HackerTube / Video
Fast Inverse Square Root — A Quake III Algorithm
Nemean
A walkthrough of the Quake III fast inverse square root, explaining where the constant 0x5f3759df comes from. It covers IEEE 754 floats, the bit hack that approximates a logarithm, and a Newton's method refinement.
HN recommends it as an approachable explanation that makes the famous algorithm finally make sense.
4 Hacker News mentions · 2021–2022