[1.9pre-796-g8169991] ZPack's E3M7 glitch + HOM issue

[Blue Shadow]

Specs:

• Intel(R) Core(TM) i7-3630QM CPU @ 2.40GHz
  AMD Radeon HD 7670M

While I was playing that map pack (E3M7 - Blackrock, specifically) with 2.0.2 beta, I encountered this issue you see in the spoilered screenshots. I thought it could be something to do with the beta itself, however it'd seem that the noted development build in the title has it, too. ZDoom doesn't display the issue:

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[NeoHippo]

That's the scene of the first courtyard, I presume.

That problem does not show up with my GTX460.



Maybe it's because of the map's complexity.
Perhaps a different Catalyst version will display it properly ?

[Blue Shadow]

That's the scene of the first courtyard, I presume.

No, the courtyard renders fine. What I'm showing there is from a different area. You can warp to it using one of the coordinates on the screenshots (they were all taken in the same general area where the issue is showing). Make sure to stay under the surface of the blood pool.

[NeoHippo]

Oh, right, up there in the northern part, after you jump into the pool of blood.

Looking at it with GZDB I'm not surprised that those HOM's occur. My goodness, the complexity
of the map is astounding. My hat off to Vader to keep everything straight. It makes my head
spin just looking at it.

He uses two of the worst offenders for generating HOMs, 3D sectors with Transfer_Heights, bounded by stacked sectors.
No wonder the DOOM engine can't keep up.

[Graf Zahl]

Transfer_Heights plus portals is a surefire way to make the GL renderer break and unfortunately there's not much to do about it.
The problem is that the static portal data cannot easily be adjusted to the hackery with sector properties as employed by Transfer_Heights.
But this is the first time I have seen that in an actual map...

[Ralgor]

It's not just that development build. 1.8.6 does the same thing.

However, Zdoom 2.7.1 renders this fine.

[NeoHippo]

Out of curiosity I ran the map through early revisions











Might be useful.

[Graf Zahl]

It took me a bit of time to wrap my head around it but ultimately this was just a result of a small oversight:

When gl_FakeFlat applies the effects of Boom's deep water it needs to kill the original sector's ceiling portal in the sector copy it creates, as obviously the original ceiling plane is no longer relevant.

The glitch was also present before r1180, btw, but it never propagated beyond its origin sector there - that was added around that time to make portals work more like in ZDoom. In the older screenshots you still can see a small sliver of the effect, too.