SDL_VideoGL is an alternative API for the SDL video subsystem. The two APIs are very similar. So the learning curve is minimal. The incentive to use SDL_VideoGL is that it uses OpenGL on the backend to acheive a faster rendering of graphics.
This software can be used for relief and normal maps calculation by 3D sculptors and designers. Reliefer can be called from Blender by means of Python script. It's a GPU-based visual computing application so requres OpenGL 2 compitable video subsystem.