3 ms·
I don't know how heavily it was used in Quake but I'd bet quite a lot. Carmack didn't mess around optimizing things for no reason, he was (and is) pretty focuse
by taneq 6y ago
I don't know how heavily it was used in Quake but I'd bet quite a lot. Carmack didn't mess around optimizing things for no reason, he was (and is) pretty focused on spending time (coder and CPU) where it will do most good.
Also, a "mere" 1% speedup seems trivial for most general coding but squeezing 1% out of optimized game code is like blood from a stone. Add a bunch of similar tricks together and you can see 10-20% overall improvement which is huge.
- Kranar 6y agoI mean it's now ingrained in programming lore, but the reality is that Carmack has nothing to do with this and Carmack himself has never taken credit for it. The fast inverse square root dates back to the 80s and has its roots in SGI's systems. One of the developers who worked at SGI would eventually go on to work at ID developing Quake and worked on this optimization.
- taneq 6y agoOh, I didn't mean to imply Carmack invented it - he himself is pretty clear that he didn't. I just meant that incremental improvements in efficiency like this can add up surprisingly fast, and that once the low hanging fruit are taken, they're well worth doing.