“The Quake III Algorithm That Defies Math”

Question

https://attackofthefanboy.com/articles/the-quake-iii-algorithm-that-defies-math-explained/

I know next to nothing about programming and physics, but I do know this article intrigues me. I’m mostly interested in how the algorithm “allowed the game to function faster and more smoothly,” and why it’s “seemingly mathematically impossible.”

In: 119

Answer 1

Suppose you are tasked with converting speed limit signs from miles per hour (MPH) to kilometers per hour (KPH). Your supervisor tells you, “Don’t worry, just multiply the MPH by 1.609344,” and leaves you to get to work.

You don’t have a calculator.

But – you make the observation that you get close enough to the right answer by adding:

KPH ~ MPH + MPH/2 + MPH/10

All of which is pretty easy to do in your head, and will give you an answer close enough that it won’t matter on a sign.

The inverse square algorithm seeks to get close enough to the right answer by doing quick calculations rather than slow complicated calculations.