http://bugs.winehq.org/show_bug.cgi?id=7284
--- Comment #28 from Alexander Dorofeyev alexd4@inbox.lv 2009-03-28 17:34:41 --- Created an attachment (id=20174) --> (http://bugs.winehq.org/attachment.cgi?id=20174) rcp of 0 testcase
A while ago I spent some time debugging this, and as far as I can tell the problem originates in the vertex shader, and it has something to do with taking a reciprocal of zero (supposed to produce infinity afaik) then multiplying it by zero. On windows this seems to result in a black color (i.e. zero) on wine - white. And least this contributes a part of the problem, I believe. Unfortunately I got busy / lazy and never finished fixing this. I'm trying to look into it again now, put together a testcase for this. Renders a black quad on windows and white quad on wine, on my machine. But this needs to be tested on non-nvidia machines. This stuff with divide by zero - I'm not sure it's well-defined behavior at all.