An important lighting parameter is SurfaceScale, which determines how high the border should be elevated for the sake of light imitation. You saw how it affects the result in the preceding examples.
But you can choose what to elevate exactly by using the setBumpInput(Effect input) method. Technically, you can use any effect as a bump map here, but most convenient will be ImageInput. In the selected image, transparent areas will stay flat and everything else will be elevated and highlighted.
In the following example, the Packt logo was used as an ImageInput:
I've highlighted the most important parts of the code:
//chapter8/light/BumpInputDemo.java ...
