VTK/Examples/Cxx/PolyData/MiscPointData

#include <vtkCellData.h>
#include <vtkDoubleArray.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPointData.h>
#include <vtkSmartPointer.h>
#include <vtkXMLPolyDataReader.h>
#include <vtkPolyDataNormals.h>
#include <vtkFloatArray.h>
#include <vtkMath.h>
#include <string>
 
int main(int argc, char *argv[])
{
  // Parse command line arguments
  if(argc != 2)
    {
    std::cout << "Required arguments: Filename" << std::endl;
    return EXIT_FAILURE;
    }
 
  // Get filename from command line
  std::string filename = argv[1]; //first command line argument
 
  // Read the file
  vtkSmartPointer<vtkXMLPolyDataReader> reader = 
    vtkSmartPointer<vtkXMLPolyDataReader>::New();
  std::cout << "Reading " << filename << std::endl;
  reader->SetFileName(filename.c_str());
  reader->Update();
 
  // Extract the polydata
  vtkSmartPointer<vtkPolyData> polydata = reader->GetOutput();
 
  // Get the number of points in the polydata
  vtkIdType idNumPointsInFile = polydata->GetNumberOfPoints();
 
  // Add distances to each point
  vtkSmartPointer<vtkFloatArray> distances =
    vtkSmartPointer<vtkFloatArray>::New();
  distances->SetNumberOfComponents(1);
  distances->SetName("Distances");
 
  for (vtkIdType i = 0; i < idNumPointsInFile; i++)
    {	
    distances->InsertNextValue(vtkMath::Random(0.0,1.0));
    }
 
  polydata->GetPointData()->AddArray(distances);
 
  return EXIT_SUCCESS;
}