private void onMouseButtonEventQueued(MouseButtonEvent evt, NiftyInputConsumer nic) {
        x = evt.getX();
        y = height - evt.getY();
        handleMouseEvent(evt.getButtonIndex(), evt.isPressed(), nic, evt);
    }
@param height The height of the viewport. Used to convert
bottom-left origin to upper-left origin.
jme3-niftygui/src/main/java/com/jme3/niftygui/InputSystemJme.java