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; };