[游戏开发]Unity Editor相机的部分实现

主要功能：移动（鼠标右键+WASD，滚轮按下及滚轮拉近），旋转，正交俯视相机（空格键切换），聚焦功能（给定FocusTarget,并按下F键）。

EditorCamera:

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

public class EditorCamera : BaseCamera
{
    #region 3D

    private float _smoothMoveSpeed = 5;  //位移变化平滑值(作用于所有相机位移操作)
    private Vector3 _moveTarget = Vector3.zero; //平移目标值

    //zoom
    private float _zoomSpeed = 3;

    //move
    private float _moveSpeed = 0.5f;
    private Vector3 _moveOffset = Vector3.zero;

    //rotate
    private float _rotateSpeed = 3;

    //drag
    private bool _invertDrag = false;
    private float _dragSpeed = 1;

    #endregion

    #region 2D

    //zoom
    private bool _invert2DZoom = false;
    private float _2DZoomSpeed = 10;
    private float _2DZoomSmoothSpeed = 5;
    private float _2DZoomOffset = 0;
    private float _2DZoomTarget = 0;

    #endregion

    #region switch projection

    public bool IsOrtho()
    {
        return _camera.orthographic;
    }
    private bool _isSwitchProjection = false;
    private float t = 0;
    Matrix4x4 orthMat = Matrix4x4.identity;
    Matrix4x4 persMat = Matrix4x4.identity;

    #endregion

    private Camera _camera;
    public Transform FocusTarget { set; get; }

    private void Start()
    {
        _camera = GetComponent<Camera>();
        _moveTarget = transform.position;
        _2DZoomTarget = _camera.orthographicSize;
    }

    // perspective projection  othographic projection相互切换
    public void SwitchProjection()
    {
        if (!_isSwitchProjection && Input.GetKeyDown(KeyCode.Space))
        {
            //记录矩阵信息
            bool isOrth = _camera.orthographic;
            if (isOrth)
            {
                orthMat = _camera.projectionMatrix;
                _camera.orthographic = !isOrth;
                persMat = _camera.projectionMatrix;
            }
            else
            {
                persMat = _camera.projectionMatrix;
                _camera.orthographic = !isOrth;
                orthMat = _camera.projectionMatrix;
            }

            _camera.orthographic = isOrth;

            //投影矩阵切换
            _isSwitchProjection = true;
            if (isOrth)
            {

                transform.DORotateQuaternion(Quaternion.LookRotation(Vector3.forward), 0.5f).OnComplete(() =>
                {
                    t = 1;
                    DOTween.To(() => t, x => t = x, 0, 1f).SetEase(Ease.OutCubic).OnComplete(() =>
                    {
                        _camera.orthographic = !isOrth;
                        _isSwitchProjection = false;
                    });
                });
            }
            else
            {

                transform.DORotateQuaternion(Quaternion.LookRotation(Vector3.down), 0.5f).OnComplete(() =>
                {
                    t = 0;
                    DOTween.To(() => t, x => t = x, 1, 1f).SetEase(Ease.OutCubic).OnComplete(() =>
                    {
                        _camera.orthographic = !isOrth;
                        _isSwitchProjection = false;
                    });
                });
            }
        }

        if (_isSwitchProjection)
        {
            _camera.projectionMatrix = ExtensionMethod.MatrixLerp(persMat, orthMat, t);
        }
        
    }

    private void Update()
    {
        SwitchProjection();
        Focus(FocusTarget);
    }

    private void Focus(Transform target)
    {
        if (Input.GetKeyDown(KeyCode.F) && target != null)
        {
            //获取物体的尺寸
            Vector3 scale = target.localScale;
            Quaternion originRotation = target.rotation;
            target.rotation = Quaternion.identity;
            target.localScale = Vector3.one;
            Renderer[] renders = target.GetComponentsInChildren<Renderer>();
            Vector3 boundCenter = Vector3.zero;
            foreach (var VARIABLE in renders)
            {
                boundCenter += VARIABLE.bounds.center;
            }

            boundCenter /= target.childCount;

            Bounds bounds = new Bounds(boundCenter, Vector3.zero);
            foreach (var VARIABLE in renders)
            {
                bounds.Encapsulate(VARIABLE.bounds);
            }
            target.rotation = originRotation;
            target.localScale = scale;

            //设置相机位置
            bounds.size = new Vector3(bounds.size.x * scale.x, bounds.size.y * scale.y, bounds.size.z * scale.z);
            float maxLength = Vector3.Distance(bounds.max, bounds.min);
            float angle = _camera.fieldOfView / 2 * Mathf.Deg2Rad;
            float distance = _camera.aspect > 1
                ? maxLength / (2 * Mathf.Sin(angle))
                : maxLength / (2 * _camera.aspect * Mathf.Sin(angle));
            Vector3 targetPos = target.TransformPoint(bounds.center - target.position) - _camera.transform.forward * distance;
            _moveTarget = targetPos;
            //正交相机时改变size
            if (IsOrtho())
            {
                _2DZoomTarget = maxLength / 2 + 1;
            }
        }
    }

    protected override void Move()
    {
        _moveOffset = Vector3.zero;
        if (Input.GetMouseButton(1) && !IsOrtho())
        {
            Vector3 direction = Vector3.zero;
            if (Input.GetKey(_forwardKey))
                direction = transform.forward;
            if (Input.GetKey(_backKey))
                direction = -transform.forward;
            if (Input.GetKey(_leftKey))
                direction = -transform.right;
            if (Input.GetKey(_rightKey))
                direction = transform.right;
            _moveOffset += direction * _moveSpeed;
        }

        if (_moveOffset != Vector3.zero)
            _moveTarget = transform.position + _moveOffset;
        transform.position = Vector3.Lerp(transform.position, _moveTarget, _smoothMoveSpeed * Time.deltaTime);
    }

    protected override void Rotate()
    {
        if (Input.GetMouseButton(1) && !IsOrtho())
            {
                float mouseX = Input.GetAxis(_mouseXStr);
                float mouseY = Input.GetAxis(_mouseYStr);
                transform.RotateAround(transform.position, Vector3.up, mouseX * _rotateSpeed);
                transform.RotateAround(transform.position, -transform.right, mouseY * _rotateSpeed);
            }
    }

    protected override void Zoom()
    {
        float moveAmount = Input.GetAxis(_mouseScrollWheelStr);
        if (moveAmount == 0)
            return;
        if (IsOrtho())
        {
            _2DZoomOffset = 0;
            int invert = _invert2DZoom ? 1 : -1;
            if (moveAmount != 0)
            {
                _2DZoomOffset += moveAmount * _2DZoomSpeed * invert;
            }

            if (_2DZoomOffset != 0)
            {
                _2DZoomTarget = _camera.orthographicSize + _2DZoomOffset;
            }

            _2DZoomTarget = Mathf.Clamp(_2DZoomTarget, 0.1f, 30);
            _camera.orthographicSize = Mathf.Lerp(_camera.orthographicSize, _2DZoomTarget, _2DZoomSmoothSpeed * Time.deltaTime);
        }
        else
        {
            _moveOffset = Vector3.zero;
            if (moveAmount != 0)
            {
                _moveOffset += moveAmount * _zoomSpeed * transform.forward;
            }
            if (_moveOffset != Vector3.zero)
                _moveTarget = transform.position + _moveOffset;
            transform.position = Vector3.Lerp(transform.position, _moveTarget, _smoothMoveSpeed * Time.deltaTime);
        }
    }

    protected override void Drag()
    {
        _moveOffset = Vector3.zero;
        if (Input.GetMouseButton(2))
        {
            float invert = _invertDrag ? 1 : -1;
            float mouseX = Input.GetAxis(_mouseXStr) * invert;
            float mouseY = Input.GetAxis(_mouseYStr) * invert;
            float mulpti = IsOrtho() ? _camera.orthographicSize : 1;
            _moveOffset += transform.right * mouseX * _dragSpeed * mulpti;
            _moveOffset += transform.up * mouseY * _dragSpeed * mulpti;
        }

        if (_moveOffset != Vector3.zero)
            _moveTarget = transform.position + _moveOffset;
        transform.position = Vector3.Lerp(transform.position, _moveTarget, _smoothMoveSpeed * Time.deltaTime);
    }
}

BaseCamera:

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

public abstract class BaseCamera : MonoBehaviour
{
    protected KeyCode _forwardKey = KeyCode.W;
    protected KeyCode _backKey = KeyCode.S;
    protected KeyCode _leftKey = KeyCode.A;
    protected KeyCode _rightKey = KeyCode.D;
    protected readonly string _mouseXStr = "Mouse X";
    protected readonly string _mouseYStr = "Mouse Y";
    protected readonly string _mouseScrollWheelStr = "Mouse ScrollWheel";

    protected abstract void Rotate();
    protected abstract void Move();

    protected abstract void Zoom();
    protected abstract void Drag();

    private void LateUpdate()
    {
        Rotate();
        Move();
        Zoom();
        Drag();
    }
}