# If you're here for Euclidean Doom, you're in the wrong room

July 12, 2024 11:12 PM Subscribe

Non-Euclidean Doom: A 2022 talk by Luke Gotszling about taking the already-very-slightly-wrong value of pi encoded in iD Software's seminal 1993 title Doom and pushing it into actually-quite-wrong values to see what will happen. (Nothing good will happen.)

When I dream, I'm clearing dreaming in non-Euclidean space. The world works like Pi = 3 or so.

Noble Prize to the person who can prove it.

posted by Comstar at 11:53 PM on July 12 [1 favorite]

Noble Prize to the person who can prove it.

posted by Comstar at 11:53 PM on July 12 [1 favorite]

Fun find. Alpha Waves was a French videogame from 1990 that used a number of optimizations to deal with the same limitations that Doom faced, including lookup tables and integer calculations, for lack of the kind of 3d and floating point acceleration hardware that we take for granted today.

Lookup tables are great ways to speed things up, whether you have a perfect or (pi-misapproximated) imprefect hash table. Getting the reverse complement of a genomic sequence, for instance, is still so very much faster with an array and some pointer arithmetic, than by using bloated and inefficient (if convenient) data structures in modern languages.

I'd have been curious to know if there are other irrational or transcendental numbers that can accidentally or deliberately create interesting and playable geometries. Golden ratio, Feigenbaum constant, etc. I've been watching a lot of PBS Space Time and the idea that our universe and its physics, chemistry, and biology work the way they do because of accidentally useful dimensionless constants makes me wonder about tweaking parameters in these games and getting something that not only still works but is also playable in a fun, new, surprising way.

posted by They sucked his brains out! at 12:45 AM on July 13 [2 favorites]

Lookup tables are great ways to speed things up, whether you have a perfect or (pi-misapproximated) imprefect hash table. Getting the reverse complement of a genomic sequence, for instance, is still so very much faster with an array and some pointer arithmetic, than by using bloated and inefficient (if convenient) data structures in modern languages.

I'd have been curious to know if there are other irrational or transcendental numbers that can accidentally or deliberately create interesting and playable geometries. Golden ratio, Feigenbaum constant, etc. I've been watching a lot of PBS Space Time and the idea that our universe and its physics, chemistry, and biology work the way they do because of accidentally useful dimensionless constants makes me wonder about tweaking parameters in these games and getting something that not only still works but is also playable in a fun, new, surprising way.

posted by They sucked his brains out! at 12:45 AM on July 13 [2 favorites]

I enjoyed this video and would swear it was raised somewhere previously but I can't find the link.

I would have added graphics relating "sum of angles inside a triangle" to the flatnes of a 2D plane, so you can see that using values above Pi (and up to 3 Pi, with the caveat of using the great circles of a sphere) are like spherical geometry, and values between 0 and Pi are like hyperbolic geometry.

posted by k3ninho at 12:52 AM on July 13

I would have added graphics relating "sum of angles inside a triangle" to the flatnes of a 2D plane, so you can see that using values above Pi (and up to 3 Pi, with the caveat of using the great circles of a sphere) are like spherical geometry, and values between 0 and Pi are like hyperbolic geometry.

posted by k3ninho at 12:52 AM on July 13

Also funny to think about a bad constant from the 90s propagating through one repository after another in 2024. AIs like GitHub Copilot mindlessly scraping faulty code and helping it reproduce through the ages without checking any of it; GIGO in action.

posted by They sucked his brains out! at 1:31 AM on July 13 [5 favorites]

posted by They sucked his brains out! at 1:31 AM on July 13 [5 favorites]

That's a good round-up. One game that's missing, possibly because it is Euclidean but probably not in a way that Euclid would have dreamed, is 4D Golf. (Disclaimer: I've done a Q&A with the makers of 4D Golf, and also with three of the games on Zeno's list, and I've exchanged cordial messages with Zeno himself. Funny thing, as one reads his writings, his words get smaller and smaller but never seem to end....)

posted by JHarris at 3:43 AM on July 13 [3 favorites]

posted by JHarris at 3:43 AM on July 13 [3 favorites]

Well, I was

The most interesting part of this for me was the bit where the speaker was talking about lookup tables, partially because it's kind of jarring that modern hackers might not know about them but also because your computer is

posted by phooky at 4:56 AM on July 13 [2 favorites]

*heading*for the Euclidean Doom session, but I somehow veered off course.The most interesting part of this for me was the bit where the speaker was talking about lookup tables, partially because it's kind of jarring that modern hackers might not know about them but also because your computer is

*still*using LUTs to compute trig functions. It's not an "old computer slow" thing; trig is hard and your shiny new nvidia card is still using interpolated LUTs under the hood.posted by phooky at 4:56 AM on July 13 [2 favorites]

*It's not an "old computer slow" thing; trig is hard*

I started my career doing hardware, about 25 years ago, but veered off to software after just a couple of years. Last year I started to get back into hardware again with a hobby project, initially using microcontrollers but changing gear to FPGAs in the last couple weeks. So many 1990s problems are still 2020s problems. The scales may have changed, but the outlines are still pretty recognizable.

posted by notoriety public at 5:32 AM on July 13 [6 favorites]

Metafilter: you're here for Euclidean doom

posted by Mogur at 6:27 AM on July 13 [1 favorite]

posted by Mogur at 6:27 AM on July 13 [1 favorite]

As a terrifying demise, Non-Euclidean Doom is unparalleled.

posted by notoriety public at 9:09 AM on July 13 [2 favorites]

posted by notoriety public at 9:09 AM on July 13 [2 favorites]

notoriety public, that seems a tad hyperbolic to me.

posted by xigxag at 11:54 PM on July 13 [1 favorite]

posted by xigxag at 11:54 PM on July 13 [1 favorite]

guys you can't just draw a straight line between this and the downfall of civilization

posted by cortex at 7:38 AM on July 14

posted by cortex at 7:38 AM on July 14

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