For about 4 weeks the game has polygon distortion especially on the Nevada map. Its not on every map but it can be seen with the ingame benchmark.
Radeon HD 7970
OpenGL renderer string: Gallium 0.4 on AMD TAHITI (DRM 2.48.0 / 4.9.0-rc4-gbc33b0c, LLVM 4.0.0)
OpenGL core profile version string: 4.5 (Core Profile) Mesa 13.1.0-devel (git-b27be18)
Could you provide an apitrace that reproduces the issue?
I tried getting this to work but I dont get any output file.
DEBUGGER="apitrace trace" steam steam://rungameid/201700
What am Im doing wrong here?
If you want to do a regression testing,
this somewhat broke arround here: https://cgit.freedesktop.org/mesa/mesa/commit/?id=74e39de9324d2d2333cda6adca50ae2a3fc36de2
Does reverting that commit fix the issue?
I managed to get a trace. Hope it works for you.
(In reply to Samuel Pitoiset from comment #3)
> Does reverting that commit fix the issue?
I can't test (I would do if someone could show me how). I do weekly Mesa builds and Im quite sure it broke in the week when this commit appeared.
Problem is still there as of mesa git from Friday.
Also, the trying replaying my trace hangs the GPU.
I finally was able to start bisecting this, I was going back to Mesa from early October but couldnt find the culprit. I used PKGBUILD provided from here: https://aur.archlinux.org/packages/lib32-mesa-git/
Then I followed these instructions:
I guess since the executable name of the game is dirt.i386 so bisecting the 32bit package is the right one?
Im a bit lost here, I will try older Kernel and libdrm but after that Im running out of ideas what could caused this, any other ideas would be appreciated.
BTW, judging from the screenshots in https://bugs.freedesktop.org/show_bug.cgi?id=99136 it looks this is the same problem. Its interesting to see that enabling a minor heavy graphic option causes such crazy graphical corruption. He enables blood effects and in Dirt you have to set Crowd from OFF to LOW or higher. While ULTRA option makes the problem even worse.
Fun Fact: I tested Tomb Raider Benchmark, and the average FPS on went from 48fps with Mesa from October to 58fps with current Mesa git. So really good job on this!
Created attachment 130076 [details]
garbled graphics #1
Found the problem. Seems like using -Ofast wasnt a good idea. Using -03 everything works as it should.
Still attaching screenshot showing the problem in case it is useful to others.
Still the same with -Ofast.
Ofast disregards strict standards compliance. -Ofast enables all -O3 optimizations. It also enables optimizations that are not valid for all standard-compliant programs.
In other words don't use it with Mesa :)