vtkPVFoamMeshVolume.C

Go to the documentation of this file.

/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Copyright (C) 2011-2025 OpenFOAM Foundation
     \\/     M anipulation  |
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.
 
    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
    You should have received a copy of the GNU General Public License
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
\*---------------------------------------------------------------------------*/
 
#include "vtkPVFoam.H"
#include "vtkPVFoamReader.h"
#include "vtkOpenFOAMPoints.H"
 
// OpenFOAM includes
#include "volFields.H"
#include "cellModeller.H"
#include "polygonTriangulate.H"
 
// VTK includes
#include "vtkCellArray.h"
#include "vtkIdTypeArray.h"
#include "vtkUnstructuredGrid.h"
 
// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
vtkUnstructuredGrid* Foam::vtkPVFoam::volumeVTKMesh
(
    const fvMesh& mesh,
    polyDecomp& decompInfo
)
{
    const cellModel& tet = *(cellModeller::lookup("tet"));
    const cellModel& pyr = *(cellModeller::lookup("pyr"));
    const cellModel& prism = *(cellModeller::lookup("prism"));
    const cellModel& wedge = *(cellModeller::lookup("wedge"));
    const cellModel& tetWedge = *(cellModeller::lookup("tetWedge"));
    const cellModel& hex = *(cellModeller::lookup("hex"));
 
    vtkUnstructuredGrid* vtkmesh = vtkUnstructuredGrid::New();
 
    const cellShapeList& cellShapes = mesh.cellShapes();
 
    // Number of additional points needed by the decomposition of polyhedra
    label nAddPoints = 0;
 
    // Number of additional cells generated by the decomposition of polyhedra
    label nAddCells = 0;
 
    // face owner is needed to determine the face orientation
    const labelList& owner = mesh.faceOwner();
 
    labelList& superCells = decompInfo.superCells();
    labelList& addPointCellLabels = decompInfo.addPointCellLabels();
 
    // Scan for cells which need to be decomposed and count additional points
    // and cells
    if (!reader_->GetUseVTKPolyhedron())
    {
        forAll(cellShapes, celli)
        {
            const cellModel& model = cellShapes[celli].model();
 
            if
            (
                model != hex
             && model != wedge
             && model != prism
             && model != pyr
             && model != tet
             && model != tetWedge
            )
            {
                const cell& cFaces = mesh.cells()[celli];
 
                forAll(cFaces, cFacei)
                {
                    const face& f = mesh.faces()[cFaces[cFacei]];
 
                    if (f.size() != 4)
                    {
                        nAddCells += f.nTriangles();
                    }
                    else
                    {
                        nAddCells ++;
                    }
                }
 
                nAddCells--;
                nAddPoints++;
            }
        }
    }
 
    // Set size of additional point addressing array
    // (from added point to original cell)
    addPointCellLabels.setSize(nAddPoints);
 
    // Set size of additional cells mapping array
    // (from added cell to original cell)
    superCells.setSize(mesh.nCells() + nAddCells);
 
    DebugInFunction
        << "nCells=" << mesh.nCells()
        << ", nPoints=" << mesh.nPoints()
        << ", nAddCells=" << nAddCells
        << ", nAddPoints=" << nAddPoints << endl;
 
    // Convert OpenFOAM mesh vertices to VTK
    vtkPoints* vtkpoints = vtkPoints::New();
    vtkpoints->Allocate(mesh.nPoints() + nAddPoints);
 
    const Foam::pointField& points = mesh.points();
 
    forAll(points, i)
    {
        vtkInsertNextOpenFOAMPoint(vtkpoints, points[i]);
    }
 
    vtkmesh->Allocate(mesh.nCells() + nAddCells);
 
    // Create a triangulation engine
    polygonTriangulate triEngine;
 
    // Set counters for additional points and additional cells
    label addPointi = 0, addCelli = 0;
 
    // Create storage for points - needed for mapping from OpenFOAM to VTK
    // data types - max 'order' = hex = 8 points
    vtkIdType nodeIds[8];
 
    // face-stream for a polyhedral cell
    // [numFace0Pts, id1, id2, id3, numFace1Pts, id1, id2, id3, ...]
    DynamicList<vtkIdType> faceStream(256);
 
    forAll(cellShapes, celli)
    {
        const cellShape& cellShape = cellShapes[celli];
        const cellModel& cellModel = cellShape.model();
 
        superCells[addCelli++] = celli;
 
        if (cellModel == tet)
        {
            for (int j = 0; j < 4; j++)
            {
                nodeIds[j] = cellShape[j];
            }
            vtkmesh->InsertNextCell
            (
                VTK_TETRA,
                4,
                nodeIds
            );
        }
        else if (cellModel == pyr)
        {
            for (int j = 0; j < 5; j++)
            {
                nodeIds[j] = cellShape[j];
            }
            vtkmesh->InsertNextCell
            (
                VTK_PYRAMID,
                5,
                nodeIds
            );
        }
        else if (cellModel == prism)
        {
            // VTK has a different node order for VTK_WEDGE
            // their triangles point outwards!
            nodeIds[0] = cellShape[0];
            nodeIds[1] = cellShape[2];
            nodeIds[2] = cellShape[1];
            nodeIds[3] = cellShape[3];
            nodeIds[4] = cellShape[5];
            nodeIds[5] = cellShape[4];
 
            vtkmesh->InsertNextCell
            (
                VTK_WEDGE,
                6,
                nodeIds
            );
        }
        else if (cellModel == tetWedge && !reader_->GetUseVTKPolyhedron())
        {
            // Treat as squeezed prism (VTK_WEDGE)
 
            nodeIds[0] = cellShape[0];
            nodeIds[1] = cellShape[2];
            nodeIds[2] = cellShape[1];
            nodeIds[3] = cellShape[3];
            nodeIds[4] = cellShape[4];
            nodeIds[5] = cellShape[3];
 
            vtkmesh->InsertNextCell
            (
                VTK_WEDGE,
                6,
                nodeIds
            );
        }
        else if (cellModel == wedge)
        {
            // Treat as squeezed hex
 
            nodeIds[0] = cellShape[0];
            nodeIds[1] = cellShape[1];
            nodeIds[2] = cellShape[2];
            nodeIds[3] = cellShape[2];
            nodeIds[4] = cellShape[3];
            nodeIds[5] = cellShape[4];
            nodeIds[6] = cellShape[5];
            nodeIds[7] = cellShape[6];
 
            vtkmesh->InsertNextCell
            (
                VTK_HEXAHEDRON,
                8,
                nodeIds
            );
        }
        else if (cellModel == hex)
        {
            for (int j = 0; j < 8; j++)
            {
                nodeIds[j] = cellShape[j];
            }
            vtkmesh->InsertNextCell
            (
                VTK_HEXAHEDRON,
                8,
                nodeIds
            );
        }
        else if (reader_->GetUseVTKPolyhedron())
        {
            // Polyhedral cell - use VTK_POLYHEDRON
            const labelList& cFaces = mesh.cells()[celli];
 
#ifdef HAS_VTK_POLYHEDRON
            vtkIdType nFaces = cFaces.size();
            vtkIdType nLabels = nFaces;
 
            // count size for face stream
            forAll(cFaces, cFacei)
            {
                const face& f = mesh.faces()[cFaces[cFacei]];
                nLabels += f.size();
            }
 
            // build face-stream
            // [numFace0Pts, id1, id2, id3, numFace1Pts, id1, id2, id3, ...]
            // point Ids are global
            faceStream.clear();
            faceStream.reserve(nLabels + nFaces);
 
            forAll(cFaces, cFacei)
            {
                const face& f = mesh.faces()[cFaces[cFacei]];
                const bool isOwner = (owner[cFaces[cFacei]] == celli);
                const label nFacePoints = f.size();
 
                // number of labels for this face
                faceStream.append(nFacePoints);
 
                if (isOwner)
                {
                    forAll(f, fp)
                    {
                        faceStream.append(f[fp]);
                    }
                }
                else
                {
                    // Fairly immaterial if we reverse the list
                    // or use face::reverseFace()
                    forAllReverse(f, fp)
                    {
                        faceStream.append(f[fp]);
                    }
                }
            }
 
            vtkmesh->InsertNextCell(VTK_POLYHEDRON, nFaces, faceStream.data());
#else
            // This is a horrible substitute
            // but avoids crashes when there is no vtkPolyhedron support
 
            // Establish unique node ids used
            HashSet<vtkIdType, Hash<label>> hashUniqId(2*256);
 
            forAll(cFaces, cFacei)
            {
                const face& f = mesh.faces()[cFaces[cFacei]];
 
                forAll(f, fp)
                {
                    hashUniqId.insert(f[fp]);
                }
            }
 
            // Use face stream to store unique node ids:
            faceStream = hashUniqId.sortedToc();
 
            vtkmesh->InsertNextCell
            (
                VTK_CONVEX_POINT_SET,
                vtkIdType(faceStream.size()),
                faceStream.data()
            );
#endif
        }
        else
        {
            // Polyhedral cell. Decompose into tets + prisms.
 
            // Mapping from additional point to cell
            addPointCellLabels[addPointi] = celli;
 
            // Create a new vertex from the cell-centre. If the mesh doesn't
            // have cell-centres stored then compute the centre on the fly.
            // These polyhedra should (hopefully) only be a small minority of
            // the cells, and computing cell-centres throughout the mesh is
            // quite expensive and involves a lot of memory (it also creates
            // face areas and centres and cell volumes).
            const label newVertexLabel = mesh.nPoints() + addPointi;
            vtkInsertNextOpenFOAMPoint
            (
                vtkpoints,
                mesh.has(&primitiveMesh::cellCentres)
              ? mesh.cellCentres()[celli]
              : mesh.cells()[celli].centre(mesh.points(), mesh.faces())
            );
 
            // Whether to insert cell in place of original or not.
            bool substituteCell = true;
 
            const labelList& cFaces = mesh.cells()[celli];
            forAll(cFaces, cFacei)
            {
                const face& f = mesh.faces()[cFaces[cFacei]];
                const bool isOwner = (owner[cFaces[cFacei]] == celli);
 
                // Do decomposition into triFcs and quadFcs.
                faceList triFcs(f.size() == 4 ? 0 : f.nTriangles());
                faceList quadFcs(f.size() == 4 ? 1 : 0);
                if (f.size() != 4)
                {
                    triEngine.triangulate
                    (
                        UIndirectList<point>(mesh.points(), f)
                    );
                    forAll(triEngine.triPoints(), trii)
                    {
                        triFcs[trii] = triEngine.triPoints(trii, f);
                    }
                }
                else
                {
                    quadFcs[0] = f;
                }
 
                forAll(quadFcs, quadI)
                {
                    if (substituteCell)
                    {
                        substituteCell = false;
                    }
                    else
                    {
                        superCells[addCelli++] = celli;
                    }
 
                    const face& quad = quadFcs[quadI];
 
                    // Ensure we have the correct orientation for the
                    // base of the primitive cell shape.
                    // If the cell is face owner, the orientation needs to be
                    // flipped.
                    // At the moment, VTK doesn't actually seem to care if
                    // negative cells are defined, but we'll do it anyhow
                    // (for safety).
                    if (isOwner)
                    {
                        nodeIds[0] = quad[3];
                        nodeIds[1] = quad[2];
                        nodeIds[2] = quad[1];
                        nodeIds[3] = quad[0];
                    }
                    else
                    {
                        nodeIds[0] = quad[0];
                        nodeIds[1] = quad[1];
                        nodeIds[2] = quad[2];
                        nodeIds[3] = quad[3];
                    }
                    nodeIds[4] = newVertexLabel;
                    vtkmesh->InsertNextCell
                    (
                        VTK_PYRAMID,
                        5,
                        nodeIds
                    );
                }
 
                forAll(triFcs, triI)
                {
                    if (substituteCell)
                    {
                        substituteCell = false;
                    }
                    else
                    {
                        superCells[addCelli++] = celli;
                    }
 
                    const face& tri = triFcs[triI];
 
                    // See note above about the orientation.
                    if (isOwner)
                    {
                        nodeIds[0] = tri[2];
                        nodeIds[1] = tri[1];
                        nodeIds[2] = tri[0];
                    }
                    else
                    {
                        nodeIds[0] = tri[0];
                        nodeIds[1] = tri[1];
                        nodeIds[2] = tri[2];
                    }
                    nodeIds[3] = newVertexLabel;
 
                    vtkmesh->InsertNextCell
                    (
                        VTK_TETRA,
                        4,
                        nodeIds
                    );
                }
            }
 
            addPointi++;
        }
    }
 
    vtkmesh->SetPoints(vtkpoints);
    vtkpoints->Delete();
 
    return vtkmesh;
}
 
 
// ************************************************************************* //