//-----------------------------------------------------------------------
        //typedef std::vector<PathCoordinate> PathIntersection;
        public static void _extrudeIntersectionImpl(ref TriangleBuffer buffer, std_vector <MultiPath.PathCoordinate> intersection, MultiPath multiPath, Shape shape, Track shapeTextureTrack)
        {
            Vector3    intersectionLocation = multiPath.getPath((int)intersection[0].pathIndex).getPoint((int)intersection[0].pointIndex);
            Quaternion firstOrientation     = Utils._computeQuaternion(multiPath.getPath((int)intersection[0].pathIndex).getDirectionBefore((int)intersection[0].pointIndex));
            Vector3    refX = firstOrientation * Vector3.UNIT_X;
            Vector3    refZ = firstOrientation * Vector3.UNIT_Z;

            std_vector <Vector2> v2s = new std_vector <Vector2>();
            std_vector <MultiPath.PathCoordinate> coords = new std_vector <MultiPath.PathCoordinate>();
            std_vector <float> direction = new std_vector <float>();

            for (int i = 0; i < intersection.size(); ++i)
            {
                Path path       = multiPath.getPath((int)intersection[i].pathIndex);
                int  pointIndex = (int)intersection[i].pointIndex;
                if (pointIndex > 0 || path.isClosed())
                {
                    Vector3 vb  = path.getDirectionBefore(pointIndex);
                    Vector2 vb2 = new Vector2(vb.DotProduct(refX), vb.DotProduct(refZ));
                    v2s.push_back(vb2);
                    coords.push_back(intersection[i]);
                    direction.push_back(1);
                }
                if (pointIndex < path.getSegCount() || path.isClosed())
                {
                    Vector3 va  = -path.getDirectionAfter(pointIndex);
                    Vector2 va2 = new Vector2(va.DotProduct(refX), va.DotProduct(refZ));
                    v2s.push_back(va2);
                    coords.push_back(intersection[i]);
                    direction.push_back(-1);
                }
            }

            std_map <Radian, int> angles = new std_map <Radian, int>();

            for (int i = 1; i < v2s.Count; ++i)
            {
                //angles[Utils.angleTo(v2s[0], v2s[i])] = i;
                angles.insert(Utils.angleTo(v2s[0], v2s[i]), i);
            }
            std_vector <int> orderedIndices = new std_vector <int>();

            orderedIndices.push_back(0);
            //for (std_map<Radian, int>.Enumerator it = angles.begin(); it != angles.end(); ++it)
            foreach (var it in angles)
            {
                orderedIndices.push_back(it.Value);
            }
            for (int i = 0; i < orderedIndices.size(); ++i)
            {
                int    idx         = orderedIndices[i];
                int    idxBefore   = orderedIndices[Utils.modulo(i - 1, orderedIndices.Count)];
                int    idxAfter    = orderedIndices[Utils.modulo(i + 1, orderedIndices.Count)];
                Radian angleBefore = (Utils.angleBetween(v2s[idx], v2s[idxBefore]) - (Radian)Math.PI) / 2;
                Radian angleAfter  = ((Radian)Math.PI - Utils.angleBetween(v2s[idx], v2s[idxAfter])) / 2;

                int  pointIndex = (int)((int)coords[idx].pointIndex - direction[idx]);
                Path path       = multiPath.getPath((int)coords[idx].pathIndex);

                Quaternion qStd      = Utils._computeQuaternion(path.getAvgDirection(pointIndex) * direction[idx]);
                float      lineicPos = 0f;
                float      uTexCoord = path.getLengthAtPoint(pointIndex) / path.getTotalLength();

                // Shape making the joint with "standard extrusion"
                _extrudeShape(ref buffer, shape, path.getPoint(pointIndex), qStd, qStd, 1.0f, 1.0f, 1.0f, shape.getTotalLength(), uTexCoord, true, shapeTextureTrack);

                // Modified shape at the intersection
                Quaternion q = new Quaternion();
                if (direction[idx] > 0f)
                {
                    q = Utils._computeQuaternion(path.getDirectionBefore((int)coords[idx].pointIndex));
                }
                else
                {
                    q = Utils._computeQuaternion(-path.getDirectionAfter((int)coords[idx].pointIndex));
                }
                Quaternion qLeft      = q * new Quaternion(angleBefore, Vector3.UNIT_Y);
                Quaternion qRight     = q * new Quaternion(angleAfter, Vector3.UNIT_Y);
                float      scaleLeft  = 1.0f / Math.Abs(Math.Cos(angleBefore));
                float      scaleRight = 1.0f / Math.Abs(Math.Cos(angleAfter));

                uTexCoord = path.getLengthAtPoint((int)coords[idx].pointIndex) / path.getTotalLength();
                _extrudeShape(ref buffer, shape, path.getPoint((int)coords[idx].pointIndex), qLeft, qRight, 1.0f, scaleLeft, scaleRight, shape.getTotalLength(), uTexCoord, false, shapeTextureTrack);
            }
        }
        //-----------------------------------------------------------------------
        public static void _extrudeCapImpl(ref TriangleBuffer buffer, MultiShape multiShapeToExtrude, MultiPath extrusionMultiPath, TrackMap scaleTracks, TrackMap rotationTracks)
        {
            std_vector <int> indexBuffer = new std_vector <int>();
            // PointList pointList;
            std_vector <Vector2> pointList = new std_vector <Vector2>();

            Triangulator t = new Triangulator();

            t.setMultiShapeToTriangulate(multiShapeToExtrude);
            t.triangulate(indexBuffer, pointList);

            for (uint i = 0; i < extrusionMultiPath.getPathCount(); ++i)
            {
                Path  extrusionPath = extrusionMultiPath.getPath((int)i);
                Track scaleTrack    = null;
                Track rotationTrack = null;
                if (scaleTracks.find(i) != -1)         // scaleTracks.end())
                {
                    scaleTrack = scaleTracks[i];       //.find(i).second;
                }
                if (rotationTracks.find(i) != -1)      // rotationTracks.end())
                {
                    rotationTrack = rotationTracks[i]; //.find(i).second;
                }
                //begin cap
                //if (extrusionMultiPath.getIntersectionsMap().find(MultiPath.PathCoordinate(i, 0)) == extrusionMultiPath.getIntersectionsMap().end())
                if (extrusionMultiPath.getIntersectionsMap().find(new MultiPath.PathCoordinate(i, 0)) == -1)
                {
                    buffer.rebaseOffset();
                    buffer.estimateIndexCount((uint)indexBuffer.Count);
                    buffer.estimateVertexCount((uint)pointList.Count);

                    Quaternion qBegin = Utils._computeQuaternion(extrusionPath.getDirectionAfter(0));
                    if (rotationTrack != null)
                    {
                        float angle = rotationTrack.getFirstValue();
                        qBegin = qBegin * new Quaternion((Radian)angle, Vector3.UNIT_Z);
                    }
                    float scaleBegin = 1.0f;
                    if (scaleTrack != null)
                    {
                        scaleBegin = scaleTrack.getFirstValue();
                    }

                    for (int j = 0; j < pointList.size(); j++)
                    {
                        Vector2 vp2    = pointList[j];
                        Vector3 vp     = new Vector3(vp2.x, vp2.y, 0);
                        Vector3 normal = -Vector3.UNIT_Z;

                        Vector3 newPoint = extrusionPath.getPoint(0) + qBegin * (scaleBegin * vp);
                        buffer.vertex(newPoint, qBegin * normal, vp2);
                    }
                    for (int i2 = 0; i2 < indexBuffer.Count / 3; i2++)
                    {
                        buffer.index(indexBuffer[i2 * 3]);
                        buffer.index(indexBuffer[i2 * 3 + 2]);
                        buffer.index(indexBuffer[i2 * 3 + 1]);
                    }
                }

                //end cap
                //if (extrusionMultiPath.getIntersectionsMap().find(MultiPath.PathCoordinate(i, extrusionPath.getSegCount())) == extrusionMultiPath.getIntersectionsMap().end())
                if (extrusionMultiPath.getIntersectionsMap().find(new MultiPath.PathCoordinate(i, (uint)extrusionPath.getSegCount())) == -1)
                {
                    buffer.rebaseOffset();
                    buffer.estimateIndexCount((uint)indexBuffer.Count);
                    buffer.estimateVertexCount((uint)pointList.Count);

                    Quaternion qEnd = Utils._computeQuaternion(extrusionPath.getDirectionBefore(extrusionPath.getSegCount()));
                    if (rotationTrack != null)
                    {
                        float angle = rotationTrack.getLastValue();
                        qEnd = qEnd * new Quaternion((Radian)angle, Vector3.UNIT_Z);
                    }
                    float scaleEnd = 1.0f;
                    if (scaleTrack != null)
                    {
                        scaleEnd = scaleTrack.getLastValue();
                    }

                    for (int j = 0; j < pointList.Count; j++)
                    {
                        Vector2 vp2 = pointList[j];
                        Vector3 vp  = new Vector3(vp2.x, vp2.y, 0f);
                        //C++ TO C# CONVERTER WARNING: The following line was determined to be a copy constructor call - this should be verified and a copy constructor should be created if it does not yet exist:
                        //ORIGINAL LINE: Vector3 normal = Vector3::UNIT_Z;
                        Vector3 normal = (Vector3.UNIT_Z);

                        Vector3 newPoint = extrusionPath.getPoint(extrusionPath.getSegCount()) + qEnd * (scaleEnd * vp);
                        buffer.vertex(newPoint, qEnd * normal, vp2);
                    }
                    for (int ii = 0; ii < indexBuffer.Count / 3; ii++)
                    {
                        buffer.index(indexBuffer[ii * 3]);
                        buffer.index(indexBuffer[ii * 3 + 1]);
                        buffer.index(indexBuffer[ii * 3 + 2]);
                    }
                }
            }
        }