Last Change: 2018-09-07, 16:50
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al_draw_filled_polygon_with_holes − Allegro 5 API
#include <allegro5/allegro_primitives.h> void al_draw_filled_polygon_with_holes(const float *vertices, const int *vertex_counts, ALLEGRO_COLOR color)
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.
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vertices − Interleaved array of (x, y) vertex coordinates for each of the polygons, including holes. |
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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. |
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color − Color of the filled polygon |
All hole vertices must use the opposite order (clockwise with y down) of the polygon vertices. 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).
5.1.0
al_draw_filled_polygon(3alleg5), al_draw_filled_polygon_with_holes(3alleg5), al_triangulate_polygon(3alleg5)