把脚本挂载到主摄像机上, 把要跟随的物体拉到 target 上
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
/**
* 备注：本脚本必须赋予主镜头
*/
public class CameraRotateAround : MonoBehaviour
{
public Transform target;//主相机要围绕其旋转的物体
public float distance = 7.0f;//主相机与目标物体之间的距离
private float eulerAngles_x;
private float eulerAngles_y;
//水平滚动相关
public int distanceMax = 10;//主相机与目标物体之间的最大距离
public int distanceMin = 3;//主相机与目标物体之间的最小距离
public float xSpeed = 70.0f;//主相机水平方向旋转速度
//垂直滚动相关
public int yMaxLimit = 60;//最大y（单位是角度）
public int yMinLimit = -10;//最小y（单位是角度）
public float ySpeed = 70.0f;//主相机纵向旋转速度
//滚轮相关
public float MouseScrollWheelSensitivity = 1.0f;//鼠标滚轮灵敏度（备注：鼠标滚轮滚动后将调整相机与目标物体之间的间隔）
public LayerMask CollisionLayerMask;
void Start()
{
Vector3 eulerAngles = this.transform.eulerAngles;//当前物体的欧拉角
this.eulerAngles_x = eulerAngles.y;
this.eulerAngles_y = eulerAngles.x;
}
void LateUpdate()
{
if (this.target != null)
{
this.eulerAngles_x += ((Input.GetAxis("Mouse X") * this.xSpeed) * this.distance) * 0.02f;
this.eulerAngles_y -= (Input.GetAxis("Mouse Y") * this.ySpeed) * 0.02f;
this.eulerAngles_y = ClampAngle(this.eulerAngles_y, (float)this.yMinLimit, (float)this.yMaxLimit);
Quaternion quaternion = Quaternion.Euler(this.eulerAngles_y, this.eulerAngles_x, (float)0);
this.distance = Mathf.Clamp(this.distance - (Input.GetAxis("Mouse ScrollWheel") * MouseScrollWheelSensitivity), (float)this.distanceMin, (float)this.distanceMax);
//从目标物体处，到当前脚本所依附的对象（主相机）发射一个射线，如果中间有物体阻隔，则更改this.distance（这样做的目的是为了不被挡住）
RaycastHit hitInfo = new RaycastHit();
if (Physics.Linecast(this.target.position, this.transform.position, out hitInfo, this.CollisionLayerMask))
{
this.distance = hitInfo.distance - 0.05f;
}
Vector3 vector = ((Vector3)(quaternion * new Vector3((float)0, (float)0, -this.distance))) + this.target.position;
//更改主相机的旋转角度和位置
this.transform.rotation = quaternion;
this.transform.position = vector;
}
}
//把角度限制到给定范围内
public float ClampAngle(float angle, float min, float max)
{
while (angle < -360)
{
angle += 360;
}
while (angle > 360)
{
angle -= 360;
}
return Mathf.Clamp(angle, min, max);
}
}