PlatonicSolids

Description¶

Display all five Platonic solids in a grid.

Platonic solids are regular, convex polyhedrons. They are constructed by congruent (identical in shape and size) regular (all angles equal and all sides equal) polygonal faces with the same number of faces meeting at each vertex.

Five solids satisfy the above criteria:

Figure	Tetrahedron	Cube	Octahedron	Icosahedron	Dodecahedron
Vertices	4	8	6 (2 × 3)	12 (4 × 3)	20 (8 + 4 × 3)
Edges	6	12	12	30	30
Faces	4	6	8	20	12

The relationship between vertices, edges and faces is given by Euler's formula:

V - E + F = 2

Other languages

See (Python), (PythonicAPI)

Question

If you have a question about this example, please use the VTK Discourse Forum

Code¶

PlatonicSolids.cxx

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkLookupTable.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPlatonicSolidSource.h>
#include <vtkPolyDataMapper.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkTextActor.h>
#include <vtkTextMapper.h>
#include <vtkTextProperty.h>

#include <functional>
#include <string>
#include <tuple>
#include <vector>

namespace {

/** Get the platonic solid names and initial orientations.
 *
 * @return The solids and their initial orientations.
 */
std::vector<std::tuple<std::string, double, double, double>>
GetNameOrientation();

/** Get a specialised lookup table for the platonic solids.
 *
 * Since each face of a vtkPlatonicSolidSource has a different
 * cell scalar, we create a lookup table with a different colour
 * for each face.
 * The colors have been carefully chosen so that adjacent cells
 * are colored distinctly.
 *
 * @return The lookup table.
 */
vtkNew<vtkLookupTable> GetPlatonicLUT();

} // namespace

int main(int, char*[])
{
  vtkNew<vtkNamedColors> colors;

  std::vector<vtkSmartPointer<vtkPolyDataMapper>> mappers;
  std::vector<vtkSmartPointer<vtkActor>> actors;
  std::vector<vtkSmartPointer<vtkTextMapper>> textMappers;
  std::vector<vtkSmartPointer<vtkActor2D>> textActors;
  std::vector<vtkSmartPointer<vtkRenderer>> renderers;

  // Create a common text property.
  vtkNew<vtkTextProperty> textProperty;
  textProperty->SetFontSize(16);
  textProperty->SetJustificationToCentered();

  // Create the render window and interactor.
  vtkNew<vtkRenderWindow> renWin;
  renWin->SetWindowName("PlatonicSolids");
  vtkNew<vtkRenderWindowInteractor> iRen;
  iRen->SetRenderWindow(renWin);

  // Platonic solids and orientation for display.
  auto nameOrientation = GetNameOrientation();
  auto lut = GetPlatonicLUT();
  std::vector<vtkSmartPointer<vtkPlatonicSolidSource>> PlatonicSolids;

  for (auto i = 0; i < nameOrientation.size(); ++i)
  {
    PlatonicSolids.push_back(vtkSmartPointer<vtkPlatonicSolidSource>::New());
    PlatonicSolids[i]->SetSolidType(i);

    mappers.push_back(vtkSmartPointer<vtkPolyDataMapper>::New());
    mappers[i]->SetInputConnection(PlatonicSolids[i]->GetOutputPort());
    mappers[i]->SetLookupTable(lut);
    mappers[i]->SetScalarRange(0, 19);

    actors.push_back(vtkSmartPointer<vtkActor>::New());
    actors[i]->SetMapper(mappers[i]);

    textMappers.push_back(vtkSmartPointer<vtkTextMapper>::New());
    textMappers[i]->SetInput(std::get<0>(nameOrientation[i]).c_str());
    textMappers[i]->SetTextProperty(textProperty);

    textActors.push_back(vtkSmartPointer<vtkActor2D>::New());
    textActors[i]->SetMapper(textMappers[i]);
    textActors[i]->SetPosition(120, 16);

    renderers.push_back(vtkSmartPointer<vtkRenderer>::New());
    renderers[i]->AddActor(actors[i]);
    renderers[i]->AddViewProp(textActors[i]);

    renWin->AddRenderer(renderers[i]);
  }

  // Set up the viewports
  auto gridDimensionsX = 3;
  auto gridDimensionsY = 2;
  auto rendererSize = 300;
  renWin->SetSize(rendererSize * gridDimensionsX,
                  rendererSize * gridDimensionsY);
  for (auto row = 0; row < gridDimensionsY; ++row)
  {
    for (auto col = 0; col < gridDimensionsX; ++col)
    {
      auto index = row * gridDimensionsX + col;

      // (xmin, ymin, xmax, ymax)
      double viewport[4] = {
          static_cast<double>(col) / gridDimensionsX,
          static_cast<double>(gridDimensionsY - (row + 1)) / gridDimensionsY,
          static_cast<double>(col + 1) / gridDimensionsX,
          static_cast<double>(gridDimensionsY - row) / gridDimensionsY};
      if (index > (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("SlateGray").GetData());
        ren->SetViewport(viewport);
        renWin->AddRenderer(ren);
        continue;
      }

      renderers[index]->SetViewport(viewport);
      renderers[index]->SetBackground(
          colors->GetColor3d("SlateGray").GetData());
      renderers[index]->ResetCamera();
      renderers[index]->GetActiveCamera()->Azimuth(
          std::get<1>(nameOrientation[index]));
      renderers[index]->GetActiveCamera()->Elevation(
          std::get<2>(nameOrientation[index]));
      renderers[index]->GetActiveCamera()->Zoom(
          std::get<3>(nameOrientation[index]));
    }
  }

  iRen->Initialize();
  renWin->Render();
  iRen->Start();

  return EXIT_SUCCESS;
}

namespace {

std::vector<std::tuple<std::string, double, double, double>>
GetNameOrientation()
{
  auto getTuple = [](std::string const& name, double const& azimuth,
                     double const& elevation, double const& zoom) {
    return std::make_tuple(name, azimuth, elevation, zoom);
  };

  std::vector<std::tuple<std::string, double, double, double>> res;
  res.push_back(getTuple("Tetrahedron", 45.0, 30.0, 1.0));
  res.push_back(getTuple("Cube", -60.0, 45.0, 0.8));
  res.push_back(getTuple("Octahedron", -15.0, 10.0, 1.0));
  res.push_back(getTuple("Icosahedron", 4.5, 18.0, 1.0));
  res.push_back(getTuple("Dodecahedron", 171.0, 22.0, 1.0));

  return res;
}

vtkNew<vtkLookupTable> GetPlatonicLUT()
{
  vtkNew<vtkLookupTable> lut;
  lut->SetNumberOfTableValues(20);
  lut->SetTableRange(0.0, 19.0);
  lut->Build();
  lut->SetTableValue(0, 0.1, 0.1, 0.1);
  lut->SetTableValue(1, 0, 0, 1);
  lut->SetTableValue(2, 0, 1, 0);
  lut->SetTableValue(3, 0, 1, 1);
  lut->SetTableValue(4, 1, 0, 0);
  lut->SetTableValue(5, 1, 0, 1);
  lut->SetTableValue(6, 1, 1, 0);
  lut->SetTableValue(7, 0.9, 0.7, 0.9);
  lut->SetTableValue(8, 0.5, 0.5, 0.5);
  lut->SetTableValue(9, 0.0, 0.0, 0.7);
  lut->SetTableValue(10, 0.5, 0.7, 0.5);
  lut->SetTableValue(11, 0, 0.7, 0.7);
  lut->SetTableValue(12, 0.7, 0, 0);
  lut->SetTableValue(13, 0.7, 0, 0.7);
  lut->SetTableValue(14, 0.7, 0.7, 0);
  lut->SetTableValue(15, 0, 0, 0.4);
  lut->SetTableValue(16, 0, 0.4, 0);
  lut->SetTableValue(17, 0, 0.4, 0.4);
  lut->SetTableValue(18, 0.4, 0, 0);
  lut->SetTableValue(19, 0.4, 0, 0.4);
  return lut;
}

} // namespace

CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(PlatonicSolids)

find_package(VTK COMPONENTS 
  CommonColor
  CommonCore
  FiltersSources
  InteractionStyle
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "PlatonicSolids: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(PlatonicSolids MACOSX_BUNDLE PlatonicSolids.cxx )
  target_link_libraries(PlatonicSolids PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS PlatonicSolids
  MODULES ${VTK_LIBRARIES}
)

Download and Build PlatonicSolids¶

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

cd PlatonicSolids/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:

./PlatonicSolids

WINDOWS USERS

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