public HalfEdge GetEdge(Vertex a, Vertex b, Face f, HalfEdge abNext)
{
List<HalfEdge> appropriateEdges;
if (edges.ContainsKey(b))
{
appropriateEdges = edges[b];
}
else
{
appropriateEdges = new List<HalfEdge>();
edges[b] = appropriateEdges;
}
var query = appropriateEdges.Where(x => x.Twin.End == a);
switch (query.Count())
{
case 0:
{
HalfEdge edge = new HalfEdge(this, null, true);
HalfEdge twin = edge.Twin;
edge.End = b;
twin.End = a;
edge.Face = f;
edge.Next = abNext;
return edge;
}
case 1:
{
var edge = query.First();
if (abNext != null && edge.Next != abNext && edge.Next != null)
throw new ArgumentException("Edge already attached to edge " + edge.Next);
if (f != null && edge.Face != f && edge.Face != null)
throw new ArgumentException("Edge already attached to face " + edge.Face);
edge.Face = f ?? edge.Face;
edge.Next = abNext ?? edge.Next;
return edge;
}
default:
throw new MeshMalformedException("More than one edge already exists between " + a + " and " + b);
}
}
public void Deleted(Vertex v)
{
}
public void Added(Vertex v)
{
//changes.Push(new AddVertex(v));
}
public EndSplitMidpointHalfEdge(HalfEdge e, Vertex m)
{
//throw new NotImplementedException();
}
public AddVertex(Vertex v)
{
Position = v.Position;
}
public void SplitMidpointEnd(Face f, Vertex mid)
{
throw new NotImplementedException();
}
public void SplitMidpointEnd(HalfEdge e, Vertex mid)
{
changes.Push(new EndSplitMidpointHalfEdge(e, mid));
}
public void SplitMidpointBegin(HalfEdge e, Vertex mid)
{
changes.Push(new BeginSplitMidpointHalfEdge(e, mid));
}
public static Mesh Cylinder(int segments, int slices, float radius, float height, Mesh m = null)
{
if (slices < 2)
throw new ArgumentException("Must be more than 2 slices");
height /= 2f;
m = m ?? new Mesh();
Vertex[][] sliceVerts = new Vertex[slices][];
for (int i = 0; i < slices; i++)
sliceVerts[i] = new Vertex[segments];
float angle = 0;
float step = MathHelper.TwoPi / (float)segments;
for (int segment = 0; segment < segments; segment++)
{
Vector2 xy = new Vector2((float)Math.Sin(angle), (float)Math.Cos(angle));
for (int slice = 0; slice < slices; slice++)
{
float l = slice / (float)slices;
float z = MathHelper.Lerp(-height, height, l);
sliceVerts[slice][segment] = m.GetVertex(new Vector3(xy, z), "slice:" + slice + " seg:" + segment);
}
angle += step;
}
m.GetFace(sliceVerts[0].Reverse());
m.GetFace(sliceVerts[slices - 1]);
for (int segment = 0; segment < segments; segment++)
{
for (int slice = 0; slice < slices - 1; slice++)
{
m.GetFace(
sliceVerts[slice][segment],
sliceVerts[slice][(segment + 1) % segments],
sliceVerts[slice + 1][(segment + 1) % segments],
sliceVerts[slice + 1][segment]
);
}
}
return m;
}
public HalfEdge Split(Vertex midpoint)
{
Mesh.InformSplitMidpointBegin(this, midpoint);
if (midpoint.Equals(End) || midpoint.Equals(Twin.End))
return this;
var a = Twin.End;
var m = midpoint;
var b = End;
Twin.End = m;
var bm = Twin;
var mb = this;
var am = Mesh.GetEdge(a, m, Face, Face == null ? null : mb, mb.Twin.Face, mb.Twin.Next);
var ma = am.Twin;
if (Face != null)
{
bm.Next = ma;
Face.Edges.Where(e => e.Next == this).First().Next = am;
}
if (Twin.Face != null)
{
Twin.Face.Edges.Where(e => e.Next == Twin).First().Next = bm;
}
Mesh.InformSplitMidpointEnd(this, midpoint);
return am;
}
/// <summary>
/// Inserts a midpoint into this face
/// Deletes this face
/// </summary>
/// <param name="midpoint">The midpoint.</param>
public void InsertMidpoint(Vertex midpoint)
{
Mesh.InformSplitMidpointBegin(this, midpoint);
var edges = Edges.ToArray();
Delete();
for (int i = 0; i < edges.Length; i++)
{
var v1 = edges[i].End;
var v2 = edges[(i + 1) % edges.Length].End;
Mesh.GetFace(v1, v2, midpoint);
}
Mesh.InformSplitMidpointEnd(this, midpoint);
}
public HalfEdge GetEdge(Vertex a, Vertex b, Face abf, HalfEdge abNext, Face baf, HalfEdge baNext)
{
throw new NotImplementedException();
}
