CellEdgeNeighbors
VTKExamples/Cxx/PolyData/CellEdgeNeighbors
Description
Determine which cells share an edge with a specified cell.
Code
CellEdgeNeighbors.cxx
#include <vtkVersion.h>
#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 <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();
vtkIdType cellId = 0;
vtkSmartPointer<vtkIdList> cellPointIds =
vtkSmartPointer<vtkIdList>::New();
triangleFilter->GetOutput()->GetCellPoints(cellId, cellPointIds);
std::list<vtkIdType> neighbors;
for(vtkIdType i = 0; i < cellPointIds->GetNumberOfIds(); i++)
{
vtkSmartPointer<vtkIdList> idList =
vtkSmartPointer<vtkIdList>::New();
//add one of the edge points
idList->InsertNextId(cellPointIds->GetId(i));
//add the other edge point
if(i+1 == cellPointIds->GetNumberOfIds())
{
idList->InsertNextId(cellPointIds->GetId(0));
}
else
{
idList->InsertNextId(cellPointIds->GetId(i+1));
}
//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 << "Edge 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<vtkDataSetMapper> sphereMapper =
vtkSmartPointer<vtkDataSetMapper>::New();
sphereMapper->SetInputConnection(sphereSource->GetOutputPort());
vtkSmartPointer<vtkActor> sphereActor =
vtkSmartPointer<vtkActor>::New();
sphereActor->SetMapper(sphereMapper);
sphereActor->GetProperty()->SetEdgeColor(0, 0, 0);
sphereActor->GetProperty()->EdgeVisibilityOn();
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());
#if VTK_MAJOR_VERSION <= 5
extractSelection->SetInput(1, selection);
#else
extractSelection->SetInputData(1, selection);
#endif
extractSelection->Update();
mainCellMapper->SetInputConnection(extractSelection->GetOutputPort());
}
vtkSmartPointer<vtkActor> mainCellActor =
vtkSmartPointer<vtkActor>::New();
mainCellActor->SetMapper(mainCellMapper);
mainCellActor->GetProperty()->SetColor(1,0,0);
// 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());
#if VTK_MAJOR_VERSION <= 5
extractSelection->SetInput(1, selection);
#else
extractSelection->SetInputData(1, selection);
#endif
extractSelection->Update();
neighborCellsMapper->SetInputConnection(extractSelection->GetOutputPort());
}
vtkSmartPointer<vtkActor> neighborCellsActor =
vtkSmartPointer<vtkActor>::New();
neighborCellsActor->SetMapper(neighborCellsMapper);
neighborCellsActor->GetProperty()->SetColor(0,1,0);
// 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(.3, .2, .1); // Background color dark red
// Render and interact
renderWindow->Render();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(CellEdgeNeighbors)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(CellEdgeNeighbors MACOSX_BUNDLE CellEdgeNeighbors.cxx)
target_link_libraries(CellEdgeNeighbors ${VTK_LIBRARIES})
Download and Build CellEdgeNeighbors
Click here to download CellEdgeNeighbors and its CMakeLists.txt file. Once the tarball CellEdgeNeighbors.tar has been downloaded and extracted,
cd CellEdgeNeighbors/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:
./CellEdgeNeighbors
WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.