ImplicitSphere

#include <vtkActor.h>
#include <vtkContourFilter.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSampleFunction.h>
#include <vtkSphere.h>

#include <algorithm>
#include <array>

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

  // Set the background color.
  std::array<unsigned char, 4> bkg{{51, 77, 102, 255}};
  colors->SetColor("BkgColor", bkg.data());

  vtkNew<vtkSphere> sphere;

  // Sample the function.
  vtkNew<vtkSampleFunction> sample;
  sample->SetSampleDimensions(50, 50, 50);
  sample->SetImplicitFunction(sphere);
  double value = 2.0;
  double xmin = -value, xmax = value, ymin = -value, ymax = value,
         zmin = -value, zmax = value;
  sample->SetModelBounds(xmin, xmax, ymin, ymax, zmin, zmax);

  // Create the 0 isosurface.
  vtkNew<vtkContourFilter> contours;
  contours->SetInputConnection(sample->GetOutputPort());
  contours->GenerateValues(1, 1, 1);

  // Map the contours to graphical primitives.
  vtkNew<vtkPolyDataMapper> contourMapper;
  contourMapper->SetInputConnection(contours->GetOutputPort());
  contourMapper->ScalarVisibilityOff();

  // Create an actor for the contours.
  vtkNew<vtkActor> contourActor;
  contourActor->SetMapper(contourMapper);

  // Visualize
  vtkNew<vtkRenderer> renderer;
  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  renderWindow->SetWindowName("ImplicitSphere");

  vtkNew<vtkRenderWindowInteractor> interactor;
  interactor->SetRenderWindow(renderWindow);

  renderer->AddActor(contourActor);
  renderer->SetBackground(colors->GetColor3d("BkgColor").GetData());

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

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(ImplicitSphere)

find_package(VTK COMPONENTS 
  CommonColor
  CommonCore
  CommonDataModel
  FiltersCore
  ImagingHybrid
  InteractionStyle
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "ImplicitSphere: 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(ImplicitSphere MACOSX_BUNDLE ImplicitSphere.cxx )
  target_link_libraries(ImplicitSphere PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS ImplicitSphere
  MODULES ${VTK_LIBRARIES}
)

cd ImplicitSphere/build

cmake ..

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

make

./ImplicitSphere