u3d：使用鼠标拖曳改变摄像机的位置

 using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
/// <summary>
/// 鼠标拖延滑动摄像机
/// </summary>
public class MouseDrag : MonoBehaviour {

    public Camera cam;
    // Use this for initialization
    void Start () {
        
    }
    /// <summary>
    /// 移动的参量,改变参数值来改变摄像机的偏移差值
    /// </summary>
    public float moveOffest=45;
    Vector2 currentMousePos;
    // Update is called once per frame
    void Update ()
    {
        if (Input.GetMouseButtonDown(0))
        {
            currentMousePos = Input.mousePosition;
        }
        if (Input.GetMouseButton(0))
        {
            //currentMousePos = Vector2.Lerp(currentMousePos,Input.mousePosition,0.99f);
            //print(Time.deltaTime*50);

            float offest = currentMousePos.x - Input.mousePosition.x;
            currentMousePos = Input.mousePosition;
            print(offest+":offest");
            cam.transform.position = new Vector3(cam.transform.position.x+offest/moveOffest,cam.transform.position.y,cam.transform.position.z);
        }
    }

}