private static void AddPolylineWithLabels(S2Polyline polyline, EdgeType edge_type,
Int32 label_begin, S2Builder builder, EdgeLabelMap edge_label_map)
{
for (int i = 0; i + 1 < polyline.NumVertices(); ++i)
{
Int32 label = label_begin + i;
builder.SetLabel(label);
// With undirected edges, reverse the direction of every other input edge.
int dir = edge_type == EdgeType.DIRECTED ? 1 : (i & 1);
builder.AddEdge(polyline.Vertex(i + (1 - dir)), polyline.Vertex(i + dir));
S2Point key = polyline.Vertex(i) + polyline.Vertex(i + 1);
edge_label_map[key].Add(label);
}
}
// Add a polyline to the input geometry.
public void AddPolyline(S2Polyline polyline)
{
bound_ = bound_.Union(polyline.GetRectBound());
for (int i = 0; i < polyline.NumVertices(); ++i)
{
points_.Add(polyline.Vertex(i));
}
}