Unity2D找茬游戏

设置背景back，通过使用

RectTransformUtility.ScreenPointToLocalPointInRectangle

点击背景时实例化错误Spite，正确的地方用Button实现。

    public Canvas canvas;
    public Image back;
    public Image image;
    public AudioSource cuowu;
    public bool button;
    void Update()
    {
        if (Input.GetMouseButtonUp(0))
        {
            Vector2 _pos = Vector2.one;
            RectTransformUtility.ScreenPointToLocalPointInRectangle(back.transform as RectTransform,
                Input.mousePosition, canvas.worldCamera, out _pos);
            Debug.Log("pos:" + _pos);
            Image img = Instantiate(image);
            img.rectTransform.SetParent(canvas.transform);
            Vector3 position = new Vector3(_pos.x + Screen.width / 2, _pos.y + Screen.height / 2, 0);
            img.rectTransform.position = position;
            cuowu.Play();
        }
    }