[Bug 10423] Painkiller Single-Player Demo #3: change in shader_glsl_lit() caused white turrets

http://bugs.winehq.org/show_bug.cgi?id=10423

--- Comment #26 from Stefan Dösinger  2011-08-22 09:18:11 CDT ---
I can reproduce this bug(OSX 10.6, Geforce 9600). The game uses a HAL device
with HARDWAREVERTEXPROCESSING | PUREDEVICE as flags, so there's no software
vertex processing involved.

Testing various versions of the change it looks like it doesn't matter what the
0.0^0.0 case returns, as long as it is not NaN. But apparently that's what at
least my GPU returns for pow(0.0, 0.0). Even Inf is OK. The ARB backend works
as well, but I haven't checked what its LIT returns in this case.

I'll write a test for LIT that makes sure that the result in this special case
is anything but NaN and fix the GLSL LIT implementation.