VTK/Examples/Cxx/Filtering/SelectionSource

SelectionSource.cxx

#include <vtkPointSource.h>
#include <vtkExtractSelection.h>
#include <vtkPolyData.h>
#include <vtkSelectionNode.h> // for POINT and INDICES enum values
#include <vtkSelectionSource.h>
#include <vtkSmartPointer.h>

int main(int, char *[])
{
  // Note - this generates 50 points and a single poly-vertex cell.
  vtkSmartPointer<vtkPointSource> pointSource = 
      vtkSmartPointer<vtkPointSource>::New();
  pointSource->SetNumberOfPoints(50);
  pointSource->Update();

  std::cout << "There are " << pointSource->GetOutput()->GetNumberOfPoints() << " input points." << std::endl;
  
  vtkSmartPointer<vtkSelectionSource> selectionSource = 
      vtkSmartPointer<vtkSelectionSource>::New();
  selectionSource->SetFieldType(vtkSelectionNode::POINT);
  selectionSource->SetContentType(vtkSelectionNode::INDICES);

  // Without this line, all points are passed through because the 11 points
  // we will select below are some of the points of the poly-vertex created
  // by the PointSource, so the cell (by default) gets passed through since
  // it contains some selected points, so therefore all of the points
  // (the 50 belonging to the poly-vertex) also get passed through, which
  // is not what we are trying to demonstrate.
  selectionSource->SetContainingCells(false);

  for (vtkIdType i = 10; i <= 20; i++)
    {
    selectionSource->AddID(0, i);
    }

  selectionSource->Update();

  vtkSmartPointer<vtkExtractSelection> extractSelection = 
      vtkSmartPointer<vtkExtractSelection>::New();
  extractSelection->SetInputConnection(0, pointSource->GetOutputPort());
  extractSelection->SetInputConnection(1, selectionSource->GetOutputPort());
  extractSelection->Update();

  vtkDataSet* ds = vtkDataSet::SafeDownCast (extractSelection->GetOutput());
  
  std::cout << "There are " << ds->GetNumberOfPoints() << " output points." << std::endl;

  return EXIT_SUCCESS;
}

Please try the new VTKExamples website.

CMakeLists.txt

cmake_minimum_required(VERSION 2.8)

PROJECT(SelectionSource)

find_package(VTK REQUIRED)
include(${VTK_USE_FILE})

add_executable(SelectionSource MACOSX_BUNDLE SelectionSource.cxx)

if(VTK_LIBRARIES)
  target_link_libraries(SelectionSource ${VTK_LIBRARIES})
else()
  target_link_libraries(SelectionSource vtkHybrid vtkWidgets)
endif()

Download and Build SelectionSource

Click here to download SelectionSource. and its CMakeLists.txt file.

Once the tarball SelectionSource.tar has been downloaded and extracted,

cd SelectionSource/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:

./SelectionSource

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.