Plasma decal incorrect in hardware rendering

[Nash]

Fire the Plasma Rifle at a wall. Take a look at the blue, fading decal.

- In software rendering (either Carmack or Softpoly, any colour depth), it fades to transparent.
- In hardware rendering (either OpenGL or Vulkan), it fades to black, before abruptly disappearing.

The software rendering one looks correct to me.

[Graf Zahl]

Works fine for me.

[Nash]

Still happens with latest commit as of this writing (3b41848). Examine the video closely, as I don't know how else to demonstrate this. Pictures won't show it clearly enough. In the video, you can see the animation differences more clearly.

Note that this behaviour is ancient, I have noticed this for a very long time - even while Randi was still around, even.

[Graf Zahl]

Please post your INI. I need to find what causes it. For me it doesn't happen.

[Nash]

Ok. Note that while there are a bunch of autoloads in the INI, my report (and also the video) is ran with -noautoload so mods are not the cause.

[_mental_]

Seems to be caused solely by SSAO. For me, other settings are irrelevant.

[Graf Zahl]

Yet another one...

Half of the reported render glitches I know of are being caused by SSAO. This feature really needs to be declared as experimental and incomplete...

[Nash]

This glitch doesn't happen with the green BFG lightning, by the way. Only the plasma...

[Graf Zahl]

The green lightning is an alpha texture which is tinted green. The plasma decal is a translucent sprite. How this can affect SSAO I do not know.

[dpJudas]

Since the SSAO pass only sees normal vectors and depth values, it has to be one of those two. Maybe one is drawn in the solid part of the scene and one in the translucent?

[Graf Zahl]

Decals are drawn in a separate pass that belongs to the solid block. The normal for a decal should always be the same as for the underlying surface. Can it be that this is uninitialized somehow and only works by happenstance for alpha-shaded decals?

[dpJudas]

If I turn on gl_ssao_debug 4 (shows the contents of normal gbuffer) and fire the plasma there's a white mark on the wall that then goes away. Unfortunately due to how it presented I can't easily tell if that's a translucent thing drawn afterwards (like how you can see the things drawn on top), or if that's a clear sign of a broken normal being written.

[Marisa the Magician]

Apologies for the bump, but will this ever be dealt with?

I mean, sure, SSAO is kind of crap but still...

[Graf Zahl]

Unlikely. The only reason SSAO got in in the first place was public demand, despite my reservations for the feature's shortcomings.