public static UnionFind <VertexNode> MakeUnionFind(HalfEdgeMesh mesh)
{
UnionFind <VertexNode> uf = new UnionFind <VertexNode>(mesh.Vertices.Length);
Matrix <double>[] faceQuadrics = new Matrix <double> [mesh.Faces.Length];
for (int i = 0; i < faceQuadrics.Length; i++)
{
Face f = mesh.Faces[i];
if (f.IsBoundary)
{
continue;
}
Vector3 normal = f.Normal;
Vector3 v1 = f.anyHalfEdge.tailVertex.position;
float d = -Vector3.Dot(v1, normal);
Vector <double> v = DenseVector.OfArray(new double[] { normal.x, normal.y, normal.z, d });
faceQuadrics[i] = v.OuterProduct(v);
}
for (int i = 0; i < uf.NumNodes; i++)
{
VertexNode current = uf[i];
current.position = mesh.Vertices[i].position;
current.containingUF = uf;
ErrorQuadric vertQuadric = new ErrorQuadric();
// Iterate over all faces surrounding this vertex and sum up the face quadrics
HalfEdge start = mesh.Vertices[i].anyHalfEdge;
HalfEdge he = start;
do
{
Face f = he.face;
if (!f.IsBoundary)
{
Matrix <double> faceQuadric = faceQuadrics[he.face.Index];
vertQuadric.AddQuadric(faceQuadric);
}
he = he.flip.next;
}while (he != start);
current.quadric = vertQuadric;
current.mergedPoints = new HashSet <int>();
current.mergedPoints.Add(i);
current.Index = i;
}
return(uf);
}
void ConstructAdjacencyLists()
{
adjacency = new HashSet <int> [heMesh.Vertices.Length];
for (int i = 0; i < heMesh.Vertices.Length; i++)
{
VertexNode root = uf.Find(i);
HashSet <int> points = root.MergedPoints;
// If the adjacency set for this equiv. class hasn't been
// created yet, create it.
if (adjacency[root.Index] == null)
{
HashSet <int> adj = new HashSet <int>();
// We make sure that every point in this class references
// the same set.
foreach (int p in points)
{
adjacency[p] = adj;
}
}
// Add all neighbors from all points in the equiv. class
foreach (int p in points)
{
Vertex thisVert = heMesh.Vertices[p];
HalfEdge startHE = thisVert.anyHalfEdge;
HalfEdge he = thisVert.anyHalfEdge;
do
{
int neighborInd = he.headVertex.Index;
int neighborRoot = uf.Find(neighborInd).Index;
// Only add the neighbor if it isn't in the same equiv. class.
if (!points.Contains(neighborRoot))
{
adjacency[p].Add(neighborRoot);
}
he = he.flip.next;
}while (he != startHE);
}
}
}
public override void Merge(UnionFindNode child)
{
VertexNode childNode = child as VertexNode;
if (child.Parent != child)
{
throw new System.Exception("Merge wasn't given parent node");
}
quadric.AddQuadric(childNode.quadric);
//position = (position + childNode.position) / 2;
//position = quadric.OptimalPoint(position, childNode.position);
int n1 = mergedPoints.Count;
int n2 = childNode.mergedPoints.Count;
position = ((n1 * position) + (n2 * childNode.position)) / (n1 + n2);
currentCost = Cost(position);
mergedPoints.UnionWith(childNode.mergedPoints);
}