獲取滑鼠3個鍵的響應如下：
滑鼠左鍵GetMouseButton(0)
滑鼠右鍵GetMouseButton(1)
滑鼠中鍵GetMouseButton(2)


只要在MouseLook.cs中的Update()的相應位置加上Input.GetMouseButton(1)就可以了。

以下為全部內容

using UnityEngine;
using System.Collections;

/// MouseLook rotates the transform based on the mouse delta.
/// Minimum and Maximum values can be used to constrain the possible rotation

/// To make an FPS style character:
/// - Create a capsule.
/// - Add a rigid body to the capsule
/// - Add the MouseLook script to the capsule.
///   -> Set the mouse look to use LookX. (You want to only turn character but not tilt it)
/// - Add FPSWalker script to the capsule

/// - Create a camera. Make the camera a child of the capsule. Reset it's transform.
/// - Add a MouseLook script to the camera.
///   -> Set the mouse look to use LookY. (You want the camera to tilt up and down like a head. The character already turns.)
[AddComponentMenu("Camera-Control/Mouse Look")]
public class MouseLook : MonoBehaviour {

public enum RotationAxes { MouseXAndY = 0, MouseX = 1, MouseY = 2 }
public RotationAxes axes = RotationAxes.MouseXAndY;
public float sensitivityX = 15F;
public float sensitivityY = 15F;

public float minimumX = -360F;
public float maximumX = 360F;

public float minimumY = -60F;
public float maximumY = 60F;

float rotationX = 0F;
float rotationY = 0F;

Quaternion originalRotation;

void Update ()
{
  if(Input.GetMouseButton(0))
   {
    if (axes == RotationAxes.MouseXAndY)
    {
    // Read the mouse input axis
    rotationX += Input.GetAxis("Mouse X") * sensitivityX;
    rotationY += Input.GetAxis("Mouse Y") * sensitivityY;

    rotationX = ClampAngle (rotationX, minimumX, maximumX);
    rotationY = ClampAngle (rotationY, minimumY, maximumY);
   
    Quaternion xQuaternion = Quaternion.AngleAxis (rotationX, Vector3.up);
    Quaternion yQuaternion = Quaternion.AngleAxis (rotationY, Vector3.left);
   
    transform.localRotation = originalRotation * xQuaternion * yQuaternion;
     }
   else if (axes == RotationAxes.MouseX)
   {
    rotationX += Input.GetAxis("Mouse X") * sensitivityX;
    rotationX = ClampAngle (rotationX, minimumX, maximumX);

    Quaternion xQuaternion = Quaternion.AngleAxis (rotationX, Vector3.up);
    transform.localRotation = originalRotation * xQuaternion;
   }
   else
   {
    rotationY += Input.GetAxis("Mouse Y") * sensitivityY;
    rotationY = ClampAngle (rotationY, minimumY, maximumY);

    Quaternion yQuaternion = Quaternion.AngleAxis (rotationY, Vector3.left);
    transform.localRotation = originalRotation * yQuaternion;
    }
   }
}

void Start ()
{
   // Make the rigid body not change rotation
   if (rigidbody)
    rigidbody.freezeRotation = true;
   originalRotation = transform.localRotation;
}

public static float ClampAngle (float angle, float min, float max)
{
   if (angle < -360F)
    angle += 360F;
   if (angle > 360F)
    angle -= 360F;
   return Mathf.Clamp (angle, min, max);
}
}