255,255,255,0.5)';
                    c.fillText(part.id, part.position.x + 10, part.position.y - 10);
                }
            }
        };
    
        /**
         * Description
         * @private
         * @method collisions
         * @param {render} render
         * @param {pair[]} pairs
         * @param {RenderingContext} context
         */
        Render.collisions = function(render, pairs, context) {
            var c = context,
                options = render.options,
                pair,
                collision,
                corrected,
                bodyA,
                bodyB,
                i,
                j;
    
            c.beginPath();
    
            // render collision positions
            for (i = 0; i < pairs.length; i++) {
                pair = pairs[i];
    
                if (!pair.isActive)
                    continue;
    
                collision = pair.collision;
                for (j = 0; j < pair.activeContacts.length; j++) {
                    var contact = pair.activeContacts[j],
                        vertex = contact.vertex;
                    c.rect(vertex.x - 1.5, vertex.y - 1.5, 3.5, 3.5);
                }
            }
    
            if (options.wireframes) {
                c.fillStyle = 'rgba(255,255,255,0.7)';
            } else {
                c.fillStyle = 'orange';
            }
            c.fill();
    
            c.beginPath();
    
            // render collision normals
            for (i = 0; i < pairs.length; i++) {
                pair = pairs[i];
    
                if (!pair.isActive)
                    continue;
    
                collision = pair.collision;
    
                if (pair.activeContacts.length > 0) {
                    var normalPosX = pair.activeContacts[0].vertex.x,
                        normalPosY = pair.activeContacts[0].vertex.y;
    
                    if (pair.activeContacts.length === 2) {
                        normalPosX = (pair.activeContacts[0].vertex.x + pair.activeContacts[1].vertex.x) / 2;
                        normalPosY = (pair.activeContacts[0].vertex.y + pair.activeContacts[1].vertex.y) / 2;
                    }
    
                    if (collision.bodyB === collision.supports[0].body || collision.bodyA.isStatic === true) {
                        c.moveTo(normalPosX - collision.normal.x * 8, normalPosY - collision.normal.y * 8);
                    } else {
                        c.moveTo(normalPosX + collision.normal.x * 8, normalPosY + collision.normal.y * 8);
                    }
    
                    c.lineTo(normalPosX, normalPosY);
                }
            }
    
            if (options.wireframes) {
                c.strokeStyle = 'rgba(255,165,0,0.7)';
            } else {
                c.strokeStyle = 'orange';
            }
    
            c.lineWidth = 1;
            c.stroke();
        };
    
        /**
         * Description
         * @private
         * @method separations
         * @param {render} render
         * @param {pair[]} pairs
         * @param {RenderingContext} context
         */
        Render.separations = function(render, pairs, context) {
            var c = context,
                options = render.options,
                pair,
                collision,
                corrected,
                bodyA,
                bodyB,
                i,
                j;
    
            c.beginPath();
    
            // render separations
            for (i = 0; i < pairs.length; i++) {
                pair = pairs[i];
    
                if (!pair.isActive)
                    continue;
    
                collision = pair.collision;
                bodyA = collision.bodyA;
                bodyB = collision.bodyB;
    
                var k = 1;
    
                if (!bodyB.isStatic && !bodyA.isStatic) k = 0.5;
                if (bodyB.isStatic) k = 0;
    
                c.moveTo(bodyB.position.x, bodyB.position.y);
                c.lineTo(bodyB.position.x - collision.penetration.x * k, bodyB.position.y - collision.penetration.y * k);
    
                k = 1;
    
                if (!bodyB.isStatic && !bodyA.isStatic) k = 0.5;
                if (bodyA.isStatic) k = 0;
    
                c.moveTo(bodyA.position.x, bodyA.position.y);
                c.lineTo(bodyA.position.x + collision.penetration.x * k, bodyA.position.y + collision.penetration.y * k);
            }
    
            if (options.wireframes) {
                c.strokeStyle = 'rgba(255,165,0,0.5)';
            } else {
                c.strokeStyle = 'orange';
            }
            c.stroke();
        };
    
        /**
         * Description
         * @private
         * @method grid
         * @param {render} render
         * @param {grid} grid
         * @param {RenderingContext} context
         */
        Render.grid = function(render, grid, context) {
            var c = context,
                options = render.options;
    
            if (options.wireframes) {
                c.strokeStyle = 'rgba(255,180,0,0.1)';
            } else {
                c.strokeStyle = 'rgba(255,180,0,0.5)';
            }
    
            c.beginPath();
    
            var bucketKeys = Common.keys(grid.buckets);
    
            for (var i = 0; i < bucketKeys.length; i++) {
                var bucketId = bucketKeys[i];
    
                if (grid.buckets[bucketId].length < 2)
                    continue;
    
                var region = bucketId.split(/C|R/);
                c.rect(0.5 + parseInt(region[1], 10) * grid.bucketWidth,
                        0.5 + parseInt(region[2], 10) * grid.bucketHeight,
                        grid.bucketWidth,
                        grid.bucketHeight);
            }
    
            c.lineWidth = 1;
            c.stroke();
        };
    
        /**
         * Description
         * @private
         * @method inspector
         * @param {inspector} inspector
         * @param {RenderingContext} context
         */
        Render.inspector = function(inspector, context) {
            var engine = inspector.engine,
                selected = inspector.selected,
                render = inspector.render,
                options = render.options,
                bounds;
    
            if (options.hasBounds) {
                var boundsWidth = render.bounds.max.x - render.bounds.min.x,
                    boundsHeight = render.bounds.max.y - render.bounds.min.y,
                    boundsScaleX = boundsWidth / render.options.width,
                    boundsScaleY = boundsHeight / render.options.height;
    
                context.scale(1 / boundsScaleX, 1 / boundsScaleY);
                context.translate(-render.bounds.min.x, -render.bounds.min.y);
            }
    
            for (var i = 0; i < selected.length; i++) {
                var item = selected[i].data;
    
                context.translate(0.5, 0.5);
                context.lineWidth = 1;
                context.strokeStyle = 'rgba(255,165,0,0.9)';
                context.setLineDash([1,2]);
    
                switch (item.type) {
    
                case 'body':
    
                    // render body selections
                    bounds = item.bounds;
                    context.beginPath();
                    context.rect(Math.floor(bounds.min.x - 3), Math.floor(bounds.min.y - 3),
                                 Math.floor(bounds.max.x - bounds.min.x + 6), Math.floor(bounds.max.y - bounds.min.y + 6));
                    context.closePath();
                    context.stroke();
    
                    break;
    
                case 'constraint':
    
                    // render constraint selections
                    var point = item.pointA;
                    if (item.bodyA)
                        point = item.pointB;
                    context.beginPath();
                    context.arc(point.x, point.y, 10, 0, 2 * Math.PI);
                    context.closePath();
                    context.stroke();
    
                    break;
    
                }
    
                context.setLineDash([]);
                context.translate(-0.5, -0.5);
            }
    
            // render selection region
            if (inspector.selectStart !== null) {
                context.translate(0.5, 0.5);
                context.lineWidth = 1;
                context.strokeStyle = 'rgba(255,165,0,0.6)';
                context.fillStyle = 'rgba(255,165,0,0.1)';
                bounds = inspector.selectBounds;
                context.beginPath();
                context.rect(Math.floor(bounds.min.x), Math.floor(bounds.min.y),
                             Math.floor(bounds.max.x - bounds.min.x), Math.floor(bounds.max.y - bounds.min.y));
                context.closePath();
                context.stroke();
                context.fill();
                context.translate(-0.5, -0.5);
            }
    
            if (options.hasBounds)
                context.setTransform(1, 0, 0, 1, 0, 0);
        };
    
        /**
         * Description
         * @method _createCanvas
         * @private
         * @param {} width
         * @param {} height
         * @return canvas
         */
        var _createCanvas = function(width, height) {
            var canvas = document.createElement('canvas');
            canvas.width = width;
            canvas.height = height;
            canvas.oncontextmenu = function() { return false; };
            canvas.onselectstart = function() { return false; };
            return canvas;
        };
    
        /**
         * Gets the pixel ratio of the canvas.
         * @method _getPixelRatio
         * @private
         * @param {HTMLElement} canvas
         * @return {Number} pixel ratio
         */
        var _getPixelRatio = function(canvas) {
            var context = canvas.getContext('2d'),
                devicePixelRatio = window.devicePixelRatio || 1,
                backingStorePixelRatio = context.webkitBackingStorePixelRatio || context.mozBackingStorePixelRatio
                                          || context.msBackingStorePixelRatio || context.oBackingStorePixelRatio
                                          || context.backingStorePixelRatio || 1;
    
            return devicePixelRatio / backingStorePixelRatio;
        };
    
        /**
         * Gets the requested texture (an Image) via its path
         * @method _getTexture
         * @private
         * @param {render} render
         * @param {string} imagePath
         * @return {Image} texture
         */
        var _getTexture = function(render, imagePath) {
            var image = render.textures[imagePath];
    
            if (image)
                return image;
    
            image = render.textures[imagePath] = new Image();
            image.src = imagePath;
    
            return image;
        };
    
        /**
         * Applies the background to the canvas using CSS.
         * @method applyBackground
         * @private
         * @param {render} render
         * @param {string} background
         */
        var _applyBackground = function(render, background) {
            var cssBackground = background;
    
            if (/(jpg|gif|png)$/.test(background))
                cssBackground = 'url(' + background + ')';
    
            render.canvas.style.background = cssBackground;
            render.canvas.style.backgroundSize = "contain";
            render.currentBackground = background;
        };
    
        /*
        *
        *  Events Documentation
        *
        */
    
        /**
        * Fired before rendering
        *
        * @event beforeRender
        * @param {} event An event object
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /**
        * Fired after rendering
        *
        * @event afterRender
        * @param {} event An event object
        * @param {number} event.timestamp The engine.timing.timestamp of the event
        * @param {} event.source The source object of the event
        * @param {} event.name The name of the event
        */
    
        /*
        *
        *  Properties Documentation
        *
        */
    
        /**
         * A back-reference to the `Matter.Render` module.
         *
         * @property controller
         * @type render
         */
    
        /**
         * A reference to the `Matter.Engine` instance to be used.
         *
         * @property engine
         * @type engine
         */
    
        /**
         * A reference to the element where the canvas is to be inserted (if `render.canvas` has not been specified)
         *
         * @property element
         * @type HTMLElement
         * @default null
         */
    
        /**
         * The canvas element to render to. If not specified, one will be created if `render.element` has been specified.
         *
         * @property canvas
         * @type HTMLCanvasElement
         * @default null
         */
    
        /**
         * The configuration options of the renderer.
         *
         * @property options
         * @type {}
         */
    
        /**
         * The target width in pixels of the `render.canvas` to be created.
         *
         * @property options.width
         * @type number
         * @default 800
         */
    
        /**
         * The target height in pixels of the `render.canvas` to be created.
         *
         * @property options.height
         * @type number
         * @default 600
         */
    
        /**
         * A flag that specifies if `render.bounds` should be used when rendering.
         *
         * @property options.hasBounds
         * @type boolean
         * @default false
         */
    
        /**
         * A `Bounds` object that specifies the drawing view region.
         * Rendering will be automatically transformed and scaled to fit within the canvas size (`render.options.width` and `render.options.height`).
         * This allows for creating views that can pan or zoom around the scene.
         * You must also set `render.options.hasBounds` to `true` to enable bounded rendering.
         *
         * @property bounds
         * @type bounds
         */
    
        /**
         * The 2d rendering context from the `render.canvas` element.
         *
         * @property context
         * @type CanvasRenderingContext2D
         */
    
        /**
         * The sprite texture cache.
         *
         * @property textures
         * @type {}
         */
    
    })();
    
    },{"../body/Composite":2,"../collision/Grid":6,"../core/Common":14,"../core/Events":16,"../core/Mouse":19,"../geometry/Bounds":26,"../geometry/Vector":28}],32:[function(_dereq_,module,exports){
    /**
    * The `Matter.RenderPixi` module is an example renderer using pixi.js.
    * See also `Matter.Render` for a canvas based renderer.
    *
    * @class RenderPixi
    * @deprecated the Matter.RenderPixi module will soon be removed from the Matter.js core.
    * It will likely be moved to its own repository (but maintenance will be limited).
    */
    
    var RenderPixi = {};
    
    module.exports = RenderPixi;
    
    var Bounds = _dereq_('../geometry/Bounds');
    var Composite = _dereq_('../body/Composite');
    var Common = _dereq_('../core/Common');
    var Events = _dereq_('../core/Events');
    var Vector = _dereq_('../geometry/Vector');
    
    (function() {
    
        var _requestAnimationFrame,
            _cancelAnimationFrame;
    
        if (typeof window !== 'undefined') {
            _requestAnimationFrame = window.requestAnimationFrame || window.webkitRequestAnimationFrame
                                          || window.mozRequestAnimationFrame || window.msRequestAnimationFrame 
                                          || function(callback){ window.setTimeout(function() { callback(Common.now()); }, 1000 / 60); };
       
            _cancelAnimationFrame = window.cancelAnimationFrame || window.mozCancelAnimationFrame 
                                          || window.webkitCancelAnimationFrame || window.msCancelAnimationFrame;
        }
        
        /**
         * Creates a new Pixi.js WebGL renderer
         * @method create
         * @param {object} options
         * @return {RenderPixi} A new renderer
         * @deprecated
         */
        RenderPixi.create = function(options) {
            Common.warn('RenderPixi.create: Matter.RenderPixi is deprecated (see docs)');
    
            var defaults = {
                controller: RenderPixi,
                engine: null,
                element: null,
                frameRequestId: null,
                canvas: null,
                renderer: null,
                container: null,
                spriteContainer: null,
                pixiOptions: null,
                options: {
                    width: 800,
                    height: 600,
                    background: '#fafafa',
                    wireframeBackground: '#222',
                    hasBounds: false,
                    enabled: true,
                    wireframes: true,
                    showSleeping: true,
                    showDebug: false,
                    showBroadphase: false,
                    showBounds: false,
                    showVelocity: false,
                    showCollisions: false,
                    showAxes: false,
                    showPositions: false,
                    showAngleIndicator: false,
                    showIds: false,
                    showShadows: false
                }
            };
    
            var render = Common.extend(defaults, options),
                transparent = !render.options.wireframes && render.options.background === 'transparent';
    
            // init pixi
            render.pixiOptions = render.pixiOptions || {
                view: render.canvas,
                transparent: transparent,
                antialias: true,
                backgroundColor: options.background
            };
    
            render.mouse = options.mouse;
            render.engine = options.engine;
            render.renderer = render.renderer || new PIXI.WebGLRenderer(render.options.width, render.options.height, render.pixiOptions);
            render.container = render.container || new PIXI.Container();
            render.spriteContainer = render.spriteContainer || new PIXI.Container();
            render.canvas = render.canvas || render.renderer.view;
            render.bounds = render.bounds || { 
                min: {
                    x: 0,
                    y: 0
                }, 
                max: { 
                    x: render.options.width,
                    y: render.options.height
                }
            };
    
            // event listeners
            Events.on(render.engine, 'beforeUpdate', function() {
                RenderPixi.clear(render);
            });
    
            // caches
            render.textures = {};
            render.sprites = {};
            render.primitives = {};
    
            // use a sprite batch for performance
            render.container.addChild(render.spriteContainer);
    
            // insert canvas
            if (Common.isElement(render.element)) {
                render.element.appendChild(render.canvas);
            } else {
                Common.warn('No "render.element" passed, "render.canvas" was not inserted into document.');
            }
    
            // prevent menus on canvas
            render.canvas.oncontextmenu = function() { return false; };
            render.canvas.onselectstart = function() { return false; };
    
            return render;
        };
    
        /**
         * Continuously updates the render canvas on the `requestAnimationFrame` event.
         * @method run
         * @param {render} render
         * @deprecated
         */
        RenderPixi.run = function(render) {
            (function loop(time){
                render.frameRequestId = _requestAnimationFrame(loop);
                RenderPixi.world(render);
            })();
        };
    
        /**
         * Ends execution of `Render.run` on the given `render`, by canceling the animation frame request event loop.
         * @method stop
         * @param {render} render
         * @deprecated
         */
        RenderPixi.stop = function(render) {
            _cancelAnimationFrame(render.frameRequestId);
        };
    
        /**
         * Clears the scene graph
         * @method clear
         * @param {RenderPixi} render
         * @deprecated
         */
        RenderPixi.clear = function(render) {
            var container = render.container,
                spriteContainer = render.spriteContainer;
    
            // clear stage container
            while (container.children[0]) { 
                container.removeChild(container.children[0]); 
            }
    
            // clear sprite batch
            while (spriteContainer.children[0]) { 
                spriteContainer.removeChild(spriteContainer.children[0]); 
            }
    
            var bgSprite = render.sprites['bg-0'];
    
            // clear caches
            render.textures = {};
            render.sprites = {};
            render.primitives = {};
    
            // set background sprite
            render.sprites['bg-0'] = bgSprite;
            if (bgSprite)
                container.addChildAt(bgSprite, 0);
    
            // add sprite batch back into container
            render.container.addChild(render.spriteContainer);
    
            // reset background state
            render.currentBackground = null;
    
            // reset bounds transforms
            container.scale.set(1, 1);
            container.position.set(0, 0);
        };
    
        /**
         * Sets the background of the canvas 
         * @method setBackground
         * @param {RenderPixi} render
         * @param {string} background
         * @deprecated
         */
        RenderPixi.setBackground = function(render, background) {
            if (render.currentBackground !== background) {
                var isColor = background.indexOf && background.indexOf('#') !== -1,
                    bgSprite = render.sprites['bg-0'];
    
                if (isColor) {
                    // if solid background color
                    var color = Common.colorToNumber(background);
                    render.renderer.backgroundColor = color;
    
                    // remove background sprite if existing
                    if (bgSprite)
                        render.container.removeChild(bgSprite); 
                } else {
                    // initialise background sprite if needed
                    if (!bgSprite) {
                        var texture = _getTexture(render, background);
    
                        bgSprite = render.sprites['bg-0'] = new PIXI.Sprite(texture);
                        bgSprite.position.x = 0;
                        bgSprite.position.y = 0;
                        render.container.addChildAt(bgSprite, 0);
                    }
                }
    
                render.currentBackground = background;
            }
        };
    
        /**
         * Description
         * @method world
         * @param {engine} engine
         * @deprecated
         */
        RenderPixi.world = function(render) {
            var engine = render.engine,
                world = engine.world,
                renderer = render.renderer,
                container = render.container,
                options = render.options,
                bodies = Composite.allBodies(world),
                allConstraints = Composite.allConstraints(world),
                constraints = [],
                i;
    
            if (options.wireframes) {
                RenderPixi.setBackground(render, options.wireframeBackground);
            } else {
                RenderPixi.setBackground(render, options.background);
            }
    
            // handle bounds
            var boundsWidth = render.bounds.max.x - render.bounds.min.x,
                boundsHeight = render.bounds.max.y - render.bounds.min.y,
                boundsScaleX = boundsWidth / render.options.width,
                boundsScaleY = boundsHeight / render.options.height;
    
            if (options.hasBounds) {
                // Hide bodies that are not in view
                for (i = 0; i < bodies.length; i++) {
                    var body = bodies[i];
                    body.render.sprite.visible = Bounds.overlaps(body.bounds, render.bounds);
                }
    
                // filter out constraints that are not in view
                for (i = 0; i < allConstraints.length; i++) {
                    var constraint = allConstraints[i],
                        bodyA = constraint.bodyA,
                        bodyB = constraint.bodyB,
                        pointAWorld = constraint.pointA,
                        pointBWorld = constraint.pointB;
    
                    if (bodyA) pointAWorld = Vector.add(bodyA.position, constraint.pointA);
                    if (bodyB) pointBWorld = Vector.add(bodyB.position, constraint.pointB);
    
                    if (!pointAWorld || !pointBWorld)
                        continue;
    
                    if (Bounds.contains(render.bounds, pointAWorld) || Bounds.contains(render.bounds, pointBWorld))
                        constraints.push(constraint);
                }
    
                // transform the view
                container.scale.set(1 / boundsScaleX, 1 / boundsScaleY);
                container.position.set(-render.bounds.min.x * (1 / boundsScaleX), -render.bounds.min.y * (1 / boundsScaleY));
            } else {
                constraints = allConstraints;
            }
    
            for (i = 0; i < bodies.length; i++)
                RenderPixi.body(render, bodies[i]);
    
            for (i = 0; i < constraints.length; i++)
                RenderPixi.constraint(render, constraints[i]);
    
            renderer.render(container);
        };
    
    
        /**
         * Description
         * @method constraint
         * @param {engine} engine
         * @param {constraint} constraint
         * @deprecated
         */
        RenderPixi.constraint = function(render, constraint) {
            var engine = render.engine,
                bodyA = constraint.bodyA,
                bodyB = constraint.bodyB,
                pointA = constraint.pointA,
                pointB = constraint.pointB,
                container = render.container,
                constraintRender = constraint.render,
                primitiveId = 'c-' + constraint.id,
                primitive = render.primitives[primitiveId];
    
            // initialise constraint primitive if not existing
            if (!primitive)
                primitive = render.primitives[primitiveId] = new PIXI.Graphics();
    
            // don't render if constraint does not have two end points
            if (!constraintRender.visible || !constraint.pointA || !constraint.pointB) {
                primitive.clear();
                return;
            }
    
            // add to scene graph if not already there
            if (Common.indexOf(container.children, primitive) === -1)
                container.addChild(primitive);
    
            // render the constraint on every update, since they can change dynamically
            primitive.clear();
            primitive.beginFill(0, 0);
            primitive.lineStyle(constraintRender.lineWidth, Common.colorToNumber(constraintRender.strokeStyle), 1);
            
            if (bodyA) {
                primitive.moveTo(bodyA.position.x + pointA.x, bodyA.position.y + pointA.y);
            } else {
                primitive.moveTo(pointA.x, pointA.y);
            }
    
            if (bodyB) {
                primitive.lineTo(bodyB.position.x + pointB.x, bodyB.position.y + pointB.y);
            } else {
                primitive.lineTo(pointB.x, pointB.y);
            }
    
            primitive.endFill();
        };
        
        /**
         * Description
         * @method body
         * @param {engine} engine
         * @param {body} body
         * @deprecated
         */
        RenderPixi.body = function(render, body) {
            var engine = render.engine,
                bodyRender = body.render;
    
            if (!bodyRender.visible)
                return;
    
            if (bodyRender.sprite && bodyRender.sprite.texture) {
                var spriteId = 'b-' + body.id,
                    sprite = render.sprites[spriteId],
                    spriteContainer = render.spriteContainer;
    
                // initialise body sprite if not existing
                if (!sprite)
                    sprite = render.sprites[spriteId] = _createBodySprite(render, body);
    
                // add to scene graph if not already there
                if (Common.indexOf(spriteContainer.children, sprite) === -1)
                    spriteContainer.addChild(sprite);
    
                // update body sprite
                sprite.position.x = body.position.x;
                sprite.position.y = body.position.y;
                sprite.rotation = body.angle;
                sprite.scale.x = bodyRender.sprite.xScale || 1;
                sprite.scale.y = bodyRender.sprite.yScale || 1;
            } else {
                var primitiveId = 'b-' + body.id,
                    primitive = render.primitives[primitiveId],
                    container = render.container;
    
                // initialise body primitive if not existing
                if (!primitive) {
                    primitive = render.primitives[primitiveId] = _createBodyPrimitive(render, body);
                    primitive.initialAngle = body.angle;
                }
    
                // add to scene graph if not already there
                if (Common.indexOf(container.children, primitive) === -1)
                    container.addChild(primitive);
    
                // update body primitive
                primitive.position.x = body.position.x;
                primitive.position.y = body.position.y;
                primitive.rotation = body.angle - primitive.initialAngle;
            }
        };
    
        /**
         * Creates a body sprite
         * @method _createBodySprite
         * @private
         * @param {RenderPixi} render
         * @param {body} body
         * @return {PIXI.Sprite} sprite
         * @deprecated
         */
        var _createBodySprite = function(render, body) {
            var bodyRender = body.render,
                texturePath = bodyRender.sprite.texture,
                texture = _getTexture(render, texturePath),
                sprite = new PIXI.Sprite(texture);
    
            sprite.anchor.x = body.render.sprite.xOffset;
            sprite.anchor.y = body.render.sprite.yOffset;
    
            return sprite;
        };
    
        /**
         * Creates a body primitive
         * @method _createBodyPrimitive
         * @private
         * @param {RenderPixi} render
         * @param {body} body
         * @return {PIXI.Graphics} graphics
         * @deprecated
         */
        var _createBodyPrimitive = function(render, body) {
            var bodyRender = body.render,
                options = render.options,
                primitive = new PIXI.Graphics(),
                fillStyle = Common.colorToNumber(bodyRender.fillStyle),
                strokeStyle = Common.colorToNumber(bodyRender.strokeStyle),
                strokeStyleIndicator = Common.colorToNumber(bodyRender.strokeStyle),
                strokeStyleWireframe = Common.colorToNumber('#bbb'),
                strokeStyleWireframeIndicator = Common.colorToNumber('#CD5C5C'),
                part;
    
            primitive.clear();
    
            // handle compound parts
            for (var k = body.parts.length > 1 ? 1 : 0; k < body.parts.length; k++) {
                part = body.parts[k];
    
                if (!options.wireframes) {
                    primitive.beginFill(fillStyle, 1);
                    primitive.lineStyle(bodyRender.lineWidth, strokeStyle, 1);
                } else {
                    primitive.beginFill(0, 0);
                    primitive.lineStyle(1, strokeStyleWireframe, 1);
                }
    
                primitive.moveTo(part.vertices[0].x - body.position.x, part.vertices[0].y - body.position.y);
    
                for (var j = 1; j < part.vertices.length; j++) {
                    primitive.lineTo(part.vertices[j].x - body.position.x, part.vertices[j].y - body.position.y);
                }
    
                primitive.lineTo(part.vertices[0].x - body.position.x, part.vertices[0].y - body.position.y);
    
                primitive.endFill();
    
                // angle indicator
                if (options.showAngleIndicator || options.showAxes) {
                    primitive.beginFill(0, 0);
    
                    if (options.wireframes) {
                        primitive.lineStyle(1, strokeStyleWireframeIndicator, 1);
                    } else {
                        primitive.lineStyle(1, strokeStyleIndicator);
                    }
    
                    primitive.moveTo(part.position.x - body.position.x, part.position.y - body.position.y);
                    primitive.lineTo(((part.vertices[0].x + part.vertices[part.vertices.length-1].x) / 2 - body.position.x), 
                                     ((part.vertices[0].y + part.vertices[part.vertices.length-1].y) / 2 - body.position.y));
    
                    primitive.endFill();
                }
            }
    
            return primitive;
        };
    
        /**
         * Gets the requested texture (a PIXI.Texture) via its path
         * @method _getTexture
         * @private
         * @param {RenderPixi} render
         * @param {string} imagePath
         * @return {PIXI.Texture} texture
         * @deprecated
         */
        var _getTexture = function(render, imagePath) {
            var texture = render.textures[imagePath];
    
            if (!texture)
                texture = render.textures[imagePath] = PIXI.Texture.fromImage(imagePath);
    
            return texture;
        };
    
    })();
    
    },{"../body/Composite":2,"../core/Common":14,"../core/Events":16,"../geometry/Bounds":26,"../geometry/Vector":28}]},{},[30])(30)
    });