POLYTYPE_ATEX(3)

💅 POLYTYPE_ATEX — bestie's guide to affine texture mapping

okay so real talk, this is a page from the Allegro manual (you know, the game programming library) and it's about one very specific little guy: the polygon rendering mode type POLYTYPE_ATEX. it's giving niche but important. let's get into it 🫶

✨ SYNOPSIS ✨

#include <allegro.h>

#define POLYTYPE_ATEX

like, that's it. that's the whole setup. one include, one define, and you're in business 💖

🌸 DESCRIPTION 🌸

so POLYTYPE_ATEX is an affine texture mapped polygon. what does that mean fr? it means the texture gets stretched across the polygon using a simple 2d linear interpolation. it's fast — like, genuinely speedy, no cap — but it is not mathematically correct. and the way that matters is everything here 😭

here's the vibe check: it can look OK if the polygon is fairly small, or if it's flat-on to the camera. those are the two situations where it behaves itself. ✨

but because it doesn't deal with perspective foreshortening, it can produce strange warping artifacts. that's the catch. it's the "looks great until it absolutely doesn't" of rendering modes 💀

and how do you see this for yourself? the manpage says: run Allegro's test program and see what happens to the polygon3d() test when you zoom in very close to the cube. do it. watch the cube get weird. it's a whole experience 🙈

not me warning you again: no perspective foreshortening = warping artifacts. small or flat-on = fine. everything in between = gamble. 👑

👑 SEE ALSO 👑

• polygon3d(3)
• ex3d(3)

go read those next, bestie, iykyk 💜

and that's the whole page! this was Allegro, version 4.4.3, serving you this iconic little manual page. slay, stay warpy, and go zoom in on that cube for me 🌈💅🎀