feature: 添加旋转、平移、缩放摄像头功能

Assets/CameraBehaviour.cs

@@ -0,0 +1,145 @@
+using UnityEngine;
+
+public class CameraBehaviour : MonoBehaviour
+{
+    public Transform target;
+
+    private const int MouseWheelSensitivity = 1; //滚轮灵敏度设置
+    private const int MouseZoomMin = 1; //相机距离最小值
+    private const int MouseZoomMax = 20; //相机距离最大值
+    private const float XSpeed = 250.0f;
+    private const float YSpeed = 120.0f;
+
+    private const int YMinLimit = -360;
+    private const int YMaxLimit = 360;
+
+    private float _eulerX; //存储相机的euler角
+    private float _eulerY; //存储相机的euler角
+
+    private float _distance = 5; //相机和target之间的距离，因为相机的Z轴总是指向target，也就是相机z轴方向上的距离
+    private Vector3 _targetOnScreenPosition; //目标的屏幕坐标，第三个值为z轴距离
+    private Quaternion _cameraRotation; //存储相机的姿态四元数
+    private Vector3 _targetPosition; //target的位置
+    private Vector3 _initPosition; //平移时用于存储平移的起点位置
+    private Vector3 _cameraX; //相机的x轴方向向量
+    private Vector3 _cameraY; //相机的y轴方向向量
+    private Vector3 _cameraZ; //相机的z轴方向向量
+
+    private Vector3 _initScreenPosition; //中键刚按下时鼠标的屏幕坐标（第三个值其实没什么用）
+    private Vector3 _cursorScreenPosition; //当前鼠标的屏幕坐标（第三个值其实没什么用）
+
+    private void Start()
+    {
+        //这里就是设置一下初始的相机视角以及一些其他变量，这里的x和y。。。是和下面getAxis的mouse x与mouse y对应
+        var angles = transform.eulerAngles;
+        _eulerX = angles.y;
+        _eulerY = angles.x;
+        _targetPosition = target.position;
+        _cameraRotation = Quaternion.Euler(_eulerY + 60, _eulerX, 0);
+        // 引入中间变量 提高代码效率
+        var transform1 = transform;
+        transform1.rotation = _cameraRotation; //设置相机姿态
+        /*var position =
+            _cameraRotation * new Vector3(0.0F, 0.0F, -_distance) +
+            _targetPosition; //四元数表示一个旋转，四元数乘以向量相当于把向量旋转对应角度，然后加上目标物体的位置就是相机位置了*/
+        transform1.position = _cameraRotation * new Vector3(0, 0, -_distance) + _targetPosition; //设置相机位置
+    }
+
+    private void Update()
+    {
+        //鼠标右键旋转功能
+        if (Input.GetMouseButton(1))
+        {
+            _eulerX += Input.GetAxis("Mouse X") * XSpeed * 0.02f;
+            _eulerY -= Input.GetAxis("Mouse Y") * YSpeed * 0.02f;
+
+            _eulerY = ClampAngle(_eulerY, YMinLimit, YMaxLimit);
+
+            _cameraRotation = Quaternion.Euler(_eulerY + 60, _eulerX, 0);
+            var position = _cameraRotation * new Vector3(0.0f, 0.0f, -_distance) + _targetPosition;
+
+            // 引入中间变量 提高代码效率
+            var transform1 = transform;
+            transform1.rotation = _cameraRotation;
+            transform1.position = position;
+        }
+        else if (Input.GetAxis("Mouse ScrollWheel") != 0) //鼠标滚轮缩放功能
+        {
+            if (_distance >= MouseZoomMin && _distance <= MouseZoomMax)
+            {
+                _distance -= Input.GetAxis("Mouse ScrollWheel") * MouseWheelSensitivity;
+            }
+
+            if (_distance < MouseZoomMin)
+            {
+                _distance = MouseZoomMin;
+            }
+
+            if (_distance > MouseZoomMax)
+            {
+                _distance = MouseZoomMax;
+            }
+
+            transform.position = _cameraRotation * new Vector3(0.0F, 0.0F, -_distance) + _targetPosition;
+        }
+
+        //鼠标中键平移
+        if (Input.GetMouseButtonDown(2))
+        {
+            // 添加中间变量
+            // 提高代码效率
+            var transform1 = transform;
+            _cameraX = transform1.right;
+            _cameraY = transform1.up;
+            _cameraZ = transform1.forward;
+
+            _initScreenPosition = new Vector3(Input.mousePosition.x, Input.mousePosition.y, _targetOnScreenPosition.z);
+
+            //targetOnScreenPosition.z为目标物体到相机平面的法线距离
+            _targetOnScreenPosition = Camera.main!.WorldToScreenPoint(_targetPosition);
+            _initPosition = _targetPosition;
+        }
+
+        if (Input.GetMouseButton(2))
+        {
+            _cursorScreenPosition = new Vector3(Input.mousePosition.x, Input.mousePosition.y, _targetOnScreenPosition.z);
+            //0.01这个系数是控制平移的速度，要根据相机和目标物体的distance来灵活选择
+            target.position = _initPosition - 0.01f * ((_cursorScreenPosition.x - _initScreenPosition.x) * _cameraX +
+                                                      (_cursorScreenPosition.y - _initScreenPosition.y) * _cameraY);
+
+            //重新计算位置
+            var mPosition = _cameraRotation * new Vector3(0.0F, 0.0F, -_distance) + target.position;
+            transform.position = mPosition;
+
+            // //用这个会让相机的平移变得更平滑，但是可能在你ButtonUp时未使相机移动到应到的位置，导致再进行旋转与缩放操作时出现短暂抖动
+            //transform.position=Vector3.Lerp(transform.position,mPosition,Time.deltaTime*moveSpeed);
+        }
+
+        if (Input.GetMouseButtonUp(2))
+        {
+            Debug.Log("upOnce");
+            //平移结束把cameraTargetPosition的位置更新一下，不然会影响缩放与旋转功能
+            _targetPosition = target.position;
+        }
+    }
+
+    //将angle限制在min~max之间
+    private static float ClampAngle(float angle, float min, float max)
+    {
+        if (angle < -360)
+            angle += 360;
+        if (angle > 360)
+            angle -= 360;
+        return Mathf.Clamp(angle, min, max);
+    }
+
+    /*void testScreenToWorldPoint()
+    {
+        //第三个坐标指的是在相机z轴指向方向上的距离
+        Vector3 screenPoint = Camera.main.WorldToScreenPoint(_targetPosition);
+        Debug.Log("ScreenPoint: " + screenPoint);
+
+        // var worldPosition = Camera.main.ScreenToWorldPoint(new Vector3(1,1,10));
+        // Debug.Log("worldPosition: "+worldPosition);
+    }*/
+}

Assets/CameraBehaviour.cs.meta

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Assets/Scenes/SampleScene.unity

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