Weird decal behaviour (being cut off) in different renderers

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Weird decal behaviour (being cut off) in different renderers

Postby Sinael » Sat Apr 25, 2020 4:53 am

Decals appear/disappear/ get cut off halfway with distance, behave differently on different renderers.
Further up the columns there's a scorch mark that gets replaced with blood splat (that was under it) when you get close.

Noticed when was playing a Refracted Reality wad with DAKKA
Could'nt replicate on test map since i don't know everything that went into this bug so here's my version of GZDoom, mods and save file (Refracted Reality is 240mb) ... ZDtest.rar
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Re: Weird decal behaviour (being cut off) in different rende

Postby Redneckerz » Sat Apr 25, 2020 6:45 am

250 MB is a very hefty download just to look at an issue and isn't really encouraging people to check who are on limited bandwidth plans.
  • What version of GZDoom is used?
  • Which different renderers are you using?
  • In which renderer does the weird decal behavior appear?

Please post your GZDoom ini. It will give additional details.

My first thought is that its something RR does that triggers an issue, which means its not GZDoom related, but i leave that to more capable hands.
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Re: Weird decal behaviour (being cut off) in different rende

Postby Sinael » Sat Apr 25, 2020 7:47 am

GZDoom 4.3.3
Wad is Refracted Reality, Map 11
Mod is DAKKA
The splash decal was from rocket launcher.
Now I remember it happening a few times in other places different wads.
The renderers used are shown in the video.
Hardware renderers - shows all decals, they get cut off when get close, some decals disappear when approached
Software renderers - decals ALWAYS get cut off, and the decals that show but disappear depending on the distance do not show AT ALL in software.
I tried changing various settings including texture, lightmodes and various hardware rendering settings, none had any effect on the matter.

I think it has something to do when one decal is applied to 2 connected linedefs, like it's on a corner or something along those lines.
Upon inspection of the area it seems that the column in question consists of 2 sectors, the upper sector being less than a unit away from lower, so it's dechnically 2 walls. The decal applies to both when looked from distance, but disappears from lower wall when approached.

Here's INI and save file
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Re: Weird decal behaviour (being cut off) in different rende

Postby Graf Zahl » Mon May 04, 2020 2:45 pm

What you experience here is a lack of depth resolution - unless the depth buffer in graphics hardware is changed to a better format it is unavoidable that such issues happen.
To clarify, this is an issue inherent with how current graphics hardware works.
It may be reducible a bit by setting the depth range a bit more smart than always going for the technical limit of 65536 map units but it cannot be eliminated altogether.
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