KDTreeAccessPoints
VTKExamples/Cxx/DataStructures/KDTreeAccessPoints
Description
This example demonstrates how to build a KDTree, get its number of points, and get a point by ID.
Code
KDTreeAccessPoints.cxx
#include <vtkVersion.h>
#include <vtkSmartPointer.h>
#include <vtkPoints.h>
#include <vtkCellArray.h>
#include <vtkPolyData.h>
#include <vtkXMLPolyDataReader.h>
#include <vtkIdList.h>
#include <vtkKdTree.h>
#include <vtkDataSetCollection.h>
#include <vtkVertexGlyphFilter.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();
points->InsertNextPoint (x);
points->InsertNextPoint (y);
points->InsertNextPoint (z);
vtkSmartPointer<vtkPolyData> polydata =
vtkSmartPointer<vtkPolyData>::New();
polydata->SetPoints(points);
//the tree needs cells, so add vertices to each point
vtkSmartPointer<vtkVertexGlyphFilter> vertexFilter =
vtkSmartPointer<vtkVertexGlyphFilter>::New();
#if VTK_MAJOR_VERSION <= 5
vertexFilter->SetInputConnection(polydata->GetProducerPort());
#else
vertexFilter->SetInputData(polydata);
#endif
vertexFilter->Update();
//Create the tree
vtkSmartPointer<vtkKdTree> kDTree =
vtkSmartPointer<vtkKdTree>::New();
kDTree->AddDataSet(vertexFilter->GetOutput());
kDTree->BuildLocator();
//get the number of points in the tree like this
kDTree->GetDataSets()->InitTraversal();
std::cout << "Number of points in tree: " << kDTree->GetDataSets()->GetNextDataSet()->GetNumberOfPoints() << std::endl;
//or you can get the number of points in the tree like this
std::cout << "Number of points in tree: " << kDTree->GetDataSet(0)->GetNumberOfPoints() << std::endl;
//get the 0th point in the tree
double p[3];
kDTree->GetDataSet(0)->GetPoint(0,p);
std::cout << "p: " << p[0] << " " << p[1] << " " << p[2] << std::endl;
return EXIT_SUCCESS;
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(KDTreeAccessPoints)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(KDTreeAccessPoints MACOSX_BUNDLE KDTreeAccessPoints.cxx)
target_link_libraries(KDTreeAccessPoints ${VTK_LIBRARIES})
Download and Build KDTreeAccessPoints
Click here to download KDTreeAccessPoints and its CMakeLists.txt file. Once the tarball KDTreeAccessPoints.tar has been downloaded and extracted,
cd KDTreeAccessPoints/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:
./KDTreeAccessPoints
WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.