OctreeFindPointsWithinRadius

#include <vtkSmartPointer.h>
#include <vtkPoints.h>
#include <vtkPointSource.h>
#include <vtkPolyData.h>
#include <vtkCellArray.h>
#include <vtkIdList.h>
#include <vtkOctreePointLocator.h>

int main(int, char *[])
{
  // Create some random points
  vtkSmartPointer<vtkPointSource> pointSource =
    vtkSmartPointer<vtkPointSource>::New();
  pointSource->SetNumberOfPoints(10);
  pointSource->Update();

  // Create the tree
  vtkSmartPointer<vtkOctreePointLocator> octree =
    vtkSmartPointer<vtkOctreePointLocator>::New();
  octree->SetDataSet(pointSource->GetOutput());
  octree->BuildLocator();

  // Find the k closest points to (0,0,0)
  vtkIdType k = 1;
  double testPoint[3] = {0.0, 0.0, 0.0};
  vtkSmartPointer<vtkIdList> result =
    vtkSmartPointer<vtkIdList>::New();

  octree->FindPointsWithinRadius(1.0, testPoint, result);

  for(vtkIdType i = 0; i < k; i++)
  {
    vtkIdType point_ind = result->GetId(i);
    double p[3];
    pointSource->GetOutput()->GetPoint(point_ind, p);
    std::cout << "Closest point " << i << ": Point "
              << point_ind << ": (" << p[0] << ", "
              << p[1] << ", " << p[2] << ")" << std::endl;
  }

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(OctreeFindPointsWithinRadius)

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

cd OctreeFindPointsWithinRadius/build 

cmake ..

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

make

./OctreeFindPointsWithinRadius