Unity 3D——射线的应用

RaycastHit raycastHit = new RaycastHit(); Ray ray;

  ray = mainCamera.ScreenPointToRay(Input.GetTouch(0).position);   if (Physics.Raycast(ray, out raycastHit, 6000f))        {            if (raycastHit.collider.GetComponent<BuildingControl>() != null)             {                  raycastHit.collider.GetComponent<BuildingControl>().Click();             }        }