setSize(width, height) {
        if(width !== this.width || height !== this.height) {
            this._shouldUpdate = true;
        }

        this.width = width;
        this.height = height;
    }
Sets the camera width and height
     Update the camera projection matrix only if the width or height actually changed

     params:
     @width (float, optional): width value to use
     @height (float, optional): height value to use
*