Input.GetAxis("Mouse ScrollWheel")控制摄像机视野缩放
Camera.main.fieldOfView += Input.GetAxis("Mouse ScrollWheel") * 10;
Debug.Log(Camera.main.fieldOfView);
文章来自：http://www.cnblogs.com/ZeroMurder/p/5930606.html
Camera.main.fieldOfView += Input.GetAxis("Mouse ScrollWheel") * 10;
Debug.Log(Camera.main.fieldOfView);