Clamp angle

private void ClampAngle()
    {
        if (Cursor.visible == true)
            return;

        Quaternion yQuaternion = Quaternion.AngleAxis(Input.GetAxis("Mouse Y") * sensitivity * Time.deltaTime, -Vector3.right);
        Quaternion xQuaternion = Quaternion.AngleAxis(Input.GetAxis("Mouse X") * sensitivity * Time.deltaTime, Vector3.up);

        //Проверяем угол между условным "центром" и нужным вращением
        if (Quaternion.Angle(transform.rotation, cameraTransform.localRotation * xQuaternion) < 15)
        {
            if (Quaternion.Angle(transform.rotation, cameraTransform.localRotation * yQuaternion) < 15)
            {
                cameraTransform.localRotation *= xQuaternion * yQuaternion;
            }
            else
            {
                cameraTransform.localRotation *= xQuaternion;
            }
        }
        else
        {
            if (Quaternion.Angle(transform.rotation, cameraTransform.localRotation * yQuaternion) < 15)
            {
                cameraTransform.localRotation *= yQuaternion;
            }
            else
            {
                return;
            }
        }

        cameraTransform.localEulerAngles = new Vector3(cameraTransform.localEulerAngles.x, cameraTransform.localEulerAngles.y, 0);
    }