/// <summary>
/// Determines if a Vertex is inside the Polygon using Fast Winding Number method
/// </summary>
/// <param name="vertex"></param>
/// <returns></returns>
public bool ContainsVertex(Vertex vertex)
{
// http://geomalgorithms.com/a03-_inclusion.html
Ray ray = Ray.XAxis(vertex);
int windNumber = 0;
foreach (Edge edge in edges)
{
if (vertex.OnEdge(edge))
{
return(true);
}
Vertex intersection = ray.Intersection(edge) as Vertex;
if (intersection != null)
{
if (edge.StartVertex.Y <= vertex.Y)
{
if (edge.EndVertex.Y > vertex.Y)
{
if (vertex.IsLeftFrom(edge) > 0)
{
++windNumber;
}
}
}
else
{
if (edge.EndVertex.Y < vertex.Y)
{
if (vertex.IsLeftFrom(edge) < 0)
{
--windNumber;
}
}
}
}
}
// If windNumber is different from 0, vertex is in polygon
return(windNumber != 0);
}
