@Override
    public void onAction(String name, boolean isPressed, float tpf) {
        if (name.equals(TOGGLE_UPDATE) && isPressed) {
            offView.setEnabled(!offView.isEnabled());
        }
    }
This test renders a scene to a texture, then displays the texture on a cube.
jme3-examples/src/main/java/jme3test/post/TestRenderToTexture.java