@Override
    protected void controlRender(RenderManager rm, ViewPort vp) {
    }
Render this control. Invoked once per frame, provided the
control is enabled and added to a scene. Should be invoked only by a
subclass or by AbstractControl.

@param rm the render manager (not null)
@param vp the view port to render (not null)
jme3-jbullet/src/main/java/com/jme3/bullet/debug/BulletRigidBodyDebugControl.java