ZDoom

Summary 0000607
Sprite-based decals have dark grey edges with Ambient Occlusion enabled

Description
Pictures and description posted in this thread: viewtopic.php?f=50&t=56039

Decals that use sprite graphics have a dark grey edge to them. This appeared some time between GZDoom 2.2.0 and 2.3.2.

Steps To Reproduce
Fire the plasma gun at a wall and look at the decals. Some mods can be used for even more obvious examples. e.g. my Burghead mod.

See the linked ZDoom thread for pictures: viewtopic.php?f=50&t=56039

I can only reproduce it if I change the decal's properties to render with normal translucency. My guess would be that you somehow got a bad replacement loaded. With the stock definition all is correct for me.

Nope, not a bad replacement. I've done tests with completely clean installs and nothing loaded other than gzdoom.pk3 and still got the problem.

However, I now know what causes it: Ambient Occlusion. With ambient occlusion at any setting other than "Off" the decals appear like the ones I posted pictures of.

Ok, then it's something for dpJudas to check.