vtk-m/vtkm/worklet/triangulate/TriangulateExplicit.h
Kenneth Moreland 4239d13b3e Make triangulate implementation more general
The triangulate and tetrahedra worklet implementations were for some
reason grabbing raw arrays out of `CellSetExplicit` and using those for
lookup tables. Rather than do that, simply use a
`WorkletVisitCellsWithPoints` automatically provide the values of these
cells. The advantage of this approach is that it simplifies the code and
also generalize it to cell sets that do not provide this explicit
representation. For example, the new implementation also works with
`CellSetExtrude`.
2021-09-08 12:49:11 -06:00

132 lines
4.2 KiB
C++

//============================================================================
// Copyright (c) Kitware, Inc.
// All rights reserved.
// See LICENSE.txt for details.
//
// This software is distributed WITHOUT ANY WARRANTY; without even
// the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
// PURPOSE. See the above copyright notice for more information.
//============================================================================
#ifndef vtk_m_worklet_TriangulateExplicit_h
#define vtk_m_worklet_TriangulateExplicit_h
#include <vtkm/cont/ArrayHandle.h>
#include <vtkm/cont/ArrayHandleGroupVec.h>
#include <vtkm/cont/CellSetExplicit.h>
#include <vtkm/cont/DataSet.h>
#include <vtkm/cont/Field.h>
#include <vtkm/worklet/DispatcherMapField.h>
#include <vtkm/worklet/DispatcherMapTopology.h>
#include <vtkm/worklet/ScatterCounting.h>
#include <vtkm/worklet/WorkletMapField.h>
#include <vtkm/worklet/WorkletMapTopology.h>
#include <vtkm/worklet/internal/TriangulateTables.h>
namespace vtkm
{
namespace worklet
{
/// \brief Compute the triangulate cells for an explicit grid data set
class TriangulateExplicit
{
public:
TriangulateExplicit() {}
//
// Worklet to count the number of triangles generated per cell
//
class TrianglesPerCell : public vtkm::worklet::WorkletVisitCellsWithPoints
{
public:
using ControlSignature = void(CellSetIn cells, ExecObject tables, FieldOut triangleCount);
using ExecutionSignature = _3(CellShape, IncidentElementCount, _2);
using InputDomain = _1;
VTKM_CONT
TrianglesPerCell() {}
template <typename CellShapeTag>
VTKM_EXEC vtkm::IdComponent operator()(
CellShapeTag shape,
vtkm::IdComponent numPoints,
const vtkm::worklet::internal::TriangulateTablesExecutionObject& tables) const
{
return tables.GetCount(shape, numPoints);
}
};
//
// Worklet to turn cells into triangles
// Vertices remain the same and each cell is processed with needing topology
//
class TriangulateCell : public vtkm::worklet::WorkletVisitCellsWithPoints
{
public:
using ControlSignature = void(CellSetIn cellset,
ExecObject tables,
FieldOutCell connectivityOut);
using ExecutionSignature = void(CellShape, PointIndices, _2, _3, VisitIndex);
using InputDomain = _1;
using ScatterType = vtkm::worklet::ScatterCounting;
template <typename CountArrayType>
VTKM_CONT static ScatterType MakeScatter(const CountArrayType& countArray)
{
return ScatterType(countArray);
}
// Each cell produces triangles and write result at the offset
template <typename CellShapeTag, typename ConnectivityInVec, typename ConnectivityOutVec>
VTKM_EXEC void operator()(
CellShapeTag shape,
const ConnectivityInVec& connectivityIn,
const vtkm::worklet::internal::TriangulateTablesExecutionObject& tables,
ConnectivityOutVec& connectivityOut,
vtkm::IdComponent visitIndex) const
{
vtkm::IdComponent3 triIndices = tables.GetIndices(shape, visitIndex);
connectivityOut[0] = connectivityIn[triIndices[0]];
connectivityOut[1] = connectivityIn[triIndices[1]];
connectivityOut[2] = connectivityIn[triIndices[2]];
}
};
template <typename CellSetType>
vtkm::cont::CellSetSingleType<> Run(const CellSetType& cellSet,
vtkm::cont::ArrayHandle<vtkm::IdComponent>& outCellsPerCell)
{
vtkm::cont::CellSetSingleType<> outCellSet;
vtkm::cont::Invoker invoke;
// Output topology
vtkm::cont::ArrayHandle<vtkm::Id> outConnectivity;
vtkm::worklet::internal::TriangulateTables tables;
// Determine the number of output cells each input cell will generate
invoke(TrianglesPerCell{}, cellSet, tables, outCellsPerCell);
// Build new cells
invoke(TriangulateCell{},
TriangulateCell::MakeScatter(outCellsPerCell),
cellSet,
tables,
vtkm::cont::make_ArrayHandleGroupVec<3>(outConnectivity));
// Add cells to output cellset
outCellSet.Fill(
cellSet.GetNumberOfPoints(), vtkm::CellShapeTagTriangle::Id, 3, outConnectivity);
return outCellSet;
}
};
}
} // namespace vtkm::worklet
#endif // vtk_m_worklet_TriangulateExplicit_h