Bizarre 3DO Doom Glitch

[Boyes1989]

So I stumbled upon a couple of videos that I had posted on my old YouTube account back in 2012 and then completely forgotten about and figured I'd share them on here. These might have been linked on here previously, however that seems doubtful as the view counts are so low.

 

This is running on real stock 3DO hardware, not an emulator.

 

I can't remember what actually caused this glitch as it happened so long ago, but maybe some members of the board have some ideas on what may have caused it. 

 

Video 1

 

Video 2

 

Various sprites are getting stuck in the boarders. This includes enemies, projectiles and decorations. Basically anything that isn't nailed down. The animations are stuck on a 2-3 frame loop. Interestingly it doesn't slow the game down much more than it already was, despite how many sprites get stuck in the boarders, however their animation speed does vary depending on what is on screen in the actual gameplay area.

 

Has anyone else comes across this glitch/bug, or something similar?

 

Also, I would have embedded the videos but wasn't quite sure how.

[ZeroTheEro]

Not sure I ever seen this bug before. pretty neat, though.

Also to embed just put the full youtube link and it will embed automatically

[viti95]

I think that happens when the border isn't draw properly (it's one step bigger than it should), leaving an empty space not updated each frame. The result it's similar to the hall of mirrors effect (but just for sprites). Maybe @Optimus knows really what's happening there.

Edited July 13, 2021 by viti95

[Optimus]

I assume this videos is running the original commercial 3DO Doom, not OptiDoom? Seems so if the video is 9 years ago.

 

What's happening is that simply the border isn't drawn. And the way it was originally designed, the sprites weren't clipped against the game window (inside the border), and in a final pass the border will be redrawn every frame and hide this fact. While the wall columns and floor rows will be clipped against the smaller game window, for reasons unknown to me (maybe to avoid extra boundary checks and save a bit of CPU?) the sprites are the exception. So, since nothing is erased since the previous frame (and the are 3 pages flipped) you get a hall of mirrors effect on the border. Now, why did this happen in the commercial version? One guess is that the border data failed to load from the CD (it has happened to me when I burn a new CD and sometimes it wasn't written well and didn't load resources properly), so border graphics are missing (or it's all zeros/black so it gets full transparent) and nothing is rendered on top of the sprites outside in the border.

Edited July 13, 2021 by Optimus