Matrix ortho(float l, float r, float b, float t, float n, float f)
{
    std::array<float, 16> ortho
    {
        {
            2.0f / (r - l), 0.0f, 0.0f, (r + l) / (r - l),
            0.0f, 2.0f / (t - b), 0.0f, (t + b) / (t - b),
            0.0f, 0.0f, -2.0f / (f - n), (f + n) / (f - n),
            0.0f, 0.0f, 0.0f, 1.0f
        }
    };
    //        ortho[0]  = 2.0f / ( r - l );
    //        ortho[3] = ( r + l ) / ( r - l );
    //        ortho[5]  = 2.0f / ( t - b );
    //        ortho[7] = ( t + b ) / ( t - b );
    //        ortho[10] = -2.0f / ( f - n );
    //        ortho[11] = ( f + n ) / ( f - n );
    //        ortho[12] = 0.0f;
    //        ortho[13] = 0.0f;
    //        ortho[14] = 0.0f;
    //        ortho[15] = 1.0f;
    return Matrix(std::move(ortho));
}