// TODO: Euler operators from http://www.cgal.org/Manual/3.2/doc_html/cgal_manual/HalfedgeDS_ref/Class_HalfedgeDS_decorator.html#Cross_link_anchor_573
/// <summary>
/// Split the face across a diagonal between two vertices a and b.
/// The returned edge has a pair of faces accessible through its
/// Faces property. edge.Faces.First will always be the new face
/// instance. edge.Faces.Second will always be the original reduced
/// face instance that was supplied as a parameter.
/// </summary>
/// <param name="face">The face to be split</param>
/// <param name="a">The start of the diagonal</param>
/// <param name="b">The end of the diagonal</param>
/// <returns></returns>
public TEdge SplitFace(FaceBase face, VertexBase a, VertexBase b)
{
// Two vertices alone are not sufficient to determine a
// unique face, so the face is also supplied. (The two
// vertices may lie on the same boundary between two faces.
Half p = a.FindHalfEdge(half => (half.Face == face));
Half q = b.FindHalfEdge(half => (half.Face == face));
Half h = p.previous;
Half g = q.previous;
return(SplitFace(h, g));
}
public override bool Equals(object obj)
{
if (obj == null)
{
return(false);
}
VertexBase otherVertex = obj as VertexBase;
if (otherVertex == null)
{
return(false);
}
return(id == otherVertex.id);
}
/// <summary>
/// Find a free incident half-edge after half1 and before half2. Here 'free' is defined as
/// as having a null face to the left. The edge should be inbound to the query vertex.
/// </summary>
/// <param name="vertex"></param>
/// <param name="begin"></param>
/// <param name="end"></param>
/// <returns></returns>
private static Half FindFreeIncident(VertexBase vertex, Half begin, Half end)
{
Debug.Assert(begin.Target == vertex);
Debug.Assert(end.Target == vertex);
Debug.Assert(begin.Target == end.Target);
Half current = begin;
do
{
if (current.IsFree)
{
return(current);
}
current = current.VertexNext;
}while (current != end);
return(null);
}
public VertexBase(VertexBase other) :
this()
{
}
public bool Remove(VertexBase item)
{
throw new NotImplementedException();
}
/// <summary>
/// Find a free incident half-edge around vertex.
/// </summary>
/// <param name="vertex">The vertex around which the search is to be performed</param>
/// <returns>An inbound half-edge with a null face, or null if none could be found.</returns>
private static Half FindFreeIncident(VertexBase vertex)
{
Half incident = vertex.half.pair;
return(FindFreeIncident(vertex, incident, incident));
}
/// <summary>
/// Find an existing half-edge between fromVertex to toVertex
/// </summary>
/// <param name="fromVertex">The hald-edge source.</param>
/// <param name="toVertex">The half-edge target.</param>
/// <returns>An existing half-edge, or null.</returns>
private static Half FindHalf(VertexBase fromVertex, VertexBase toVertex)
{
Half result = fromVertex.FindHalfEdge(half => half.Target == toVertex);
return(result);
}
/// <summary>
/// Find the edge connecting
/// </summary>
/// <param name="v1">The first vertex</param>
/// <param name="v2">The second vertex</param>
/// <returns>The edge between first vertex and second vertex, or null if none exists</returns>
public TEdge Find(VertexBase v1, VertexBase v2)
{
Half half = FindHalf(v1, v2);
return(half != null ? (TEdge)half.Edge : null);
}
