Demonstrate drawing tiles with hold_bitmap_drawing

draw_tiles.c

#include <stdio.h>
#include <allegro5/allegro.h>
#include <allegro5/allegro_color.h>
#include <allegro5/allegro_image.h>

const int SCREEN_W = 500;
const int SCREEN_H = 500;
const int TILE_SIZE = 16;
const char *TILESET_NAME = "tileset.png";

int main() {
    ALLEGRO_DISPLAY *display = NULL;
    ALLEGRO_BITMAP  *tileset = NULL;

    al_init();
    al_init_image_addon();

    display = al_create_display(SCREEN_W, SCREEN_H);
    tileset = al_load_bitmap(TILESET_NAME);

    while (1) {
        float start_time = al_get_time();

        // blank the display and prepare to draw tiles
        al_clear_to_color(al_map_rgb(0,0,0));
        al_hold_bitmap_drawing(true);

        // fill the screen with tiles drawn from a single bitmap
        for (int y = 0 ; y <= SCREEN_H - TILE_SIZE ; y += TILE_SIZE)
            for (int x = 0 ; x <= SCREEN_W - TILE_SIZE ; x += TILE_SIZE)
                al_draw_bitmap_region(
                    tileset,                    // source bitmap
                    0, 0, TILE_SIZE, TILE_SIZE, // source rect
                    x, y,                       // destination (top-left)
                    0);                         // flags

        // done drawing tiles for this frame
        al_hold_bitmap_drawing(false);
        al_flip_display();

        float framerate = 1 / (al_get_time() - start_time);
        printf("%f, ", framerate);
    }

    al_destroy_bitmap(tileset);
    al_destroy_display(display);

    return 0;
}