CellTypeSource
vtk-examples/Cxx/GeometricObjects/CellTypeSource
Description¶
This example uses vtkCellTypeSource to generate a vtkUnstructuredGrid. If a cell does not fill a rectangular area or volume, then multiple cells will be generated. For example, a vtkTetra requires 12 cells to fill a cube. A vtkTriangle requires two cells to fill a square. vtkCellTypeSource generates a uniform set of coordinates. The example perturbs those coordinates to illustrate the results of the vtkTessellatorFilter. Also, each cell is passed through vtkShrinkFilter to help identify the cells. Each generated cell also has a unique color.
The example takes an optional argument, a vtkCell name.
For example, to generate vtkTriangles, run
CellTypeSource [vtkTriangle](https://www.vtk.org/doc/nightly/html/classvtkTriangle.html#details)
Other languages
See (Python)
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
CellTypeSource.cxx
#include <vtkActor.h>
#include <vtkActor2D.h>
#include <vtkCamera.h>
#include <vtkCellData.h>
#include <vtkCellType.h>
#include <vtkCellTypeSource.h>
#include <vtkCellTypes.h>
#include <vtkColorSeries.h>
#include <vtkDataSetMapper.h>
#include <vtkIntArray.h>
#include <vtkLookupTable.h>
#include <vtkMath.h>
#include <vtkMinimalStandardRandomSequence.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkShrinkFilter.h>
#include <vtkTessellatorFilter.h>
#include <vtkTextMapper.h>
#include <vtkTextProperty.h>
#include <vtkUnstructuredGrid.h>
#include <map>
int main(int argc, char* argv[])
{
std::string cellName = "vtkTetra";
if (argc > 1)
{
cellName = std::string(argv[1]);
}
// Store cell class names in a map
std::map<std::string, int> cellMap;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_LINE)] = VTK_LINE;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_EDGE)] =
VTK_QUADRATIC_EDGE;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_CUBIC_LINE)] =
VTK_CUBIC_LINE;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_TRIANGLE)] = VTK_TRIANGLE;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_TRIANGLE)] =
VTK_QUADRATIC_TRIANGLE;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUAD)] = VTK_QUAD;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_QUAD)] =
VTK_QUADRATIC_QUAD;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_TETRA)] = VTK_TETRA;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_HEXAHEDRON)] =
VTK_HEXAHEDRON;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_WEDGE)] = VTK_WEDGE;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_PYRAMID)] = VTK_PYRAMID;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_WEDGE)] =
VTK_QUADRATIC_WEDGE;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_PYRAMID)] =
VTK_QUADRATIC_PYRAMID;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_HEXAHEDRON)] =
VTK_QUADRATIC_HEXAHEDRON;
cellMap[vtkCellTypes::GetClassNameFromTypeId(VTK_QUADRATIC_TETRA)] =
VTK_QUADRATIC_TETRA;
if (cellMap.find(std::string(cellName)) == cellMap.end())
{
std::cout << "Cell type " << cellName << " is not supported." << std::endl;
return EXIT_FAILURE;
}
vtkNew<vtkCellTypeSource> source;
source->SetCellType(cellMap[cellName]);
source->Update();
std::cout << "Cell: " << cellName << std::endl;
vtkPoints* originalPoints = source->GetOutput()->GetPoints();
vtkNew<vtkPoints> points;
points->SetNumberOfPoints(source->GetOutput()->GetNumberOfPoints());
vtkNew<vtkMinimalStandardRandomSequence> rng;
rng->SetSeed(5070); // for testing
for (auto i = 0; i < points->GetNumberOfPoints(); ++i)
{
double perturbation[3];
for (auto j = 0; j < 3; ++j)
{
rng->Next();
perturbation[j] = rng->GetRangeValue(-0.1, 0.1);
}
double currentPoint[3];
originalPoints->GetPoint(i, currentPoint);
points->SetPoint(i, currentPoint[0] + perturbation[0],
currentPoint[1] + perturbation[1],
currentPoint[2] + perturbation[2]);
}
source->GetOutput()->SetPoints(points);
int numCells = source->GetOutput()->GetNumberOfCells();
std::cout << "Number of cells: " << numCells << std::endl;
vtkNew<vtkIntArray> idArray;
idArray->SetNumberOfTuples(numCells);
for (auto i = 0; i < numCells; ++i)
{
idArray->InsertTuple1(i, i + 1);
}
idArray->SetName("Ids");
source->GetOutput()->GetCellData()->AddArray(idArray);
source->GetOutput()->GetCellData()->SetActiveScalars("Ids");
vtkNew<vtkShrinkFilter> shrink;
shrink->SetInputConnection(source->GetOutputPort());
shrink->SetShrinkFactor(.8);
vtkNew<vtkTessellatorFilter> tessellate;
tessellate->SetInputConnection(shrink->GetOutputPort());
tessellate->SetMaximumNumberOfSubdivisions(3);
// Create a lookup table to map cell data to colors
vtkNew<vtkLookupTable> lut;
vtkNew<vtkColorSeries> colorSeries;
int seriesEnum = colorSeries->BREWER_QUALITATIVE_SET3;
;
colorSeries->SetColorScheme(seriesEnum);
colorSeries->BuildLookupTable(lut, colorSeries->ORDINAL);
// Fill in a few known colors, the rest will be generated if needed
vtkNew<vtkNamedColors> colors;
// Create a mapper and actor
vtkNew<vtkDataSetMapper> mapper;
mapper->SetInputConnection(source->GetOutputPort());
mapper->SetInputConnection(shrink->GetOutputPort());
mapper->SetScalarRange(0, numCells + 1);
mapper->SetLookupTable(lut);
mapper->SetScalarModeToUseCellData();
mapper->SetResolveCoincidentTopologyToPolygonOffset();
if (source->GetCellType() == VTK_QUADRATIC_PYRAMID ||
source->GetCellType() == VTK_QUADRATIC_WEDGE)
{
mapper->SetInputConnection(shrink->GetOutputPort());
}
else
{
mapper->SetInputConnection(tessellate->GetOutputPort());
}
vtkNew<vtkActor> actor;
actor->SetMapper(mapper);
actor->GetProperty()->EdgeVisibilityOn();
// actor->GetProperty()->SetLineWidth(3);
vtkNew<vtkTextProperty> textProperty;
textProperty->SetFontSize(20);
textProperty->SetJustificationToCentered();
textProperty->SetColor(colors->GetColor3d("Lamp_Black").GetData());
vtkNew<vtkTextMapper> textMapper;
textMapper->SetInput(cellName.c_str());
textMapper->SetTextProperty(textProperty);
vtkNew<vtkActor2D> textActor;
textActor->SetMapper(textMapper);
textActor->SetPosition(320, 20);
// Create a renderer, render window, and interactor
vtkNew<vtkRenderer> renderer;
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->SetWindowName("CellTypeSource");
renderWindow->AddRenderer(renderer);
vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
renderWindowInteractor->SetRenderWindow(renderWindow);
// Add the actors to the scene
renderer->AddViewProp(textActor);
renderer->AddActor(actor);
renderer->SetBackground(colors->GetColor3d("Silver").GetData());
renderer->ResetCamera();
renderer->GetActiveCamera()->Azimuth(30);
renderer->GetActiveCamera()->Elevation(30);
renderer->ResetCameraClippingRange();
// Render and interact
renderWindow->SetSize(640, 480);
renderWindow->Render();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(CellTypeSource)
find_package(VTK COMPONENTS
vtkCommonColor
vtkCommonCore
vtkCommonDataModel
vtkFiltersGeneral
vtkFiltersSources
vtkInteractionStyle
vtkRenderingContextOpenGL2
vtkRenderingCore
vtkRenderingFreeType
vtkRenderingGL2PSOpenGL2
vtkRenderingOpenGL2
QUIET
)
if (NOT VTK_FOUND)
message("Skipping CellTypeSource: ${VTK_NOT_FOUND_MESSAGE}")
return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
# old system
include(${VTK_USE_FILE})
add_executable(CellTypeSource MACOSX_BUNDLE CellTypeSource.cxx )
target_link_libraries(CellTypeSource PRIVATE ${VTK_LIBRARIES})
else ()
# include all components
add_executable(CellTypeSource MACOSX_BUNDLE CellTypeSource.cxx )
target_link_libraries(CellTypeSource PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS CellTypeSource
MODULES ${VTK_LIBRARIES}
)
endif ()
Download and Build CellTypeSource¶
Click here to download CellTypeSource and its CMakeLists.txt file. Once the tarball CellTypeSource.tar has been downloaded and extracted,
cd CellTypeSource/build
If VTK is installed:
cmake ..
If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:
cmake -DVTK_DIR:PATH=/home/me/vtk_build ..
Build the project:
make
and run it:
./CellTypeSource
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.