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Comment by adastra22 | Hacker News Reader

This is incorrect. It is exactly the same algorithm as circuits in the GPU or as instructions on the CPU. No difference, except one: the way data is pipelined on the GPU makes texture blending free, or nearly so. So to show off, every 3D game back then turned it on (an OpenGL/Glide/D3D configuration option) and everything got smoothed out, often with no option to turn it off. That's why it ends up looking different: because the game itself selected different interpolation in accelerated vs software rendered. It was a game choice.

These days you can use different presets to override those choices, and have your 8K, 240Hz Quake look software rasterized, if you want.

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> This is incorrect

Incorrect how? It's correct in that software renderers of the time TFA describes mostly looked like this, and GPU renderers didn't (of course, they weren't called GPUs back then), and there's a reason for this. Even you admit it later in your comment.

So saying "it has nothing to do" with software renderers (of the time) is wrong. It has something to do with how software renderers vs GPUs were used during that era in practice. It's also true you can simulate one with the other, but that doesn't make it incorrect or unrelated.

> So to show off, every 3D game back then turned it on (an OpenGL/Glide/D3D configuration option) and everything got smoothed out, often with no option to turn it off. That's why it ends up looking different

So it had something to do after all! So TFA has a point. He means software renderers in the sense you're describing here, and it's clear from the text. He's not implying you cannot use a GPU to achieve the same result.

This is ridiculous. He explained it perfectly and he was right stating that it has "nothing to do with software rendering". The fact that people specifically chose to do it differently on hardware makes nothing about what the article mentions specific to software rendering. Otherwise if you do the smoothing on the CPU you have to call it a hardware renderer now to be consistent.

It's not ridiculous. It's also perfectly clear from TFA, one has to go out of their way to misinterpret this.

E.g.

> Software renderers generally sample textures pixel by pixel, so every texel stays a crisp square. Early 3D cards smoothed textures with bilinear filtering, which looked impressive in 1997 but turns everything soft and blurry to my eye now.

The author is a hobbyist discussing things in context. Early 3D cards, bilinear filtering as done in '97, etc. You cannot take random words and criticize the article. This seems to be a retrogaming hobbyist blog about doing stuff with old hardware and games.

Nitpicking is pointless.

The point is that the look is not inherent to software rendering. You're misinterpreting this as some kind of denial of historical association. You're own quote there identifies texture filtering as the difference. Explaining that you can get those sharp textures with hardware acceleration, isn’t “pointless nitpicking.”

I don't think anyone (including the original author) is saying that the look is inherent to software renderers. The point being made is that software renders of the day tended to do things in a particular way (because CPU speed was limited), and when some of these games gained hardware renderers, they did things in a different particular way, because more computationally-expensive (for a CPU) blending modes were more or less free on a GPU.

I do agree that the author may have missed the fact that they could have overridden texture blending modes via their GPU driver, and gotten a similar graphical look using the hardware renderer. But even that's a little uncertain; there are some other comments in other subthreads that point out that the hardware rendering modes on many of these older games also did other stuff that wasn't feasible with the software renderer, and those other things sometimes can't be tweaked/disabled. So if your goal is "exact same visual style as the software renderer", you might actually have to use the software renderer.

I think the comments section is the perfect place to nitpick something like this.

Software renderers can do bilinear filtering. It does not change any aspect of how the software renderer works. I’ve implemented this, so I know: it’s a couple of lines change in the texture lookup. But it adds three lerps per channel, per pixel, whereas nearest neighbor requires none. That’s 9 multiply-adds in the tightest inner loop that would normally have zero. In the 3D accelerators of the era, the pipelines were all fixed-function (programmability is why NVIDIA renamed it GPU when they released the GeForce 256), so those lerps were in the silicon whether you used them or not. Bilinear filtering had zero impact on render speed, so long as you weren’t saturating video RAM with the added texture lookups.

TL;DR a software rendered game and a 3D accelerated game from that era looked VERY different, but that difference was largely down to a feature that was often implemented in the software renderer, and was only a couple of lines in the innermost loop. But rarely used outside of a few choice effects due to the massive performance impacts. On 3D accelerators it was free, and default-on.

(I’m an old fart that cut my teeth in programming writing software renderers with the community at Flipcode, if anyone remembers that.)

I'm not disputing the technical details of anything you're saying. I don't think the author of TFA is, either.

So when you say "this is incorrect", and also:

> Software renderers can do bilinear filtering.

What do you mean? Nobody is disputing they can. The author is talking, in my opinion, about how software and hardware renderers of that time behaved in practice in games you could buy at the time. It's just that peppering the text with "at the time", "typical" and "in practice" makes for very cumbersome reading.

I'm also an old fart, by the way :) I don't remember Flipcode, but I wrote software renderers for fun and also for my CS coursework. I read my Abrash and my Foley & van Dam, etc. I then lost track of that, time was finite and I had to choose my hobbies more carefully!

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