Originally Posted by tothemax6
I really don't know much about the matter, but shouldn't it be a simple as recompiling the same code in a Linux compiler, instead of a Windows compiler?
That's where the Direct3D/OpenGL comes in. The main code can just be recompiled for Linux but the graphics code is sing the Direct3D api to save the programmers from having to do it on their own. That's not compatible with OpenGL so it take smore work if they don't use OpenGL to start with.