Two reasons:
- Makes it more straight-forward to add brightmaps to the non-power-of-two rendering functions.
- Made it easier to split off brightmap rendering. Hopefully improves performance, but I haven't thoroughly tested this.
- Software* + OpenGL support
- *Not supported: R_DrawColumnShadowed_8
- This has something to do with walls and FOF lights.
However, I don't see an easy code solution and I don't
know how to even test this.
- Ensures that column drawer doesn't read out of bounds
the brightmap column.
- Refactored code in r_segs.cpp, so it checks
R_TextureHasBrightmap.
- Added comments for plane brightmaps and sprite
brightmaps, that these are still error-prone.
