At the moment I don't have any plans for that.
GLSL is a really powerful and nice shading language. Some advantages of it over CG are:
- It is not vendor specific
- It is integrated directly into OpenGL without the need for additional libraries
- Development is pushed by the Khrons group (OpenGL 3.0 and 4.0 are coming this year)
- It doesn't have different profiles which cause additional trouble
Honestly I don't see any advantage in CG. Integrating a second shading language would probably require some hacks and parallel code paths since some features of GLSL are certainly not directly available in CG. One of the best features of Horde is that it is small and clean and I wouldn't want to destroy that
So my question is, why having a second language if you can do the same with the one that is available?