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Comment by ivanbakel | Hacker News Reader

>This is not real-time raytracing on standard SNES hardware, as the title implies.

I'm not sure the title implies that. Performant raytracing on SNES hardware would be (to my understanding) pure magic - SNES modes may have been good, but none of them were that good. Just reimplementing raytracing in software on a SNES would also not really be that interesting technically. It can already do any kind of calculation, if slowly.

Expansion cards are established ways to improve the SNES's hardware capabilities, as many cartridges did, especially toward the end of the console's lifetime. It's not dishonest to describe using one as doing something "on the SNES" - especially when part of the writeup is about technical challenges interfacing the expansion chip with the actual console.

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It sort of is. The SNES was sold as a specific unit with specific licensed cartridges, and has a well known set of expansion chops shipped in cartridges. I think it's pretty well understood that because of this when someone says "on the SNES" they mean using the existing hardware, possibly plus existing chips shipped at the time. The idea conveyed is that this could have been done at the time if only the expertise and effort were put into it.

Sort of like the Commodore demo scene. What they can accomplish with the original hardware is amazing. If they were relying on additional hardware to do so, it's less interesting (but may still be interesting, and an accomplishment, as this is).

A more accurate title based on how people might think of this might be "SuperRT – Hacking SNES hardware to support realtime raytracing" (and even then you're going to get people assuming it's all original hardware).

The SNES, unlike e.g. the Genesis, had a really heavy history of using add-on chips on carts. In fact, its entire architecture was very specifically designed to permit and encourage this, which is why e.g. the Genesis 32X had to intercept the video out port on the Genesis, but Super Nintendo carts could just bolt-on a SuperFX/Cx3/SA-1/what-have-you and go about their merry way. (Even the the unreleased Nintendo PlayStation would have been able to directly interface with the existing hardware, not do the 32X route of video interception.)

Where you may be making a valid point is that I don't know how many people outside the dev scene know how common cart-based extra CPUs were. But doing this feels entirely in the spirit of how development on the SNES actually worked, even at the time--and as someone who's done some SNES development work, I knew from the headline alone roughly how it would necessarily be implemented. The closest analog I can think of would be like seeing a blog post, "calling native Win32 from pure JavaScript," and then being disappointed that ffi was involved. That's literally the only way it could possibly work in the first place, so of course that's what it is going to have to be about.

I don't think the SNES actually had anything in its design that made extensibility easier on it than the Genesis.

This and the Super FX - not to mention the Sega CD or the Sega SVP used in Virtua Racing - etc. all just uploaded video data via the cartridge port and blitted it to the screen console-side.

The only reason the 32X needed to do the weird video interception kludge was to get around the Genesis' poor colour depth, and exactly the same thing would be needed if you wanted to do that on the SNES (the SNES had less of a need for that, but...)

Somewhat strangely, a single shogi game used a 32bit 21mhz ARM cpu (significantly more powerful than the baseline SNES hardware) to run the AI on. A large enough number of those in parallel could possibly display a low res real time raytraced scene decently.

>I'm not sure the title implies that

Sure it does.. it says "Realtime Raytracing on the SNES". To any normal person "SNES" means a super nintendo you would have at home.. not one that has expansion cards etc.

Anyway cool project but the title is indeed a bit misleading.

The expansion chips were in the game cartridges, though. This article is talking about how you could potentially make a game cart that you could plug into an SNES as normal and have it play with real time raytracing.

I don't think it's misleading, given the SNES history. For me the SNES was famous for its expansion chips - I immediately assumed one like the super fx chip that gave it 3d graphics.

The title may be skewed towards an audience that knows slightly obscure details of SNES history, rather than misleading the general audience.

I'm guessing the division comes down to generational ignorance. Commenters on both the oldest fringe and the younger half of the age curve aren't going to remember the big deal Nintendo made about these chips.

The title is no more deceptive for using an expansion chip than a game like Mario Kart is deceptive for calling itself an SNES game even though it also used an expansion chip.

Almost any popular SNES game you can think of came with extra technology included in the cartridge and commercials often bragged about it, like the SuperFX chip used by Star Fox.

Heck if it weren't for expansion chips, you wouldn't even be able to play Super Mario World or Zelda, since the SNES had no persistent storage, all save games were stored physically on the cartridge itself.

As I understand it, if the OP put their chips and wires into a SNES cartridge, you could take that cartridge, plug it in, and you would see their ray tracing demo on your stock SNES.

This is just like Nintendo adding their own co-processors over the lifetime of the system, albeit with more advanced technology. If Mario Kart is running on the SNES, so is this.

Perhaps one way to put it:

You couldn't download this demo into a ROM image and run it on an emulator. To make it run, you'd have to beg the author of the emulator to actually support your chip.

This is more than a silly, pedantic distinction; emulators are probably the way that >95% of the current SNES playerbase runs the software, and they're likely to remain that way … forever? I don't see the interest in running SNES games ever really going away, since they're fun in a timeless way (like classic books/film), so emulators that support it are likely to stick around for several centuries, barring civilizational collapse. Actual hardware's pretty close to dying out (the recent "SNES Classic" physical devices, afaik, are just neatly packaged emulators).

So I think it really does matter whether it runs in an emulator or not.

(Not to diminish the fairly awesome technical prowess of this hack)

That's true of probably 90% of ROM images though. To get most SNES ROMs to work you need to not only emulate the SNES console itself but also emulate the individual game's chipset. Most SNES games use one of the following expansion chipsets:

https://en.wikipedia.org/wiki/List_of_Super_NES_enhancement_...

Many SNES games include one-off chipsets that common SNES emulators implement as well; for example just something simple like saving your game can't be done on an SNES and needs an expansion chip.

> So I think it really does matter whether it runs in an emulator or not.

If you were to write a SNES emulator that only emulated the console itself, it would not be able to run the many SNES games that use addon chips. SNES emulators include code that emulate the addon chips originally contained in the cartridges[1].

So, I think your test is a false one. Games run in the emulator because the emulator added emulation for the chips in the game. This game cartridge would also run on a SNES emulator if you emulated its chips.

[1] Code to emulate the behavior of the DSP chip in Super Mario Kart (among many others): https://github.com/bsnes-emu/bsnes/tree/master/bsnes/sfc/dsp

I'm confused. Did you really think somebody found a way to do real-time raytracing on a stock SNES? I saw the title and the first thing I thought is "It's not possible, so clearly they did some black magic fuckery to subvert the system's limitations". I wasn't disappointed either, because it's impressive what he managed to do. Maybe try not to take every title completely literally? And maybe try a little bit harder to appreciate people's creativity and hard work?

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