s_atlassed_sprite * c_sprite_atlas::add_sprite(ALLEGRO_BITMAP * sprite)
{
    if(lowest_free >= max_sprites)
        return 0;
    s_atlassed_sprite * tempsprite = new s_atlassed_sprite;
    int sx;
    int sy;
    sx = lowest_free % sprites_x;
    sy = lowest_free / sprites_x;
    tempsprite->sprite = al_create_sub_bitmap(sprite_atlas, sx*SPRITEWIDTH, sy*FULLSPRITEHEIGHT, SPRITEWIDTH, FULLSPRITEHEIGHT);
    tempsprite->index = lowest_free;

    usage[lowest_free] = tempsprite;

    //find the next empty spot
    for (; lowest_free < max_sprites; lowest_free++)
    {
        if (!usage[lowest_free]) break;
    }
    return tempsprite;
}

void c_sprite_atlas::delete_sprite(s_atlassed_sprite * sprite)
{
    int tempdex = sprite->index;
    if(tempdex < lowest_free) lowest_free = tempdex;
    al_destroy_bitmap(sprite->sprite);
    delete usage[tempdex];
    usage[tempdex] = 0;
}