Hacker News Reader

Comment by flipacholas | Hacker News Reader

The lack of floating point unit on the PS1 is commonly misinterpreted, see https://www.copetti.org/writings/consoles/playstation/#tab-5...

View on HN

I'm not sure why you think the "Models/textures flicker due to lack of Z-buffering" is not accurate. I mean, sure, models/textures can flicker for other reasons too so technically that can be inaccurate but lack of z-buffer is one of the most common reasons since the majority of 3D games software relied on z sorting polygons that couldn't always be sorted perfectly (static geometry could be preprocessed with, e.g., a BSP tree, but as long as dynamic geometry entered the picture things became much hairier).

Or is it that it isn't a problem of PS1 but a problem of games - which, again sure, this might be true but that'd be the splittiest of hair splitting :-P it is the lack of a hardware feature that drove the games do what they do, so it isn't entirely "blameless".

> Or is it that it isn't a problem of PS1 but a problem of games

Yes, this is what I wanted to emphasize.

My intent wasn't to say that the 'lack of z-buffering' statement was incorrect (it's still true), but that there's a fundamental issue behind it, the visible/hidden surface determination, and now it depends on the developer's implementation. I believe this is overlooked on non-technical sites.

With this, I just wanted to make it more informative for the reader. I don't think the question is if the PS1 has a z-buffer or not. Sure, z-buffering is a solution, but there's the reasoning behind it that I wanted to transmit it to the reader.

Anyway, that's just my opinion.

Your citation contradicts itself. The polygon jitter exists for lack of floating point unit. While it's possible to emulate the necessary precision, it's uneconomical without the acceleration provided by a dedicated processing unit. Without floating point, the PSX isn't fast enough to render complex scenes in real-time accurately; Hence the jitter.

I don't mind being wrong and I will correct the article if needed. That being said, I'm interested in debating this, what if the PS1's GPU had implemented some sort of sub-pixel precision and edge antialiasing? Do you think the lack of floating-point vertex coordinates would have been noticeable? (I'm assuming the 'jitter' means the sudden jumps when polygons move slowly).

I have no idea :)

Reply on news.ycombinator.com