al_draw_prim(3)

💖 NAME 💖

okay so bestie, al_draw_prim(3) is the page, and it lives in the Library Functions Manual — al_draw_prim is part of the Allegro 5 API. Periodt. 💅

✨ SYNOPSIS ✨

#include <allegro5/allegro_primitives.h>

int al_draw_prim(const void* vtxs, const ALLEGRO_VERTEX_DECL* decl,
                 ALLEGRO_BITMAP* texture, int start, int end, int type)

🦋 DESCRIPTION 🦋

Lowkey it draws a subset of the vertex array you pass in. Vibe check, parameters:

• texture — texture to use, pass NULL to use only color shaded primitves
• vtxs — pointer to an array of vertices
• decl — pointer to a vertex declaration from al_create_vertex_decl(3). If this is NULL, the vertices are assumed to be of the ALLEGRO_VERTEX(3) type
• start — start index of the subset of the vertex array to draw
• end — one past the last index of the subset of the vertex array to draw
• type — a member of the ALLEGRO_PRIM_TYPE(3) enumeration, specifying what kind of primitive to draw

Returns: Number of primitives drawn. 🫶

For example, to draw a textured triangle you could use:

ALLEGRO_COLOR white = al_map_rgb_f(1, 1, 1);
ALLEGRO_VERTEX v[] = {
   {.x = 128, .y = 0, .z = 0, .color = white, .u = 128, .v = 0},
   {.x = 0, .y = 256, .z = 0, .color = white, .u = 0, .v = 256},
   {.x = 256, .y = 256, .z = 0, .color = white, .u = 256, .v = 256}};
al_draw_prim(v, NULL, texture, 0, 3, ALLEGRO_PRIM_TRIANGLE_LIST);

🌈 SEE ALSO 🌈

• ALLEGRO_VERTEX(3)
• ALLEGRO_PRIM_TYPE(3)
• ALLEGRO_VERTEX_DECL(3)
• al_draw_indexed_prim(3)

xoxo, the Allegro reference manual 💅 signing off from al_draw_prim(3) ✨