Unity 3d无法在此范围内声明名为`ray'的局部变量

Question

我正在制作一些触控按钮而且我收到错误：

  

错误CS0136：一个名为ray' cannot be declared in this scope because it would give a different meaning to ray＆＃39;的局部变量，已在'父＆＃39;中使用范围来表示别的东西

代码：

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public class NewBehaviourScript : MonoBehaviour {

    public LayerMask TouchInputMask;

    private List<GameObject> TouchList = new List<GameObject>();
    private GameObject[] TouchesOld;
    private RaycastHit2D hit;

    void Update () {

#if UNITY_EDITOR
        if (Input.GetMouseButton(0) || Input.GetMouseButtonDown(0) || Input.GetMouseButtonUp(0)) {
            TouchesOld = new GameObject[TouchList.Count];
            TouchList.CopyTo(TouchesOld);
            TouchList.Clear();
        }





            Ray2D ray = camera.ScreenPointToRay(Input.mousePosition);


            if (Physics.Raycast(ray, out hit,TouchInputMask)){

                gameObject recipient = hit.transform.gameObject;

                TouchList.Add(recipient);

            if (Input.GetMouseButtonDown(0)) {
                    recipient.SendMessage("OnTouchDown", hit.point, SendMessageOptions.DontRequireReceiver);
                }
            if (Input.GetMouseButtonUp(0)) {
                    recipient.SendMessage("OnTouchUp", hit.point, SendMessageOptions.DontRequireReceiver);
                }
            if (Input.GetMouseButton(0)) {
                    recipient.SendMessage("OnTouchStay", hit.point, SendMessageOptions.DontRequireReceiver);
                }


            }

        foreach (GameObject g in TouchesOld) {
            if (!TouchList.Contains(g)) {
                g.SendMessage("OnTouchExit", hit.point, SendMessageOptions.DontRequireReceiver);
            }
        }


#endif


        if (Input.touchCount > 0) {
            TouchesOld = new GameObject[TouchList.Count];
            TouchList.CopyTo(TouchesOld);
            TouchList.Clear();
        }

        foreach (Touch touch in Input.touches) {



            Ray2D ray = camera.ScreenPointToRay(touch.position);


            if (Physics.Raycast(ray, out hit,TouchInputMask)){

                gameObject recipient = hit.transform.gameObject;

                TouchList.Add(recipient);

                if (touch.phase == TouchPhase.Began) {
                    recipient.SendMessage("OnTouchDown", hit.point, SendMessageOptions.DontRequireReceiver);
                }
                if (touch.phase == TouchPhase.Ended) {
                    recipient.SendMessage("OnTouchUp", hit.point, SendMessageOptions.DontRequireReceiver);
                }
                if (touch.phase == TouchPhase.Stationary || touch.phase == TouchPhase.Moved) {
                    recipient.SendMessage("OnTouchStay", hit.point, SendMessageOptions.DontRequireReceiver);
                }
                if (touch.phase == TouchPhase.Canceled) {
                    recipient.SendMessage("OnTouchExit", hit.point, SendMessageOptions.DontRequireReceiver);
                }

            }
        }
        foreach (GameObject g in TouchesOld) {
            if (!TouchList.Contains(g)) {
                g.SendMessage("OnTouchExit", hit.point, SendMessageOptions.DontRequireReceiver);
            }
        }
    }

}