I wanted to share an update on this, I have done some troubleshooting and here are my results. First, i split that big map into two smaller maps. I felt this could help, but alas, one of my playtesters found the issue on the map after it was split up.
To try to narrow the problem down a bit, I got a copy of the game from the playtester who was having the bug. Like the version I sent everyone in this thread, I loaded the save file with the bad game, and attempted to eliminate things which could cause the problem one by one, except by making changes to the map which would render the save file un-openable. Here's what I have tried so far. I retained the changes made in each previous troubleshooting step, so at the end, these were all the changes I made together:
- Switched to OpenGL (things worked correctly), made a new save, then reopened that save under Vulkan, issue persisted into the new save. Works fine in OpenGL, has the same problem in Vulkan.
- I deleted all the GLDEFS and brightmaps from the PK3. The issue persisted.
- I deleted 8 angles from all the enemy sprites, reducing them from 16 angles to the standard Doom 8 angles. The issue persisted.
- I deleted all TEXTURES lumps and ANIMDEFS, the issue persisted.
- I deleted every texture in the game, the issue persisted.
- I removed "PixelRatio" from the ZMAPINFO lump, issue persisted
- deleted INI file from directory, issue persisted
- disabled dynamic lights, changed texture filtering to none. issue remains
- deleted ZNODES from the affected map - very surprised that the game loaded after this was removed - still the same problem.
- cleared node cache - still the same issue
- I deleted every sprite in the game except for hud sprites, the issue persisted.
- I deleted all /graphics and /fonts the issue persisted.
So even with essentially every graphical asset removed from the game, the problem persisted.
Correct me if I am wrong, but shouldn't eliminating all graphical assets rule out the possibility that there is an issue with running out of texture memory or the like? I admit I'm not really someone who understands hardware rendering all that well, so I apologize if that's not the right way to describe the problem. But, ultimately, the problem persists when the game has close to no graphics assets at all.