相互独立移动对象，能够在 Unity 2D 中同时移动

Question

我有两个对象。关键是我需要上下移动对象（按住并拖动），同时我需要独立地上下移动另一个对象（按住并拖动）。像这样的东西： Example

在网上搜索后，我找到了一个小脚本，但它一次只能触摸一次，并且只能拖动一个对象。另外，如果我用第二根手指触摸，对象会将其位置更改为第二根手指位置：

public class Move : MonoBehaviour {
    private Vector3 offset; 

  void OnMouseDown() {
      offset = gameObject.transform.position - Camera.main.ScreenToWorldPoint(new Vector3(-2.527f, Input.mousePosition.y));
  }

  void OnMouseDrag() {    
      Vector3 curScreenPoint = new Vector3(-2.527f, Input.mousePosition.y);
      Vector3 curPosition = Camera.main.ScreenToWorldPoint(curScreenPoint) + offset;
      transform.position = curPosition;    
  }
}

我只是不明白如何让两个对象同时拖放。我是 Unity 新手，老实说，我对控制器有疑问

Answer 1

对于触摸屏，我建议您使用Touch 而不是鼠标事件。 Touch 类支持同时进行多个触摸以及一些有用的信息，例如 Touch.phase（开始、移动、静止等）。我编写了一个脚本，您可以将它附加到带有“可拖动”标签的多个对象上，使对象独立移动。当您使用一根手指输入 otherObj 时，拖放应该移动的另一个对象，它应该可以工作。此版本仅适用于 2 个 obj。

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

public class PlayerActionHandler : MonoBehaviour
{
private Camera _cam;

public bool beingDragged;
public Vector3 offset;

public Vector3 currPos;

public int fingerIndex;
public GameObject otherObj;
// Start is called before the first frame update
void Start()
{
    _cam = Camera.main;
}

// Update is called once per frame
void Update()
{
    //ONLY WORKS FOR 2 OBJECTS
    if (Input.touchCount == 1 && Input.GetTouch(0).phase == TouchPhase.Began)
    {
        var raycast = _cam.ScreenPointToRay(Input.GetTouch(0).position);
        RaycastHit hit;
        if (Physics.Raycast(raycast, out hit))
        {
            //use this tag if you want only chosen objects to be draggable 
            if (hit.transform.CompareTag("Draggable"))
            {
                if(hit.transform.name == name)
                {
                    //set being dragged and finger index so we can move the object 
                    beingDragged = true;
                    offset = gameObject.transform.position - _cam.ScreenToWorldPoint(Input.GetTouch(0).position);
                    offset = new Vector3(offset.x, offset.y, 0);
                    fingerIndex = 0;
                }
            }
        }
    }else if (Input.touchCount == 1 && beingDragged)
    {
        otherObj.transform.SetParent(transform);
        if (Input.GetTouch(fingerIndex).phase == TouchPhase.Moved ){
            Vector3 pos = _cam.ScreenToWorldPoint(Input.GetTouch(fingerIndex).position);
            currPos = new Vector3(pos.x, pos.y,0) + offset;
            transform.position = currPos;

        }
    }
    //ONLY WORKS FOR 2 OBJECTS_END
    else if (beingDragged && Input.touchCount > 1)
     {
         //We tie each finger to an object so the object only moves when tied finger moves
         if (Input.GetTouch(fingerIndex).phase == TouchPhase.Moved ){
             Vector3 pos = _cam.ScreenToWorldPoint(Input.GetTouch(fingerIndex).position);
             currPos = new Vector3(pos.x, pos.y,0) + offset;
             transform.position = currPos;

         }
     }else if (Input.touchCount > 0)
       {
           for (var i = 0; i < Input.touchCount; i++)
           {
               //We find the fingers which just touched the screen
               if(Input.GetTouch(i).phase == TouchPhase.Began)
               {
                   var raycast = _cam.ScreenPointToRay(Input.GetTouch(i).position);
                   RaycastHit hit;
                   if (Physics.Raycast(raycast, out hit))
                   {
                       //use this tag if you want only chosen objects to be draggable 
                       if (hit.transform.CompareTag("Draggable"))
                       {
                           if(hit.transform.name == name)
                           {
                               //set being dragged and finger index so we can move the object 
                               beingDragged = true;
                               offset = gameObject.transform.position - _cam.ScreenToWorldPoint(Input.GetTouch(i).position);
                               offset = new Vector3(offset.x, offset.y, 0);
                               fingerIndex = i;
                           }
                       }
                   }
               }
           }

       }else if (Input.touchCount == 0)
       {
           //if all fingers are lifted no object is being dragged
           beingDragged = false;
       }
}

}