http://bugs.winehq.org/show_bug.cgi?id=6932
------- Additional Comments From e0425955@student.tuwien.ac.at 2006-29-12 09:30 ------- Have you tried enabling visual treatment and overbright in the game (both together)? The whole scene is black then (for me), but if I revert the patch it becomes visible again - but semi-transparent, although with only Visual Treatment and no Overbright its black in both cases.
I couldn't try this before (see http://bugs.winehq.org/show_bug.cgi?id=6997), and just noticed if I set OffscreenRenderMode to fbo I avoid the slowness that somehow results with high VisualTreatment (preventing me from testing) (at least on 2 GeForce FX GPUs I tested) as result of the backbuffer contents being copied back to a texture.
It's possible that the blackness is NOT caused by the blending though, needs to be investigated further, I guess.