# SaveSceneToFieldData

VTKExamples/Cxx/Utilities/SaveSceneToFieldData

### Description

This example saves a vtkCamera's parameters in the vtkFieldData of a vkDataSet.

To see how the scene is saved and restored,

1. Interact with the scene. Press the e key to exit the first iteractor. The current state of the scene's vtkCamera will be saved in the vtkDataSet's vtkFieldData.

2. Interact with the scene again. Press the e key to exit the second interactor. The scene will be restored to the previous state.

3. Press the e key to exit the example.

Info

This example uses snippets.

### Code

SaveSceneToFieldData.cxx

    #include <vtkSmartPointer.h>

    #include <vtkActor.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkCamera.h>

    #include <vtkNamedColors.h>
    #include <vtkTimerLog.h>
    #include <vtksys/SystemTools.hxx>

    #include <vtkBYUReader.h>
    #include <vtkOBJReader.h>
    #include <vtkPLYReader.h>
    #include <vtkPolyDataReader.h>
    #include <vtkSTLReader.h>
    #include <vtkXMLPolyDataReader.h>
    #include <vtkSphereSource.h>

    namespace
    {
    vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName);
    }
    #include <vtkFieldData.h>
    #include <vtksys/RegularExpression.hxx>
    namespace
    {
    void SaveSceneToFieldData(vtkDataSet *data,
                              vtkActor *actor,
                              vtkCamera *camera);
    void RestoreSceneFromFieldData(vtkDataSet *data,
                                   vtkActor *actor,
                                   vtkCamera *camera);
    }
    int main (int argc, char *argv[])
    {
      vtkSmartPointer<vtkPolyData> polyData = ReadPolyData(argc > 1 ? argv[1] : "");;

      // Visualize
      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputData(polyData);

      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->SetDiffuseColor(colors->GetColor3d("Crimson").GetData());
      actor->GetProperty()->SetSpecular(.6);
      actor->GetProperty()->SetSpecularPower(30);
    ;
      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->AddActor(actor);
      renderer->SetBackground(colors->GetColor3d("Silver").GetData());

      // Interact to change camera
      renderWindow->Render();
      renderWindowInteractor->Start();

      // After the interaction is done, save the scene
      SaveSceneToFieldData(polyData, actor, renderer->GetActiveCamera());
      renderWindow->Render();
      renderWindowInteractor->Start();

      // After interaction , restore the scene
      RestoreSceneFromFieldData(polyData, actor, renderer->GetActiveCamera());
      renderWindow->Render();
      renderWindowInteractor->Start();

    return EXIT_SUCCESS;
    }

    #include <sstream>
    namespace
    {
    void SaveSceneToFieldData(vtkDataSet *data,
                              vtkActor * /* actor */,
                              vtkCamera *camera)
    {
      std::ostringstream buffer;
      double vector[3];
      double scalar;

      camera->GetFocalPoint(vector);
      buffer << "Camera:FocalPoint "
             << vector[0] << ", "
             << vector[1] << ", "
             << vector[2] << std::endl;
      camera->GetPosition(vector);
      buffer << "Camera:Position "
               << vector[0] << ", "
               << vector[1] << ", "
               << vector[2] << std::endl;
      camera->GetViewUp(vector);
      buffer << "Camera:ViewUp "
               << vector[0] << ", "
               << vector[1] << ", "
               << vector[2] << std::endl;
      scalar = camera->GetViewAngle();
      buffer << "Camera:ViewAngle "
               << scalar << std::endl;
      camera->GetClippingRange(vector);
      buffer << "Camera:ClippingRange "
               << vector[0] << ", "
               << vector[1] << std::endl;
      vtkSmartPointer<vtkStringArray> cameraArray =
        vtkSmartPointer<vtkStringArray>::New();
      cameraArray->SetNumberOfValues(1);
      cameraArray->SetValue(0, buffer.str());
      cameraArray->SetName("Camera");
      data->GetFieldData()->AddArray(cameraArray);
    }
    }
    namespace
    {
    void  RestoreSceneFromFieldData(vtkDataSet *data,
                                   vtkActor * /* actor */,
                                   vtkCamera *camera)
    {

      std::istringstream buffer;

      // Get the saved camera information from the field data
      if (vtkStringArray::SafeDownCast(
            data->GetFieldData()->GetAbstractArray("Camera")))
      {
        buffer.str(vtkStringArray::SafeDownCast(
                     data->GetFieldData()->GetAbstractArray("Camera"))->GetValue(0));
      }
      else
      {
        return;
      }

      std::string line;

      vtksys::RegularExpression reCP("^Camera:Position");
      vtksys::RegularExpression reCFP("^Camera:FocalPoint");
      vtksys::RegularExpression reCVU("^Camera:ViewUp");
      vtksys::RegularExpression reCVA("^Camera:ViewAngle");
      vtksys::RegularExpression reCCR("^Camera:ClippingRange");
      vtksys::RegularExpression floatNumber(
          "[^0-9\\.\\-]*([0-9e\\.\\-]*[^,])[^0-9\\.\\-]*([0-9e\\.\\-]*[^,])[^0-9\\.\\-]*([0-9e\\.\\-]*[^,])");
      vtksys::RegularExpression floatScalar("[^0-9\\.\\-]*([0-9\\.\\-e]*[^,])");

      while (std::getline(buffer,line))
      {
        if (reCFP.find(line))
        {
          std::string rest(line, reCFP.end());
          if (floatNumber.find(rest))
          {
            camera->SetFocalPoint(
              atof(floatNumber.match(1).c_str()),
              atof(floatNumber.match(2).c_str()),
              atof(floatNumber.match(3).c_str()));
          }
        }
        else if (reCP.find(line))
        {
          std::string rest(line, reCP.end());
          if (floatNumber.find(rest))
          {
            camera->SetPosition(
              atof(floatNumber.match(1).c_str()),
              atof(floatNumber.match(2).c_str()),
              atof(floatNumber.match(3).c_str()));
          }
        }
        else if (reCVU.find(line))
        {
          std::string rest(line, reCVU.end());
          if (floatNumber.find(rest))
          {
            camera->SetViewUp(
              atof(floatNumber.match(1).c_str()),
              atof(floatNumber.match(2).c_str()),
              atof(floatNumber.match(3).c_str()));
          }
        }
        else if (reCVA.find(line))
        {
          std::string rest(line, reCVA.end());
          if (floatScalar.find(rest))
          {
            camera->SetViewAngle(
              atof(floatScalar.match(1).c_str()));
          }
        }
        else if (reCCR.find(line))
        {
          std::string rest(line, reCCR.end());
          if (floatNumber.find(rest))
          {
            camera->SetClippingRange(
              atof(floatNumber.match(1).c_str()),
              atof(floatNumber.match(2).c_str()));
          }
        }
        else
        {
          std::cout << "Unrecognized line: " << line << std::endl;
        }
      }
    }
    }
    namespace
    {
    vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName)
    {
      vtkSmartPointer<vtkPolyData> polyData;
      std::string extension = vtksys::SystemTools::GetFilenameExtension(std::string(fileName));
      if (extension == ".ply")
      {
        vtkSmartPointer<vtkPLYReader> reader =
          vtkSmartPointer<vtkPLYReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".vtp")
      {
        vtkSmartPointer<vtkXMLPolyDataReader> reader =
          vtkSmartPointer<vtkXMLPolyDataReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".obj")
      {
        vtkSmartPointer<vtkOBJReader> reader =
          vtkSmartPointer<vtkOBJReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".stl")
      {
        vtkSmartPointer<vtkSTLReader> reader =
          vtkSmartPointer<vtkSTLReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".vtk")
      {
        vtkSmartPointer<vtkPolyDataReader> reader =
          vtkSmartPointer<vtkPolyDataReader>::New();
        reader->SetFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else if (extension == ".g")
      {
        vtkSmartPointer<vtkBYUReader> reader =
          vtkSmartPointer<vtkBYUReader>::New();
        reader->SetGeometryFileName (fileName);
        reader->Update();
        polyData = reader->GetOutput();
      }
      else
      {
        vtkSmartPointer<vtkSphereSource> source =
          vtkSmartPointer<vtkSphereSource>::New();
        source->Update();
        polyData = source->GetOutput();
      }
      return polyData;
    }
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(SaveSceneToFieldData)

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

    add_executable(SaveSceneToFieldData MACOSX_BUNDLE SaveSceneToFieldData.cxx )

    target_link_libraries(SaveSceneToFieldData ${VTK_LIBRARIES})

### Download and Build SaveSceneToFieldData

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

    cd SaveSceneToFieldData/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:

    ./SaveSceneToFieldData

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.