subtract textures

OpenGL OpenGL: Advanced Coding
1

Hi you all,

I need to do texture subtractions as fast as posible. Any suggestions?

Yangshu

2

try this extensions:

ARB_texture_env_combine
EXT_texture_env_combine
NV_register_combiners

3

also glBlendEquation(GL_FUNC_SUBTRACT), on a card that supports none of the above.
It’s part of the imaging subset, so performance may(will) vary wildly from card to card.