从透视矩阵计算正交矩阵的参数

Question

以下两种方法取自ios GLKit框架：

GLK_INLINE GLKMatrix4 GLKMatrix4MakeOrtho(float left, float right,
                                                 float bottom, float top,
                                                 float nearZ, float farZ)
{
    float ral = right + left;
    float rsl = right - left;
    float tab = top + bottom;
    float tsb = top - bottom;
    float fan = farZ + nearZ;
    float fsn = farZ - nearZ;

    GLKMatrix4 m = { 2.0f / rsl, 0.0f, 0.0f, 0.0f,
                     0.0f, 2.0f / tsb, 0.0f, 0.0f,
                     0.0f, 0.0f, -2.0f / fsn, 0.0f,
                     -ral / rsl, -tab / tsb, -fan / fsn, 1.0f };

    return m;
}

GLK_INLINE GLKMatrix4 GLKMatrix4MakePerspective(float fovyRadians, float aspect, float nearZ, float farZ)
{
    float cotan = 1.0f / tanf(fovyRadians / 2.0f);

    GLKMatrix4 m = { cotan / aspect, 0.0f, 0.0f, 0.0f,
                     0.0f, cotan, 0.0f, 0.0f,
                     0.0f, 0.0f, (farZ + nearZ) / (nearZ - farZ), -1.0f,
                     0.0f, 0.0f, (2.0f * farZ * nearZ) / (nearZ - farZ), 0.0f };

    return m;
}

我想顺利地从透视图移动到正视图，反之亦然。在给定透视矩阵和参数的情况下，我应该如何计算正交矩阵的正确参数？