Is there a good 3d realtime software renderer with features similar to OpenGL/DirectX? Something similar of what cairo or anti-grain do for 2d, but in 3d.
I actually just know Mesa witch has a software OpenGL implementation , and Coco3d.
It should be open source 🙂
For a pixel rendering engine why not have look at the DOOM rendering engine sources.
Another smaller and more standard API/OpenGL implementation called TinyGL could be something to look at too.