How to use software vetex processing?

OpenGL OpenGL: Advanced Coding
1

For some reason I need to use software vertex processing to get the processed vertices to the CPU’ system memory for further computation.

Can I do software vertex processing in opengl? And how do I do this?

Regards
Lee Sandberg
AB Colorod Media

2

You cannot use OpenGL to transform your verts and return a buffer to the transformed data. You will have to write the routines to do this yourself.

3

In the worst case, you can try using a feedback buffer, but iirc this returns vertices of transformed and pixel-clipped fragments, so you’re in for a performance ride. See spec 1.1 section 5.3. I used this technique to muck with ST coordinates in a way that wouldn’t fit on the texture matrix, after they were TexGen’ed by the GL.

Edit: spoeling

[This message has been edited by bpeers (edited 08-02-2002).]