# 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.

Other Languages

See (Python), (CSharp)

### Code

ParametricObjectsDemo.cxx

    #include <vtkActor.h>
    #include <vtkActor2D.h>
    #include <vtkCamera.h>
    #include <vtkMinimalStandardRandomSequence.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.
      std::array<unsigned char , 4> bkg{{26, 51, 102, 255}};
        colors->SetColor("BkgColor", bkg.data());

      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();
      vtkSmartPointer<vtkMinimalStandardRandomSequence> rng =
        vtkSmartPointer<vtkMinimalStandardRandomSequence>::New();
      rng->SetSeed(8775070); // For testing.
      for (auto i = 0; i < 10; ++i)
      {
        rng->Next();
        auto x = rng->GetRangeValue(0.0, 1.0);
        rng->Next();
        auto y = rng->GetRangeValue(0.0, 1.0);
        rng->Next();
        auto z = rng->GetRangeValue(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(12);
      textProperty->SetJustificationToCentered();

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

      // Create a parametric function source, renderer, mapper, and actor
      // for each object
      for (auto 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("Banana").GetData());
        actors[i]->GetProperty()->SetSpecular(.5);
        actors[i]->GetProperty()->SetSpecularPower(20);
        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());
        renderers[i]->AddActor(actors[i]);
        renderers[i]->AddActor(textactors[i]);
        renderers[i]->SetBackground(colors->GetColor3d("BkgColor").GetData());
      }

      // Setup the viewports
      auto xGridDimensions = 4;
      auto yGridDimensions = 4;
      auto rendererSize = 200;
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->SetWindowName("Parametric Objects Demonstration");
      renderWindow->SetSize(rendererSize * xGridDimensions,
                            rendererSize * yGridDimensions);

      for(auto row = 0; row < yGridDimensions; row++)
      {
        for(auto col = 0; col < xGridDimensions; col++)
        {
          int index = row * xGridDimensions + col;

          // (xmin, ymin, xmax, ymax)
          double viewport[4] = {
            static_cast<double>(col) / xGridDimensions,
            static_cast<double>(yGridDimensions - (row + 1))/ yGridDimensions,
            static_cast<double>(col + 1) / xGridDimensions,
            static_cast<double>(yGridDimensions - row) / yGridDimensions
          };

          if(index > int(actors.size()) - 1)
          {
            // Add a renderer even if there is no actor.
            // This makes the render window background all the same color.
            vtkSmartPointer<vtkRenderer> ren = vtkSmartPointer<vtkRenderer>::New();
            ren->SetBackground(colors->GetColor3d("BkgColor").GetData());
            ren->SetViewport(viewport);
            renderWindow->AddRenderer(ren);
            continue;
          }

          renderers[index]->SetViewport(viewport);
          renderers[index]->ResetCamera();
          renderers[index]->GetActiveCamera()->Azimuth(30);
          renderers[index]->GetActiveCamera()->Elevation(-30);
          renderers[index]->ResetCameraClippingRange();
          renderWindow->AddRenderer(renderers[index]);
        }
      }

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

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(ParametricObjectsDemo)

    find_package(VTK COMPONENTS
      vtkCommonColor
      vtkCommonComputationalGeometry
      vtkCommonCore
      vtkFiltersSources
      vtkInteractionStyle
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping ParametricObjectsDemo: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(ParametricObjectsDemo MACOSX_BUNDLE ParametricObjectsDemo.cxx )
      target_link_libraries(ParametricObjectsDemo PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(ParametricObjectsDemo MACOSX_BUNDLE ParametricObjectsDemo.cxx )
      target_link_libraries(ParametricObjectsDemo PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS ParametricObjectsDemo
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### 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.