Get Allegro up and running

#include "allegro5/allegro.h"
#include "allegro5/allegro_font.h"

int main (int argc, char *argv[])
{
	al_init();
	al_init_font_addon();
	
	ALLEGRO_DISPLAY *display = al_create_display(640, 480);
	ALLEGRO_EVENT_QUEUE *queue = al_create_event_queue();
	ALLEGRO_TIMER* timer = al_create_timer(1.0 / 30.0);
	ALLEGRO_FONT* font = al_create_builtin_font();
	
	
	bool running = true;
	bool redraw = false;
	
	ALLEGRO_EVENT event;
	
	al_register_event_source(queue, al_get_display_event_source(display));
	al_register_event_source(queue, al_get_timer_event_source(timer));
	
	al_start_timer(timer);
	
	while(running)
	{
		
		al_wait_for_event(queue, &event);
		switch(event.type)
		{
		case ALLEGRO_EVENT_TIMER:
		{
			redraw = true;
			break;
		}
		case ALLEGRO_EVENT_DISPLAY_CLOSE:
		{
			running = false;
			break;
		}
		case ALLEGRO_EVENT_DISPLAY_HALT_DRAWING:
		{
			al_stop_timer(timer);
			redraw = false;
			al_acknowledge_drawing_halt(display);
			break;
		}
		case ALLEGRO_EVENT_DISPLAY_RESUME_DRAWING:
		{
			al_acknowledge_drawing_resume(display);
			al_start_timer(timer);
			break;
		}
		}

		if(redraw && al_is_event_queue_empty(queue))
        {
            al_clear_to_color(al_map_rgb(0, 100, 0));
            al_draw_text(font, al_map_rgb(255, 255, 255), 320, 240, ALLEGRO_ALIGN_CENTER, "Hello world!");
            al_flip_display();
            redraw = false;
        }
	}
	
	// Allegro takes a second or two to close down
	al_destroy_display(display);
	al_destroy_event_queue(queue);
	al_destroy_timer(timer);
	
	return 0;
}