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IncrementalOctreePointLocator

vtk-examples/Cxx/DataStructures/IncrementalOctreePointLocator

Question

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Code

IncrementalOctreePointLocator.cxx

#include <vtkIdList.h>
#include <vtkIncrementalOctreePointLocator.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkPolyData.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};

  vtkNew<vtkPoints> points;
  points->InsertNextPoint(x);
  points->InsertNextPoint(y);
  points->InsertNextPoint(z);

  vtkNew<vtkPolyData> polydata;
  polydata->SetPoints(points);

  // Create the tree
  vtkNew<vtkIncrementalOctreePointLocator> octree;
  octree->SetDataSet(polydata);
  octree->BuildLocator();

  double testPoint[3] = {2.0, 0.0, 0.0};

  {
    // Find the closest points to TestPoint
    //  double closestPointDist;
    vtkIdType iD = octree->FindClosestPoint(testPoint);
    std::cout << "The closest point is point " << iD << std::endl;

    // Get the coordinates of the closest point
    double closestPoint[3];
    octree->GetDataSet()->GetPoint(iD, closestPoint);
    std::cout << "Coordinates: " << closestPoint[0] << " " << closestPoint[1]
              << " " << closestPoint[2] << std::endl;
  }

  // Insert a point
  double pnew[3] = {2.1, 0, 0};
  octree->InsertNextPoint(pnew);

  {
    // Find the closest points to TestPoint
    //  double closestPointDist;
    vtkIdType iD = octree->FindClosestPoint(testPoint);
    std::cout << "The closest point is point " << iD << std::endl;

    // Get the coordinates of the closest point
    double closestPoint[3];
    octree->GetDataSet()->GetPoint(iD, closestPoint);
    std::cout << "Coordinates: " << closestPoint[0] << " " << closestPoint[1]
              << " " << closestPoint[2] << std::endl;
  }

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(IncrementalOctreePointLocator)

find_package(VTK COMPONENTS 
  vtkCommonCore
  vtkCommonDataModel
  QUIET
)

if (NOT VTK_FOUND)
  message("Skipping IncrementalOctreePointLocator: ${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(IncrementalOctreePointLocator MACOSX_BUNDLE IncrementalOctreePointLocator.cxx )
  target_link_libraries(IncrementalOctreePointLocator PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(IncrementalOctreePointLocator MACOSX_BUNDLE IncrementalOctreePointLocator.cxx )
  target_link_libraries(IncrementalOctreePointLocator PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS IncrementalOctreePointLocator
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build IncrementalOctreePointLocator

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

cd IncrementalOctreePointLocator/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:

./IncrementalOctreePointLocator

WINDOWS USERS

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