@Override
    public void update(float tpf) {
        super.update(tpf);
        //update all object links
        updateRigidBodies();
        updateGhosts();
        updateCharacters();
        updateJoints();
        updateVehicles();
        //update our debug root node
        physicsDebugRootNode.updateLogicalState(tpf);
        physicsDebugRootNode.updateGeometricState();
    }
Update this state prior to rendering. Should be invoked only by a
subclass or by the AppStateManager. Invoked once per frame, provided the
state is attached and enabled.

@param tpf the time interval between frames (in seconds, &ge;0)
jme3-jbullet/src/main/java/com/jme3/bullet/debug/BulletDebugAppState.java