@Override
            public void update(float tpf) {
                super.update(tpf);

                angle += tpf * 2f;
                angle %= FastMath.TWO_PI;

                pl.setPosition(new Vector3f(FastMath.cos(angle) * 4f, 0.5f, FastMath.sin(angle) * 4f));
                lightMdl.setLocalTranslation(pl.getPosition());
            }
This test creates a scene with a bump-mapped quad and an orbiting light.
jme3-screenshot-tests/src/test/java/org/jmonkeyengine/screenshottests/material/TestSimpleBumps.java