keyboard-controls.js

require('../../lib/keyboard.polyfill');

const MAX_DELTA = 0.2,
    PROXY_FLAG = '__keyboard-controls-proxy';

const KeyboardEvent = window.KeyboardEvent;

/**
 * Keyboard Controls component.
 *
 * Stripped-down version of: https://github.com/donmccurdy/aframe-keyboard-controls
 *
 * Bind keyboard events to components, or control your entities with the WASD keys.
 *
 * Why use KeyboardEvent.code? "This is set to a string representing the key that was pressed to
 * generate the KeyboardEvent, without taking the current keyboard layout (e.g., QWERTY vs.
 * Dvorak), locale (e.g., English vs. French), or any modifier keys into account. This is useful
 * when you care about which physical key was pressed, rather thanwhich character it corresponds
 * to. For example, if you’re a writing a game, you might want a certain set of keys to move the
 * player in different directions, and that mapping should ideally be independent of keyboard
 * layout. See: https://developers.google.com/web/updates/2016/04/keyboardevent-keys-codes
 *
 * @namespace wasd-controls
 * keys the entity moves and if you release it will stop. Easing simulates friction.
 * to the entity when pressing the keys.
 * @param {bool} [enabled=true] - To completely enable or disable the controls
 */
module.exports = AFRAME.registerComponent('keyboard-controls', {
  schema: {
    enabled:           { default: true },
    debug:             { default: false }
  },

  init: function () {
    this.dVelocity = new THREE.Vector3();
    this.localKeys = {};
    this.listeners = {
      keydown: this.onKeyDown.bind(this),
      keyup: this.onKeyUp.bind(this),
      blur: this.onBlur.bind(this)
    };
    this.attachEventListeners();
  },

  /*******************************************************************
  * Movement
  */

  isVelocityActive: function () {
    return this.data.enabled && !!Object.keys(this.getKeys()).length;
  },

  getVelocityDelta: function () {
    const data = this.data,
        keys = this.getKeys();

    this.dVelocity.set(0, 0, 0);
    if (data.enabled) {
      if (keys.KeyW || keys.ArrowUp)    { this.dVelocity.z -= 1; }
      if (keys.KeyA || keys.ArrowLeft)  { this.dVelocity.x -= 1; }
      if (keys.KeyS || keys.ArrowDown)  { this.dVelocity.z += 1; }
      if (keys.KeyD || keys.ArrowRight) { this.dVelocity.x += 1; }
    }

    return this.dVelocity.clone();
  },

  /*******************************************************************
  * Events
  */

  play: function () {
    this.attachEventListeners();
  },

  pause: function () {
    this.removeEventListeners();
  },

  remove: function () {
    this.pause();
  },

  attachEventListeners: function () {
    window.addEventListener('keydown', this.listeners.keydown, false);
    window.addEventListener('keyup', this.listeners.keyup, false);
    window.addEventListener('blur', this.listeners.blur, false);
  },

  removeEventListeners: function () {
    window.removeEventListener('keydown', this.listeners.keydown);
    window.removeEventListener('keyup', this.listeners.keyup);
    window.removeEventListener('blur', this.listeners.blur);
  },

  onKeyDown: function (event) {
    if (AFRAME.utils.shouldCaptureKeyEvent(event)) {
      this.localKeys[event.code] = true;
      this.emit(event);
    }
  },

  onKeyUp: function (event) {
    if (AFRAME.utils.shouldCaptureKeyEvent(event)) {
      delete this.localKeys[event.code];
      this.emit(event);
    }
  },

  onBlur: function () {
    for (let code in this.localKeys) {
      if (this.localKeys.hasOwnProperty(code)) {
        delete this.localKeys[code];
      }
    }
  },

  emit: function (event) {
    // TODO - keydown only initially?
    // TODO - where the f is the spacebar

    // Emit original event.
    if (PROXY_FLAG in event) {
      // TODO - Method never triggered.
      this.el.emit(event.type, event);
    }

    // Emit convenience event, identifying key.
    this.el.emit(event.type + ':' + event.code, new KeyboardEvent(event.type, event));
    if (this.data.debug) console.log(event.type + ':' + event.code);
  },

  /*******************************************************************
  * Accessors
  */

  isPressed: function (code) {
    return code in this.getKeys();
  },

  getKeys: function () {
    if (this.isProxied()) {
      return this.el.sceneEl.components['proxy-controls'].getKeyboard();
    }
    return this.localKeys;
  },

  isProxied: function () {
    const proxyControls = this.el.sceneEl.components['proxy-controls'];
    return proxyControls && proxyControls.isConnected();
  }

});