BW Anaglyph creation ...

Dear all,

I would like create a BW anaglyph with OpenGL. This requires to convert the left and right “images” in the RGB framebuffer to greyscale, as the RGB components of the final anaglyph image are calculated as:

R = RGB2grey( Right Image )
G = RGB2grey( Left Image )
B = RGB2grey( Left Image )

where RGB2grey is short for a conversion from RGB to greyscale.

Does anybody know how to accomplish such a conversion (in the framebuffer) in a fast way? I found some stuff from Siggraph 97 where the Accumulation buffer is used to desaturize an image (which I guess would actually do what I want), but it was only code in a test environment that wouldn’t run on my machine. Maybe someone knows more about this technique???

Best regards