I've finally pinned down some code that can transition into the Mesa3D / Gallium3D projects for Haiku. My plan at the moment is to try and move the winsys code and some of the GL screen initialization code into Mesa.
If you have entirely too much time on your hands you can see my progress on the Mesa code here:
http://cgit.haiku-os.org/haiku/tree/src/add-ons/opengl/swpipe/bitmap_wrapper.cpp http://cgit.haiku-os.org/haiku/tree/src/add-ons/opengl/swpipe/SoftwareWinsys.cppAnd the following file would see reductions in code and rely on functions within Mesa:
Mainline Mesa + Haiku won't see any commits until i've proven that the changes work.