three.js/examples/js/loaders/vrml/ThreeJs/Animation/PositionInterpolator.js

/**
 * @author Bart McLeod, [email protected]
 * @since May 25, 2016
 *
 * Adds animation and interaction support to the VrmlParser.Renderer.ThreeJs
 * @todo: take time into account
 */
// we use below notation to create exports for the Google closure compiler

/**
 * The OrientationInterpolator wraps the essential properties of its original VRML node counterpart
 * and adds functionality to support animation in Three.js.
 *
 * @param originalNode
 * @constructor
 */
VrmlParser.Renderer.ThreeJs.Animation['PositionInterpolator'] = function (originalNode, debug) {
  this.key = originalNode.key;
  this.keyValue = originalNode.keyValue;
  this.debug = debug ? true : false;
}

VrmlParser.Renderer.ThreeJs.Animation.PositionInterpolator.prototype = {

  /**
   * Utility to easily switch logging on and off with the debug flag.
   * @param obj
   */
  log: function (obj) {
    if ( this.debug ) {
      console.log(obj);
    }
  },

  tween: function (target, endPosition) {
    return new TWEEN
      .Tween(target.position)
      .to(endPosition)
      .start(+new Date())
      ;
  },

  /**
   * Gets the animation callback method, which can play the animation associated with this OrientationInterpolator.
   * @param Object3D target
   * @param callable finish A method that will be called when the callback is ready to be removed
   */
  getCallback: function (target, finish) {
    var scope = this;

    // assumption that the first position is the position the target is already at, so we start with the next
    var index = 1;

    var p = this.getPosition(index);

    this.log(p);
    this.log(target);

    var tween = this.tween(target, p);

    tween.onComplete(function () {
      // take next key or finish
      index++;

      if ( index >= scope.keyValue.length ) {
        console.log('finish');
        // now make the end position of the target exactly the same as p, to correct any rounding errors from tweening
        target.position = p;
        finish();
        return;
      }

      p = scope.getPosition(index);
      scope.log(p);
      tween = scope.tween(target, p);
      tween.onComplete = this;
    });

    /**
     * The animation callback
     *
     * @param float delta time difference
     * @param callable finish will be called by the callback when it is ready to be removed
     */
    var callback = function (delta) {
      tween.update(+new Date());
    };

    return callback;
  },

  getPosition: function (index) {
    var v = this.keyValue[index];
    return new THREE.Vector3(v.x, v.y, v.z);
  }
};