# PolyDataFilter

VTKExamples/Cxx/Developers/PolyDataFilter

### Description

This example demonstrates a filter named vtkTestPolyDataFilter that takes a vtkPolyData as input and produces a vtkPolyData as output.

### Code

PolyDataFilter.cxx

    #include <vtkSmartPointer.h>

    #include <vtkTestPolyDataFilter.h>

    int main(int, char *[])
    {
      vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();
      points->InsertNextPoint(0.0, 0.0, 0.0);

      vtkSmartPointer<vtkPolyData> inputPolydata =
        vtkSmartPointer<vtkPolyData>::New();
      inputPolydata->SetPoints(points);

      std::cout << "Input points: " << inputPolydata->GetNumberOfPoints()
                << std::endl;

      vtkSmartPointer<vtkTestPolyDataFilter> filter =
        vtkSmartPointer<vtkTestPolyDataFilter>::New();
    #if VTK_MAJOR_VERSION <= 5
      filter->SetInput(inputPolydata);
    #else
      filter->SetInputData(inputPolydata);
    #endif
      filter->Update();

      vtkPolyData* outputPolydata = filter->GetOutput();

      std::cout << "Output points: " << outputPolydata->GetNumberOfPoints()
                << std::endl;

      return EXIT_SUCCESS;
    }

vtkTestPolyDataFilter.h

    #ifndef __vtkTestPolyDataFilter_h
    #define __vtkTestPolyDataFilter_h

    #include <vtkPolyDataAlgorithm.h>

    class vtkTestPolyDataFilter : public vtkPolyDataAlgorithm
    {
    public:
      vtkTypeMacro(vtkTestPolyDataFilter,vtkPolyDataAlgorithm);
      void PrintSelf(ostream& os, vtkIndent indent);

      static vtkTestPolyDataFilter *New();

    protected:
      vtkTestPolyDataFilter();
      ~vtkTestPolyDataFilter();

      int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *);

    private:
      vtkTestPolyDataFilter(const vtkTestPolyDataFilter&);  // Not implemented.
      void operator=(const vtkTestPolyDataFilter&);  // Not implemented.

    };

    #endif

vtkTestPolyDataFilter.cxx

    #include <vtkTestPolyDataFilter.h>

    #include <vtkObjectFactory.h>
    #include <vtkStreamingDemandDrivenPipeline.h>
    #include <vtkInformationVector.h>
    #include <vtkInformation.h>
    #include <vtkDataObject.h>
    #include <vtkSmartPointer.h>

    vtkStandardNewMacro(vtkTestPolyDataFilter);

    vtkTestPolyDataFilter::vtkTestPolyDataFilter()
    {
      this->SetNumberOfInputPorts(1);
      this->SetNumberOfOutputPorts(1);
    }

    vtkTestPolyDataFilter::~vtkTestPolyDataFilter()
    {
    }

    int vtkTestPolyDataFilter::RequestData(vtkInformation *vtkNotUsed(request),
                                                 vtkInformationVector **inputVector,
                                                 vtkInformationVector *outputVector)
    {

      // get the input and output
      vtkPolyData* input = vtkPolyData::GetData(inputVector[0],0);
      vtkPolyData* output = vtkPolyData::GetData(outputVector,0);

      input->GetPoints()->InsertNextPoint(1.0, 1.0, 1.0);

      output->ShallowCopy(input);

      return 1;
    }

    //----------------------------------------------------------------------------
    void vtkTestPolyDataFilter::PrintSelf(ostream& os, vtkIndent indent)
    {
      this->Superclass::PrintSelf(os,indent);
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(PolyDataFilter)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(PolyDataFilter MACOSX_BUNDLE PolyDataFilter.cxx  vtkTestPolyDataFilter.cxx)

    target_link_libraries(PolyDataFilter ${VTK_LIBRARIES})

### Download and Build PolyDataFilter

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

    cd PolyDataFilter/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:

    ./PolyDataFilter

WINDOWS USERS

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