work/Assets/Script/Tool/RotateRound.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using DG.Tweening;
using UnityEngine.EventSystems;

public class RotateRound : MonoBehaviour, IPointerDownHandler,IDragHandler,IPointerUpHandler,IPointerEnterHandler,IPointerExitHandler
{
    public Transform _camera;
    public Transform target;

    private Vector2 mouseClickPos = Vector2.zero;
    private Vector2 mouseLastPos = Vector2.zero;
    private Vector3 cameraPos;
    private float _viewDistance;
    float speed = 15f;
    int roteDir = 0;

    public bool mouseWheelOpen = false;
    // Start is called before the first frame update
    void Start()
    {
        cameraPos.x = _camera.localPosition.x;
        cameraPos.y = _camera.localPosition.y;
        cameraPos.z = _camera.localPosition.z;
    }

    private void Update()
    {

        if (mouseWheelOpen)
        {
            //鼠标滚轮控制远近
            if (Input.GetAxis("Mouse ScrollWheel") != 0)
            {
                _viewDistance = Input.GetAxis("Mouse ScrollWheel") * Time.deltaTime * 100f*50;
                _viewDistance = Mathf.Clamp(_viewDistance, -100, 100);

                cameraPos =_camera.localPosition+ _camera.forward.normalized * _viewDistance;

                _camera.localPosition = cameraPos;
            }

        }
    }


    public void OnPointerDown(PointerEventData eventData)
    {

        mouseClickPos = Input.mousePosition;
        mouseLastPos = mouseClickPos;

    }

    public void OnDrag(PointerEventData eventData)
    {
        //鼠标左键控制左右，上下轴旋转
        if (Input.GetMouseButton(0))
        {
            Vector2 TempMousePos = Input.mousePosition;
            float x_Rote = TempMousePos.x - mouseClickPos.x;
            float y_Rote = TempMousePos.y - mouseClickPos.y;

            if (Mathf.Abs(x_Rote) > 5f&&roteDir==0)
            {
                //方向锁
                roteDir = 1;

            }else if (Mathf.Abs(y_Rote) > 5f && roteDir == 0)
            {
                //方向锁
                roteDir = 2;
            }

            switch (roteDir)
            {
                case 1:
                    x_Rote = TempMousePos.x - mouseLastPos.x;
                    _camera.transform.RotateAround(target.position, Vector3.up, x_Rote * speed * Time.deltaTime);
                    mouseLastPos.x = TempMousePos.x;
                    break;
                case 2:
                    y_Rote = TempMousePos.y - mouseLastPos.y;
                    _camera.transform.RotateAround(target.position, Vector3.right, y_Rote * speed * Time.deltaTime);

                    mouseLastPos.y = TempMousePos.y;
                    break;
            }
           
        }

        //鼠标滚轮平移视角
        if (Input.GetMouseButton(2))
        {
            Vector2 TempMousePos = Input.mousePosition;
            float x_move = TempMousePos.x - mouseClickPos.x;
            float y_move = TempMousePos.y - mouseClickPos.y;

            if(Mathf.Abs(x_move)>2f|| Mathf.Abs(y_move) > 2f)
            {
                x_move = TempMousePos.x - mouseLastPos.x;
                y_move = TempMousePos.y - mouseLastPos.y;
                _camera.transform.localPosition += new Vector3(x_move * Time.deltaTime * speed*3, -y_move * Time.deltaTime * speed*3, 0);
                mouseLastPos.x = TempMousePos.x;
                mouseLastPos.y = TempMousePos.y;
            }
           
        }

    }

    public void OnPointerUp(PointerEventData eventData)
    {
        mouseClickPos = Vector2.zero;
        mouseLastPos = Vector2.zero;
        roteDir = 0;
    }

    public void OnPointerEnter(PointerEventData eventData)
    {
        mouseWheelOpen = true;
    }

    public void OnPointerExit(PointerEventData eventData)
    {
       mouseWheelOpen = false;
    }
}