11–13 of 13 posts
Reminded me of Quake's trick[1] of calculating the perspective correction every 16 pixels, as you then effectively got it for free on a Pentium processor. [1]: https://www.bluesnews.com/abrash/chap68.shtml
I remember that Descent, released earlier, had used the same trick.
3D graphics is a rich and old field with lots of tricks like this. It's cool to see faster algorithms and alternative explanations in the comments!
Earlier quoted context omitted.
It turns out we all could count cycles. Seriously, this keeps getting overhyped as some gigantic insight when it was really just a consequence of the Pentium having been released in 1993. And with the Pentium, you got both reliable FPU availability (none of the 486SX pain), and the cycle count for FDIV dropped by almost 50% (73->39 IIRC) Everybody doing 3d gfx knew you needed a perspective divide and was looking at w…
I seem to recall reading about it in one of the demo code articles floating about at the time, similar to this one[1]. But Quake is the one that stuck with me for some reason, and it's easy to link to. [1]: https://www.lysator.liu.se/~mikaelk/doc/perspectivetexture/
But also worth noting that that article is dated one year after quake, two years after descent.
Also, lysator... there's a name I haven't heard in a while! Thanks for reminding me.