That being said, I'd like to put this out for consideration. And Graf - before you close this - maybe somebody in the community might be willing to help with this. I'll offer a hand with it when I can - I need to get a working Windows compiling platform first though (and that's going to take a while yet).
I think if the wrapper itself is improved upon a bit, it can easily be made into a special GZDoom-usable DLL which translates its internal OpenGL API calls to Direct3D. What it's missing is shader support and a few OpenGL 1.2+ (and later) features.
This won't help at all with cross-platform portability, but at least it will make GZDoom more usable with Intel and ATI cards since they seem to be a dime a dozen these days and both manufacturers are intent on breaking their drivers.
The wrapper in question can be downloaded here: http://sourceforge.net/projects/gldirect/files/ (newer versions of GZDoom will reject the wrapper since it is only OpenGL 1.1, unfortunately
)It is based on the Mesa3D project - a newer version of the wrapper can probably be compiled from here: http://www.mesa3d.org/ but I doubt it will offer much more than what's already there.
If this works it might even be possible to import some code from Mesa3D, and after a bit of optimization and removal of functions that are not used, offer a preliminary 32-bit software renderer within GZDoom itself.
The Direct3D portion is based on GLDirect which was for a long time developed and maintained by SciTech (though they apparently did not originally start this project).
