Unity Third Person CameraController

void CameraMovement()
    {
        if (currentTarget == null)
            return;
        /*defaultDistance是2.5f，随着不断刷新，
        distance会逐渐接近defaultDistance,实现鼠标缓慢跟随鼠标的效果*/
        distance = Mathf.Lerp(distance, defaultDistance, smoothFollow * Time.deltaTime);
        /*剔除的距离，0*/
        cullingDistance = Mathf.Lerp(cullingDistance, distance, Time.deltaTime);
        /*计算相机的方向，再标准化，targetLookAt只是中间变量，和currentTarget一致*/
        var camDir = (forward * targetLookAt.forward) + (rightOffset * targetLookAt.right);

        camDir = camDir.normalized;

        /*根据currentTarget的当前中心点的位置,但好像是0，有点问题*/
        var targetPos = new Vector3(currentTarget.position.x, currentTarget.position.y + offSetPlayerPivot, currentTarget.position.z);
        Debug.Log("offSetPlayerPivot"+offSetPlayerPivot);

        
        currentTargetPos = targetPos;
        /*height = 1.4f;*/
        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,一般都是false
        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 
        //culling 剔除      
        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);
        }
        
        /*lookPoint，target的位置往前2个单位*/
        var lookPoint = current_cPos + targetLookAt.forward * 2f;
        /*lookPoint再往右，Vector3.Dot也叫点积,它返回1个-1.0～1.0之间的一个值*/
        lookPoint += targetLookAt.right * Vector3.Dot(camDir * distance, targetLookAt.right);
       // Debug.Log();
        targetLookAt.position = current_cPos;

        Quaternion newRot = Quaternion.Euler(mouseY, mouseX, 0);
        Debug.Log(targetLookAt);
        targetLookAt.rotation = Quaternion.Slerp(targetLookAt.rotation, newRot, smoothCameraRotation * Time.deltaTime);
        /*current_cPos可以认为就是目标的位置,distance就是相机和目标之间的距离，这个值应该是恒定的2.5f*/
        transform.position = current_cPos + (camDir * distance);
        Debug.Log("distance"+distance);

        var rotation = Quaternion.LookRotation((lookPoint) - transform.position);

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