Files
2026-03-04 10:03:45 +08:00

174 lines
3.1 KiB
C#

using System.Collections.Generic;
using TriangleNet.Geometry;
namespace TriangleNet.Topology.DCEL
{
public class DcelMesh
{
protected List<Vertex> vertices;
protected List<HalfEdge> edges;
protected List<Face> faces;
public List<Vertex> Vertices => vertices;
public List<HalfEdge> HalfEdges => edges;
public List<Face> Faces => faces;
public IEnumerable<IEdge> Edges => EnumerateEdges();
public DcelMesh()
: this(initialize: true)
{
}
protected DcelMesh(bool initialize)
{
if (initialize)
{
vertices = new List<Vertex>();
edges = new List<HalfEdge>();
faces = new List<Face>();
}
}
public virtual bool IsConsistent(bool closed = true, int depth = 0)
{
foreach (Vertex vertex in vertices)
{
if (vertex.id >= 0)
{
if (vertex.leaving == null)
{
return false;
}
if (vertex.Leaving.Origin.id != vertex.id)
{
return false;
}
}
}
foreach (Face face in faces)
{
if (face.ID >= 0)
{
if (face.edge == null)
{
return false;
}
if (face.id != face.edge.face.id)
{
return false;
}
}
}
foreach (HalfEdge edge2 in edges)
{
if (edge2.id >= 0)
{
if (edge2.twin == null)
{
return false;
}
if (edge2.origin == null)
{
return false;
}
if (edge2.face == null)
{
return false;
}
if (closed && edge2.next == null)
{
return false;
}
}
}
foreach (HalfEdge edge3 in edges)
{
if (edge3.id < 0)
{
continue;
}
HalfEdge twin = edge3.twin;
HalfEdge next = edge3.next;
if (edge3.id != twin.twin.id)
{
return false;
}
if (closed)
{
if (next.origin.id != twin.origin.id)
{
return false;
}
if (next.twin.next.origin.id != edge3.twin.origin.id)
{
return false;
}
}
}
if (closed && depth > 0)
{
foreach (Face face2 in faces)
{
if (face2.id >= 0)
{
HalfEdge edge = face2.edge;
HalfEdge next2 = edge.next;
int id = edge.id;
int num = 0;
while (next2.id != id && num < depth)
{
next2 = next2.next;
num++;
}
if (next2.id != id)
{
return false;
}
}
}
}
return true;
}
public void ResolveBoundaryEdges()
{
Dictionary<int, HalfEdge> dictionary = new Dictionary<int, HalfEdge>();
foreach (HalfEdge edge in edges)
{
if (edge.twin == null)
{
HalfEdge halfEdge = (edge.twin = new HalfEdge(edge.next.origin, Face.Empty));
halfEdge.twin = edge;
dictionary.Add(halfEdge.origin.id, halfEdge);
}
}
int count = edges.Count;
foreach (HalfEdge value in dictionary.Values)
{
value.id = count++;
value.next = dictionary[value.twin.origin.id];
edges.Add(value);
}
}
protected virtual IEnumerable<IEdge> EnumerateEdges()
{
List<IEdge> list = new List<IEdge>(edges.Count / 2);
foreach (HalfEdge edge in edges)
{
HalfEdge twin = edge.twin;
if (edge.id < twin.id)
{
list.Add(new Edge(edge.origin.id, twin.origin.id));
}
}
return list;
}
}
}