[quake2] difference between glx and sdl opengl implementation

Brendan Burns brendanburns at comcast.net
Tue Mar 29 09:07:35 EST 2005

Yeah, I should look at how the gamma stuff is done in SDL.  I suspect 
that SDL makes it impossible for q2 to set the gamma directly, but I'll 


On Mar 29, 2005, at 8:12 AM, Anders Storsveen wrote:

> I've been doing a little investigation and I have figured out that the 
> glx implementation uses some kind of hwgamma (the one I can set 
> through nvidia-settings), and sdl uses some sort of hack. The hwgamma 
> version changes instantly when chaning the slider in the video 
> setting, and it just changes the gamma (which results in a little more 
> yellowish but still crisp picture), the sdl implementation is some 
> sort of hack like in brightness so it washes out hte colors and 
> contrasts. If you set an insanly high brightness value in sdl you will 
> have no texture at all, just colors.
> however I also did the same thing in windowed mode, and then both 
> seemed to use hwgamma, colors and texture of both sdl and glx were 
> similiar. So it seems that the SDL implementation has a problem 
> getting the hwgamma control in fullscreen. I've tried looking into the 
> code, and I think I found the code which handles it, but couldn't 
> figure it out.
> would be great with sdl with hwgamma, since I think glx looks best, 
> but has a broken mouse for me.
> On Fri, 18 Mar 2005 03:51:51 +0100, Brendan Burns 
> <brendanburns at comcast.net> wrote:
>> This is probably a difference between either a) the bit depth of the
>> SDL renderer versus the GLX renderer or b) the alpha of the renderer.
>>   Both of these are adjustable through cvars...
>> --brendan
>> On Mar 17, 2005, at 7:32 PM, Anders Storsveen wrote:
>>> I notice that SDL and glx rendering looks different. Its the same
>>> difference that used to be between nvidia and 3dfx when in windows.
>>> glx looks the way 3dfx did, with its yellow-ish graphics and sdl 
>>> looks
>>> like nvidia did, with more orange/brown colors. I have always liked
>>> the glx/3dfx colors better, too bad the mouse is better in SDL ... :/
>>> --
>>> Using Opera's revolutionary e-mail client: http://www.opera.com/m2/
> -- 
> Anders Storsveen
> The Next Generation
> http://www.generation.no

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