updateScrollPosition(lastXDelta, lastYDelta) {
        // actually update the plane position only if last X delta or last Y delta is not equal to 0
        if(lastXDelta || lastYDelta) {
            // set new positions based on our delta without triggering reflow
            this._boundingRect.document.top += lastYDelta * this.renderer.pixelRatio;
            this._boundingRect.document.left += lastXDelta * this.renderer.pixelRatio;

            // apply them
            this._applyWorldPositions();
        }
    }
This function updates the plane position based on the Curtains class scroll manager values

     params:
     @lastXDelta (float): last scroll value along X axis
     @lastYDelta (float): last scroll value along Y axis
*