vtk-m/vtkm/rendering/Triangulator.h
Allison Vacanti 5db762ee71 Refactor topology mappings to clarify meaning.
The `From` and `To` nomenclature for topology mapping has been confusing for
both users and developers, especially at lower levels where the intention of
mapping attributes from one element to another is easily conflated with the
concept of mapping indices (which maps in the exact opposite direction).

These identifiers have been renamed to `VisitTopology` and `IncidentTopology`
to clarify the direction of the mapping. The order in which these template
parameters are specified for `WorkletMapTopology` have also been reversed,
since eventually there may be more than one `IncidentTopology`, and having
`IncidentTopology` at the end will allow us to replace it with a variadic
template parameter pack in the future.

Other implementation details supporting these worklets, include `Fetch` tags,
`Connectivity` classes, and methods on the various `CellSet` classes (such as
`PrepareForInput` have also reversed their template arguments. These will need
to be cautiously updated.

The convenience implementations of `WorkletMapTopology` have been renamed for
clarity as follows:

```
WorkletMapPointToCell --> WorkletVisitCellsWithPoints
WorkletMapCellToPoint --> WorkletVisitPointsWithCells
```

The `ControlSignature` tags have been renamed as follows:

```
FieldInTo --> FieldInVisit
FieldInFrom --> FieldInMap
FromCount --> IncidentElementCount
FromIndices --> IncidentElementIndices
```
2019-08-06 11:27:26 -04:00

712 lines
23 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_rendering_Triangulator_h
#define vtk_m_rendering_Triangulator_h
#include <typeinfo>
#include <vtkm/cont/Algorithm.h>
#include <vtkm/cont/ArrayHandleCounting.h>
#include <vtkm/cont/CellSetPermutation.h>
#include <vtkm/cont/DataSet.h>
#include <vtkm/rendering/raytracing/MeshConnectivityBuilder.h>
#include <vtkm/worklet/DispatcherMapField.h>
#include <vtkm/worklet/DispatcherMapTopology.h>
#include <vtkm/worklet/WorkletMapField.h>
#include <vtkm/worklet/WorkletMapTopology.h>
namespace vtkm
{
namespace rendering
{
/// \brief Triangulator creates a minimal set of triangles from a cell set.
///
/// This class creates a array of triangle indices from both 3D and 2D
/// explicit cell sets. This list can serve as input to opengl and the
/// ray tracer scene renderers.
///
class Triangulator
{
public:
class CountTriangles : public vtkm::worklet::WorkletVisitCellsWithPoints
{
public:
VTKM_CONT
CountTriangles() {}
using ControlSignature = void(CellSetIn cellset, FieldOut);
using ExecutionSignature = void(CellShape, _2);
VTKM_EXEC
void operator()(vtkm::CellShapeTagGeneric shapeType, vtkm::Id& triangles) const
{
if (shapeType.Id == vtkm::CELL_SHAPE_TRIANGLE)
triangles = 1;
else if (shapeType.Id == vtkm::CELL_SHAPE_QUAD)
triangles = 2;
else if (shapeType.Id == vtkm::CELL_SHAPE_TETRA)
triangles = 4;
else if (shapeType.Id == vtkm::CELL_SHAPE_HEXAHEDRON)
triangles = 12;
else if (shapeType.Id == vtkm::CELL_SHAPE_WEDGE)
triangles = 8;
else if (shapeType.Id == vtkm::CELL_SHAPE_PYRAMID)
triangles = 6;
else
triangles = 0;
}
VTKM_EXEC
void operator()(vtkm::CellShapeTagHexahedron vtkmNotUsed(shapeType), vtkm::Id& triangles) const
{
triangles = 12;
}
VTKM_EXEC
void operator()(vtkm::CellShapeTagQuad vtkmNotUsed(shapeType), vtkm::Id& triangles) const
{
triangles = 2;
}
VTKM_EXEC
void operator()(vtkm::CellShapeTagWedge vtkmNotUsed(shapeType), vtkm::Id& triangles) const
{
triangles = 8;
}
}; //class CountTriangles
template <int DIM>
class TrianglulateStructured : public vtkm::worklet::WorkletVisitCellsWithPoints
{
public:
using ControlSignature = void(CellSetIn cellset, FieldInCell, WholeArrayOut);
using ExecutionSignature = void(IncidentElementIndices, _2, _3);
VTKM_CONT
TrianglulateStructured() {}
#if defined(VTKM_MSVC)
#pragma warning(push)
#pragma warning(disable : 4127) //conditional expression is constant
#endif
template <typename CellNodeVecType, typename OutIndicesPortal>
VTKM_EXEC void operator()(const CellNodeVecType& cellIndices,
const vtkm::Id& cellIndex,
OutIndicesPortal& outputIndices) const
{
vtkm::Id4 triangle;
if (DIM == 2)
{
const vtkm::Id triangleOffset = cellIndex * 2;
// 0-1-2
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[1];
triangle[3] = cellIndices[2];
triangle[0] = cellIndex;
outputIndices.Set(triangleOffset, triangle);
// 0-3-2
triangle[2] = cellIndices[3];
outputIndices.Set(triangleOffset + 1, triangle);
}
else if (DIM == 3)
{
const vtkm::Id triangleOffset = cellIndex * 12;
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[1];
triangle[3] = cellIndices[5];
triangle[0] = cellIndex;
outputIndices.Set(triangleOffset, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[5];
triangle[3] = cellIndices[4];
outputIndices.Set(triangleOffset + 1, triangle);
triangle[1] = cellIndices[1];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[6];
outputIndices.Set(triangleOffset + 2, triangle);
triangle[1] = cellIndices[1];
triangle[2] = cellIndices[6];
triangle[3] = cellIndices[5];
outputIndices.Set(triangleOffset + 3, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[7];
triangle[3] = cellIndices[6];
outputIndices.Set(triangleOffset + 4, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[6];
triangle[3] = cellIndices[2];
outputIndices.Set(triangleOffset + 5, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[4];
triangle[3] = cellIndices[7];
outputIndices.Set(triangleOffset + 6, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[7];
triangle[3] = cellIndices[3];
outputIndices.Set(triangleOffset + 7, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[3];
triangle[3] = cellIndices[2];
outputIndices.Set(triangleOffset + 8, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[1];
outputIndices.Set(triangleOffset + 9, triangle);
triangle[1] = cellIndices[4];
triangle[2] = cellIndices[5];
triangle[3] = cellIndices[6];
outputIndices.Set(triangleOffset + 10, triangle);
triangle[1] = cellIndices[4];
triangle[2] = cellIndices[6];
triangle[3] = cellIndices[7];
outputIndices.Set(triangleOffset + 11, triangle);
}
}
#if defined(VTKM_MSVC)
#pragma warning(pop)
#endif
};
class IndicesSort : public vtkm::worklet::WorkletMapField
{
public:
VTKM_CONT
IndicesSort() {}
using ControlSignature = void(FieldInOut);
using ExecutionSignature = void(_1);
VTKM_EXEC
void operator()(vtkm::Id4& triangleIndices) const
{
// first field contains the id of the cell the
// trianlge belongs to
vtkm::Id temp;
if (triangleIndices[1] > triangleIndices[3])
{
temp = triangleIndices[1];
triangleIndices[1] = triangleIndices[3];
triangleIndices[3] = temp;
}
if (triangleIndices[1] > triangleIndices[2])
{
temp = triangleIndices[1];
triangleIndices[1] = triangleIndices[2];
triangleIndices[2] = temp;
}
if (triangleIndices[2] > triangleIndices[3])
{
temp = triangleIndices[2];
triangleIndices[2] = triangleIndices[3];
triangleIndices[3] = temp;
}
}
}; //class IndicesSort
struct IndicesLessThan
{
VTKM_EXEC_CONT
bool operator()(const vtkm::Id4& a, const vtkm::Id4& b) const
{
if (a[1] < b[1])
return true;
if (a[1] > b[1])
return false;
if (a[2] < b[2])
return true;
if (a[2] > b[2])
return false;
if (a[3] < b[3])
return true;
return false;
}
};
class UniqueTriangles : public vtkm::worklet::WorkletMapField
{
public:
VTKM_CONT
UniqueTriangles() {}
using ControlSignature = void(WholeArrayIn, WholeArrayOut);
using ExecutionSignature = void(_1, _2, WorkIndex);
VTKM_EXEC
bool IsTwin(const vtkm::Id4& a, const vtkm::Id4& b) const
{
return (a[1] == b[1] && a[2] == b[2] && a[3] == b[3]);
}
template <typename IndicesPortalType, typename OutputFlagsPortalType>
VTKM_EXEC void operator()(const IndicesPortalType& indices,
OutputFlagsPortalType& outputFlags,
const vtkm::Id& index) const
{
if (index == 0)
return;
//if we are a shared face, mark ourself and neighbor for destruction
if (IsTwin(indices.Get(index), indices.Get(index - 1)))
{
outputFlags.Set(index, 0);
outputFlags.Set(index - 1, 0);
}
}
}; //class UniqueTriangles
class Trianglulate : public vtkm::worklet::WorkletVisitCellsWithPoints
{
public:
VTKM_CONT
Trianglulate() {}
using ControlSignature = void(CellSetIn cellset, FieldInCell, WholeArrayOut);
using ExecutionSignature = void(_2, CellShape, PointIndices, WorkIndex, _3);
template <typename VecType, typename OutputPortal>
VTKM_EXEC void operator()(const vtkm::Id& triangleOffset,
vtkm::CellShapeTagWedge vtkmNotUsed(shapeType),
const VecType& cellIndices,
const vtkm::Id& cellId,
OutputPortal& outputIndices) const
{
vtkm::Id4 triangle;
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[1];
triangle[3] = cellIndices[2];
triangle[0] = cellId;
outputIndices.Set(triangleOffset, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[5];
triangle[3] = cellIndices[4];
outputIndices.Set(triangleOffset + 1, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[0];
triangle[3] = cellIndices[2];
outputIndices.Set(triangleOffset + 2, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[5];
outputIndices.Set(triangleOffset + 3, triangle);
triangle[1] = cellIndices[1];
triangle[2] = cellIndices[4];
triangle[3] = cellIndices[5];
outputIndices.Set(triangleOffset + 4, triangle);
triangle[1] = cellIndices[1];
triangle[2] = cellIndices[5];
triangle[3] = cellIndices[2];
outputIndices.Set(triangleOffset + 5, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[3];
triangle[3] = cellIndices[4];
outputIndices.Set(triangleOffset + 6, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[4];
triangle[3] = cellIndices[1];
outputIndices.Set(triangleOffset + 7, triangle);
}
template <typename VecType, typename OutputPortal>
VTKM_EXEC void operator()(const vtkm::Id& triangleOffset,
vtkm::CellShapeTagQuad vtkmNotUsed(shapeType),
const VecType& cellIndices,
const vtkm::Id& cellId,
OutputPortal& outputIndices) const
{
vtkm::Id4 triangle;
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[1];
triangle[3] = cellIndices[2];
triangle[0] = cellId;
outputIndices.Set(triangleOffset, triangle);
triangle[2] = cellIndices[3];
outputIndices.Set(triangleOffset + 1, triangle);
}
template <typename VecType, typename OutputPortal>
VTKM_EXEC void operator()(const vtkm::Id& triangleOffset,
vtkm::CellShapeTagHexahedron vtkmNotUsed(shapeType),
const VecType& cellIndices,
const vtkm::Id& cellId,
OutputPortal& outputIndices) const
{
vtkm::Id4 triangle;
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[1];
triangle[3] = cellIndices[5];
triangle[0] = cellId;
outputIndices.Set(triangleOffset, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[5];
triangle[3] = cellIndices[4];
outputIndices.Set(triangleOffset + 1, triangle);
triangle[1] = cellIndices[1];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[6];
outputIndices.Set(triangleOffset + 2, triangle);
triangle[1] = cellIndices[1];
triangle[2] = cellIndices[6];
triangle[3] = cellIndices[5];
outputIndices.Set(triangleOffset + 3, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[7];
triangle[3] = cellIndices[6];
outputIndices.Set(triangleOffset + 4, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[6];
triangle[3] = cellIndices[2];
outputIndices.Set(triangleOffset + 5, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[4];
triangle[3] = cellIndices[7];
outputIndices.Set(triangleOffset + 6, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[7];
triangle[3] = cellIndices[3];
outputIndices.Set(triangleOffset + 7, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[3];
triangle[3] = cellIndices[2];
outputIndices.Set(triangleOffset + 8, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[1];
outputIndices.Set(triangleOffset + 9, triangle);
triangle[1] = cellIndices[4];
triangle[2] = cellIndices[5];
triangle[3] = cellIndices[6];
outputIndices.Set(triangleOffset + 10, triangle);
triangle[1] = cellIndices[4];
triangle[2] = cellIndices[6];
triangle[3] = cellIndices[7];
outputIndices.Set(triangleOffset + 11, triangle);
}
template <typename VecType, typename OutputPortal>
VTKM_EXEC void operator()(const vtkm::Id& triangleOffset,
vtkm::CellShapeTagGeneric shapeType,
const VecType& cellIndices,
const vtkm::Id& cellId,
OutputPortal& outputIndices) const
{
vtkm::Id4 triangle;
if (shapeType.Id == vtkm::CELL_SHAPE_TRIANGLE)
{
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[1];
triangle[3] = cellIndices[2];
triangle[0] = cellId;
outputIndices.Set(triangleOffset, triangle);
}
if (shapeType.Id == vtkm::CELL_SHAPE_QUAD)
{
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[1];
triangle[3] = cellIndices[2];
triangle[0] = cellId;
outputIndices.Set(triangleOffset, triangle);
triangle[2] = cellIndices[3];
outputIndices.Set(triangleOffset + 1, triangle);
}
if (shapeType.Id == vtkm::CELL_SHAPE_TETRA)
{
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[3];
triangle[3] = cellIndices[1];
triangle[0] = cellId;
outputIndices.Set(triangleOffset, triangle);
triangle[1] = cellIndices[1];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[3];
outputIndices.Set(triangleOffset + 1, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[3];
outputIndices.Set(triangleOffset + 2, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[1];
outputIndices.Set(triangleOffset + 3, triangle);
}
if (shapeType.Id == vtkm::CELL_SHAPE_HEXAHEDRON)
{
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[1];
triangle[3] = cellIndices[5];
triangle[0] = cellId;
outputIndices.Set(triangleOffset, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[5];
triangle[3] = cellIndices[4];
outputIndices.Set(triangleOffset + 1, triangle);
triangle[1] = cellIndices[1];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[6];
outputIndices.Set(triangleOffset + 2, triangle);
triangle[1] = cellIndices[1];
triangle[2] = cellIndices[6];
triangle[3] = cellIndices[5];
outputIndices.Set(triangleOffset + 3, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[7];
triangle[3] = cellIndices[6];
outputIndices.Set(triangleOffset + 4, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[6];
triangle[3] = cellIndices[2];
outputIndices.Set(triangleOffset + 5, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[4];
triangle[3] = cellIndices[7];
outputIndices.Set(triangleOffset + 6, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[7];
triangle[3] = cellIndices[3];
outputIndices.Set(triangleOffset + 7, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[3];
triangle[3] = cellIndices[2];
outputIndices.Set(triangleOffset + 8, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[1];
outputIndices.Set(triangleOffset + 9, triangle);
triangle[1] = cellIndices[4];
triangle[2] = cellIndices[5];
triangle[3] = cellIndices[6];
outputIndices.Set(triangleOffset + 10, triangle);
triangle[1] = cellIndices[4];
triangle[2] = cellIndices[6];
triangle[3] = cellIndices[7];
outputIndices.Set(triangleOffset + 11, triangle);
}
if (shapeType.Id == vtkm::CELL_SHAPE_WEDGE)
{
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[1];
triangle[3] = cellIndices[2];
triangle[0] = cellId;
outputIndices.Set(triangleOffset, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[5];
triangle[3] = cellIndices[4];
outputIndices.Set(triangleOffset + 1, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[0];
triangle[3] = cellIndices[2];
outputIndices.Set(triangleOffset + 2, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[5];
outputIndices.Set(triangleOffset + 3, triangle);
triangle[1] = cellIndices[1];
triangle[2] = cellIndices[4];
triangle[3] = cellIndices[5];
outputIndices.Set(triangleOffset + 4, triangle);
triangle[1] = cellIndices[1];
triangle[2] = cellIndices[5];
triangle[3] = cellIndices[2];
outputIndices.Set(triangleOffset + 5, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[3];
triangle[3] = cellIndices[4];
outputIndices.Set(triangleOffset + 6, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[4];
triangle[3] = cellIndices[1];
outputIndices.Set(triangleOffset + 7, triangle);
}
if (shapeType.Id == vtkm::CELL_SHAPE_PYRAMID)
{
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[4];
triangle[3] = cellIndices[1];
triangle[0] = cellId;
outputIndices.Set(triangleOffset, triangle);
triangle[1] = cellIndices[1];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[4];
outputIndices.Set(triangleOffset + 1, triangle);
triangle[1] = cellIndices[2];
triangle[2] = cellIndices[3];
triangle[3] = cellIndices[4];
outputIndices.Set(triangleOffset + 2, triangle);
triangle[1] = cellIndices[0];
triangle[2] = cellIndices[4];
triangle[3] = cellIndices[3];
outputIndices.Set(triangleOffset + 3, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[2];
triangle[3] = cellIndices[1];
outputIndices.Set(triangleOffset + 4, triangle);
triangle[1] = cellIndices[3];
triangle[2] = cellIndices[1];
triangle[3] = cellIndices[0];
outputIndices.Set(triangleOffset + 5, triangle);
}
}
}; //class Trianglulate
public:
VTKM_CONT
Triangulator() {}
VTKM_CONT
void ExternalTrianlges(vtkm::cont::ArrayHandle<vtkm::Id4>& outputIndices,
vtkm::Id& outputTriangles)
{
//Eliminate unseen triangles
vtkm::worklet::DispatcherMapField<IndicesSort> sortInvoker;
sortInvoker.Invoke(outputIndices);
vtkm::cont::Algorithm::Sort(outputIndices, IndicesLessThan());
vtkm::cont::ArrayHandle<vtkm::UInt8> flags;
flags.Allocate(outputTriangles);
vtkm::cont::ArrayHandleConstant<vtkm::Id> one(1, outputTriangles);
vtkm::cont::Algorithm::Copy(one, flags);
//Unique triangles will have a flag = 1
vtkm::worklet::DispatcherMapField<UniqueTriangles>().Invoke(outputIndices, flags);
vtkm::cont::ArrayHandle<vtkm::Id4> subset;
vtkm::cont::Algorithm::CopyIf(outputIndices, flags, subset);
outputIndices = subset;
outputTriangles = subset.GetNumberOfValues();
}
VTKM_CONT
void Run(const vtkm::cont::DynamicCellSet& cellset,
vtkm::cont::ArrayHandle<vtkm::Id4>& outputIndices,
vtkm::Id& outputTriangles)
{
bool fastPath = false;
if (cellset.IsSameType(vtkm::cont::CellSetStructured<3>()))
{
//vtkm::cont::CellSetStructured<3> cellSetStructured3D =
// cellset.Cast<vtkm::cont::CellSetStructured<3>>();
//raytracing::MeshConnectivityBuilder<Device> builder;
//outputIndices = builder.ExternalTrianglesStructured(cellSetStructured3D);
//outputTriangles = outputIndices.GetNumberOfValues();
//fastPath = true;
vtkm::cont::CellSetStructured<3> cellSetStructured3D =
cellset.Cast<vtkm::cont::CellSetStructured<3>>();
const vtkm::Id numCells = cellSetStructured3D.GetNumberOfCells();
vtkm::cont::ArrayHandleCounting<vtkm::Id> cellIdxs(0, 1, numCells);
outputIndices.Allocate(numCells * 12);
vtkm::worklet::DispatcherMapTopology<TrianglulateStructured<3>>(TrianglulateStructured<3>())
.Invoke(cellSetStructured3D, cellIdxs, outputIndices);
outputTriangles = numCells * 12;
}
else if (cellset.IsSameType(vtkm::cont::CellSetStructured<2>()))
{
vtkm::cont::CellSetStructured<2> cellSetStructured2D =
cellset.Cast<vtkm::cont::CellSetStructured<2>>();
const vtkm::Id numCells = cellSetStructured2D.GetNumberOfCells();
vtkm::cont::ArrayHandleCounting<vtkm::Id> cellIdxs(0, 1, numCells);
outputIndices.Allocate(numCells * 2);
vtkm::worklet::DispatcherMapTopology<TrianglulateStructured<2>>(TrianglulateStructured<2>())
.Invoke(cellSetStructured2D, cellIdxs, outputIndices);
outputTriangles = numCells * 2;
// no need to do external faces on 2D cell set
fastPath = true;
}
else
{
vtkm::cont::ArrayHandle<vtkm::Id> trianglesPerCell;
vtkm::worklet::DispatcherMapTopology<CountTriangles>(CountTriangles())
.Invoke(cellset, trianglesPerCell);
vtkm::Id totalTriangles = 0;
totalTriangles = vtkm::cont::Algorithm::Reduce(trianglesPerCell, vtkm::Id(0));
vtkm::cont::ArrayHandle<vtkm::Id> cellOffsets;
vtkm::cont::Algorithm::ScanExclusive(trianglesPerCell, cellOffsets);
outputIndices.Allocate(totalTriangles);
vtkm::worklet::DispatcherMapTopology<Trianglulate>(Trianglulate())
.Invoke(cellset, cellOffsets, outputIndices);
outputTriangles = totalTriangles;
}
//get rid of any triagles we cannot see
if (!fastPath)
{
ExternalTrianlges(outputIndices, outputTriangles);
}
}
}; // class Triangulator
}
} //namespace vtkm::rendering
#endif //vtk_m_rendering_Triangulator_h