unity3d实现控制摄像机放大缩小视野加左右可旋转视角角度

using UnityEngine;
using System.Collections;

//摄像机跟随
public class FollowPlayer : MonoBehaviour {

private Transform player;//角色
private Vector3 offsetPosition;//位置便宜
private bool isRotating=false;//是否有在滑动

public float distance;//向量长度
public float scrollSpeed=3;//拉近拉远的速度
public float rotareSpeed=2;//旋转的速度

void Start ()
{
player=GameObject.FindGameObjectWithTag(Tags.player).transform;
transform.LookAt(player.position);
offsetPosition=transform.position-player.position;//得到偏移量

}

void Update ()
{
transform.position=offsetPosition+player.position;
RotateView();
ScrollView();

}

//处理视野的拉近和拉远效果
void ScrollView()
{
// print(Input.GetAxis("Mouse ScrollWheel"));//鼠标向后滑动返回负数（拉近视野），向前正数（拉远视野）
distance = offsetPosition.magnitude;
distance += Input.GetAxis("Mouse ScrollWheel")*scrollSpeed;
distance=Mathf.Clamp(distance,2,18);
offsetPosition=offsetPosition.normalized*distance;//改变位置便移
}

//控制视野左右上下旋转

void RotateView()
{
//Input.GetAxis("Mouse X");//得到鼠标水平方向的滑动
//Input.GetAxis("Mouse Y");//得到鼠标在垂直方向的滑动
if(Input.GetMouseButtonDown(1))
{
isRotating=true;

}

if(Input.GetMouseButtonUp(1))
{
isRotating=false;

}

if(isRotating)
{

transform.RotateAround(player.position,player.up, rotareSpeed*Input.GetAxis("Mouse X"));//围捞角色滑动 左右

Vector3 originalPos=transform.position;
Quaternion originalRotation=transform.rotation;

transform.RotateAround(player.position,transform.right,-rotareSpeed*Input.GetAxis("Mouse Y"));//上下 (会影响到的属性一个是Position,一个是rotation)
//限制上下滑动的度数大小
float x=transform.eulerAngles.x;
if(x<10||x>80)//当超出范围之后，我们将属性归位，让旋转无效
{
transform.position=originalPos;
transform.rotation=originalRotation;

}

}

offsetPosition=transform.position-player.position;

}

}