al_draw_triangle - Allegro 5 API

       Draws an outlined triangle.

       Parameters:

       • x1, y1, x2, y2, x3, y3 - Three points of the triangle

       • color - Color of the triangle

       • thickness - Thickness of the lines, pass <= 0 to draw hairline lines

       al_draw_triangle - Allegro 5 API

al_draw_filled_triangle(3alleg5), al_draw_soft_triangle(3alleg5)

Allegro reference manual                                                               al_draw_triangle(3alleg5)

              #include <allegro5/allegro_primitives.h>

              void al_draw_triangle(float x1, float y1, float x2, float y2,
                 float x3, float y3, ALLEGRO_COLOR color, float thickness)