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¶
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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.