TEXTURE CACHE OVERFLOW: PSX Doom Suburbs

[VonHeer]

I just finished a stream with a lovely crash on Suburbs. Apparently the poor ps1 just can't handle a dozen enemies and a BFG blash in that level. As much as a dread losing all of my weapons for when I retry the level, I must say- I love being surprised.

 

Does anyone know any other crash-prone levels throughout the console Doom ports?

 

https://www.twitch.tv/videos/774109730

Sorry it's just a link. I can't get it to embed itself correctly.

[Impboy4]

Quote

Working with the GPU was an exercise in VRAM space allocation. For this game it is a trivial task when it comes to framebuffers, CLUTs, static (HUD) contents, and even wall/flat since they are all the same dimension. Things get more complicated when it comes to sprites.

Because they have different dimension, sprites lead to fragmentation. Moreover if textures can cover large area and are repeated, sprites are often unique and many of them can be needed in unpredictable capacity. The worse case scenario is when a frame requires a certain number of sprites but they cannot fit in VRAM. This is called a "Texture Cache Overflow" and there is no recovery. When it happens, the game crashes and displays a cryptic error message reminding some of us of the dreaded "No more visplanes".

From: https://fabiensanglard.net/doom_psx/

[SaladBadger]

I recall Kaiser mentioning he had a trick where he'd go into automap before the BFG ball comes out in order to try to avoid this issue.

[Lila Feuer]

This is an easy level to crash on UV I've done it twice on real hardware lol.

[VonHeer]

I heard about that leveo being crash prone. I even said I hope I don't crash it. This was with real hardware. I wonder if emulating it with some options could prevent it. 

[Dark Pulse]

On 10/18/2020 at 8:19 PM, VonHeer said:

I heard about that leveo being crash prone. I even said I hope I don't crash it. This was with real hardware. I wonder if emulating it with some options could prevent it. 

Nope. It's fundamentally a limit of there being too much different sprites around at once.

 

Basically, you'd have to either reduce monster count or use less weapons (since all PSprite stuff also takes up some of that). Other stuff that could reduce it (like reducing rotation frames) are kind of out of your control due to AI movements and the like.

 

So in short, your best way to do it would be to try to keep weapon choice to a minimum, ideally the hitscan-based weapons.