al_triangulate_polygon(3alleg5)

💖 al_triangulate_polygon — Allegro 5 API 💖

okay bestie, welcome to the 3alleg5 page for al_triangulate_polygon ✨ this is the Allegro 5 API and she is ready to slice your polygons into lil triangle confetti 🎀

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✨ SYNOPSIS ✨

#include <allegro5/allegro_primitives.h>

bool al_triangulate_polygon(
   const float* vertices, size_t vertex_stride, const int* vertex_counts,
   void (*emit_triangle)(int, int, int, void*), void* userdata)

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🦋 DESCRIPTION 🦋

So here's the vibe: this function takes one simple polygon and chops it up into triangles 🔺🔺🔺 — and you can also subtract zero or more other simple polygons from it, and those subtracted ones are the holes. The holes are like, "not me being a void in your shape 💀" and the main polygon is like "periodt".

⚠️ real talk though: the holes cannot touch or intersect with the outline of the main polygon. Like, zero contact. Don't even try it 🙈

And when we say simple, we mean the polygon does not have to be convex (she can be as lumpy as she wants, we love her for that 💅), but it must not be self-overlapping. Self-overlapping is giving chaos and we don't do that here.

🌸 Parameters 🌸

• vertices — an interleaved array of (x, y) vertex coordinates, for every single one of the polygons, holes included. Everybody's in the same array, no cap 🫶
• vertex_stride — the distance, in bytes, between successive pairs of vertices in that array. It's giving "how far apart are your besties standing" 💫
• vertex_counts — how many vertices each polygon has. The main polygon's vertex count lives at vertex_counts[0] and it must be at least three (a triangle is the bare minimum, you can't have a shape with two points, bestie 😭). Every element after that says how many vertices each hole has. And the whole array must be terminated with an element with value zero — that zero is the little "k that's it, we're done here" 🎀
• emit_triangle — a function that gets called for every set of three points that form a triangle. She receives the indices of the points in vertices, plus userdata. Iconic callback energy 👑
• userdata — arbitrary data that gets passed straight through to emit_triangle. Whatever you want, it's yours, she won't judge 💜

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⭐ SINCE ⭐

5.1.0 — yes she's been around, she's a legend 🌈

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👀 SEE ALSO 👀

• al_draw_filled_polygon_with_holes(3alleg5) — the sister function, she draws the thing you just triangulated 🦋✨

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mwah 💋 that's the whole page! This was the Allegro reference manual, page al_triangulate_polygon(3alleg5) — go forth and triangulate, bestie, you're gonna slay 🔥👑💅