Almost - it does not support sloped 3D floors at all, not even opaque. It also have small problems if 3D floor is touching sloped real floor, but not so often.
There are also 2 another, maybe bad things, you can't use skybox or mirror while watching 3D floor. It is good to add skybox in map with 3D floors, but when any 3D floor visible, skybox won't be. Mirrors are something different - if you use them, it will not render 3D floors correctly. You can use mirrors on places where it is not possible to see 3D floor(s).
I guess there are places for optimization, but right now i have no better idea.
EDIT: fixes, patch is few posts below
So, what does work:
- non sloped 3D floors
- 3D floor lighting (on sprites and other walls)
What does not work:
- sloped 3D floors
- extra effects (like fake fog)
- polyobjects (inside 3D floors, outside its OK)
Something more complex (sorry, i forgot vid_fps 1):
There are also places with huge FPS drop, caused by too many 3D floors and things.
Here is visible how sorting works: