cross_product(3alleg4)

💖 cross_product — bestie edition 💖

okay so you're reading the Allegro manual for cross_product and cross_product_f, and honestly? you're in the right place. this is from the Allegro game programming library, and we're about to calculate a cross product together. no cap. 🎀

✨ NAME ✨

cross_product, cross_product_f — Calculates the cross product. Allegro game programming library. 💅

🌸 SYNOPSIS 🌸

#include <allegro.h>

void cross_product(fixed x1, y1, z1, x2, y2, z2, *xout, *yout, *zout);

void cross_product_f(float x1, y1, z1, x2, y2, z2, *xout, *yout, *zout);

🦋 DESCRIPTION 🦋

ok so the whole vibe here: this function calculates the cross product of (x1, y1, z1) × (x2, y2, z2), and then it stores the result in (*xout, *yout, *zout). that's it, that's the function. ✨

and here's the part that's genuinely iconic: the cross product comes out perpendicular to both of the input vectors. like, it's literally built different — it points off at a right angle to both of them at the same time. 🫶

so what do you actually do with that? you use it to generate polygon normals. that's the main character use case, bestie. normals. polygons. slay. 👑

👀 SEE ALSO 👀

• dot_product(3alleg4) — the other product, the one that's giving scalar energy 🍓
• polygon_z_normal(3alleg4) — the one that actually puts your normals to work 💜
• normalize_vector(3alleg4) — so your vectors don't get too long for their own good 😭
• exstars(3alleg4) — an example, go look at it, fr fr 🌟

ngl this page is short and sweet and that's the point. it's giving minimalism. not me writing a whole essay about a cross product. 💀

Allegro version 4.4.3 — cross_product(3alleg4), and that's the whole page, bestie. hope your normals are perpendicular and your vectors are normalized. 💖✨🎀 bye!! 🦋