2/17/2026 at 2:36:07 PM
by DamnInteresting
2/17/2026 at 3:01:30 PM
https://en.wikipedia.org/wiki/Fast_inverse_square_root for those who just want the info without AI fillerby dcanelhas
2/17/2026 at 3:00:25 PM
It's not a mystery per se.It's explained exceptionally well here [0].
by bastscho
2/17/2026 at 3:13:45 PM
Yeah, it wasn’t a real mystery (as noted in the Wikipedia article, it already existed in the numerical literature). But practically it would have surprised a lot of programmers in the days before Wikipedia, when you’d have had to read a somewhat specialized textbook or a paper to learn about it.Plus the exact constant selected and the method used to derive it remains a minor mystery, right? In the sense that it is good but non-optimal.
by bee_rider
2/17/2026 at 3:15:20 PM
The "mystery" being referred to in the title is how the magic number was derived. This is what most of the article talks about.by Antibabelic
2/17/2026 at 3:06:20 PM
Calling it a "mystery" gets suckers like me to click the link.by calibas
2/17/2026 at 3:02:02 PM
The wikipedia article gives a lot more detail and history than this fluff piece:by ginko
2/17/2026 at 3:40:01 PM
Ignore the clickbait aspect. It is one of the craziest flexes in game development.The guy had made Doom (nice fast pseudo 3D), Quake (fast 3D), and now made it look great.
Finding obscure math and figuring out that it was the correct fit for his renderer is just so bonkers.
by leshokunin
2/17/2026 at 4:26:48 PM
This could have been a good article except for all the AI slop. The future is bleak.by josefritzishere