Problem with Vulkan's HDR

p0n1at0wsk1 · Post by **p0n1at0wsk1** » Mon Nov 23, 2020 8:37 am

So, I've updated GZDoom to the latest version (4.5.0), and that's now what I see when HDR is on (for example, in Heretic):

And that's how the game looks like when I turn HDR off:

For comparison, this is how it looks in GZDoom 4.4.2 with HDR turned on (on my display it makes the image a bit darker version of the image above):

And without HDR it looks basically the same as in 4.5.0.

So, the question is: is that how HDR supposed to look like? It makes the game too dark and faded(?) on output compared to the previous GZDoom version, where I could just increase the brightness setting with some contrast above and the image will be more or less visible on my display (unlike the latest version, where neither brightness, nor gamma correction will help).
FYI, I have the latest version of Windows 10 (20H2, build 19042.630), GTX 1050 Ti with the latest driver version (457.30 to be exact), a display with HDR10 support and 2560x1080 resolution (native 21:9).

EDIT: Oof, seems that I wrote a slightly wrong driver version. Also, I wanna say that I made these screenshots with default brightness, gamma and contrast settings.

Post by **dpJudas** » Mon Nov 23, 2020 9:13 am

This bug may have been introduced by the srgb to linear fix I got Rachael to apply. Undoing that commit will probably fix it.

I can't really test anything HDR related anymore as I sold my HDR monitors.

Post by **drfrag** » Thu Dec 03, 2020 3:50 am

What was that fix for? I think i'm going to revert that commit.

p0n1at0wsk1 · Post by **p0n1at0wsk1** » Wed Oct 12, 2022 6:49 am

I've tested the latest master (GZDoom g4.9pre-278-g37039721b, to be exact), and it seems that the problem's solved!

The only thing is that the brightness is off while HDR is on, but it's not that much of a problem and does seem to be on my end (screenshots look fine, while in-game my monitor outputs a darker image). But, thankfully, I can compensate that by upping the brightness and contrast.

Thanks for investigating this! (even if it took quite a while to do that

)

Post by **dpJudas** » Wed Oct 12, 2022 7:59 am

Honestly I'm not sure what is the correct thing to do to the brightness. On this Dell Alienware QD-OLED monitor I can't find any consistency in the brightness between SDR and HDR. If I turn on HDR mode in Windows the desktop image becomes a lot brighter than when it is off.

Ultimately I decided to just keep the brightness relatively low as then at least the user can adjust it to what they like in the UI. I'm generally afraid to dick too much around with it as I'm not sure how much what I'm seeing on this particular monitor matches what the reference values should be expected to be. It also doesn't help my general knowledge about color spaces, transfer functions and tone mapping is very poor. From my poor understanding the brightness should be correct if I converted sRGB to linear and then fed that into a scRGB linear frame buffer, but what we got was a washed out picture.

I opted for just doing a 2.2 gamma conversion instead, which creates this image that is a bit on the darker side. I prefer dark over washed out.

PS. It took this long to fix since I didn't have a HDR monitor anymore until this weekend!

MasterBeavis · Post by **MasterBeavis** » Tue Oct 18, 2022 6:38 pm

yea have the same issue no amount of tweaking fixes HDR in GZDoom its always too dark then washed out

ZDoom