// Update is called once per frame
    void Update()
    {
        if (Input.GetMouseButtonDown(0))
        {
            RaycastHit hit;
            Ray        ray = Camera.main.ScreenPointToRay(Input.mousePosition);

            if (Physics.Raycast(ray, out hit, 3.0f))
            {
                if (hit.transform == transform)
                {
                    // If we click the button with the mouse
                    // Make the cannon shoot
                    CannonScript cs = hit.transform.parent.GetComponent <CannonScript>();
                    cs.Shoot();
                }
            }
        }
    }