GZDoom 4.8.2 lighting sector issue

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Captain Keen burner

GZDoom 4.8.2 lighting sector issue

Post by Captain Keen burner »

Hi, I have an account here but it says it’s deactivated and I can’t seem to reactivate it.

Anyway, I am trying to report an issue with GZDoom 4.8 that’s a new issue. I posted about this on Doomworld and will put that link at the bottom of this message. Thank you.

Something appears to be messed up with how lighting effects actors and they often flicker between being light and dark when they normally shouldn’t. Doomkid has seen this in some videos on NiGHTS108’s channel among others. An obvious example is in E3M6 (Inferno) of Stickney Installation, the enemies over the lava keep dipping into shadow randomly. All of them at once will go into shadow and out, seemingly unprompted by anything in the environment. This is using GZDoom 4.8.2 with software rendering.

I double checked Stickney E3M6 with GZDoom 4.6.1 and the error is NOT there, and I checked it again with 4.7.1 and the error was also NOT there, so it's something that has changed between 4.7.1 and the later 4.8 versions.

On GitHub, someone else posted about it here: https://github.com/ZDoom/gzdoom/issues/1692

“I went spelunking in the source code to see if I can fix this issue, I tracked down the problem to commit 344c634, the parent commit does not seem to exhibit this bug, or it's more elusive. I'm trying to figure out what occurred in that commit to break it.

While looking at what would fix it, I did notice that the floor and ceiling light values extracted from the FakeFlat call are no longer used, instead deferring to extracting them from frontsector directly, which doesn't always seem to have correct results. I implemented a small hack to always use the light from the thing's reported sector, which works for simple levels like Doom 2 MAP02, but presumably breaks any compatibility with fake floor/ceiling stuff.

I'm not sure what the best way to proceed would be.”

Again, it’s a new issue for 4.8 that didn’t exist in earlier versions, so I imagine there has to be a real fix. Thank you!!

Doomworld link: https://www.doomworld.com/forum/topic/1 ... g-sectors/
Captain Keen burner

Re: GZDoom 4.8.2 lighting sector issue

Post by Captain Keen burner »

Hey, just wanted to say I just tried the new GZDoom 4.9.0 and this issue appears to be fixed! Unless I'm crazy?? Anyway nice job, wanted to post this reply here in case anyone else sees this and is curious about the status of this quirk. As always, appreciate the hard work of everyone who has a hand in the creation and upkeep of GZDoom. Thank you!

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