# ParametricObjectsDemo

VTKExamples/Cxx/GeometricObjects/ParametricObjectsDemo

### Description

See Parametric Equations for Surfaces by Andrew Maclean for an excellent description of these beautiful parametric surfaces.

This example also demonstrates how to manipulate lists of VTK objects using vectors. Notice how parameters of the various Parametric Objects are accessed and set in the parametricObjects vector.

### Code

ParametricObjectsDemo.cxx

    #include <vtkActor.h>
    #include <vtkActor2D.h>
    #include <vtkCamera.h>
    #include <vtkMath.h>
    #include <vtkNamedColors.h>
    #include <vtkParametricFunctionSource.h>
    #include <vtkPoints.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkSmartPointer.h>
    #include <vtkTextMapper.h>
    #include <vtkTextProperty.h>

    #include <vtkParametricBoy.h>
    #include <vtkParametricConicSpiral.h>
    #include <vtkParametricCrossCap.h>
    #include <vtkParametricDini.h>
    #include <vtkParametricEllipsoid.h>
    #include <vtkParametricEnneper.h>
    #include <vtkParametricFigure8Klein.h>
    #include <vtkParametricKlein.h>
    #include <vtkParametricMobius.h>
    #include <vtkParametricRandomHills.h>
    #include <vtkParametricRoman.h>
    #include <vtkParametricSpline.h>
    #include <vtkParametricSuperEllipsoid.h>
    #include <vtkParametricSuperToroid.h>
    #include <vtkParametricTorus.h>

    #include <array>
    #include <vector>

    int main(int, char* [])
    {
      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

      // Set the background color.
      auto SetColor = [&colors](std::array<double, 3>& v,
                                std::string const& colorName) {
        auto const scaleFactor = 256.0;
        std::transform(std::begin(v), std::end(v), std::begin(v),
                       [=](double const& n) { return n / scaleFactor; });
        colors->SetColor(colorName, v.data());
        return;
      };
      std::array<double, 3> bkg{{25, 51, 102}};
      SetColor(bkg, "BkgColor");

      std::vector<vtkSmartPointer<vtkParametricFunction>> parametricObjects;
      parametricObjects.push_back(vtkSmartPointer<vtkParametricBoy>::New());
      parametricObjects.push_back(vtkSmartPointer<vtkParametricConicSpiral>::New());
      parametricObjects.push_back(vtkSmartPointer<vtkParametricCrossCap>::New());
      parametricObjects.push_back(vtkSmartPointer<vtkParametricDini>::New());

      parametricObjects.push_back(vtkSmartPointer<vtkParametricEllipsoid>::New());
      static_cast<vtkParametricEllipsoid*>(parametricObjects.back().GetPointer())
        ->SetXRadius(.5);
      static_cast<vtkParametricEllipsoid*>(parametricObjects.back().GetPointer())
        ->SetYRadius(2.0);

      parametricObjects.push_back(vtkSmartPointer<vtkParametricEnneper>::New());
      parametricObjects.push_back(
        vtkSmartPointer<vtkParametricFigure8Klein>::New());
      parametricObjects.push_back(vtkSmartPointer<vtkParametricKlein>::New());
      parametricObjects.push_back(vtkSmartPointer<vtkParametricMobius>::New());
      static_cast<vtkParametricMobius*>(parametricObjects.back().GetPointer())
        ->SetRadius(2.0);
      static_cast<vtkParametricMobius*>(parametricObjects.back().GetPointer())
        ->SetMinimumV(-0.5);
      static_cast<vtkParametricMobius*>(parametricObjects.back().GetPointer())
        ->SetMaximumV(0.5);

      vtkSmartPointer<vtkParametricRandomHills> randomHills =
        vtkSmartPointer<vtkParametricRandomHills>::New();
      randomHills->AllowRandomGenerationOff();
      parametricObjects.push_back(randomHills);

      parametricObjects.push_back(vtkSmartPointer<vtkParametricRoman>::New());

      parametricObjects.push_back(
        vtkSmartPointer<vtkParametricSuperEllipsoid>::New());
      static_cast<vtkParametricSuperEllipsoid*>(
        parametricObjects.back().GetPointer())
        ->SetN1(.50);
      static_cast<vtkParametricSuperEllipsoid*>(
        parametricObjects.back().GetPointer())
        ->SetN2(.1);

      parametricObjects.push_back(vtkSmartPointer<vtkParametricSuperToroid>::New());
      static_cast<vtkParametricSuperToroid*>(parametricObjects.back().GetPointer())
        ->SetN1(.2);
      static_cast<vtkParametricSuperToroid*>(parametricObjects.back().GetPointer())
        ->SetN2(3.0);

      parametricObjects.push_back(vtkSmartPointer<vtkParametricTorus>::New());

      // The spline needs points
      vtkSmartPointer<vtkParametricSpline> spline =
        vtkSmartPointer<vtkParametricSpline>::New();
      vtkSmartPointer<vtkPoints> inputPoints = vtkSmartPointer<vtkPoints>::New();
      vtkMath::RandomSeed(8775070);
      for (int p = 0; p < 10; p++)
      {
        double x = vtkMath::Random(0.0, 1.0);
        double y = vtkMath::Random(0.0, 1.0);
        double z = vtkMath::Random(0.0, 1.0);
        inputPoints->InsertNextPoint(x, y, z);
      }
      spline->SetPoints(inputPoints);
      parametricObjects.push_back(spline);

      std::vector<vtkSmartPointer<vtkParametricFunctionSource>>
        parametricFunctionSources;
      std::vector<vtkSmartPointer<vtkRenderer>> renderers;
      std::vector<vtkSmartPointer<vtkPolyDataMapper>> mappers;
      std::vector<vtkSmartPointer<vtkActor>> actors;
      std::vector<vtkSmartPointer<vtkTextMapper>> textmappers;
      std::vector<vtkSmartPointer<vtkActor2D>> textactors;

      // Create one text property for all
      vtkSmartPointer<vtkTextProperty> textProperty =
        vtkSmartPointer<vtkTextProperty>::New();
      textProperty->SetFontSize(10);
      textProperty->SetJustificationToCentered();

      vtkSmartPointer<vtkProperty> backProperty =
        vtkSmartPointer<vtkProperty>::New();
      backProperty->SetColor(colors->GetColor3d("Red").GetData());

      // Create a parametric function source, renderer, mapper, and actor
      // for each object
      for (unsigned int i = 0; i < parametricObjects.size(); i++)
      {
        parametricFunctionSources.push_back(
          vtkSmartPointer<vtkParametricFunctionSource>::New());
        parametricFunctionSources[i]->SetParametricFunction(parametricObjects[i]);
        parametricFunctionSources[i]->SetUResolution(51);
        parametricFunctionSources[i]->SetVResolution(51);
        parametricFunctionSources[i]->SetWResolution(51);
        parametricFunctionSources[i]->Update();

        mappers.push_back(vtkSmartPointer<vtkPolyDataMapper>::New());
        mappers[i]->SetInputConnection(
          parametricFunctionSources[i]->GetOutputPort());

        actors.push_back(vtkSmartPointer<vtkActor>::New());
        actors[i]->SetMapper(mappers[i]);
        actors[i]->GetProperty()->SetColor(colors->GetColor3d("White").GetData());
        actors[i]->SetBackfaceProperty(backProperty);

        textmappers.push_back(vtkSmartPointer<vtkTextMapper>::New());
        textmappers[i]->SetInput(parametricObjects[i]->GetClassName());
        textmappers[i]->SetTextProperty(textProperty);

        textactors.push_back(vtkSmartPointer<vtkActor2D>::New());
        textactors[i]->SetMapper(textmappers[i]);
        textactors[i]->SetPosition(100, 16);
        renderers.push_back(vtkSmartPointer<vtkRenderer>::New());
      }

      auto gridDimensions = 4;

      // Need a renderer even if there is no actor
      for (auto i = static_cast<int>(parametricObjects.size());
           i < gridDimensions * gridDimensions; i++)
      {
        renderers.push_back(vtkSmartPointer<vtkRenderer>::New());
      }

      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      int rendererSize = 200;
      renderWindow->SetSize(rendererSize * gridDimensions,
                            rendererSize * gridDimensions);

      for (auto row = 0; row < gridDimensions; row++)
      {
        for (auto col = 0; col < gridDimensions; col++)
        {
          auto index = row * gridDimensions + col;
          auto x0 = double(col) / gridDimensions;
          auto y0 = double(gridDimensions - row - 1) / gridDimensions;
          auto x1 = double(col + 1) / gridDimensions;
          auto y1 = double(gridDimensions - row) / gridDimensions;
          renderWindow->AddRenderer(renderers[index]);
          renderers[index]->SetViewport(x0, y0, x1, y1);

          if (index > static_cast<int>(parametricObjects.size() - 1))
          {
            continue;
          }

          renderers[index]->AddActor(actors[index]);
          renderers[index]->AddActor(textactors[index]);
          renderers[index]->SetBackground(colors->GetColor3d("BkgColor").GetData());
          renderers[index]->ResetCamera();
          renderers[index]->GetActiveCamera()->Azimuth(30);
          renderers[index]->GetActiveCamera()->Elevation(-30);
          renderers[index]->GetActiveCamera()->Zoom(0.9);
          renderers[index]->ResetCameraClippingRange();
        }
      }

      vtkSmartPointer<vtkRenderWindowInteractor> interactor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      interactor->SetRenderWindow(renderWindow);

      renderWindow->Render();
      interactor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ParametricObjectsDemo)

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

    add_executable(ParametricObjectsDemo MACOSX_BUNDLE ParametricObjectsDemo.cxx )

    target_link_libraries(ParametricObjectsDemo ${VTK_LIBRARIES})

### Download and Build ParametricObjectsDemo

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

    cd ParametricObjectsDemo/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:

    ./ParametricObjectsDemo

WINDOWS USERS

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