Single-buffered games - Bubsy 3D

[atomic837]

I recently came across this article, "Could Bubsy 3D on Sony Playstation been a better looking game?" (http://mgarcia.org/2018/06/05/could-bubsy-3d-on-sony-playstation-been-a-better-looking-game/) from the website blog by Mike MGarcia (http://mgarcia.org/?blog=1).

It's an interesting analysis of Bubsy 3D and the Playstation's early development library woes. One of the intriguing points that the author illustrates is that Bubsy 3D is a single-buffered open-world PS1 game running at one of its highest resolutions of 512x480. From the research that I've done, Bubsy 3D may well be the only 3D Playstation game running at a full 480 line frame buffer, albeit only single-buffered. Heck, this was a feat that even PS2 would have trouble with in its early life! From my experience, Bubsy 3D has a very sharp/clean image and runs at a mostly locked 30 fps. See VRAM viewer image below:

http://mgarcia.org/2018/06/05/could...me/Sony_Playstation_files/DfQEqNUVAAA0jwF.jpg

This is fairly intriguing to me as I assumed that modern 3D console games were almost required to run a double-buffer setup to prevent serious screen artifacts and display glitches. Understandably, Bubsy's flat-shaded aesthetic is extremely primitive which likely explains Eidetic's leeway, but I'm curious if anyone has any insight on the other drawbacks, limitations, or advantages to going with a simple single-buffer setup. Did the developer have to really hold back the polygon budget to insure that there were plentiful triangles to spare for the next frame cycle? Perhaps restrict textures to a certain minimal size to preserve any and all fill-rate? Thoughts?

 

[milk]

I recently came across this article, "Could Bubsy 3D on Sony Playstation been a better looking game?" (http://mgarcia.org/2018/06/05/could-bubsy-3d-on-sony-playstation-been-a-better-looking-game/) from the website blog by Mike MGarcia (http://mgarcia.org/?blog=1).

It's an interesting analysis of Bubsy 3D and the Playstation's early development library woes. One of the intriguing points that the author illustrates is that Bubsy 3D is a single-buffered open-world PS1 game running at one of its highest resolutions of 512x480. From the research that I've done, Bubsy 3D may well be the only 3D Playstation game running at a full 480 line frame buffer, albeit only single-buffered. Heck, this was a feat that even PS2 would have trouble with in its early life! From my experience, Bubsy 3D has a very sharp/clean image and runs at a mostly locked 30 fps. See VRAM viewer image below:

http://mgarcia.org/2018/06/05/could...me/Sony_Playstation_files/DfQEqNUVAAA0jwF.jpg

This is fairly intriguing to me as I assumed that modern 3D console games were almost required to run a double-buffer setup to prevent serious screen artifacts and display glitches. Understandably, Bubsy's flat-shaded aesthetic is extremely primitive which likely explains Eidetic's leeway, but I'm curious if anyone has any insight on the other drawbacks, limitations, or advantages to going with a simple single-buffer setup. Did the developer have to really hold back the polygon budget to insure that there were plentiful triangles to spare for the next frame cycle? Perhaps restrict textures to a certain minimal size to preserve any and all fill-rate? Thoughts?

Well, from looking at the VRAM viewer alone, had they gone with double-buffering, they'd be left with nothing but that bottom sliver of VRAM left for textures (which a large portion seems to be holding pallette data?) which is close to nothing.

And I assume they have to ve able to render everything within the V-Blank time, which is very short, with no spillover. Not managing to finish rendering before that would mean an incomplete frame with some arbitrary objects missing.

Since PS1 had no Z-buffer either, all 3D games used back-to-front painters algo, relying entirely the software sorting primitives on its own and sending them to raster at the proper order. As such, whenever an incomplete frame would be sent in to display, the missing objects would invariably be precisely the ones closest to the camera, including the HUD!!!!

Good god, what a mess! Its hard to believe they truly chose to work under those restrictions. Maybe I'm misunderstanding how ps1 worked.

Also, if my interpretation is correct, the game is only running at 30fps because its either CPU bound or geometry-engine bound, or both. The rasterizer must be twiddling its thumbs for, like 90% of the time. At least that way, if the game does reaches points where it can't finish a frame in time and some objects end up missing in an odd frame, at least they have the time to catch up on the even one. That would change the visual artifact from invisible objects into flickering objects, which is a little less horrible, bot only slightly so.

Clever devs quickly understood that ps1 works best when you keep each stage of the render pipeline working in parallel for best possible use of the resources. Bubsy seems to do the precise opposite.

 

[atomic837]

I think your assessments are correct. From the smattering of developer comments that I've seen over the years, one of them made a comment about the mistake of going with that insanely high resolution (for the time), leaving very little rendering budget for any detail. I can only imagine that these relatively novice developers were unaware of where 3D games were going and assumed that flat-shaded polygons would still look next gen and appealing in 1996 (when the game finally released). Given that the Jaguar, 32X, and SNES/Genesis were still living in that flat-shaded world, you can almost understand where that might have made sense. From that perspective, a "next-gen" game would simply have to pump up the visuals by going high resolution and high frame rate (relatively), and thus Buby's graphical design was born.

I sheepishly admit to getting this game on Xmas 1996 and trying my darndest to like it. I can attest to some polygons flickering in and out on the edges of the screen, which might be an artifact of the single-buffered frame time limitations. Draw distance is passable, but only barely, with a layer of fog/fading out whole triangles. On the bright side, since this game is only 30 fps but rendering from a full frame buffer, the image quality is sharp and clean, without any of the jitter/jaggies of typical field-rendered games. And it does look.... unique.... to say the least.

I'm honestly curious if anyone is aware of any other commercial 3D games of the 32/64-bit generation that attempted to brute force a single-buffered display. Is Bubsy 3D a special snowflake?