SampleFunction

#include <vtkSmartPointer.h>
#include <vtkSampleFunction.h>
#include <vtkContourFilter.h>

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

#include <vtkSuperquadric.h>
#include <vtkNamedColors.h>

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

  vtkSmartPointer<vtkSuperquadric> implicitFunction = 
    vtkSmartPointer<vtkSuperquadric>::New();
  implicitFunction->SetPhiRoundness(2.5);
  implicitFunction->SetThetaRoundness(.5);

  // Sample the function
  vtkSmartPointer<vtkSampleFunction> sample = 
    vtkSmartPointer<vtkSampleFunction>::New();
  sample->SetSampleDimensions(50,50,50);
  sample->SetImplicitFunction(implicitFunction);
  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
  vtkSmartPointer<vtkContourFilter> contours = 
    vtkSmartPointer<vtkContourFilter>::New();
  contours->SetInputConnection(sample->GetOutputPort());
  contours->GenerateValues(1, 2.0, 2.0);

  // Map the contours to graphical primitives
  vtkSmartPointer<vtkPolyDataMapper> contourMapper = 
    vtkSmartPointer<vtkPolyDataMapper>::New();
  contourMapper->SetInputConnection(contours->GetOutputPort());
  contourMapper->SetScalarRange(0.0, 1.2);

  // Create an actor for the contours
  vtkSmartPointer<vtkActor> contourActor = 
    vtkSmartPointer<vtkActor>::New();
  contourActor->SetMapper(contourMapper);

  // -- create a box around the function to indicate the sampling volume --

  // Create outline
  vtkSmartPointer<vtkOutlineFilter> outline = 
    vtkSmartPointer<vtkOutlineFilter>::New();
  outline->SetInputConnection(sample->GetOutputPort());

  // Map it to graphics primitives
  vtkSmartPointer<vtkPolyDataMapper> outlineMapper = 
    vtkSmartPointer<vtkPolyDataMapper>::New();
  outlineMapper->SetInputConnection(outline->GetOutputPort());

  // Create an actor for it
  vtkSmartPointer<vtkActor> outlineActor = 
    vtkSmartPointer<vtkActor>::New();
  outlineActor->SetMapper(outlineMapper);
  outlineActor->GetProperty()->SetColor(0,0,0);

  // Visualize
  vtkSmartPointer<vtkRenderer> renderer = 
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow = 
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  vtkSmartPointer<vtkRenderWindowInteractor> interactor = 
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  interactor->SetRenderWindow(renderWindow);

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

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

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(SampleFunction)

find_package(VTK COMPONENTS 
  vtkCommonColor
  vtkCommonCore
  vtkCommonDataModel
  vtkFiltersCore
  vtkFiltersModeling
  vtkImagingHybrid
  vtkInteractionStyle
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping SampleFunction: ${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(SampleFunction MACOSX_BUNDLE SampleFunction.cxx )
  target_link_libraries(SampleFunction PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(SampleFunction MACOSX_BUNDLE SampleFunction.cxx )
  target_link_libraries(SampleFunction PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS SampleFunction
    MODULES ${VTK_LIBRARIES}
    )
endif () 

cd SampleFunction/build 

cmake ..

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

make

./SampleFunction