POLYTYPE_ATEX(3alleg4)

💅 POLYTYPE_ATEX — bestie edition

okay so real quick, this is a page from the Allegro manual — yep, the Allegro game programming library — and it's all about one tiny little #define that changes everything about how your polygons look. sit down, grab a strawberry 🍓, we're doing graphics theory.

✨ SYNOPSIS ✨

#include <allegro.h>

#define POLYTYPE_ATEX

that's it. that's the whole thing. one include, one define. iconic behavior honestly 👑

🌸 DESCRIPTION 🌸

so POLYTYPE_ATEX is an affine texture mapped polygon. what does that even mean bestie?? okay so basically: it stretches the texture across the polygon using a simple 2d linear interpolation. and the way that it does this is fast — like, genuinely fast, it ate and left no crumbs — but it is not mathematically correct. 😭

it can look OK if the polygon is fairly small or flat-on to the camera. that's the vibe check it passes. but here's the thing: because it doesn't deal with perspective foreshortening, it can produce strange warping artifacts. it's giving warped. it's giving cursed. 💀

want to see what this actually means with your own eyes?? run Allegro's test program and watch what happens to the polygon3d() test when you zoom in very close to the cube. no cap, the cube will start acting up and you'll be like "not me witnessing affine warping in real time 🙈". genuinely a main character moment for the artifact.

🦋 SEE ALSO 🦋

• polygon3d(3alleg4)
• ex3d(3alleg4)

Allegro, version 4.4.3 — that's the version, bestie, that's the whole source right there. tysm for reading, go texture something (small, or flat-on to the camera, for your own sanity) 💖✨🎀🫶