public Edge(Vertex start, Vertex end)
{
StartVertex = start;
EndVertex = end;
Length = StartVertex.DistanceTo(EndVertex);
Direction = Vector.ByTwoVertices(StartVertex, EndVertex);
}
/// <summary>
/// Determines if a Vertex is inside the gPolygon using Fast Winding Number method
/// </summary>
/// <param name="vertex"></param>
/// <returns></returns>
public bool ContainsVertex(Vertex vertex)
{
// http://geomalgorithms.com/a03-_inclusion.html
Vertex maxVertex = vertices.OrderByDescending(v => v.DistanceTo(vertex)).First();
double maxDistance = vertex.DistanceTo(maxVertex) * 1.5;
Vertex v2 = Vertex.ByCoordinates(vertex.X + maxDistance, vertex.Y, vertex.Z);
Edge ray = Edge.ByStartVertexEndVertex(vertex, v2);
int windNumber = 0;
foreach (Edge edge in edges)
{
if (vertex.OnEdge(edge))
{
return(true);
}
Vertex intersection = ray.Intersection(edge) as Vertex;
if (intersection is Vertex)
{
if (edge.StartVertex.Y <= vertex.Y)
{
if (edge.EndVertex.Y > vertex.Y)
{
if (IsLeft(edge, vertex) > 0)
{
++windNumber;
}
}
}
else
{
if (edge.EndVertex.Y < vertex.Y)
{
if (IsLeft(edge, vertex) < 0)
{
--windNumber;
}
}
}
}
}
// If windNumber is different from 0, vertex is in polygon
return(windNumber != 0);
}
public double DistanceTo(Vertex vertex)
{
return(vertex.DistanceTo(this));
}