Down with OPP: Other Programs' Pixels

I'm trying to figure out how I can read the graphics output from other programs for the sake of creating (meta) visualizations.

I think the key to this is finding out where the framebuffers are, or somehow accessing them. If I can start drawing bitmaps of framebuffer data from one other (abritrary) program, I'm satisfied.

The thing is, I'm a little over my head. I've never worked with low-level languages before, but the idea of reading other programs' memory seems to necessitate one's use, if only for the sake of bypassing restrictions from a compiler. But I wouldn't know how to start looking for framebuffers in memory. (Come to think of it, I've never looked for anything in memory before, at least memory I didn't allocate myself.) There is an assembly language for GPUs by OpenGL.

I've also run across Cg and GLSL in my research, which look awesome for making shaders, but I don't know if they'll help me do this specific task.

Any ideas?

>>9
I see. Thanks for clarifying.

As to what I would actually like to be grabbing: ideally I would be able to have access to just about everything the computer has been doing to create the graphics it's displaying, all buffers and states.

As a result, I don't have a particular program or type of program in mind as a "target". I'm planning for this program to be run under a typical desktop user environment, which means I probably won't be dealing with many 3D processes -- although those would probably provide the most possibilities for interesting visuals. To that effect, it would be good if I could get something out of the 3D acceleration for the desktop environment from the newer versions of Windows.