Tween.js

/**
 * Tween.js - Licensed under the MIT license
 * https://github.com/tweenjs/tween.js
 * ----------------------------------------------
 *
 * See https://github.com/tweenjs/tween.js/graphs/contributors for the full list of contributors.
 * Thank you all, you're awesome!
 */


var _Group = function () {
  this._tweens = {};
  this._tweensAddedDuringUpdate = {};
};

_Group.prototype = {
  getAll: function () {

    return Object.keys(this._tweens).map(function (tweenId) {
      return this._tweens[tweenId];
    }.bind(this));

  },

  removeAll: function () {

    this._tweens = {};

  },

  add: function (tween) {

    this._tweens[tween.getId()] = tween;
    this._tweensAddedDuringUpdate[tween.getId()] = tween;

  },

  remove: function (tween) {

    delete this._tweens[tween.getId()];
    delete this._tweensAddedDuringUpdate[tween.getId()];

  },

  update: function (time, preserve) {

    var tweenIds = Object.keys(this._tweens);

    if (tweenIds.length === 0) {
      return false;
    }

    time = time !== undefined ? time : TWEEN.now();

    // Tweens are updated in "batches". If you add a new tween during an update, then the
    // new tween will be updated in the next batch.
    // If you remove a tween during an update, it may or may not be updated. However,
    // if the removed tween was added during the current batch, then it will not be updated.
    while (tweenIds.length > 0) {
      this._tweensAddedDuringUpdate = {};

      for (var i = 0; i < tweenIds.length; i++) {

        var tween = this._tweens[tweenIds[i]];

        if (tween && tween.update(time) === false) {
          tween._isPlaying = false;

          if (!preserve) {
            delete this._tweens[tweenIds[i]];
          }
        }
      }

      tweenIds = Object.keys(this._tweensAddedDuringUpdate);
    }

    return true;

  }
};

var TWEEN = new _Group();

TWEEN.Group = _Group;
TWEEN._nextId = 0;
TWEEN.nextId = function () {
  return TWEEN._nextId++;
};


// Include a performance.now polyfill.
// In node.js, use process.hrtime.
if (typeof (window) === 'undefined' && typeof (process) !== 'undefined' && process.hrtime) {
  TWEEN.now = function () {
    var time = process.hrtime();

    // Convert [seconds, nanoseconds] to milliseconds.
    return time[0] * 1000 + time[1] / 1000000;
  };
}
// In a browser, use window.performance.now if it is available.
else if (typeof (window) !== 'undefined' &&
  window.performance !== undefined &&
  window.performance.now !== undefined) {
  // This must be bound, because directly assigning this function
  // leads to an invocation exception in Chrome.
  TWEEN.now = window.performance.now.bind(window.performance);
}
// Use Date.now if it is available.
else if (Date.now !== undefined) {
  TWEEN.now = Date.now;
}
// Otherwise, use 'new Date().getTime()'.
else {
  TWEEN.now = function () {
    return new Date().getTime();
  };
}


TWEEN.Tween = function (object, group) {
  this._object = object;
  this._valuesStart = {};
  this._valuesEnd = {};
  this._valuesStartRepeat = {};
  this._duration = 1000;
  this._repeat = 0;
  this._repeatDelayTime = undefined;
  this._yoyo = false;
  this._isPlaying = false;
  this._reversed = false;
  this._delayTime = 0;
  this._startTime = null;
  this._easingFunction = TWEEN.Easing.Linear.None;
  this._interpolationFunction = TWEEN.Interpolation.Linear;
  this._chainedTweens = [];
  this._onStartCallback = null;
  this._onStartCallbackFired = false;
  this._onUpdateCallback = null;
  this._onCompleteCallback = null;
  this._onStopCallback = null;
  this._group = group || TWEEN;
  this._id = TWEEN.nextId();

};

TWEEN.Tween.prototype = {
  getId: function getId() {
    return this._id;
  },

  isPlaying: function isPlaying() {
    return this._isPlaying;
  },

  to: function to(properties, duration) {

    this._valuesEnd = properties;

    if (duration !== undefined) {
      this._duration = duration;
    }

    return this;

  },

  start: function start(time) {

    this._group.add(this);

    this._isPlaying = true;

    this._onStartCallbackFired = false;

    this._startTime = time !== undefined ? typeof time === 'string' ? TWEEN.now() + parseFloat(time) : time : TWEEN.now();
    this._startTime += this._delayTime;

    for (var property in this._valuesEnd) {

      // Check if an Array was provided as property value
      if (this._valuesEnd[property] instanceof Array) {

        if (this._valuesEnd[property].length === 0) {
          continue;
        }

        // Create a local copy of the Array with the start value at the front
        this._valuesEnd[property] = [this._object[property]].concat(this._valuesEnd[property]);

      }

      // If `to()` specifies a property that doesn't exist in the source object,
      // we should not set that property in the object
      if (this._object[property] === undefined) {
        continue;
      }

      // Save the starting value.
      this._valuesStart[property] = this._object[property];

      if ((this._valuesStart[property] instanceof Array) === false) {
        this._valuesStart[property] *= 1.0; // Ensures we're using numbers, not strings
      }

      this._valuesStartRepeat[property] = this._valuesStart[property] || 0;

    }

    return this;

  },

  stop: function stop() {

    if (!this._isPlaying) {
      return this;
    }

    this._group.remove(this);
    this._isPlaying = false;

    if (this._onStopCallback !== null) {
      this._onStopCallback(this._object);
    }

    this.stopChainedTweens();
    return this;

  },

  end: function end() {

    this.update(this._startTime + this._duration);
    return this;

  },

  stopChainedTweens: function stopChainedTweens() {

    for (var i = 0, numChainedTweens = this._chainedTweens.length; i < numChainedTweens; i++) {
      this._chainedTweens[i].stop();
    }

  },

  group: function group(group) {
    this._group = group;
    return this;
  },

  delay: function delay(amount) {

    this._delayTime = amount;
    return this;

  },

  repeat: function repeat(times) {

    this._repeat = times;
    return this;

  },

  repeatDelay: function repeatDelay(amount) {

    this._repeatDelayTime = amount;
    return this;

  },

  yoyo: function yoyo(yy) {

    this._yoyo = yy;
    return this;

  },

  easing: function easing(eas) {

    this._easingFunction = eas;
    return this;

  },

  interpolation: function interpolation(inter) {

    this._interpolationFunction = inter;
    return this;

  },

  chain: function chain() {

    this._chainedTweens = arguments;
    return this;

  },

  onStart: function onStart(callback) {

    this._onStartCallback = callback;
    return this;

  },

  onUpdate: function onUpdate(callback) {

    this._onUpdateCallback = callback;
    return this;

  },

  onComplete: function onComplete(callback) {

    this._onCompleteCallback = callback;
    return this;

  },

  onStop: function onStop(callback) {

    this._onStopCallback = callback;
    return this;

  },

  update: function update(time) {

    var property;
    var elapsed;
    var value;

    if (time < this._startTime) {
      return true;
    }

    if (this._onStartCallbackFired === false) {

      if (this._onStartCallback !== null) {
        this._onStartCallback(this._object);
      }

      this._onStartCallbackFired = true;
    }

    elapsed = (time - this._startTime) / this._duration;
    elapsed = (this._duration === 0 || elapsed > 1) ? 1 : elapsed;

    value = this._easingFunction(elapsed);

    for (property in this._valuesEnd) {

      // Don't update properties that do not exist in the source object
      if (this._valuesStart[property] === undefined) {
        continue;
      }

      var start = this._valuesStart[property] || 0;
      var end = this._valuesEnd[property];

      if (end instanceof Array) {

        this._object[property] = this._interpolationFunction(end, value);

      } else {

        // Parses relative end values with start as base (e.g.: +10, -3)
        if (typeof (end) === 'string') {

          if (end.charAt(0) === '+' || end.charAt(0) === '-') {
            end = start + parseFloat(end);
          } else {
            end = parseFloat(end);
          }
        }

        // Protect against non numeric properties.
        if (typeof (end) === 'number') {
          this._object[property] = start + (end - start) * value;
        }

      }

    }

    if (this._onUpdateCallback !== null) {
      this._onUpdateCallback(this._object);
    }

    if (elapsed === 1) {

      if (this._repeat > 0) {

        if (isFinite(this._repeat)) {
          this._repeat--;
        }

        // Reassign starting values, restart by making startTime = now
        for (property in this._valuesStartRepeat) {

          if (typeof (this._valuesEnd[property]) === 'string') {
            this._valuesStartRepeat[property] = this._valuesStartRepeat[property] + parseFloat(this._valuesEnd[property]);
          }

          if (this._yoyo) {
            var tmp = this._valuesStartRepeat[property];

            this._valuesStartRepeat[property] = this._valuesEnd[property];
            this._valuesEnd[property] = tmp;
          }

          this._valuesStart[property] = this._valuesStartRepeat[property];

        }

        if (this._yoyo) {
          this._reversed = !this._reversed;
        }

        if (this._repeatDelayTime !== undefined) {
          this._startTime = time + this._repeatDelayTime;
        } else {
          this._startTime = time + this._delayTime;
        }

        return true;

      } else {

        if (this._onCompleteCallback !== null) {

          this._onCompleteCallback(this._object);
        }

        for (var i = 0, numChainedTweens = this._chainedTweens.length; i < numChainedTweens; i++) {
          // Make the chained tweens start exactly at the time they should,
          // even if the `update()` method was called way past the duration of the tween
          this._chainedTweens[i].start(this._startTime + this._duration);
        }

        return false;

      }

    }

    return true;

  }
};


TWEEN.Easing = {

  Linear: {

    None: function (k) {

      return k;

    }

  },

  Quadratic: {

    In: function (k) {

      return k * k;

    },

    Out: function (k) {

      return k * (2 - k);

    },

    InOut: function (k) {

      if ((k *= 2) < 1) {
        return 0.5 * k * k;
      }

      return - 0.5 * (--k * (k - 2) - 1);

    }

  },

  Cubic: {

    In: function (k) {

      return k * k * k;

    },

    Out: function (k) {

      return --k * k * k + 1;

    },

    InOut: function (k) {

      if ((k *= 2) < 1) {
        return 0.5 * k * k * k;
      }

      return 0.5 * ((k -= 2) * k * k + 2);

    }

  },

  Quartic: {

    In: function (k) {

      return k * k * k * k;

    },

    Out: function (k) {

      return 1 - (--k * k * k * k);

    },

    InOut: function (k) {

      if ((k *= 2) < 1) {
        return 0.5 * k * k * k * k;
      }

      return - 0.5 * ((k -= 2) * k * k * k - 2);

    }

  },

  Quintic: {

    In: function (k) {

      return k * k * k * k * k;

    },

    Out: function (k) {

      return --k * k * k * k * k + 1;

    },

    InOut: function (k) {

      if ((k *= 2) < 1) {
        return 0.5 * k * k * k * k * k;
      }

      return 0.5 * ((k -= 2) * k * k * k * k + 2);

    }

  },

  Sinusoidal: {

    In: function (k) {

      return 1 - Math.cos(k * Math.PI / 2);

    },

    Out: function (k) {

      return Math.sin(k * Math.PI / 2);

    },

    InOut: function (k) {

      return 0.5 * (1 - Math.cos(Math.PI * k));

    }

  },

  Exponential: {

    In: function (k) {

      return k === 0 ? 0 : Math.pow(1024, k - 1);

    },

    Out: function (k) {

      return k === 1 ? 1 : 1 - Math.pow(2, - 10 * k);

    },

    InOut: function (k) {

      if (k === 0) {
        return 0;
      }

      if (k === 1) {
        return 1;
      }

      if ((k *= 2) < 1) {
        return 0.5 * Math.pow(1024, k - 1);
      }

      return 0.5 * (- Math.pow(2, - 10 * (k - 1)) + 2);

    }

  },

  Circular: {

    In: function (k) {

      return 1 - Math.sqrt(1 - k * k);

    },

    Out: function (k) {

      return Math.sqrt(1 - (--k * k));

    },

    InOut: function (k) {

      if ((k *= 2) < 1) {
        return - 0.5 * (Math.sqrt(1 - k * k) - 1);
      }

      return 0.5 * (Math.sqrt(1 - (k -= 2) * k) + 1);

    }

  },

  Elastic: {

    In: function (k) {

      if (k === 0) {
        return 0;
      }

      if (k === 1) {
        return 1;
      }

      return -Math.pow(2, 10 * (k - 1)) * Math.sin((k - 1.1) * 5 * Math.PI);

    },

    Out: function (k) {

      if (k === 0) {
        return 0;
      }

      if (k === 1) {
        return 1;
      }

      return Math.pow(2, -10 * k) * Math.sin((k - 0.1) * 5 * Math.PI) + 1;

    },

    InOut: function (k) {

      if (k === 0) {
        return 0;
      }

      if (k === 1) {
        return 1;
      }

      k *= 2;

      if (k < 1) {
        return -0.5 * Math.pow(2, 10 * (k - 1)) * Math.sin((k - 1.1) * 5 * Math.PI);
      }

      return 0.5 * Math.pow(2, -10 * (k - 1)) * Math.sin((k - 1.1) * 5 * Math.PI) + 1;

    }

  },

  Back: {

    In: function (k) {

      var s = 1.70158;

      return k * k * ((s + 1) * k - s);

    },

    Out: function (k) {

      var s = 1.70158;

      return --k * k * ((s + 1) * k + s) + 1;

    },

    InOut: function (k) {

      var s = 1.70158 * 1.525;

      if ((k *= 2) < 1) {
        return 0.5 * (k * k * ((s + 1) * k - s));
      }

      return 0.5 * ((k -= 2) * k * ((s + 1) * k + s) + 2);

    }

  },

  Bounce: {

    In: function (k) {

      return 1 - TWEEN.Easing.Bounce.Out(1 - k);

    },

    Out: function (k) {

      if (k < (1 / 2.75)) {
        return 7.5625 * k * k;
      } else if (k < (2 / 2.75)) {
        return 7.5625 * (k -= (1.5 / 2.75)) * k + 0.75;
      } else if (k < (2.5 / 2.75)) {
        return 7.5625 * (k -= (2.25 / 2.75)) * k + 0.9375;
      } else {
        return 7.5625 * (k -= (2.625 / 2.75)) * k + 0.984375;
      }

    },

    InOut: function (k) {

      if (k < 0.5) {
        return TWEEN.Easing.Bounce.In(k * 2) * 0.5;
      }

      return TWEEN.Easing.Bounce.Out(k * 2 - 1) * 0.5 + 0.5;

    }

  }

};

TWEEN.Interpolation = {

  Linear: function (v, k) {

    var m = v.length - 1;
    var f = m * k;
    var i = Math.floor(f);
    var fn = TWEEN.Interpolation.Utils.Linear;

    if (k < 0) {
      return fn(v[0], v[1], f);
    }

    if (k > 1) {
      return fn(v[m], v[m - 1], m - f);
    }

    return fn(v[i], v[i + 1 > m ? m : i + 1], f - i);

  },

  Bezier: function (v, k) {

    var b = 0;
    var n = v.length - 1;
    var pw = Math.pow;
    var bn = TWEEN.Interpolation.Utils.Bernstein;

    for (var i = 0; i <= n; i++) {
      b += pw(1 - k, n - i) * pw(k, i) * v[i] * bn(n, i);
    }

    return b;

  },

  CatmullRom: function (v, k) {

    var m = v.length - 1;
    var f = m * k;
    var i = Math.floor(f);
    var fn = TWEEN.Interpolation.Utils.CatmullRom;

    if (v[0] === v[m]) {

      if (k < 0) {
        i = Math.floor(f = m * (1 + k));
      }

      return fn(v[(i - 1 + m) % m], v[i], v[(i + 1) % m], v[(i + 2) % m], f - i);

    } else {

      if (k < 0) {
        return v[0] - (fn(v[0], v[0], v[1], v[1], -f) - v[0]);
      }

      if (k > 1) {
        return v[m] - (fn(v[m], v[m], v[m - 1], v[m - 1], f - m) - v[m]);
      }

      return fn(v[i ? i - 1 : 0], v[i], v[m < i + 1 ? m : i + 1], v[m < i + 2 ? m : i + 2], f - i);

    }

  },

  Utils: {

    Linear: function (p0, p1, t) {

      return (p1 - p0) * t + p0;

    },

    Bernstein: function (n, i) {

      var fc = TWEEN.Interpolation.Utils.Factorial;

      return fc(n) / fc(i) / fc(n - i);

    },

    Factorial: (function () {

      var a = [1];

      return function (n) {

        var s = 1;

        if (a[n]) {
          return a[n];
        }

        for (var i = n; i > 1; i--) {
          s *= i;
        }

        a[n] = s;
        return s;

      };

    })(),

    CatmullRom: function (p0, p1, p2, p3, t) {

      var v0 = (p2 - p0) * 0.5;
      var v1 = (p3 - p1) * 0.5;
      var t2 = t * t;
      var t3 = t * t2;

      return (2 * p1 - 2 * p2 + v0 + v1) * t3 + (- 3 * p1 + 3 * p2 - 2 * v0 - v1) * t2 + v0 * t + p1;

    }

  }

};

// UMD (Universal Module Definition)
(function (root) {

  if (typeof define === 'function' && define.amd) {

    // AMD
    define([], function () {
      return TWEEN;
    });

  } else if (typeof module !== 'undefined' && typeof exports === 'object') {

    // Node.js
    module.exports = TWEEN;

  } else if (root !== undefined) {

    // Global variable
    root.TWEEN = TWEEN;

  }

})(this);