No change when trying to change gamma lavel

**Oblidor** · 09-13-2010, 01:33 PM

Hi

I have tried to change the gamma level to make the grey box almost not visible. But when I change the gamma value I see no change whatsoever. This applies to Amnesia and all the Penumbria games.

I'm using the fglrx driver for Ati HD 4870 in Xorg (Ubuntu 10.04 64-bit). I also run xcalib at boot to calibrate the screen and this works. Does the xcalib prevent the the gamma change in the game? Anybody experiencing the same problems? I don't know if it is driver problem, setup problem or the games have some problems.

Any hints much appreciated.

**Urkle** · 09-13-2010, 02:40 PM

It seems as though the ATI drivers do not support gamma changes via the SDL_SetGamma call, which performs an XF86VidModeSetGamma in X11.

I see the same issue on my ATI HD 3000 card as well, but not on my Nvidia 7300.

**Oblidor** · 09-14-2010, 10:59 AM

(09-13-2010, 02:40 PM)Urkle Wrote: It seems as though the ATI drivers do not support gamma changes via the SDL_SetGamma call, which performs an XF86VidModeSetGamma in X11.

I see the same issue on my ATI HD 3000 card as well, but not on my Nvidia 7300.

Yes, seems gamma changes are not possible in game. I solved the problem by a small script:
------
#!/bin/sh

xgamma -gamma 0.7
./Amnesia.bin64
xgamma -gamma 1.0
----

(from memory)

Running this starts amnesia with the gamma level that works best for me. This also solved the ugly shadow effects I got due to that the gamma was too high.