public void Flip(HalfEdge a_HalfEdge)
{
HalfEdge h1 = a_HalfEdge;
HalfEdge h2 = h1.Next;
HalfEdge h3 = h2.Next;
HalfEdge h4 = a_HalfEdge.Twin;
HalfEdge h5 = h4.Next;
HalfEdge h6 = h5.Next;
if (h1.Triangle == null || h4.Triangle == null)
{ return; }
// Remove old triangles
m_Triangles.Remove(a_HalfEdge.Triangle);
m_Triangles.Remove(a_HalfEdge.Twin.Triangle);
h1.Next = h6;
h6.Prev = h1;
h6.Next = h2;
h2.Prev = h6;
h2.Next = h1;
h1.Prev = h2;
h1.Origin = h3.Origin;
h4.Next = h3;
h3.Prev = h4;
h3.Next = h5;
h5.Prev = h3;
h5.Next = h4;
h4.Prev = h5;
h4.Origin = h6.Origin;
m_Triangles.Add(new Triangle(h1));
m_Triangles.Add(new Triangle(h1.Twin));
}
public Triangle(HalfEdge a_HalfEdge)
{
m_Vertices = new Vertex[3];
m_HalfEdge = a_HalfEdge;
m_Color = Color.red;
Vertex v1 = m_HalfEdge.Origin;
Vertex v2 = m_HalfEdge.Next.Origin;
Vertex v3 = m_HalfEdge.Next.Next.Origin;
Vertex v4 = m_HalfEdge.Next.Next.Next.Origin;
if (v1 == v2 || v2 == v3 || v1 == v3)
{ Debug.LogError("Triangle does not have a correct 3 vertex loop."); }
if (v1 != v4)
{ Debug.LogError("Triangle does not have a correct 3 vertex loop."); }
// Fix halfedges to this triangle
m_HalfEdge.Triangle = this;
m_HalfEdge.Next.Triangle = this;
m_HalfEdge.Next.Next.Triangle = this;
// Add vertices to the array
m_Vertices[0] = v1;
m_Vertices[1] = v2;
m_Vertices[2] = v3;
}
public HalfEdge(Vertex a_Vertex)
{
// Using new here prevents reference equality. Is it really necessary to copy?
m_Origin = new Vertex(a_Vertex.X, a_Vertex.Y, a_Vertex.Ownership);
Triangle = null;
Twin = null;
Next = null;
Prev = null;
}
protected void AddVertex(Triangle a_Triangle, Vertex a_Vertex)
{
m_Vertices.Add(a_Vertex);
m_Triangles.Remove(a_Triangle);
HalfEdge h1 = a_Triangle.HalfEdge;
HalfEdge h2 = h1.Next;
HalfEdge h3 = h2.Next;
HalfEdge h4 = new HalfEdge(h1.Origin);
HalfEdge h5 = new HalfEdge(h2.Origin);
HalfEdge h6 = new HalfEdge(h3.Origin);
HalfEdge h7 = new HalfEdge(a_Vertex);
HalfEdge h8 = new HalfEdge(a_Vertex);
HalfEdge h9 = new HalfEdge(a_Vertex);
m_HalfEdges.AddRange(new List<HalfEdge>() { h4, h5, h6, h7, h8, h9 });
h4.Twin = h7;
h7.Twin = h4;
h5.Twin = h8;
h8.Twin = h5;
h6.Twin = h9;
h9.Twin = h6;
// Set all next
h1.Next = h5;
h5.Prev = h1;
h5.Next = h7;
h7.Prev = h5;
h7.Next = h1;
h1.Prev = h7;
h2.Next = h6;
h6.Prev = h2;
h6.Next = h8;
h8.Prev = h6;
h8.Next = h2;
h2.Prev = h8;
h3.Next = h4;
h4.Prev = h3;
h4.Next = h9;
h9.Prev = h4;
h9.Next = h3;
h3.Prev = h9;
m_Triangles.Add(new Triangle(h1));
m_Triangles.Add(new Triangle(h2));
m_Triangles.Add(new Triangle(h3));
}
private void LegalizeEdge(Vertex a_Vertex, HalfEdge a_HalfEdge, Triangle a_Triangle)
{
if (a_Vertex == null || a_HalfEdge == null || a_Triangle == null)
{
Debug.LogError("Invalid call to LegalizeEdge");
return;
}
Vertex v1, v2, v3;
try
{
// Points to test
v1 = a_HalfEdge.Twin.Next.Next.Origin;
v2 = a_HalfEdge.Next.Twin.Next.Next.Origin;
v3 = a_HalfEdge.Next.Next.Twin.Next.Next.Origin;
}
catch (NullReferenceException)
{
Debug.LogError("Null pointers in call to LegalizeEdge");
return;
}
if (v1 == null || v2 == null || v3 == null)
{
Debug.LogError("Invalid halfedge in call to LegalizeEdge");
return;
}
if (a_Triangle.InsideCircumcenter(v1) || a_Triangle.InsideCircumcenter(v2) || a_Triangle.InsideCircumcenter(v3))
{
HalfEdge h1 = a_HalfEdge.Twin.Next.Twin;
HalfEdge h2 = a_HalfEdge.Twin.Prev.Twin;
Flip(a_HalfEdge);
LegalizeEdge(a_Vertex, h1.Twin, h1.Twin.Triangle);
LegalizeEdge(a_Vertex, h2.Twin, h2.Twin.Triangle);
}
}
private static void ProcessHalfEdge(HalfEdge a_H1, Dictionary<Vertex, HashSet<Vertex>> a_VoronoiEdges,
Dictionary<Vertex, HashSet<Vertex>> a_InternalEdges,
Dictionary<Vertex, HashSet<Vertex>> a_VoronoiToInternalEdges)
{
if (a_H1.Twin == null)
{ return; }
Triangle t1 = a_H1.Triangle;
Triangle t2 = a_H1.Twin.Triangle;
if (t1 != null && t2 != null)
{
Vertex voronoiVertex = t1.Circumcenter;
Vertex voronoiVertex2 = t2.Circumcenter;
HashSet<Vertex> existingVoronoiEdges;
if (a_VoronoiEdges.TryGetValue(voronoiVertex, out existingVoronoiEdges))
{ existingVoronoiEdges.Add(voronoiVertex2); }
else
{ a_VoronoiEdges.Add(voronoiVertex, new HashSet<Vertex>{voronoiVertex2}); }
if (a_VoronoiEdges.TryGetValue (voronoiVertex2, out existingVoronoiEdges))
{ existingVoronoiEdges.Add(voronoiVertex); }
else
{ a_VoronoiEdges.Add(voronoiVertex2, new HashSet<Vertex>{voronoiVertex}); }
foreach (Vertex inputVertex in t1.Vertices)
{
HashSet<Vertex> existingValue;
if (a_InternalEdges.TryGetValue(inputVertex, out existingValue))
{ existingValue.Add(voronoiVertex); }
else
{ a_InternalEdges.Add(inputVertex, new HashSet<Vertex>{voronoiVertex}); }
}
HashSet<Vertex> inputVertices = new HashSet<Vertex>(t1.Vertices);
HashSet<Vertex> existingInputVertices;
if (a_VoronoiToInternalEdges.TryGetValue(voronoiVertex, out existingInputVertices))
{ existingInputVertices.UnionWith(inputVertices); }
else
{ a_VoronoiToInternalEdges.Add(voronoiVertex, inputVertices); }
// Yes, yes, code duplication is bad.
foreach (Vertex inputVertex in t2.Vertices)
{
HashSet<Vertex> existingValue;
if (a_InternalEdges.TryGetValue(inputVertex, out existingValue))
{ existingValue.Add(voronoiVertex2); }
else
{ a_InternalEdges.Add(inputVertex, new HashSet<Vertex>{voronoiVertex2}); }
}
inputVertices = new HashSet<Vertex>(t2.Vertices);
existingInputVertices = null;
if (a_VoronoiToInternalEdges.TryGetValue(voronoiVertex2, out existingInputVertices))
{ existingInputVertices.UnionWith(inputVertices); }
else
{ a_VoronoiToInternalEdges.Add(voronoiVertex2, inputVertices); }
}
}
public void Create()
{
Vertex v1 = new Vertex(-500000, -500000);
Vertex v2 = new Vertex(500000, 500000);
Vertex v3 = new Vertex(-500000, 500000);
Vertex v4 = new Vertex(500000, -500000);
m_Vertices.AddRange(new List<Vertex>() { v1, v2, v3, v4 });
HalfEdge h1 = new HalfEdge(v1);
HalfEdge h2 = new HalfEdge(v2);
HalfEdge h3 = new HalfEdge(v3);
m_HalfEdges.AddRange(new List<HalfEdge>() { h1, h2, h3 });
h1.Next = h2;
h2.Next = h3;
h3.Next = h1;
h2.Prev = h1;
h3.Prev = h2;
h1.Prev = h3;
HalfEdge h4 = new HalfEdge(v2);
HalfEdge h5 = new HalfEdge(v1);
HalfEdge h6 = new HalfEdge(v4);
m_HalfEdges.AddRange(new List<HalfEdge>() { h4, h5, h6 });
h4.Twin = h1;
h1.Twin = h4;
h4.Next = h5;
h5.Next = h6;
h6.Next = h4;
h5.Prev = h4;
h6.Prev = h5;
h4.Prev = h6;
HalfEdge h7 = new HalfEdge(v1);
HalfEdge h8 = new HalfEdge(v2);
HalfEdge h9 = new HalfEdge(v3);
HalfEdge h10 = new HalfEdge(v4);
m_HalfEdges.AddRange(new List<HalfEdge>() { h7, h8, h9, h10 });
h10.Next = h7;
h7.Prev = h10;
h8.Next = h10;
h10.Prev = h8;
h9.Next = h8;
h8.Prev = h9;
h7.Next = h9;
h9.Prev = h7;
h3.Twin = h7;
h7.Twin = h3;
h8.Twin = h6;
h6.Twin = h8;
h2.Twin = h9;
h9.Twin = h2;
h10.Twin = h5;
h5.Twin = h10;
m_Triangles.Add(new Triangle(h1));
m_Triangles.Add(new Triangle(h4));
}
/// <summary>
/// Deletes HalfEdge. This delete routine cannot reclaim the node, since
/// hash table pointers may still be present.
/// </summary>
/// <param name="he">node to delete</param>
internal void Delete(HalfEdge he)
{
he.Left.Right = he.Right;
he.Right.Left = he.Left;
he.Edge = null;
}
