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SampleFunction

vtk-examples/Cxx/ImplicitFunctions/SampleFunction


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Question

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Code

SampleFunction.cxx

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

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

  vtkNew<vtkSuperquadric> implicitFunction;
  implicitFunction->SetPhiRoundness(2.5);
  implicitFunction->SetThetaRoundness(0.5);

  // Sample the function
  vtkNew<vtkSampleFunction> sample;
  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
  vtkNew<vtkContourFilter> contours;
  contours->SetInputConnection(sample->GetOutputPort());
  contours->GenerateValues(1, 2.0, 2.0);

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

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

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

  // Create outline
  vtkNew<vtkOutlineFilter> outline;
  outline->SetInputConnection(sample->GetOutputPort());

  // Map it to graphics primitives
  vtkNew<vtkPolyDataMapper> outlineMapper;
  outlineMapper->SetInputConnection(outline->GetOutputPort());

  // Create an actor for it
  vtkNew<vtkActor> outlineActor;
  outlineActor->SetMapper(outlineMapper);
  outlineActor->GetProperty()->SetColor(colors->GetColor3d("Black").GetData());

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

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

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

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

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(SampleFunction)

find_package(VTK COMPONENTS 
  vtkCommonColor
  vtkCommonCore
  vtkCommonDataModel
  vtkFiltersCore
  vtkFiltersModeling
  vtkImagingHybrid
  vtkInteractionStyle
  vtkRenderingContextOpenGL2
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingGL2PSOpenGL2
  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 ()

Download and Build SampleFunction

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

cd SampleFunction/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:

./SampleFunction

WINDOWS USERS

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