al_draw_prim - Online Linux Manual Page

Section : 3
Updated :
Source : Allegro reference manual
Note :

NAME

al_draw_prim − Allegro 5 API

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

Draws a subset of the passed vertex array.

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]al_create_vertex_decl(3). If set to 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);