/// <summary>
/// Populates |EditVertex.AdjacentVertices|.
/// </summary>
private void ComputeAdjacentVertices()
{
// Put all vertices into a KDTree.
try
{
KDTree <EditVertex> tree = new KDTree <EditVertex>(3);
foreach (var face in Faces)
{
foreach (var vert in face.Vertices)
{
var pos = vert.Position;
tree.AddPoint(new double[] { pos.X, pos.Y, pos.Z }, vert);
}
}
// For each vertices, retrieve adjacent/identical vertices by looking
// up neighbors within a very small (epsilon'ish) radius.
Faces.ParallelDo(
face =>
{
foreach (var vert in face.Vertices)
{
var pos = vert.Position;
var neighbors = tree.NearestNeighbors(new double[] { pos.X, pos.Y, pos.Z },
new SquareEuclideanDistanceFunction(),
int.MaxValue, 1e-5f);
foreach (var neighbor in neighbors)
{
vert.AdjacentVertices.Add(neighbor);
}
}
});
}
catch (Exception ex)
{
// TODO: Log.
// Unfortunately, KDTree rarely crashes.
// Long-term: fix KDTree.
// Short-term: O(n^2) brute force workaround.
Faces.ParallelDo(
face =>
{
foreach (var vert in face.Vertices)
{
var pos = vert.Position;
foreach (var otherVert in Vertices)
{
if (vert.IsApproximatelySamePosition(otherVert))
{
vert.AdjacentVertices.Add(otherVert);
}
}
}
});
}
// Vertices being adjacent should be a transitive relation, yet this is
// not guaranteed if implemented through a search radius.
HashSet <EditVertex> seen = new HashSet <EditVertex>();
foreach (var face in Faces)
{
foreach (var vert in face.Vertices)
{
if (seen.Contains(vert))
{
continue;
}
foreach (var adjacentVert in vert.AdjacentVertices)
{
vert.AdjacentVertices.UnionWith(vert.AdjacentVertices);
}
foreach (var adjacentVert in vert.AdjacentVertices)
{
adjacentVert.AdjacentVertices = vert.AdjacentVertices;
seen.Add(adjacentVert);
}
}
}
}