public virtual void MergeEdges(Vertex middleVertex)
{
List <Halfedge> edges = middleVertex.edges;
Asserts.AssertThat(edges.Count == 2, "Vertex must has exactly two halfedges connecting to it.");
RemoveVertexFromList(middleVertex);
RemoveHalfedgeFromList(edges[0].opposite);
RemoveHalfedgeFromList(edges[1].opposite);
edges[0].vertex = edges[0].next.vertex;
edges[1].vertex = edges[1].next.vertex;
edges[0].vertex.edge = edges[0];
edges[1].vertex.edge = edges[1];
edges[0].next.next.prev = edges[0];
edges[1].next.next.prev = edges[1];
edges[0].next = edges[0].next.next;
edges[1].next = edges[1].next.next;
edges[0].opposite = edges[1];
edges[1].opposite = edges[0];
if (!edges[0].isBoundary)
{
edges[0].face.edge = edges[0];
}
if (!edges[1].isBoundary)
{
edges[1].face.edge = edges[1];
}
}
/// <summary> Merges two neighboring faces as one given one of their connecting halfedge. </summary>
public virtual void MergeFaces(Halfedge edge)
{
Halfedge oppo = edge.opposite;
Face face1 = edge.face;
Face face2 = oppo.face;
Asserts.AssertThat(
(face1 != face2 && edge.next != oppo && edge.prev != oppo) ||
(face1 == face2 && (edge.next == oppo ^ edge.prev == oppo)),
$"Merge will lead to non-valid geometry! face1 {(face1 == face2 ? "==" : "!=")} face2, edge.next {(edge.next == oppo ? "==" : "!=")} oppo, edge.prev {(edge.prev == oppo ? "==" : "!=")} oppo.");
if (face1 != face2)
{
face2.edges.ForEach(e => e.face = face1);
RemoveFaceFromList(face2);
}
face1.edge = edge.next != oppo ? edge.next : edge.prev;
if (edge.next != oppo)
{
edge.next.prev = oppo.prev;
oppo.prev.next = edge.next;
edge.vertex.edge = oppo.prev;
}
else
{
RemoveVertexFromList(edge.vertex);
}
if (oppo.next != edge)
{
oppo.next.prev = edge.prev;
edge.prev.next = oppo.next;
oppo.vertex.edge = edge.prev;
}
else
{
RemoveVertexFromList(oppo.vertex);
}
RemoveHalfedgeFromList(edge);
RemoveHalfedgeFromList(oppo);
}