Unity3D拖動任意對象GameObject移動到任意地方

今天不是很忙，研究了一下拖拽GameObject移動到任意位置，沿x軸和z軸移動,其他的也就不說了，上代碼：

using UnityEngine;
using System.Collections;

public class DragAndDrog : MonoBehaviour {

    private GameObject target;
    private bool isMouseDrag;
    private Vector3 screenPosition;
    private Vector3 offset;
	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update () {
        GameObjectDragAndDrog();
	
	}

    //任意拖拽

    private GameObject ReturnGameObjectDrag(out RaycastHit hit)
    {
        target = null;
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        if (Physics.Raycast(ray.origin, ray.direction * 10, out hit))
        {
            target = hit.collider.gameObject;
        }
        return target;
    }

    //拖拽Updata
    private void GameObjectDragAndDrog()
    {
        if (Input.GetMouseButtonDown (0))
        {
            RaycastHit hitInfo;
            target = ReturnGameObjectDrag(out hitInfo);
            if (target != null)
            {
                isMouseDrag = true;
                screenPosition = Camera.main.WorldToScreenPoint(target.transform.position);
                offset = target.transform.position - Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPosition.z));
            }      
        }

        if (Input.GetMouseButtonUp(0))
        {
            isMouseDrag = false;
        }

        if (isMouseDrag)
        {

            Vector3 currentScreenSpace = new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPosition.z);
            Vector3 currentPosition = Camera.main.ScreenToWorldPoint(currentScreenSpace) + offset;
            target.transform.localPosition = new Vector3(currentPosition.x, currentPosition.y, currentPosition.z);

        }
    }

}

本腳本可以加載任意一個對象GameObject，場景中所有帶Collider的對象，當鼠標點擊拖動時候都可以沿x和z軸拖動。之前，都是要拖動那個GameObject就會寫一個腳本掛在上面，今天實現了不用每一個要拖動的GameObject都掛載腳本，也不用將移動的GameObject賦給某個變量。