Isosurface.AdaptiveDualContouring.OctreeNode.Simplify C# (CSharp) Method

        public void Simplify(float threshold, bool randomize = false)
        {
            if (type != OctreeNodeType.Internal)
                return;

            int[] signs = { -1, -1, -1, -1, -1, -1, -1, -1 };
            int mid_sign = -1;
            bool is_collapsible = true;
            //QEF3D qef = new QEF3D();
            QEFProper.QEFSolver qef = new QEFProper.QEFSolver();
            Random rnd = new Random();

            float t = threshold;
            for (int i = 0; i < 8; i++)
            {
                if (children[i] == null)
                    continue;

                if (randomize)
                    t = (float)rnd.NextDouble() * (float)rnd.NextDouble() * 20.0f;
                children[i].Simplify(t);
                OctreeNode child = children[i];

                if (child.type == OctreeNodeType.Internal)
                    is_collapsible = false;
                else
                {
                    //qef.Add(child.draw_info.position, child.draw_info.averageNormal);
                    //if (child.draw_info.qef != null)
                        qef.Add(ref child.draw_info.qef.data);

                    mid_sign = (child.draw_info.corners >> (7 - i)) & 1;
                    signs[i] = (child.draw_info.corners >> i) & 1;
                }
            }

            if (size == 16)
            {
            }

            if (!is_collapsible)
                return;

            //Vector3 pos = qef.Solve2(0, 0, 0);
            Vector3 pos = qef.Solve(1e-6f, 4, 1e-6f);
            float error = qef.GetError();

            if (error > threshold)
                return;

            OctreeDrawInfo draw_info = new OctreeDrawInfo();

            for (int i = 0; i < 8; i++)
            {
                if (signs[i] == -1)
                    draw_info.corners |= mid_sign << i;
                else
                    draw_info.corners |= signs[i] << i;
            }

            Vector3 normal = new Vector3();
            for (int i = 0; i < 8; i++)
            {
                if (children[i] != null)
                {
                    OctreeNode child = children[i];
                    if (child.type == OctreeNodeType.Pseudo || child.type == OctreeNodeType.Leaf)
                        normal += child.draw_info.averageNormal;
                }
            }

            normal.Normalize();
            draw_info.averageNormal = normal;
            draw_info.position = pos;
            draw_info.qef = qef;

            for (int i = 0; i < 8; i++)
            {
                children[i] = null;
            }

            type = OctreeNodeType.Pseudo;
            this.draw_info = draw_info;
        }