MMORPG中的相机跟随算法

先上代码

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CameraFollow : MonoBehaviour {
    //摄像机与主角的直线距离
    public float distance = 15;
    //横向角度
    public float rot = 0;
    //纵向角度
    public float roll = 30f*Mathf.PI * 2 / 360;
    //目标物体
    public GameObject target;
    //横向旋转速度
    public float rotSpeed = 0.2f;
    //纵向旋转速度
    public float rollSpeed = 0.2f;
    //纵向角度范围
    public float maxRoll = 70f * Mathf.PI * 2 / 360;
    public float minRoll = -10f * Mathf.PI * 2 / 360;
    //鼠标滚动距离范围
    public float maxDistance = 22f;
    public float minDistance = 5f;
    //距离变化速度
    public float zoomSpeed = 0.2f;
    
    //设置相机焦点目标
    public void SetTarget(GameObject target) {
        if (target.transform.Find("cameraPoint") != null)
            this.target = target.transform.Find("cameraPoint").gameObject;
        else
            this.target = target;
    }

    private void Rotate() {
        float w = Input.GetAxis("Mouse X") * rotSpeed;
        rot -= w;
    }

    private void Roll() {
        float w = Input.GetAxis("Mouse Y") * rollSpeed * 0.5f;
        roll -= w;
        if (roll > maxRoll)
            roll = maxRoll;
        if (roll < minRoll)
            roll = minRoll;
    }

    private void Zoom() {
        if (Input.GetAxis("Mouse ScrollWheel") > 0) {
            if (distance > minDistance)
                distance -= zoomSpeed;
        }
        else if (Input.GetAxis("Mouse ScrollWheel") < 0) {
            if (distance < maxDistance)
                distance += zoomSpeed;
        }
    }

    private void LateUpdate () {
        if (target == null)
            return;
        if (Camera.main == null)
            return;
        Rotate();
        Roll();
        Zoom();

        Vector3 targetPos = target.transform.position;
        Vector3 cameraPos;
        float d = distance * Mathf.Cos(roll);
        float height = distance * Mathf.Sin(roll);
        cameraPos.x = targetPos.x + d * Mathf.Cos(rot);
        cameraPos.z = targetPos.z + d * Mathf.Sin(rot);
        cameraPos.y = targetPos.y + height;

        Camera.main.transform.position = cameraPos;
        Camera.main.transform.LookAt(target.transform);
    }

}

此代码使用了3D数学中的sin和cos函数

计算了3D空间中相机与主角之间的位置关系

使得相机可以围绕主角旋转

从而360度无死角观察主角

target表示主角物体

SetTarget可以获取名为“cameraPoint”的主角物体

Rotate()函数为相机旋转

Roll()函数为相机上下角度调整

Zoom()函数为相机拉近拉远