ThresholdPoints
VTKExamples/Cxx/PolyData/ThresholdPoints
Code
ThresholdPoints.cxx
#include <vtkVersion.h>
#include <vtkIntArray.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPointData.h>
#include <vtkSmartPointer.h>
#include <vtkThresholdPoints.h>
int main(int, char *[])
{
vtkSmartPointer<vtkPoints> points =
vtkSmartPointer<vtkPoints>::New();
points->InsertNextPoint(0,0,0);
points->InsertNextPoint(1,1,1);
points->InsertNextPoint(2,2,2);
points->InsertNextPoint(3,3,3);
points->InsertNextPoint(4,4,4);
std::cout << "There are " << points->GetNumberOfPoints()
<< " points before thresholding." << std::endl;
//setup position index
vtkSmartPointer<vtkIntArray> index =
vtkSmartPointer<vtkIntArray>::New();
index->SetNumberOfComponents(1);
index->SetName("index");
index->InsertNextValue(0);
index->InsertNextValue(1);
index->InsertNextValue(2);
index->InsertNextValue(3);
index->InsertNextValue(4);
vtkSmartPointer<vtkPolyData> polydata =
vtkSmartPointer<vtkPolyData>::New();
polydata->SetPoints(points);
polydata->GetPointData()->AddArray(index);
vtkSmartPointer<vtkThresholdPoints> threshold =
vtkSmartPointer<vtkThresholdPoints>::New();
#if VTK_MAJOR_VERSION <= 5
threshold->SetInput(polydata);
#else
threshold->SetInputData(polydata);
#endif
threshold->ThresholdByLower(2);
threshold->SetInputArrayToProcess(0, 0, 0, vtkDataObject::FIELD_ASSOCIATION_POINTS, "index");
threshold->Update();
//vtkPolyData* thresholdedPolydata = threshold->GetOutput();
vtkPolyData* thresholdedPolydata = threshold->GetOutput();
std::cout << "There are " << thresholdedPolydata->GetNumberOfPoints()
<< " points after thresholding." << std::endl;
for(vtkIdType i = 0; i < thresholdedPolydata->GetNumberOfPoints(); i++)
{
double p[3];
thresholdedPolydata->GetPoint(i,p);
std::cout << "Point " << i << " : " << p[0] << " " << p[1] << " " << p[2] << std::endl;
}
return EXIT_SUCCESS;
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(ThresholdPoints)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(ThresholdPoints MACOSX_BUNDLE ThresholdPoints.cxx)
target_link_libraries(ThresholdPoints ${VTK_LIBRARIES})
Download and Build ThresholdPoints
Click here to download ThresholdPoints and its CMakeLists.txt file. Once the tarball ThresholdPoints.tar has been downloaded and extracted,
cd ThresholdPoints/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:
./ThresholdPoints
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.