title: Input.GetAxis("Mouse X"), Input.GetAxis("Mouse Y") always returns 0
body: <p>I added main user object for a 3d shooter, attached camera for it and trying to catch mouse moving in the code of the script, attached to the player game object. But can not use <code>Input.GetAxis("Mouse X")</code>, <code>Input.GetAxis("Mouse Y")</code>, because they always zero. Why? What I did wrong? <code>Input.GetAxis("Vertical")</code> and <code>Input.GetAxis("Horizontal")</code> for keys work good.</p>
  
  <pre class="lang-cs prettyprint-override"><code>using UnityEngine;
  using System.Collections;
  
  public class MouseLook : MonoBehaviour {
  
    public enum RotationAxes {
      MouseXAndY = 0,
      MouseX = 1,
      MouseY = 2
    }
  
    public RotationAxes axes = RotationAxes.MouseXAndY;
    public float sensitivityHor = 9.0f;
    public float sensitivityVert = 9.0f;
    public float minimumVert = -45.0f;
    public float maximumVert = 45.0f;
    private float _rotationX = 0;
  
    void Start() {
      Rigidbody body = GetComponent&lt;Rigidbody&gt;();
      if (body != null)
        body.freezeRotation = true;
    }
  
    void Update() {
      Debug.Log(Input.GetAxis("Mouse X"));
      Debug.Log(Input.GetAxis("Mouse Y"));
      if (axes == RotationAxes.MouseX) {
        transform.Rotate(0, Input.GetAxis("Mouse X") * sensitivityHor, 0);
      } else if (axes == RotationAxes.MouseY) {
        _rotationX -= Input.GetAxis("Mouse Y") * sensitivityVert;
        _rotationX = Mathf.Clamp(_rotationX, minimumVert, maximumVert);
        float rotationY = transform.localEulerAngles.y;
        transform.localEulerAngles = new Vector3(_rotationX, rotationY, 0);
      } else {
        _rotationX -= Input.GetAxis("Mouse Y") * sensitivityVert;
        _rotationX = Mathf.Clamp(_rotationX, minimumVert, maximumVert);
        float delta = Input.GetAxis("Mouse X") * sensitivityHor;
        float rotationY = transform.localEulerAngles.y + delta;
      }
  </code></pre>
  
  <p>I expect the output of <code>Input.GetAxis("Mouse X"</code>) to be from -1 to 1, but the actual output is 0. I see it in <code>Debug.Log</code>.</p>