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Comment by _bxg1 | Hacker News Reader

> The whole system has no floating-point capability.

Wow!

Not that uncommon back in the day. Even Doom on PC didn't use floating-point; instead relying on fixed point.

This set me reminiscing about the x87 series FP co-processors. Nice nostalgia break waiting for a build to finish, thanks!

Yes, and what few people know, is that x86 co-processors in general really only had to stick to the hardware interface given by Intel. What they actually did with that was up to the co-processor. Best known case in point were the Weitek math co-processors which were not actually machine code compatible with the Intel x87s.

Modern Vintage Gamer made a video[1] about this a few days ago

[1]: https://www.youtube.com/watch?v=x8TO-nrUtSI

Note that the video had several errors: https://www.reddit.com/r/Games/comments/fnl0o1/why_playstati...

I was going to link that video, especially considering regarding the problem of affine texture mapping. MVG discussed the common workaround in PSX: tesselating flat surfaces so the perspective distortion is minimized. I was surprised to see in OP's article that the PSX-Doom devs took a completely different approach of drawing a polygon for each scanline to emulate the PC-Doom's raymarching line-renderer.

This lead to some interesting issues when porting PC to PlayStation

https://www.gamasutra.com/view/feature/132500/dirty_coding_t...

Is this why geometries loved to jiggle and dance?

It seems so. A recent video about the graphical quirks of the PlayStation:

Why PlayStation 1 Graphics Warped and Wobbled so much https://youtu.be/x8TO-nrUtSI

The reasons mentioned in the video have nothing to do with the warping and wobbling, see what i wrote on Reddit about it: https://www.reddit.com/r/Games/comments/fnl0o1/why_playstati...

Yep. 16 bits isn't enough precision for 3D no matter how you use it.

When you get up to 32 or 64 bits, fixed and float are both very good.

That's why I was so surprised! I've heard of early PCs omitting floating-point, but it seems crazy for a platform designed specifically for games, for precisely this kind of reason.

That's not the reason, though.

Yes, though the affine texture mapping is not the only solution, just the easiest/ best conceptually at the time.

There's a port of Quake II to the Atari Falcon which has an interesting take on this lack of FP. See if interested:

http://www.atari-forum.com/viewtopic.php?f=68&t=26775&sid=78...

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