private UniversalFaceSpatialPartitioning Initialize(Surface surface, Topology topology, IVertexAttribute <Vector3> vertexPositions)
{
_surface = surface;
_topology = topology;
var edges = _topology.faceEdges;
_partitionBinaryTree = new Partition[edges.Count];
int edgesProcessed = 0;
int increment = 1;
if (edges.Count % 23 != 0)
{
increment = 23;
}
else if (edges.Count % 19 != 0)
{
increment = 19;
}
else if (edges.Count % 17 != 0)
{
increment = 17;
}
else if (edges.Count % 13 != 0)
{
increment = 13;
}
else if (edges.Count % 11 != 0)
{
increment = 11;
}
else if (edges.Count % 7 != 0)
{
increment = 7;
}
else if (edges.Count % 5 != 0)
{
increment = 5;
}
else if (edges.Count % 3 != 0)
{
increment = 3;
}
else if (edges.Count % 2 != 0)
{
increment = 2;
}
int edgeIndex = (edges.Count * 7) / 16;
// Find the first edge that will work as the root. It must be the earlier twin, and should not
// have any face-to-face wrapping or be on the boundary between an internal face and external faces.
while (edgesProcessed < edges.Count)
{
++edgesProcessed;
var edge = edges[edgeIndex];
if (edgeIndex < edge.twinIndex && (edge.wrap & EdgeWrap.FaceToFace) == EdgeWrap.None && edge.isNonBoundary)
{
_partitionBinaryTree[0] = Partition.Create(edge, vertexPositions, surface);
edgeIndex = (edgeIndex + increment) % edges.Count;
break;
}
edgeIndex = (edgeIndex + increment) % edges.Count;
}
int nextPartitionIndex = 1;
// Process all remaining non-wrapping non-boundary edges. As above, only concentrate on the earlier twins.
while (edgesProcessed < edges.Count)
{
++edgesProcessed;
var edge = edges[edgeIndex];
if (edgeIndex < edge.twinIndex && (edge.wrap & EdgeWrap.FaceToFace) == EdgeWrap.None && edge.isNonBoundary)
{
PartitionEdge(edge, vertexPositions, ref nextPartitionIndex);
}
edgeIndex = (edgeIndex + increment) % edges.Count;
}
edgesProcessed = 0;
// Process all wrapping edges, which should be at or near the leaves of the tree.
while (edgesProcessed < edges.Count)
{
++edgesProcessed;
var edge = edges[edgeIndex];
// If the edge has face-to-face wrapping, then don't restrict to only the earlier twin.
// Both twins should be processed.
if ((edge.wrap & EdgeWrap.FaceToFace) != EdgeWrap.None && edge.isNonBoundary)
{
PartitionEdge(edge, vertexPositions, ref nextPartitionIndex);
}
edgeIndex = (edgeIndex + increment) % edges.Count;
}
edgesProcessed = 0;
// Process all external edges, which should be at or near the leaves of the tree.
// Note that it is critical that boundary edges occur after all wrapping edges.
// Otherwise, false negatives (hitting an external face when a wrap should have
// led to an internal face instead) or even infinite loops are possible.
while (edgesProcessed < edges.Count)
{
++edgesProcessed;
var edge = edges[edgeIndex];
// If the edge is a boundary edge, then only process it if it's the external
// edge. The internal half doesn't need to be processed at all.
if (edge.isBoundary && edge.isExternal)
{
PartitionEdge(edge, vertexPositions, ref nextPartitionIndex);
}
edgeIndex = (edgeIndex + increment) % edges.Count;
}
if (nextPartitionIndex < _partitionBinaryTree.Length)
{
TruncateBinaryTree(nextPartitionIndex);
}
return(this);
}
public static Partition Create(Topology.FaceEdge edge, IVertexAttribute <Vector3> vertexPositions, Surface surface)
{
var prevEdge = edge.prev;
var vPos0 = vertexPositions[prevEdge];
var vPos1 = vertexPositions[edge];
var edgeVector = vPos1 - vPos0;
var edgeNormal = surface.GetNormal(vPos0);
var planeNormal = Vector3.Cross(edgeVector, edgeNormal).normalized;
return(new Partition(planeNormal, vPos0, edge.twinIndex, edge.index));
}
/// <summary>
/// Creates a spatial partitioning for the given manifold.
/// </summary>
/// <param name="surface">The surface describing the overall shape of the manifold.</param>
/// <param name="topology">The topological relations of vertices, edges, and faces of the manifold.</param>
/// <param name="vertexPositions">The positions of the manifold's vertices.</param>
/// <returns>A spatial partitioning for the given manifold.</returns>
public static UniversalFaceSpatialPartitioning Create(Surface surface, Topology topology, IVertexAttribute <Vector3> vertexPositions)
{
return(CreateInstance <UniversalFaceSpatialPartitioning>().Initialize(surface, topology, vertexPositions));
}