Question

Is it possible to perform blending with one alpha channel per component (one for red, one for green and one for blue) with OpenGL? If not, what are some possible workarounds?

Answer 1

This isn’t something that’s directly supported. It’s fairly easy to achieve on your own though:

• Render your triangle (or whatever) using the 3-channel “alpha” texture and glBlendFunc(GL_ZERO, GL_ONE_MINUS_SRC_COLOR)
• Enable multitexture and set the “alpha” texture to modulate your rgb texture
• Render your triangle with glBlendFunc(GL_ONE, GL_ONE)