GL_TEXTURE_ENV for special combining issues..

OpenGL OpenGL: Advanced Coding
1

I’ve just tested the glTexEnvf(…) func with
GL_MODULATE,GL_DECAL,GL_BLEND and GL_ADD params but i’ll enjoy more stuff with something which sounds like GL_MODULATE2X and
GL_MODULATE4X!!

Of course it’s possible to emulate these funky modes with multiple passes but with new
boards like the tnt2 or above i know that it is possible to achieve this in a single pass… hey! D3D can do it!!

Where can i find these definitions??
Are they provided in OpenGL 1.2 headers??
Please answer before i jump through my 4th floor window!!

2

The blend modes you mentioned aren’t in the base OpenGL spec; try looking into the extension ‘EXT_texture_env_combine’, it does the stuff you mentioned and is supported on TNT.