Allegro Input Keyboard Event Lesson 4

// gcc -Wall 4.c -o 4 $(pkg-config --libs allegro-5.0 allegro_image-5.0 allegro_primitives-5.0)

#define ALLEGRO_STATICLINK

#include <allegro5/allegro.h>
#include <allegro5/allegro_primitives.h>

int main() {

    int win_x = 400;
    int win_y = 400;
    bool user_exit = false;

    int pos_x = win_x / 2;
    int pos_y = win_y / 2;

    ALLEGRO_DISPLAY *display;
    ALLEGRO_EVENT_QUEUE *event_queue = NULL;

    if(!al_init()) {
        return -1;
    }

    display = al_create_display(win_x, win_y);

    if(!display) {
        return -1;
    }

    al_init_primitives_addon();
    al_install_keyboard();

    event_queue = al_create_event_queue();
    al_register_event_source(event_queue, al_get_keyboard_event_source());

    while(!user_exit) {
        ALLEGRO_EVENT ev;
        al_wait_for_event(event_queue, &ev);

        if(ev.type == ALLEGRO_EVENT_KEY_DOWN) {
            switch(ev.keyboard.keycode) {
                case ALLEGRO_KEY_UP:
                    pos_y -= 20;
                    break;
                case ALLEGRO_KEY_DOWN:
                    pos_y += 20;
                    break;
                case ALLEGRO_KEY_RIGHT:
                    pos_x += 20;
                    break;
                case ALLEGRO_KEY_LEFT:
                    pos_x -= 20;
            }

        } else if(ev.type == ALLEGRO_EVENT_KEY_UP) {
                if(ev.keyboard.keycode == ALLEGRO_KEY_ESCAPE)
                user_exit = true;
        }
    }

        al_draw_filled_rectangle(pos_x, pos_y, pos_x + 50, pos_y + 50, al_map_rgb(0, 0, 255));
        al_flip_display();
        al_clear_to_color(al_map_rgb(0, 0, 0));

    al_destroy_event_queue(event_queue);
    al_uninstall_keyboard();
    al_destroy_display(display);

    return 0;

}