Unity 限制四元数 旋转方向轴X.

Unity官方案例内的方法，写在这，方便后续查看。

    private Quaternion ClampRotationAroundXAxis(Quaternion q)
    {
        q.x /= q.w;
        q.y /= q.w;
        q.z /= q.w;
        q.w = 1.0f;

        float angleX = 2.0f * Mathf.Rad2Deg * Mathf.Atan(q.x);

        angleX = Mathf.Clamp(angleX, minRotX, maxRotX);

        q.x = Mathf.Tan(0.5f * Mathf.Deg2Rad * angleX);

        return q;
    }

例子：

m_Transform.localRotation = ClampRotationAroundXAxis(m_Transform.localRotation);