function HCameraElement(data, globalData, comp) {
  this.initFrame();
  this.initBaseData(data, globalData, comp);
  this.initHierarchy();
  var getProp = PropertyFactory.getProp;
  this.pe = getProp(this, data.pe, 0, 0, this);
  if (data.ks.p.s) {
    this.px = getProp(this, data.ks.p.x, 1, 0, this);
    this.py = getProp(this, data.ks.p.y, 1, 0, this);
    this.pz = getProp(this, data.ks.p.z, 1, 0, this);
  } else {
    this.p = getProp(this, data.ks.p, 1, 0, this);
  }
  if (data.ks.a) {
    this.a = getProp(this, data.ks.a, 1, 0, this);
  }
  if (data.ks.or.k.length && data.ks.or.k[0].to) {
    var i, len = data.ks.or.k.length;
    for (i = 0; i < len; i += 1) {
      data.ks.or.k[i].to = null;
      data.ks.or.k[i].ti = null;
    }
  }
  this.or = getProp(this, data.ks.or, 1, degToRads, this);
  this.or.sh = true;
  this.rx = getProp(this, data.ks.rx, 0, degToRads, this);
  this.ry = getProp(this, data.ks.ry, 0, degToRads, this);
  this.rz = getProp(this, data.ks.rz, 0, degToRads, this);
  this.mat = new Matrix();
  this._prevMat = new Matrix();
  this._isFirstFrame = true;
    
  // TODO: find a better way to make the HCamera element to be compatible with the LayerInterface and TransformInterface.
  this.finalTransform = {
    mProp: this,
  };
}
extendPrototype([BaseElement, FrameElement, HierarchyElement], HCameraElement);

HCameraElement.prototype.setup = function () {
  var i, len = this.comp.threeDElements.length, comp;
  for (i = 0; i < len; i += 1) {
    // [perspectiveElem,container]
    comp = this.comp.threeDElements[i];
    if (comp.type === '3d') {
      comp.perspectiveElem.style.perspective = comp.perspectiveElem.style.webkitPerspective = this.pe.v + 'px';
      comp.container.style.transformOrigin = comp.container.style.mozTransformOrigin = comp.container.style.webkitTransformOrigin = '0px 0px 0px';
      comp.perspectiveElem.style.transform = comp.perspectiveElem.style.webkitTransform = 'matrix3d(1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1)';
    }
  }
};

HCameraElement.prototype.createElements = function () {
};

HCameraElement.prototype.hide = function () {
};

HCameraElement.prototype.renderFrame = function () {
  var _mdf = this._isFirstFrame;
  var i, len;
  if (this.hierarchy) {
    len = this.hierarchy.length;
    for (i = 0; i < len; i += 1) {
      _mdf = this.hierarchy[i].finalTransform.mProp._mdf || _mdf;
    }
  }
  if (_mdf || this.pe._mdf || (this.p && this.p._mdf) || (this.px && (this.px._mdf || this.py._mdf || this.pz._mdf)) || this.rx._mdf || this.ry._mdf || this.rz._mdf || this.or._mdf || (this.a && this.a._mdf)) {
    this.mat.reset();

    if (this.hierarchy) {
      var mat;
      len = this.hierarchy.length - 1;
      for (i = len; i >= 0; i -= 1) {
        var mTransf = this.hierarchy[i].finalTransform.mProp;
        this.mat.translate(-mTransf.p.v[0], -mTransf.p.v[1], mTransf.p.v[2]);
        this.mat.rotateX(-mTransf.or.v[0]).rotateY(-mTransf.or.v[1]).rotateZ(mTransf.or.v[2]);
        this.mat.rotateX(-mTransf.rx.v).rotateY(-mTransf.ry.v).rotateZ(mTransf.rz.v);
        this.mat.scale(1 / mTransf.s.v[0], 1 / mTransf.s.v[1], 1 / mTransf.s.v[2]);
        this.mat.translate(mTransf.a.v[0], mTransf.a.v[1], mTransf.a.v[2]);
      }
    }
    if (this.p) {
      this.mat.translate(-this.p.v[0], -this.p.v[1], this.p.v[2]);
    } else {
      this.mat.translate(-this.px.v, -this.py.v, this.pz.v);
    }
    if (this.a) {
      var diffVector;
      if (this.p) {
        diffVector = [this.p.v[0] - this.a.v[0], this.p.v[1] - this.a.v[1], this.p.v[2] - this.a.v[2]];
      } else {
        diffVector = [this.px.v - this.a.v[0], this.py.v - this.a.v[1], this.pz.v - this.a.v[2]];
      }
      var mag = Math.sqrt(Math.pow(diffVector[0], 2) + Math.pow(diffVector[1], 2) + Math.pow(diffVector[2], 2));
      // var lookDir = getNormalizedPoint(getDiffVector(this.a.v,this.p.v));
      var lookDir = [diffVector[0] / mag, diffVector[1] / mag, diffVector[2] / mag];
      var lookLengthOnXZ = Math.sqrt(lookDir[2] * lookDir[2] + lookDir[0] * lookDir[0]);
      var m_rotationX = (Math.atan2(lookDir[1], lookLengthOnXZ));
      var m_rotationY = (Math.atan2(lookDir[0], -lookDir[2]));
      this.mat.rotateY(m_rotationY).rotateX(-m_rotationX);

    }
    this.mat.rotateX(-this.rx.v).rotateY(-this.ry.v).rotateZ(this.rz.v);
    this.mat.rotateX(-this.or.v[0]).rotateY(-this.or.v[1]).rotateZ(this.or.v[2]);
    this.mat.translate(this.globalData.compSize.w / 2, this.globalData.compSize.h / 2, 0);
    this.mat.translate(0, 0, this.pe.v);


    var hasMatrixChanged = !this._prevMat.equals(this.mat);
    if ((hasMatrixChanged || this.pe._mdf) && this.comp.threeDElements) {
      len = this.comp.threeDElements.length;
      var comp;
      for (i = 0; i < len; i += 1) {
        comp = this.comp.threeDElements[i];
        if (comp.type === '3d') {
          if (hasMatrixChanged) {
            comp.container.style.transform = comp.container.style.webkitTransform = this.mat.toCSS();
          }
          if (this.pe._mdf) {
            comp.perspectiveElem.style.perspective = comp.perspectiveElem.style.webkitPerspective = this.pe.v + 'px';
          }
        }
      }
      this.mat.clone(this._prevMat);
    }
  }
  this._isFirstFrame = false;
};

HCameraElement.prototype.prepareFrame = function (num) {
  this.prepareProperties(num, true);
};

HCameraElement.prototype.destroy = function () {
};
HCameraElement.prototype.getBaseElement = function () { return null; };