I was wondering if any of the OpenGL gurus here can point me in the right direction for this. I've been doing a lot of work in Doom 3, specifically hacking in an HDRi pipeline. (Hush with the Carmack 'non-trivial' statement; I have a working one already, srsly d00ds!) What I'd like to do is change the formats of some textures and buffers in order to improve the storage capacity, but unfortunately I lack the ability to directly manipulate state calls, etc. My thinking was that I might be able to actually just force all RGB8 textures to RGBA8 so I can write to/use the alpha channel. There might be some blending weirdness, but I can fix that with custom shaders and elbow grease. Can anyone help me in figuring out how I would do this?

If you want to intercept GL calls
http://www.opengl.org/wiki/index.php/Debugging_Tools

I believe I actually have that-- I was mostly looking into replacing some function parameters, kinda like a wrapper or something.

You can modify that same tool for that purpose. The source code is open.

Oh cool, I didn't see that the source was available for whatever reason XD

Any pointers on where to look for hooks, though? I see some references to a function table, so I'm assuming I need to dig around there?