Unity中拖拽3D物体并放入到指定位置

一、脚本编写

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

public class DragTest : MonoBehaviour
{
    //3D目标
    public List listTargets = new List();
    //2D目标点
    public List listUITargets = new List();

    //操作模式
    bool isUI = false;

    public Button buttonUI;
    public Button buttonModel;

    //起始坐标
    Vector3 starPos;
    private void Start()
    {
        starPos = transform.localPosition;
        buttonUI.onClick.AddListener(()=>
        {
            isUI = true;
        });
        buttonModel.onClick.AddListener(() =>
        {
            isUI = false;
        });
    }

    public void OnMouseDrag()
    {
        Vector3 screenPos = Camera.main.WorldToScreenPoint(transform.position);
        Vector3 mouseScreenPos = new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPos.z);
        transform.position = Camera.main.ScreenToWorldPoint(mouseScreenPos);
        Debug.Log("OnMouseDrag");
    }

    public void OnMouseUp()
    {
        if (isUI==false)
        {
            //是否落位
            bool isTarget = false;
            foreach (GameObject item in listTargets)
            {
                if (GetOverGameObject(Camera.main.gameObject).Contains(item))
                {
                    isTarget = true;
                    transform.position = item.transform.position;
                    break;
                }
            }
            if (isTarget == false)
            {
                transform.position = starPos;
            }
        }
        else
        {
            foreach (Image item in listUITargets)
            {
                if (GetOverUI(GameObject.Find("Canvas")).Count>0)
                {
                    List listTemp = new List();
                    listTemp.AddRange(GetOverUI(GameObject.Find("Canvas")));
                    if (listTemp.Contains(item.gameObject))
                    {
                        //简单做一个变色效果，实际应用中可能会是改Image的sprite之类的操作
                        item.GetComponent().color = Color.green;
                        break;
                    }
                }
               
            }
            transform.position = starPos;
        }

        //有时候操作次数多了会出现不能拖拽的问题，暂时没去看是什么原因，将该对象关闭打开一次可暂时解决。
        gameObject.SetActive(false);
        gameObject.SetActive(true);
    }

    //获取光标停留的3D物体
    public List GetOverGameObject(GameObject raycaster)
    {
        PointerEventData pointerEventData = new PointerEventData(EventSystem.current);
        pointerEventData.position = Input.mousePosition;
        PhysicsRaycaster pr = raycaster.GetComponent();
        List results = new List();
        pr.Raycast(pointerEventData, results);
        List listObjs = new List();
        if (results.Count != 0)
        {
            foreach (RaycastResult item in results)
            {
    
                listObjs.Add(item.gameObject);
            }
            //return listObjs;
        }
        return listObjs;
    }

    //获取光标停留的UI物体
    public List GetOverUI(GameObject canvas)
    {
        PointerEventData pointerEventData = new PointerEventData(EventSystem.current);
        pointerEventData.position = Input.mousePosition;
        GraphicRaycaster gr = canvas.GetComponent();
        List results = new List();
        gr.Raycast(pointerEventData, results);
        List listObjs = new List();
        if (results.Count != 0)
        {
            foreach (RaycastResult item in results)
            {
                listObjs.Add(item.gameObject);
            }
            //return listObjs;
        }
        return listObjs;
    }
}

二、编辑场景

1.新建一个cube作为我们用来拖拽的物体：

 2.给该cube添加我们刚刚编写的脚本：

3.场景中新建几个cube命名为Taget3D,摆在不同的位置并将这些新的cube传入到ListTartgets中: 

 

4.新建几个Image命名为TargetUI,放在不同的位置并传入到ListUITarget中 ：

5.新建两个Button分别对应传入buttonUI和buttonModel：

6.在Main Camera上添加PhisicsRaycaster组件：

 

 三、运行调试

此时点击运行，点击”模型模式“Button,然后拖动我们的cube到左边的一排Target3D物体上去，效果如下：

然后我们点击”UI模式“Button，再去拖动我们的cube与右边的一排TargetUI对象进行交互，可以看到效果如下：

 至此，我们的拖拽功能就基本实现了。