How to get 128D vector from 68+N landmarks？

Dlib just use 5 or 68 landmarks(shape_predictor_5_face_landmarks.dat/shape_predictor_68_face_landmarks.dat) to extract 128D vector. If I have a 68+N landmarks model,how can I get the 128D vector from the 68+N landmarks model?
    inline chip_details get_face_chip_details (
        const full_object_detection& det,
        const unsigned long size = 200,
        const double padding = 0.2
    )
    {
        DLIB_CASSERT(det.num_parts() == 68 || det.num_parts() == 5,
            "\t chip_details get_face_chip_details()"
            << "\n\t You have to give either a 5 point or 68 point face landmarking output to this function. "
            << "\n\t det.num_parts(): " << det.num_parts()
        );
        DLIB_CASSERT(padding >= 0 && size > 0,
            "\t chip_details get_face_chip_details()"
            << "\n\t Invalid inputs were given to this function."
            << "\n\t padding: " << padding 
            << "\n\t size:    " << size 
            );

        std::vector<dpoint> from_points, to_points;
        if (det.num_parts() == 5)
        {
            dpoint p0(0.8595674595992, 0.2134981538014);
            dpoint p1(0.6460604764104, 0.2289674387677);
            dpoint p2(0.1205750620789, 0.2137274526848);
            dpoint p3(0.3340850613712, 0.2290642403242);
            dpoint p4(0.4901123135679, 0.6277975316475);

            p0 = (padding+p0)/(2*padding+1);
            p1 = (padding+p1)/(2*padding+1);
            p2 = (padding+p2)/(2*padding+1);
            p3 = (padding+p3)/(2*padding+1);
            p4 = (padding+p4)/(2*padding+1);

            from_points.push_back(p0*size);
            to_points.push_back(det.part(0));

            from_points.push_back(p1*size);
            to_points.push_back(det.part(1));

            from_points.push_back(p2*size);
            to_points.push_back(det.part(2));

            from_points.push_back(p3*size);
            to_points.push_back(det.part(3));

            from_points.push_back(p4*size);
            to_points.push_back(det.part(4));
        }
        else
        {
            // Average positions of face points 17-67
            const double mean_face_shape_x[] = {
                0.000213256, 0.0752622, 0.18113, 0.29077, 0.393397, 0.586856, 0.689483, 0.799124,
                0.904991, 0.98004, 0.490127, 0.490127, 0.490127, 0.490127, 0.36688, 0.426036,
                0.490127, 0.554217, 0.613373, 0.121737, 0.187122, 0.265825, 0.334606, 0.260918,
                0.182743, 0.645647, 0.714428, 0.793132, 0.858516, 0.79751, 0.719335, 0.254149,
                0.340985, 0.428858, 0.490127, 0.551395, 0.639268, 0.726104, 0.642159, 0.556721,
                0.490127, 0.423532, 0.338094, 0.290379, 0.428096, 0.490127, 0.552157, 0.689874,
                0.553364, 0.490127, 0.42689
            };
            const double mean_face_shape_y[] = {
                0.106454, 0.038915, 0.0187482, 0.0344891, 0.0773906, 0.0773906, 0.0344891,
                0.0187482, 0.038915, 0.106454, 0.203352, 0.307009, 0.409805, 0.515625, 0.587326,
                0.609345, 0.628106, 0.609345, 0.587326, 0.216423, 0.178758, 0.179852, 0.231733,
                0.245099, 0.244077, 0.231733, 0.179852, 0.178758, 0.216423, 0.244077, 0.245099,
                0.780233, 0.745405, 0.727388, 0.742578, 0.727388, 0.745405, 0.780233, 0.864805,
                0.902192, 0.909281, 0.902192, 0.864805, 0.784792, 0.778746, 0.785343, 0.778746,
                0.784792, 0.824182, 0.831803, 0.824182
            };

            COMPILE_TIME_ASSERT(sizeof(mean_face_shape_x)/sizeof(double) == 68-17);

            for (unsigned long i = 17; i < det.num_parts(); ++i)
            {
                // Ignore the lower lip
                if ((55 <= i && i <= 59) || (65 <= i && i <= 67))
                    continue;
                // Ignore the eyebrows 
                if (17 <= i && i <= 26)
                    continue;

                dpoint p;
                p.x() = (padding+mean_face_shape_x[i-17])/(2*padding+1);
                p.y() = (padding+mean_face_shape_y[i-17])/(2*padding+1);
                from_points.push_back(p*size);
                to_points.push_back(det.part(i));
            }
        }

        return chip_details(from_points, to_points, chip_dims(size,size));
    }
davisking / dlib

How to get 128D vector from 68+N landmarks？ #1775
