public SubMeshes Process()
{
// Create a stack with an initial capacity matching Sqrt(#elmts), which will approximately match for
// a square mesh with quads.
_stack = new Stack <int>((int)System.Math.Sqrt(_meshData.NumberOfElements));
SubMeshes subMeshes = new SubMeshes();
subMeshes.SubMeshInfos = new List <SubMeshInfo>();
int subMeshId = 0;
ElmtSubMesh = new int[_meshData.NumberOfElements];
for (int i = 0; i < _meshData.NumberOfElements; i++)
{
if (ElmtSubMesh[i] == 0)
{
subMeshId++;
int subMeshElmtCount = BFSVisit(i, subMeshId);
subMeshes.SubMeshInfos.Add(new SubMeshInfo()
{
SubMeshId = subMeshId, NumberOfElments = subMeshElmtCount
});
}
}
subMeshes.ElmtSubMesh = ElmtSubMesh;
return(subMeshes);
}
/// <summary>
/// Find connected sub meshes.
/// </summary>
public static SubMeshes FindConnectedSubMeshes(this CMeshData meshData)
{
// We need faces information for each element.
meshData.BuildFaces(true);
BFSSubMesher subMesher = new BFSSubMesher(meshData);
SubMeshes subMeshes = subMesher.Process();
// Sort such that the sub mesh with most element is first in the list
subMeshes.SubMeshInfos.Sort((smi1, smi2) => - smi1.NumberOfElments.CompareTo(smi2.NumberOfElments));
return(subMeshes);
}
/// <summary>
/// Build boundary polygon. Returns either a <see cref="Polygon"/> or <see cref="MultiPolygon"/>
/// depending on whether the mesh is fully connected or consist of independent parts.
/// <para>
/// To always return a <see cref="MultiPolygon"/>, set the <paramref name="alwaysMultiPolygon"/> to true.
/// </para>
/// </summary>
private static Geometry BuildBoundaryGeometry(CMeshData mesh, List <CMeshFace> boundaryFaces, bool alwaysMultiPolygon)
{
// There will be one polygon for each connected sub mesh, in case there is more than one.
//System.Diagnostics.Stopwatch timer = MeshExtensions.StartTimer();
// Find all connected sub meshes.
SubMeshes subMeshes = mesh.FindConnectedSubMeshes();
//timer.ReportAndRestart("FindConnectedSubMeshes " + subMeshes.NumberOfSubMeshes);
BoundarySegmentsBuilder bsb = new BoundarySegmentsBuilder(mesh);
if (subMeshes.NumberOfSubMeshes == 1)
{
Polygon boundaryPoly = BuildSubMeshBoundaryGeometry(mesh, bsb, boundaryFaces);
if (!alwaysMultiPolygon)
{
return(boundaryPoly);
}
MultiPolygon multiPolygon = new MultiPolygon(new Polygon[] { boundaryPoly });
return(multiPolygon);
}
else // More than one sub-mesh - make a Polygon for each sub mesh
{
// Find boundary faces for each sub mesh
List <List <CMeshFace> > subMeshesBoundaryFaces = new List <List <CMeshFace> >(subMeshes.NumberOfSubMeshes);
for (int i = 0; i < subMeshes.NumberOfSubMeshes; i++)
{
subMeshesBoundaryFaces.Add(new List <CMeshFace>());
}
for (int i = 0; i < boundaryFaces.Count; i++)
{
CMeshFace bcFace = boundaryFaces[i];
int subMeshId = subMeshes.ElmtSubMesh[bcFace.LeftElement.Index];
// subMeshId's starts from 1
subMeshesBoundaryFaces[subMeshId - 1].Add(bcFace);
}
// Make boundary polygon for each sub mesh - ordered as in SubMeshInfos to get largest parts first
List <Polygon> polygons = new List <Polygon>(subMeshes.NumberOfSubMeshes);
foreach (SubMeshInfo subMeshInfo in subMeshes.SubMeshInfos)
{
List <CMeshFace> subMeshBoundaryFaces = subMeshesBoundaryFaces[subMeshInfo.SubMeshId - 1];
Polygon subMeshBoundaryPoly = BuildSubMeshBoundaryGeometry(mesh, bsb, subMeshBoundaryFaces);
polygons.Add(subMeshBoundaryPoly);
}
MultiPolygon multiPoly = new MultiPolygon(polygons.ToArray());
return(multiPoly);
}
}
