[Linux] Screen corruption happens when vid_gamma is 1.0 with gl_hwgamma_x11

[Purkkaviritys]

Hello, I noticed that if I set brightness in Daikatana's Video menu to 100% this happens:

It's tied to Daikatana's window. If I move to another virtual desktop it goes away. If I set brightness to any other value than 100% be it larger or smaller it goes away.

Screenshot tool cannot capture it. If I take a screenshot, close DK and then take a look at captured image it's normal.

I'm currently running Fedora 24 with Gnome 3 in X11. I have nVidia GTX 960 4GB with nVidia's latest proprietary drivers (367.27). This is the latest stable DK release (Jul 13 2016).

I haven't tested out if this happens in Wayland. I also haven't tested if this will happen in Debian.

One pretty big oddity is that if I record Daikatana's Linux version with OBS's Linux version, the recorded video is by default very pretty bright and washed away. If I increase the brightness in Daikatana then OBS will record somewhat darker more natural looking video. I control for this factor by using OBS's built-in screen filters to set gamma 25% down. I normally play Daikatana in Linux around 75% brightness.

[Purkkaviritys]

Update: This doesn't happen if I throw in gl_ignoregamma 1. It also fixes the discrepancies between OBS and Daikatana's visuals.

[Frank Sapone]

After much investigating, the problem is DK was using X11 Gamma instead of SDL2. @DGibson said that was because at the time SDL gamma was not working properly under linux but may have been fixed in an update.

Now we use SDL2 gamma by default and controls work fine. However, if X11 Gamma is used with gl_hwgamma_x11 CVAR set to 1.0 and vid_gamma CVAR set to 1.0 the colour corruption happens. So the bug still exists, but you may be less likely to see it unless you are forcing X11 HW Gamma.