[Bug 17423] Prince of Persia SoT: Graphic Bug

http://bugs.winehq.org/show_bug.cgi?id=17423

--- Comment #24 from Stefan Dösinger  2011-08-29 15:57:59 CDT ---
Ok, the crashday issue is the same as bug 27733(Fog coordinate vs projection
matrix). Matteo has done some debugging on 27733 and will post an explanation
there.

A short summary: the broken draws don't use vertex shaders, they're done with
the fixed function pipeline. The last row of the projection matrix is 0, 0, 0,
1, which is a special case in d3d where the depth after the projection
transformation is used for fogging rather than the pre-projection depth.
Unfortunately opengl doesn't support anything similar, so we need a fixed
function pipeline replacement shader to actually fix this.