如何在Unity 2D中实现多点触控？

Question

在此游戏中，有许多带有标签“敌人”的对象，所有这些敌人都是同一类的实例，在该类中，我使用了“ OnMouseDown”方法来处理用户的单击，但这不是完美的方法，因为它与多点触控不兼容

我在网上四处张望，找到了解决方案：

public class TouchInput : MonoBehaviour {

public LayerMask touchInputMask;

private List<GameObject> touchList = new List<GameObject>();
private GameObject[] touchesOld;
private RaycastHit hit;

void update()
{
#if UNITY_EDITOR
    if (Input.GetMouseButton(1) || Input.GetMouseButtonUp(1))
    {
        touchesOld = new GameObject[touchList.Count];
        touchList.CopyTo(touchesOld);
        touchList.Clear();

            Ray ray = GetComponent<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);
                }
                else if (Input.GetMouseButtonUp(0))
                {
                    recipient.SendMessage("OnTouchUp", hit.point, SendMessageOptions.DontRequireReceiver);
                }
                else 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)
        {
            Ray ray = GetComponent<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);
                }
                else if (touch.phase == TouchPhase.Ended)
                {
                    recipient.SendMessage("OnTouchUp", hit.point, SendMessageOptions.DontRequireReceiver);
                }
                else if (touch.phase == TouchPhase.Stationary || touch.phase == TouchPhase.Moved)
                {
                    recipient.SendMessage("OnTouchStay", hit.point, SendMessageOptions.DontRequireReceiver);
                }
                else 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);
            }
        }
    }
}

}

但是我认为该解决方案在2D游戏中不起作用（我尝试过，我将此脚本附加到了主摄像头，没有任何错误，但是似乎从来没有需要使用“ update”方法某些原因）。

有什么想法吗？

更新：

我正在使用的代码：

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

public class TouchInput : MonoBehaviour, IPointerDownHandler
{

    void Start()
    {
        addPhysics2DRaycaster();
    }

    void addPhysics2DRaycaster()
    {
        Physics2DRaycaster physicsRaycaster = GameObject.FindObjectOfType<Physics2DRaycaster>();
        if (physicsRaycaster == null)
        {
            Camera.main.gameObject.AddComponent<Physics2DRaycaster>();
        }
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        Debug.Log("Clicked: " + eventData.pointerCurrentRaycast.gameObject.name);
    }

    //Implement Other Events from Method 1

 }

主摄像头：

EventSystem：

控制台：（只有统一广告广告）

层次结构：

我的对象：