# VisualDebugging

VTKExamples/Cxx/Demos/VisualDebugging

### Code

VisualDebugging.cxx

    #include <vtkSphereSource.h>
    #include <vtkObjectFactory.h>
    #include <vtkCommand.h>
    #include <vtkPolyData.h>
    #include <vtkSmartPointer.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkInteractorStyleTrackballCamera.h>

    #include <vtkTestFilter.h>

    class CustomStyle : public vtkInteractorStyleTrackballCamera
    {
      public:
        static CustomStyle* New();
        vtkTypeMacro(CustomStyle, vtkInteractorStyleTrackballCamera);

        CustomStyle()
        {
          this->Actor = vtkSmartPointer<vtkActor>::New();
          this->Mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
          this->Filter = vtkSmartPointer<vtkTestFilter>::New();
        }

        void CallbackFunction(vtkObject* caller,
                        long unsigned int eventId,
                        void* callData )
        {
          std::cout << "CustomStyle::CallbackFunction called." << std::endl;
          vtkPolyData* intermediate = this->Filter->GetIntermediateOutput();
          intermediate->Modified();
          this->Mapper->SetInput(intermediate);
          this->Renderer->ResetCamera();
          this->Renderer->Render();
          this->Interactor->GetRenderWindow()->Render();
        }

        void OnKeyPress()
        {
          // Get the keypress
          std::string key = this->Interactor->GetKeySym();

          if(key == "s") // 'S'tart
          {
            this->Renderer->AddActor(this->Actor);
            this->Filter->AddObserver(this->Filter->RefreshEvent, this, &CustomStyle::CallbackFunction);
            this->Filter->Update();

            this->Actor->SetMapper(this->Mapper);
          }

          // Forward events
          vtkInteractorStyleTrackballCamera::OnKeyPress();
        }

      vtkRenderer* Renderer;
      vtkSmartPointer<vtkActor> Actor;
      vtkSmartPointer<vtkPolyDataMapper> Mapper;
      vtkSmartPointer<vtkTestFilter> Filter;

    };
    vtkStandardNewMacro(CustomStyle);

    int main(int argc, char *argv[])
    {
      // Create a renderer, render window, and interactor
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow(renderWindow);

      renderer->SetBackground(1,1,1); // White

      vtkSmartPointer<CustomStyle> style =
        vtkSmartPointer<CustomStyle>::New();
      style->Renderer = renderer;

      renderWindowInteractor->SetInteractorStyle(style);
      renderWindow->Render();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

vtkTestFilter.cxx

    #include <vtkTestFilter.h>

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

    vtkStandardNewMacro(vtkTestFilter);

    vtkTestFilter::vtkTestFilter()
    {
      this->SetNumberOfInputPorts(0);
      this->Output = vtkSmartPointer<vtkPolyData>::New();

      this->RefreshEvent = vtkCommand::UserEvent + 1;

    }

    int vtkTestFilter::RequestData(vtkInformation *vtkNotUsed(request),
                                                 vtkInformationVector **inputVector,
                                                 vtkInformationVector *outputVector)
    {
      // Get the info object
      vtkInformation *outInfo = outputVector->GetInformationObject(0);

      vtkPolyData *output = vtkPolyData::SafeDownCast(
          outInfo->Get(vtkDataObject::DATA_OBJECT()));

      this->Output->DeepCopy(output);

      for(unsigned int i = 0; i < 10; i++)
      {
        Iterate(i);
        this->InvokeEvent(this->RefreshEvent, NULL);
      }

      output->ShallowCopy(this->Output);

      return 1;
    }

    void vtkTestFilter::Iterate(unsigned int iteration)
    {
      vtkSmartPointer<vtkSphereSource> sphereSource =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource->SetCenter(iteration, 0, 0);
      sphereSource->SetRadius(0.2);
      sphereSource->Update();

      vtkSmartPointer<vtkAppendPolyData> appendFilter =
        vtkSmartPointer<vtkAppendPolyData>::New();
      appendFilter->AddInputConnection(this->Output->GetProducerPort());
      appendFilter->AddInputConnection(sphereSource->GetOutputPort());
      appendFilter->Update();

      this->Output->DeepCopy(appendFilter->GetOutput());
    }

vtkTestFilter.h

    #ifndef __vtkTestFilter_h
    #define __vtkTestFilter_h

    #include <vtkPolyDataAlgorithm.h>
    #include <vtkSmartPointer.h>

    class vtkTestFilter : public vtkPolyDataAlgorithm
    {
    public:
      vtkTypeMacro(vtkTestFilter,vtkPolyDataAlgorithm);
      static vtkTestFilter *New();

      vtkPolyData* GetIntermediateOutput() {return this->Output;}

      int RefreshEvent;

    protected:
      vtkTestFilter();

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

      void Iterate(unsigned int iteration);

      vtkSmartPointer<vtkPolyData> Output;
    private:
      vtkTestFilter(const vtkTestFilter&);  // Not implemented.
      void operator=(const vtkTestFilter&);  // Not implemented.

    };

    #endif

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(VisualDebugging)

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

    add_executable(VisualDebugging MACOSX_BUNDLE VisualDebugging.cxx  vtkTestFilter.cxx)

    target_link_libraries(VisualDebugging ${VTK_LIBRARIES})

### Download and Build VisualDebugging

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

    cd VisualDebugging/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:

    ./VisualDebugging

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.