第三人人称摄像机

支持的功能

设定目标后使用鼠标可以环绕目标点旋转，且会进行遮挡的适配，当有遮挡的时候会移动差值移动到没有遮挡的位置。

使用方式

将vThirdPersonCamera 挂在与摄像机上然后为target赋值。
如果有需要检测遮挡的层级可以修改：cullingLayer。
vExtensions 创建并复制代码即可，工具类。
如果高度有偏移就修改：height

using Invector;
using UnityEngine;

public class vThirdPersonCamera : MonoBehaviour
{
    #region inspector properties    

    public Transform target;
    [Tooltip("Leep的速度")]
    public float smoothCameraRotation = 12f;
    [Header("遮挡的层")] public LayerMask cullingLayer = 1 << 0;
    [Tooltip("Debug purposes, lock the camera behind the character for better align the states")]
    public bool lockCamera;

    [Header("Camera Input")]
    public string rotateCameraXInput = "Mouse X";
    public string rotateCameraYInput = "Mouse Y";


    [Header("向右偏移角度")]
    public float rightOffset = 0f;
    [Header("距离目标的距离")]
    public float defaultDistance = 2.5f;
    public float height = 1.4f;
    public float smoothFollow = 10f;
    public float xMouseSensitivity = 3f;
    public float yMouseSensitivity = 3f;
    public float yMinLimit = -40f;
    public float yMaxLimit = 80f;

    #endregion

    #region hide properties    

    [HideInInspector]
    public int indexList, indexLookPoint;
    [HideInInspector]
    public float offSetPlayerPivot;
    [HideInInspector]
    public string currentStateName;
    [HideInInspector]
    public Transform currentTarget;
    [HideInInspector]
    public Vector2 movementSpeed;

    private Transform targetLookAt;
    private Vector3 currentTargetPos;
    private Vector3 lookPoint;
    private Vector3 current_cPos;
    private Vector3 desired_cPos;
    private Camera _camera;
    private float distance = 5f;
    private float mouseY = 0f;
    private float mouseX = 0f;
    private float currentHeight;
    private float cullingDistance;
    private float checkHeightRadius = 0.4f;
    private float clipPlaneMargin = 0f;
    private float forward = -1f;
    private float xMinLimit = -360f;
    private float xMaxLimit = 360f;
    private float cullingHeight = 0.2f;
    private float cullingMinDist = 0.1f;

    #endregion

    private void Start()
    {
        Init();
    }

    private void Init()
    {
        if (target == null)
            return;

        _camera = GetComponent<Camera>();
        currentTarget = target;
        currentTargetPos = new Vector3(currentTarget.position.x, currentTarget.position.y + offSetPlayerPivot, currentTarget.position.z);

        targetLookAt = new GameObject("targetLookAt").transform;
        targetLookAt.position = currentTarget.position;
        targetLookAt.hideFlags = HideFlags.HideInHierarchy;
        targetLookAt.rotation = currentTarget.rotation;

        mouseY = currentTarget.eulerAngles.x;
        mouseX = currentTarget.eulerAngles.y;

        distance = defaultDistance;
        currentHeight = height;
    }

    private void FixedUpdate()
    {
        if (target == null || targetLookAt == null)
        {
            return;
        }

        //收到鼠标的输入
        var Y = Input.GetAxis(rotateCameraYInput);
        var X = Input.GetAxis(rotateCameraXInput);

        //旋转摄像机
        RotateCamera(X, Y);

        CameraMovement();
    }

    private void SetMainTarget(Transform newTarget)
    {
        target = newTarget;
        currentTarget = newTarget;
        mouseY = currentTarget.rotation.eulerAngles.x;
        mouseX = currentTarget.rotation.eulerAngles.y;
        Init();
    }

    /// <summary>
    /// Camera Rotation behaviour
    /// </summary>
    /// <param name="x"></param>
    /// <param name="y"></param>
    private void RotateCamera(float x, float y)
    {
        // free rotation 
        mouseX += x * xMouseSensitivity;
        mouseY -= y * yMouseSensitivity;

        movementSpeed.x = x;
        movementSpeed.y = -y;
        if (!lockCamera)
        {
            mouseY = Invector.vExtensions.ClampAngle(mouseY, yMinLimit, yMaxLimit);
            mouseX = Invector.vExtensions.ClampAngle(mouseX, xMinLimit, xMaxLimit);
        }
        else
        {
            mouseY = currentTarget.root.localEulerAngles.x;
            mouseX = currentTarget.root.localEulerAngles.y;
        }
    }

    /// <summary>
    /// Camera behaviour
    /// </summary>    
    private void CameraMovement()
    {
        if (currentTarget == null)
            return;

        distance = Mathf.Lerp(distance, defaultDistance, smoothFollow * Time.deltaTime);
        cullingDistance = Mathf.Lerp(cullingDistance, distance, Time.deltaTime);
        var camDir = (forward * targetLookAt.forward) + (rightOffset * targetLookAt.right);

        camDir = camDir.normalized;

        var targetPos = new Vector3(currentTarget.position.x, currentTarget.position.y + offSetPlayerPivot, currentTarget.position.z);
        currentTargetPos = targetPos;
        desired_cPos = targetPos + new Vector3(0, height, 0);
        current_cPos = currentTargetPos + new Vector3(0, currentHeight, 0);
        RaycastHit hitInfo;

        ClipPlanePoints planePoints = _camera.NearClipPlanePoints(current_cPos + (camDir * (distance)), clipPlaneMargin);
        ClipPlanePoints oldPoints = _camera.NearClipPlanePoints(desired_cPos + (camDir * distance), clipPlaneMargin);

        //Check if Height is not blocked 
        if (Physics.SphereCast(targetPos, checkHeightRadius, Vector3.up, out hitInfo, cullingHeight + 0.2f, cullingLayer))
        {
            var t = hitInfo.distance - 0.2f;
            t -= height;
            t /= (cullingHeight - height);
            cullingHeight = Mathf.Lerp(height, cullingHeight, Mathf.Clamp(t, 0.0f, 1.0f));
        }

        //Check if desired target position is not blocked       
        if (CullingRayCast(desired_cPos, oldPoints, out hitInfo, distance + 0.2f, cullingLayer, Color.blue))
        {
            distance = hitInfo.distance - 0.2f;
            if (distance < defaultDistance)
            {
                var t = hitInfo.distance;
                t -= cullingMinDist;
                t /= cullingMinDist;
                currentHeight = Mathf.Lerp(cullingHeight, height, Mathf.Clamp(t, 0.0f, 1.0f));
                current_cPos = currentTargetPos + new Vector3(0, currentHeight, 0);
            }
        }
        else
        {
            currentHeight = height;
        }
        //Check if target position with culling height applied is not blocked
        if (CullingRayCast(current_cPos, planePoints, out hitInfo, distance, cullingLayer, Color.cyan)) distance = Mathf.Clamp(cullingDistance, 0.0f, defaultDistance);
        var lookPoint = current_cPos + targetLookAt.forward * 2f;
        lookPoint += (targetLookAt.right * Vector3.Dot(camDir * (distance), targetLookAt.right));
        targetLookAt.position = current_cPos;

        Quaternion newRot = Quaternion.Euler(mouseY, mouseX, 0);
        targetLookAt.rotation = Quaternion.Slerp(targetLookAt.rotation, newRot, smoothCameraRotation * Time.deltaTime);
        transform.position = current_cPos + (camDir * (distance));
        var rotation = Quaternion.LookRotation((lookPoint) - transform.position);

        transform.rotation = rotation;
        movementSpeed = Vector2.zero;
    }

    /// <summary>
    /// Custom Raycast using NearClipPlanesPoints
    /// </summary>
    /// <param name="_to"></param>
    /// <param name="from"></param>
    /// <param name="hitInfo"></param>
    /// <param name="distance"></param>
    /// <param name="cullingLayer"></param>
    /// <returns></returns>
    private bool CullingRayCast(Vector3 from, Invector.ClipPlanePoints _to, out RaycastHit hitInfo, float distance, LayerMask cullingLayer, Color color)
    {
        bool value = false;

        if (Physics.Raycast(from, _to.LowerLeft - from, out hitInfo, distance, cullingLayer))
        {
            value = true;
            cullingDistance = hitInfo.distance;
        }

        if (Physics.Raycast(from, _to.LowerRight - from, out hitInfo, distance, cullingLayer))
        {
            value = true;
            if (cullingDistance > hitInfo.distance) cullingDistance = hitInfo.distance;
        }

        if (Physics.Raycast(from, _to.UpperLeft - from, out hitInfo, distance, cullingLayer))
        {
            value = true;
            if (cullingDistance > hitInfo.distance) cullingDistance = hitInfo.distance;
        }

        if (Physics.Raycast(from, _to.UpperRight - from, out hitInfo, distance, cullingLayer))
        {
            value = true;
            if (cullingDistance > hitInfo.distance) cullingDistance = hitInfo.distance;
        }

        return hitInfo.collider && value;
    }
}

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

namespace Invector
{
    public static class vExtensions
    {
        public static T[] Append<T>(this T[] arrayInitial, T[] arrayToAppend)
        {
            if (arrayToAppend == null)
            {
                throw new ArgumentNullException("The appended object cannot be null");
            }
            if ((arrayInitial is string) || (arrayToAppend is string))
            {
                throw new ArgumentException("The argument must be an enumerable");
            }
            T[] ret = new T[arrayInitial.Length + arrayToAppend.Length];
            arrayInitial.CopyTo(ret, 0);
            arrayToAppend.CopyTo(ret, arrayInitial.Length);

            return ret;
        }

        public static T[] vToArray<T>(this List<T> list)
        {
            T[] array = new T[list.Count];
            if (list == null || list.Count == 0) return array;
            for (int i = 0; i < list.Count; i++)
            {
                array[i] = list[i];
            }
            return array;
        }

        public static float ClampAngle(float angle, float min, float max)
        {
            do
            {
                if (angle < -360)
                    angle += 360;
                if (angle > 360)
                    angle -= 360;
            } while (angle < -360 || angle > 360);

            return Mathf.Clamp(angle, min, max);
        }

        public static ClipPlanePoints NearClipPlanePoints(this Camera camera, Vector3 pos, float clipPlaneMargin)
        {
            var clipPlanePoints = new ClipPlanePoints();

            var transform = camera.transform;
            var halfFOV = (camera.fieldOfView / 2) * Mathf.Deg2Rad;
            var aspect = camera.aspect;
            var distance = camera.nearClipPlane;
            var height = distance * Mathf.Tan(halfFOV);
            var width = height * aspect;
            height *= 1 + clipPlaneMargin;
            width *= 1 + clipPlaneMargin;
            clipPlanePoints.LowerRight = pos + transform.right * width;
            clipPlanePoints.LowerRight -= transform.up * height;
            clipPlanePoints.LowerRight += transform.forward * distance;

            clipPlanePoints.LowerLeft = pos - transform.right * width;
            clipPlanePoints.LowerLeft -= transform.up * height;
            clipPlanePoints.LowerLeft += transform.forward * distance;

            clipPlanePoints.UpperRight = pos + transform.right * width;
            clipPlanePoints.UpperRight += transform.up * height;
            clipPlanePoints.UpperRight += transform.forward * distance;

            clipPlanePoints.UpperLeft = pos - transform.right * width;
            clipPlanePoints.UpperLeft += transform.up * height;
            clipPlanePoints.UpperLeft += transform.forward * distance;

            return clipPlanePoints;
        }
    }

    public struct ClipPlanePoints
    {
        public Vector3 UpperLeft;
        public Vector3 UpperRight;
        public Vector3 LowerLeft;
        public Vector3 LowerRight;
    }
}