GalaxyGeometry/GalaxyGeometry.js at master · andraswebcode/GalaxyGeometry · GitHub

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/**
 * @author Andras Tovishati / https://github.com/andrastovishati/
 */

THREE.GalaxyGeometry = function(radius, numberOfStars, length, width) {

	THREE.Geometry.call(this);

	this.type = 'GalaxyGeometry';

	this.parameters = {
		radius:radius,
		numberOfStars:numberOfStars,
		length:length,
		width:width
	};

	var bufferGeometry = new THREE.GalaxyBufferGeometry(radius, numberOfStars, length, width);
	var positions = bufferGeometry.attributes.position.array;
	var itemSize = bufferGeometry.attributes.position.itemSize;

	for (var i = 0; i < positions.length; i += itemSize){
		this.vertices.push(new THREE.Vector3().fromArray(positions, i));
	}

};

THREE.GalaxyGeometry.prototype = Object.create(THREE.Geometry.prototype);
THREE.GalaxyGeometry.prototype.constructor = THREE.GalaxyGeometry;

THREE.GalaxyBufferGeometry = function(radius, numberOfStars, length, width) {

	THREE.BufferGeometry.call(this);

	this.type = 'GalaxyBufferGeometry';

	this.parameters = {
		radius:radius,
		numberOfStars:numberOfStars,
		length:length,
		width:width
	};

	radius = radius || 1;
	numberOfStars = Math.floor(numberOfStars) || 1000;
	length = length || 10;
	width = width || 0.7;

	var vertices = [];
	var _numberOfStars = numberOfStars / 2;

	for (var i = 0; i < _numberOfStars; i++){

		var _length = (length / _numberOfStars) * i;
		var _radius = (radius / _numberOfStars) * i;
		var _x = i * (1 / (_numberOfStars / 2));
		var _parabola = - Math.pow(_x - 1.1, 2) + 1.1;

		vertices.push(
			_parabola * randSpread() + Math.sin(_length) * _radius,
			_parabola * randSpread(),
			_parabola * randSpread() + Math.cos(_length) * _radius,
			- (_parabola * randSpread() + Math.sin(_length) * _radius),
			- (_parabola * randSpread()),
			- (_parabola * randSpread() + Math.cos(_length) * _radius)
		);

	}

	this.addAttribute('position', new THREE.Float32BufferAttribute(vertices, 3));

	function randSpread() {
		return (Math.random() * width - (width / 2)) * (Math.random() * width - (width / 2));
	}

};

THREE.GalaxyBufferGeometry.prototype = Object.create(THREE.BufferGeometry.prototype);
THREE.GalaxyBufferGeometry.prototype.constructor = THREE.GalaxyBufferGeometry;