GL Gamma Correction

[Baker]

There are a few different methods to correct gamma:

1. With Quake classic textures (256 shades of brown) or even Half-Life independent palette per texture, you can apply the gamma (and/or contrast) to the color table prior to upload. You cannot do this with a 24-bit image ... at least not reasonably as far as I know because such a table would be rather large (16 MB) and possibly slow/awkward to apply to replacement textures due to large size.

2. Hardware gamma. (Affects entire screen).

3. What modern DarkPlaces does with a shader.

Btw ... I have noticed in every engine that uses #2 (all of the OpenGL ones except DarkPlaces since it uses #3) ---- if I ALT-TAB out of fullscreen and then back into Quake, the hardware gamma correction resets a few seconds later to system defaults (ATI Radion Mobility) on both Windows and the Mac.

I'm trying devise a way to intercept this brightness change, as it irritates me. I've noticed it is associated with ChangeDisplaySettings.

[r00k]

I added a gamma setting on in and out of focus, um i think in key events..
now the only time the desktop is off is if in a window and gamma isnt 1

[Barnes]

[Baker]

[Barnes]

[Barnes]

ahh yes!!!
photoshop math on glsl and hlsl (im use some things)

[Baker]

It is getting far more likely I mess around with shaders in the near future.

Thanks!

[Barnes]

Any time

[Spike]

Or just don't use an ATI card, as this is very much an ATI-driver-specific issue.

Still, shader-based gamma works nicely with windows (I don't mean ms windows... damn them and their too-generic names).

[Baker]

[Baker]

Strangely enough, I wrote some code to check the system gamma ramp to see if it changed. And the ramp isn't changing so the ATI drivers are lying. And setting the same gamma ramp again doesn't work because "it didn't change" (or so the API thinks I imagine).

So what I am doing is set a timer for 3 seconds after any ChangeDisplaySettings and after 3 seconds set the gamma twice (once to system, once to user) and clear the timer. Somewhat stupid workaround by this irritates me because if I press ALT-ENTER to swap my engine from fullscreen to windowed mode or the reverse, I do want the screen brightness to be right.

I'll live with this intermediate solution until whenever I have the time to do the messing around to do shader to do gamma correction.

(I imagine ATI did this because gamers who had a game crash would be stuck with the wrong screen brightness in various games --- so I get why they did it. )

[Barnes]

[SlapMap]

Are there any gl/dx nq engines except DP that use non-system gamma? I really need something else that is usable in windowed mode w/o affecting the rest of the screen space

[Baker]

[revelator]