al_draw_filled_polygon_with_holes(3)

NAME

al_draw_filled_polygon_with_holes - Allegro 5 API

SYNOPSIS

    #include <allegro5/allegro_primitives.h>
    void al_draw_filled_polygon_with_holes(const float *vertices,
       const int *vertex_counts, ALLEGRO_COLOR color)

DESCRIPTION

Draws a filled simple polygon with zero or more other simple polygons subtracted from it - the holes. The holes cannot touch or intersect with the outline of the filled polygon.

•   vertices - Interleaved array of (x, y) vertex coordinates for each of the polygons, including holes.

•   vertex_counts - Number of vertices for each polygon. The number of vertices in the filled polygon is given by vertex_counts[0] and must be at least three. Subsequent elements indicate the number of vertices in each hole. The array must be terminated with an element with value zero.

•   color - Color of the filled polygon

When the y-axis is facing downwards (the usual) the filled polygon coordinates must be ordered anti-clockwise. All hole vertices must use the opposite order (clockwise with y down). All hole vertices must be inside the main polygon and no hole may overlap the main polygon.

For example:

    float vertices[] = {
          0,   0, // filled polygon, upper left corner
          0, 100, // filled polygon, lower left corner
        100, 100, // filled polygon, lower right corner
        100,   0, // filled polygon, upper right corner
         10,  10, // hole, upper left
         90,  10, // hole, upper right
         90,  90  // hole, lower right
    };
    int vertex_counts[] = {
       4, // number of vertices for filled polygon
       3, // number of vertices for hole
       0  // terminator
    };

There are 7 vertices: four for an outer square from (0, 0) to (100, 100) in anti-clockwise order, and three more for an inner triangle in clockwise order. The outer main polygon uses vertices 0 to 3 (inclusive) and the hole uses vertices 4 to 6 (inclusive).

SINCE

5.1.0

SEE ALSO

al_draw_filled_polygon(3), al_draw_filled_polygon_with_holes(3), al_triangulate_polygon(3)