public void setViewPort(int viewX, int viewY, int viewWidth, int viewHeight) {
        this.viewX = viewX;
        this.viewY = viewY;
        this.viewWidth = viewWidth;
        this.viewHeight = viewHeight;
    }
Set the timer that should be used to query the time based
{@link UniformBinding}s for material world parameters.

@param timer The timer to query time world parameters
jme3-core/src/main/java/com/jme3/shader/UniformBindingManager.java