SelectionSource

VTKExamples/Cxx/Filtering/SelectionSource

Code

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;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(SelectionSource)

find_package(VTK COMPONENTS 
  vtkCommonCore
  vtkCommonDataModel
  vtkFiltersExtraction
  vtkFiltersSources QUIET)
if (NOT VTK_FOUND)
  message("Skipping SelectionSource: ${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(SelectionSource MACOSX_BUNDLE SelectionSource.cxx )
  target_link_libraries(SelectionSource PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(SelectionSource MACOSX_BUNDLE SelectionSource.cxx )
  target_link_libraries(SelectionSource PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS SelectionSource
    MODULES ${VTK_LIBRARIES}
    )
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

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.