NullPoint

VTKExamples/Cxx/PolyData/NullPoint

Other Languages

See (CSharp)

Code

NullPoint.cxx

#include <vtkPoints.h>
#include <vtkPointData.h>
#include <vtkPolyData.h>
#include <vtkSmartPointer.h>
#include <vtkFloatArray.h>

int main(int, char *[])
{
  vtkSmartPointer<vtkPoints> points =
    vtkSmartPointer<vtkPoints>::New();
  points->InsertNextPoint(1,1,1);
  points->InsertNextPoint(2,2,2);
  points->InsertNextPoint(3,3,3);

  vtkSmartPointer<vtkPolyData> polydata =
    vtkSmartPointer<vtkPolyData>::New();
  polydata->SetPoints(points);

  vtkSmartPointer<vtkFloatArray> floatArray =
    vtkSmartPointer<vtkFloatArray>::New();
  floatArray->SetNumberOfValues(3);
  floatArray->SetNumberOfComponents(1);
  floatArray->SetName("FloatArray");
  for(vtkIdType i = 0; i < 3; i++)
  {
    floatArray->SetValue(i,2);
  }
  polydata->GetPointData()->AddArray(floatArray);

  vtkSmartPointer<vtkIntArray> intArray =
    vtkSmartPointer<vtkIntArray>::New();
  intArray->SetNumberOfValues(3);
  intArray->SetNumberOfComponents(1);
  intArray->SetName("IntArray");
  for(vtkIdType i = 0; i < 3; i++)
  {
    intArray->SetValue(i,2);
  }

  polydata->GetPointData()->AddArray(intArray);

  for(vtkIdType i = 0; i < 3; i++)
  {
    double p[3];
    polydata->GetPoint(i,p);
    vtkFloatArray* pointsFloatArray = vtkFloatArray::SafeDownCast(polydata->GetPointData()->GetArray("FloatArray"));
    vtkIntArray* pointsIntArray = vtkIntArray::SafeDownCast(polydata->GetPointData()->GetArray("IntArray"));
    std::cout << "Point " << i << " : " << p[0] << " " << p[1] << " " << p[2] << " "
              << pointsFloatArray->GetValue(i) << " " << pointsIntArray->GetValue(i) << std::endl;
  }

  polydata->GetPointData()->NullPoint(1);
  polydata->Modified();

  for(vtkIdType i = 0; i < 3; i++)
  {
    double p[3];
    polydata->GetPoint(i,p);
    vtkFloatArray* pointsFloatArray = vtkFloatArray::SafeDownCast(polydata->GetPointData()->GetArray("FloatArray"));
    vtkIntArray* pointsIntArray = vtkIntArray::SafeDownCast(polydata->GetPointData()->GetArray("IntArray"));
    std::cout << "Point " << i << " : " << p[0] << " " << p[1] << " " << p[2] << " "
              << pointsFloatArray->GetValue(i) << " " << pointsIntArray->GetValue(i) << std::endl;

  }

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(NullPoint)

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

Download and Build NullPoint

Click here to download NullPoint and its CMakeLists.txt file. Once the tarball NullPoint.tar has been downloaded and extracted,

cd NullPoint/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:

./NullPoint

WINDOWS USERS

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