[Fixed] [g4.8pre] Some sector shapes break Hexen stairs

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[g4.8pre] Some sector shapes break Hexen stairs

Postby treacherousfiend » Sun May 08, 2022 10:11 pm

It seems there's an issue with Hexen style stairs where certain sector shapes will break them, causing only the first 2 steps to be lowered.
I noticed this issue in MAP04 of GERMS V1F (viewtopic.php?f=42&t=65498), and was frustrated enough by it that I decided to look into it.
I've only been able to reproduce this bug with sectors shaped like a trapezoid, with the smallest step being the first one.

A test map I made can be found attached with 3 demonstration stairs.
The stairs on the left have a pretty strong angle (157 degrees), But still work for some reason
The middle stairs have a more slight angle (164 degrees), But are affected by this bug
The stairs on the right are directly copy-pasted from the broken stairs I found in GERMS.

I also used my extremely limited git knowledge to try bisecting the issue and narrowed the problem commit down to commit 63fa01205f9b111c8e6b27b54fe736f834b6b807 (
- fixed potential infinite loop in Hexen-style stair builder. Jan 6
But I unfortunately am not sure what the actual root of the problem is.
Considering the fact that the first 2 stairs work fine, it seems like it might be an issue with detecting the next sector with special 26 (Hexen stairs swap between specials 26 and 27 with every sector)
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Joined: 08 May 2022

Re: [g4.8pre] Some sector shapes break Hexen stairs

Postby Graf Zahl » Mon May 09, 2022 1:00 am

fixed. Actually, the shape of the sector does not matter - the bug happened when the lowest numbered line to a sector with the alternative stair special is the initial sector where the stair building started. This was not properly flagged as having been processed.
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Graf Zahl
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Lead GZDoom+Raze Developer
Joined: 19 Jul 2003
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Re: [g4.8pre] Some sector shapes break Hexen stairs

Postby treacherousfiend » Mon May 09, 2022 1:19 am

interesting, since I had a working stair which became not working through making it an odd shape, correlation not causation I guess. thanks for the quick fix!
Joined: 08 May 2022

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