//Add Random Item
var gx = x_to_gx (mouse_x)
var gy = y_to_gy (mouse_y)
var add_item = choose (item.hp_potion, item.stamina_potion, item.bomb)
if (count[# gx, gy] = 0)
{
    inventory_add_item (gx, gy, add_item)
}
else
{
    count[# gx, gy] ++
}