- OpenGL Renderer: Fix longstanding blending bug where zero-alpha destination fragments were being blended with instead of being overwritten. This fixes certain coloring bugs in many games. (Does not currently work with MSAA.)
- OpenGL Renderer: Do some minor code cleanup.
- OpenGL Renderer: Be a little more precise when doing polygon comparisons between opaque and translucent drawing modes. (Related to commit 5aeed21.)