public void CreatePool(int num)
{
// use one stack to reverse the order of accessing Button
// because the priority in Canvas is from top(first access) to bottom(last success)
// we should Reuse the button from bottom to top,
// when button overlapped, player can click the button below(more close to the end line, create earlier, accessing order is first)
btnPool = new Queue <GameObject>();
Stack <GameObject> tmpBtnQueue = new Stack <GameObject>();
for (int i = 0; i < num; ++i)
{
GameObject b = Instantiate(btn, note.transform) as GameObject;
tmpBtnQueue.Push(b);
//btnPool.Enqueue(b);
ButtonData tmpBD = b.GetComponent <ButtonData>();
tmpBD.SetScoreManager(scoreManager);
tmpBD.SetPoolManager(this);
tmpBD.SetSpeed(speed);
b.SetActive(false);
}
for (int i = 0; i < num; ++i)
{
btnPool.Enqueue(tmpBtnQueue.Pop());
}
isCreate = true;
}