VTK/Examples/Cxx/DataStructures/BuildOctree

#include <vtkSmartPointer.h>
#include <vtkPoints.h>
#include <vtkCellArray.h>
#include <vtkPolyData.h>
#include <vtkXMLPolyDataReader.h>
#include <vtkIdList.h>
#include <vtkOctreePointLocator.h>
#include <vtkDataSetCollection.h>
 
int main(int, char *[])
{
  // Setup point coordinates
  double x[3] = {1.0, 0.0, 0.0};
  double y[3] = {0.0, 1.0, 0.0};
  double z[3] = {0.0, 0.0, 1.0};
 
  vtkSmartPointer<vtkPoints> points = 
    vtkSmartPointer<vtkPoints>::New();
  vtkSmartPointer<vtkCellArray> vertices = 
    vtkSmartPointer<vtkCellArray>::New();
 
  for(unsigned int i = 0; i < 3; ++i)
    {
    points->InsertNextPoint ( x[i], y[i], z[i] );
    }
 
  std::cout << "There are " << points->GetNumberOfPoints() << " points." << std::endl;
 
  vtkSmartPointer<vtkPolyData> polydata = 
    vtkSmartPointer<vtkPolyData>::New();
  polydata->SetPoints(points);
 
  //Create the tree
  vtkSmartPointer<vtkOctreePointLocator> octree =
      vtkSmartPointer<vtkOctreePointLocator>::New();
  octree->SetDataSet(polydata);
  octree->BuildLocator();
 
  std::cout << "Number of points in tree: " << octree->GetDataSet()->GetNumberOfPoints() << std::endl;
 
  double p[3];
  octree->GetDataSet()->GetPoint(0,p);
  std::cout << "p: " << p[0] << " " << p[1] << " " << p[2] << std::endl;
 
  return EXIT_SUCCESS;
}