unity Physics.Raycast 函数 LayerMask用法测试

    void Update () {        //只检测a层和b层        if (Input.GetMouseButtonDown(0))        {            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);            RaycastHit hit;            int layA = LayerMask.NameToLayer("a");            int layB = LayerMask.NameToLayer("b");            if (Physics.Raycast(ray, out hit, 99999, (1 << layA) | (1 << layB) ))            {                print("============   " + hit.transform.name);            }        }    }