r_overbrightbits behavior GL1 vs GL2

[ioquake]

r_overbrightbits behavior GL1 vs GL2

[ensiform]

gamma and overbrightbits is accelerated in GL2 as a glsl shader IIRC which could be the difference.

[wareya]

The banner models on q3dm6 and other maps also seem to be lit funny, but in the opposite direction. But I'm not sure.

[wareya]

This should illustrate the problem: http://screenshotcomparison.com/comparison/180537

In vanilla quake 3, with default settings, the opengl2 rendering backend makes various elements look darker or brighter than they should be. The way lighting information propagates through the renderer is different than it should be.

The high dynamic range of lightmaps being displayed is a valid enhancement, but the armor, banner, and fog are all plainly different in a way that shouldn't be considered faithful. (There are others visible in this comparison, but those are the most obvious)

[SmileTheory]

I think this is (mostly) a misunderstanding.

GL1 overbrights differently depending on r_fullscreen. GL2 does not, and acts as if r_fullscreen was always on.

Here are some screenshots to demonstrate:

OpenGL1 renderer, r_fullscreen 0

OpenGL1 renderer, r_fullscreen 1

OpenGL2 renderer

These screenshots don't show the fog however, which is wrong regardless of overbright settings. I don't have a good fix for that, though.

[wareya]

I can't replicate your fullscreen gl1 screenshot. gl1 looks like your windowed version at all times.

edit: Okay, I got it to work the way you're describing on just gl1.

Given the objects circled in red, isn't making it so GL2 only works one way a bad idea? I would never have expected the difference to come down to GL1 being fullscreen or not, especially since it always looked the windowed way back when I was playing on linux.

[SmileTheory]

Thing is, the "one way" as you put it, is the correct way. With r_fullscreen 0, GL1 simply ignores the r_overbrightBits value, and acts as if it were set to zero. If you want GL2 to behave like GL1 non-fullscreened, just set r_overbrightBits to zero.

[wareya]

Thanks for explaining. One more thing is the 3d player head model on the HUD is a different brightness between gl1 and gl2 on default settings (it's brighter on gl1), but that might be CPMA doing something weird.

[ensiform]

You should not compare cpma directly with the stock version IMO since the source is closed we don't know for sure there's differences in its source.

[wareya]

CPMA is a mod/game, not an engine thing. Unless it's trying to detect engine variants it shouldn't have weird shading stuff going on that vanilla wouldn't if it did the same stuff.

[ensiform]

I know what CPMA is, I was simply stating that since you implied "CPMA might be doing something weird..."

The lighting in rend2 isn't going to be 1:1 perfect with vanilla still which is something @SmileTheory will need to work on I'm sure.

[SmileTheory]

Anyway, I put in a fix for the fog color in 863adfc , and everything else is fixable via cvars, so I'm closing this.

[wareya]

Thanks!

[wareya]

Looking back on this, it seems like it's not possible to get HDR lightmaps without breaking entity lighting, by using cvars.