CellPointNeighbors
VTKExamples/Cxx/PolyData/CellPointNeighbors
Description¶
Determine which cells share at least a single point with a specified cell.
Code¶
CellPointNeighbors.cxx
#include <vtkSmartPointer.h> #include <vtkSphereSource.h> #include <vtkPolyData.h> #include <vtkIdList.h> #include <vtkCell.h> #include <vtkTriangleFilter.h> #include <vtkDataSetMapper.h> #include <vtkActor.h> #include <vtkRenderWindow.h> #include <vtkRenderer.h> #include <vtkRenderWindowInteractor.h> #include <vtkIdTypeArray.h> #include <vtkSelectionNode.h> #include <vtkSelection.h> #include <vtkExtractSelection.h> #include <vtkProperty.h> #include <vtkNamedColors.h> #include <list> int main(int, char *[]) { //Create a sphere vtkSmartPointer<vtkSphereSource> sphereSource = vtkSmartPointer<vtkSphereSource>::New(); sphereSource->Update(); vtkSmartPointer<vtkTriangleFilter> triangleFilter = vtkSmartPointer<vtkTriangleFilter>::New(); triangleFilter->SetInputConnection(sphereSource->GetOutputPort()); triangleFilter->Update(); // Find all cells connected to point 0 vtkIdType cellId = 0; vtkSmartPointer<vtkIdList> cellPointIds = vtkSmartPointer<vtkIdList>::New(); triangleFilter->GetOutput()->GetCellPoints(cellId, cellPointIds); // neighbor cells may be listed multiple times // use std::set instead of std::list if you want a unique list of neighbors std::list<vtkIdType> neighbors; /*For each vertice of the cell, we calculate which cells uses that point. So if we make this, for each vertice, we have all the neighbors. In the case we use ''cellPointIds'' as a parameter of ''GeteCellNeighbors'', we will obtain an empty set. Because the only cell that is using that set of points is the current one. That is why we have to make each vertice at time.*/ for(vtkIdType i = 0; i < cellPointIds->GetNumberOfIds(); i++) { vtkSmartPointer<vtkIdList> idList = vtkSmartPointer<vtkIdList>::New(); idList->InsertNextId(cellPointIds->GetId(i)); //get the neighbors of the cell vtkSmartPointer<vtkIdList> neighborCellIds = vtkSmartPointer<vtkIdList>::New(); triangleFilter->GetOutput()->GetCellNeighbors(cellId, idList, neighborCellIds); for(vtkIdType j = 0; j < neighborCellIds->GetNumberOfIds(); j++) { neighbors.push_back(neighborCellIds->GetId(j)); } } std::cout << "Point neighbor ids are: " << std::endl; for(std::list<vtkIdType>::iterator it1 = neighbors.begin(); it1 != neighbors.end(); it1++) { std::cout << " " << *it1; } std::cout << std::endl; vtkSmartPointer<vtkNamedColors> colors = vtkSmartPointer<vtkNamedColors>::New(); vtkSmartPointer<vtkDataSetMapper> sphereMapper = vtkSmartPointer<vtkDataSetMapper>::New(); sphereMapper->SetInputConnection(sphereSource->GetOutputPort()); sphereMapper->SetResolveCoincidentTopologyToPolygonOffset(); vtkSmartPointer<vtkActor> sphereActor = vtkSmartPointer<vtkActor>::New(); sphereActor->SetMapper(sphereMapper); sphereActor->GetProperty()->SetEdgeColor(colors->GetColor3d("Lamp_Black").GetData()); sphereActor->GetProperty()->EdgeVisibilityOn(); sphereActor->GetProperty()->SetLineWidth(3); vtkSmartPointer<vtkDataSetMapper> mainCellMapper = vtkSmartPointer<vtkDataSetMapper>::New(); vtkSmartPointer<vtkDataSetMapper> neighborCellsMapper = vtkSmartPointer<vtkDataSetMapper>::New(); // Create a dataset with the cell of interest { vtkSmartPointer<vtkIdTypeArray> ids = vtkSmartPointer<vtkIdTypeArray>::New(); ids->SetNumberOfComponents(1); ids->InsertNextValue(cellId); vtkSmartPointer<vtkSelectionNode> selectionNode = vtkSmartPointer<vtkSelectionNode>::New(); selectionNode->SetFieldType(vtkSelectionNode::CELL); selectionNode->SetContentType(vtkSelectionNode::INDICES); selectionNode->SetSelectionList(ids); vtkSmartPointer<vtkSelection> selection = vtkSmartPointer<vtkSelection>::New(); selection->AddNode(selectionNode); vtkSmartPointer<vtkExtractSelection> extractSelection = vtkSmartPointer<vtkExtractSelection>::New(); extractSelection->SetInputConnection(0, sphereSource->GetOutputPort()); extractSelection->SetInputData(1, selection); extractSelection->Update(); mainCellMapper->SetInputConnection(extractSelection->GetOutputPort()); } vtkSmartPointer<vtkActor> mainCellActor = vtkSmartPointer<vtkActor>::New(); mainCellActor->SetMapper(mainCellMapper); mainCellActor->GetProperty()->SetColor(colors->GetColor3d("Tomato").GetData()); // Create a dataset with the neighbor cells { vtkSmartPointer<vtkIdTypeArray> ids = vtkSmartPointer<vtkIdTypeArray>::New(); ids->SetNumberOfComponents(1); for(std::list<vtkIdType>::iterator it1 = neighbors.begin(); it1 != neighbors.end(); it1++) { ids->InsertNextValue(*it1); } vtkSmartPointer<vtkSelectionNode> selectionNode = vtkSmartPointer<vtkSelectionNode>::New(); selectionNode->SetFieldType(vtkSelectionNode::CELL); selectionNode->SetContentType(vtkSelectionNode::INDICES); selectionNode->SetSelectionList(ids); vtkSmartPointer<vtkSelection> selection = vtkSmartPointer<vtkSelection>::New(); selection->AddNode(selectionNode); vtkSmartPointer<vtkExtractSelection> extractSelection = vtkSmartPointer<vtkExtractSelection>::New(); extractSelection->SetInputConnection(0, sphereSource->GetOutputPort()); extractSelection->SetInputData(1, selection); extractSelection->Update(); neighborCellsMapper->SetInputConnection(extractSelection->GetOutputPort()); } vtkSmartPointer<vtkActor> neighborCellsActor = vtkSmartPointer<vtkActor>::New(); neighborCellsActor->SetMapper(neighborCellsMapper); neighborCellsActor->GetProperty()->SetColor(colors->GetColor3d("Mint").GetData()); //Create a renderer, render window, and interactor vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New(); vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New(); renderWindow->AddRenderer(renderer); vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New(); renderWindowInteractor->SetRenderWindow(renderWindow); //Add the actors to the scene renderer->AddActor(sphereActor); renderer->AddActor(mainCellActor); renderer->AddActor(neighborCellsActor); renderer->SetBackground(colors->GetColor3d("Slate_grey").GetData()); //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(CellPointNeighbors) find_package(VTK COMPONENTS vtkCommonColor vtkCommonCore vtkCommonDataModel vtkFiltersCore vtkFiltersExtraction vtkFiltersSources vtkInteractionStyle vtkRenderingCore vtkRenderingFreeType vtkRenderingOpenGL2 QUIET) if (NOT VTK_FOUND) message("Skipping CellPointNeighbors: ${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(CellPointNeighbors MACOSX_BUNDLE CellPointNeighbors.cxx ) target_link_libraries(CellPointNeighbors PRIVATE ${VTK_LIBRARIES}) else () # include all components add_executable(CellPointNeighbors MACOSX_BUNDLE CellPointNeighbors.cxx ) target_link_libraries(CellPointNeighbors PRIVATE ${VTK_LIBRARIES}) # vtk_module_autoinit is needed vtk_module_autoinit( TARGETS CellPointNeighbors MODULES ${VTK_LIBRARIES} ) endif ()
Download and Build CellPointNeighbors¶
Click here to download CellPointNeighbors and its CMakeLists.txt file. Once the tarball CellPointNeighbors.tar has been downloaded and extracted,
cd CellPointNeighbors/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:
./CellPointNeighbors
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.