Automatic Unity OpenGL workarounds

[fasterthanlime]

I hear they're in the process of fixing it, but in the meantime, there's a bunch of games that don't run for a bunch of people without adding the -force-opengl3 or -force-opengl command-line arguments.

The Unity player has a log, which shouldn't be hard to find, and it could be grepped for typical messages, and the app could try relaunching using the -force-opengl option. That would fix about 3/4 of the Linux issues currently open on https://github.com/itchio/itch-compatibility-watchlist/issues

[fasterthanlime]

Thanks to Guillaume (@Sirithang on Twitter), I've discovered the -logFile option, which lets us tell the Unity player (ie. any export) where to write its log files.

The plan is now:

1. To look for a file named *_Data/Managed/UnityEngine.dll
2. If it exists, it's a Unity game, pass -logFile
3. If the game exits too quickly, parse the log files
4. If the log files contains some sort of OpenGL error, try applying workaround

I think the workarounds should be a 'Behavior' option in the app:

• Try -force-opengl (should be Default as it works the most, but will make some games look worse)
• Try exporting MESA_GL_VERSION_OVERRIDE=3.3 MESA_GLSL_VERSION_OVERRIDE=150 before launching game
• Try nothing, just report the crash

We should also have a documentation page on https://itch.io/docs/itch that explains OpenGL problems on Unity and how to work around them.

(Additionally, while I'm handling that it would be nice to take care of optirun/primusrun)

[fasterthanlime]

See itchio/itch-compatibility-watchlist#1416