var page1,page2,active_page,logo;
var tim=0;

function draw()
{
    stretch_blit(logo,active_page,0,0,logo.w,logo.h,0,0,SCREEN_W,SCREEN_H);
}

function update()
{

}

function main()
{
    allegro_init();
    set_gfx_mode("example", 640, 480);
    install_keyboard();
    install_timer();
    install_mouse();
    install_sound();
    page1 = create_bitmap(SCREEN_W, SCREEN_H);
    page2 = create_bitmap(SCREEN_W, SCREEN_H);
    logo = load_bmp("allegro.png");

    active_page = page2;

    install_int_ex(function()
    {
      clear_to_color(active_page, makecol(255, 255, 255));

        update();

      draw();

        blit(active_page,canvas,0,0,0,0,SCREEN_W,SCREEN_H);

      if (active_page == page1)
            active_page = page2;
      else
            active_page = page1;

   }, BPS_TO_TIMER(60));

    return 0;
}
END_OF_MAIN();