Hey,
if you want to create the illusion of the Planet having visible mountains etc you can take your dif Texture and create a Normal Map using ( for example ) xNormal → http://www.xnormal.net/ and its Heightmap to Normalmap feature.
In VVVV u will need to use a shader with Normal/Bump features.
Heres an example i created with dynamic normal map.
sites/default/files/imagecache/large/images/nautinormal.JPG
Or do you mean shadows from the Textfields on the planet?