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ImplicitSphere1

vtk-examples/Cxx/ImplicitFunctions/ImplicitSphere1


Description

Shows how to create a surface representing a sphere by creating an implicit sphere, sampling the implicit function, and finally contouring the sampled data to produce the surface.

Other languages

See (Python)

Question

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

Code

ImplicitSphere1.cxx

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

#include <cstdlib>

int main(int argc, char* argv[])
{
  // Define colors.
  auto colors = vtkSmartPointer<vtkNamedColors>::New();
  vtkColor3d actorColor = colors->GetColor3d("AliceBlue");
  vtkColor3d EdgeColour = colors->GetColor3d("SteelBlue");
  vtkColor3d BackgroundColour = colors->GetColor3d("Silver");

  // Create a sphere.
  auto sphere = vtkSmartPointer<vtkSphere>::New();
  sphere->SetCenter(0.0, 0.0, 0.0);
  sphere->SetRadius(0.5);

  /* The sample function generates a distance function from the implicit
         function.This is then contoured to get a polygonal surface.*/
  auto sample = vtkSmartPointer<vtkSampleFunction>::New();
  sample->SetImplicitFunction(sphere);
  sample->SetModelBounds(-.5, .5, -.5, .5, -.5, .5);
  sample->SetSampleDimensions(20, 20, 20);
  sample->ComputeNormalsOff();

  // Contour
  auto surface = vtkSmartPointer<vtkContourFilter>::New();
  surface->SetInputConnection(sample->GetOutputPort());
  surface->SetValue(0, 0.0);

  // Create a mapper and an actor.
  auto mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputConnection(surface->GetOutputPort());
  mapper->ScalarVisibilityOff();
  auto actor = vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);
  actor->GetProperty()->EdgeVisibilityOn();
  actor->GetProperty()->SetColor(actorColor.GetData());
  actor->GetProperty()->SetEdgeColor(EdgeColour.GetData());

  // A renderer and render window.
  auto renderer = vtkSmartPointer<vtkRenderer>::New();
  renderer->SetBackground(BackgroundColour.GetData());
  auto renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  renderWindow->SetWindowName("ImplicitSphere1");

  auto renderWindowInteractor =
      vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);
  // Add the actor.
  renderer->AddActor(actor);
  // Start
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(ImplicitSphere1)

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

if (NOT VTK_FOUND)
  message(FATAL_ERROR "ImplicitSphere1: 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(ImplicitSphere1 MACOSX_BUNDLE ImplicitSphere1.cxx )
  target_link_libraries(ImplicitSphere1 PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS ImplicitSphere1
  MODULES ${VTK_LIBRARIES}
)

Download and Build ImplicitSphere1

Click here to download ImplicitSphere1 and its CMakeLists.txt file. Once the tarball ImplicitSphere1.tar has been downloaded and extracted,

cd ImplicitSphere1/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:

./ImplicitSphere1

WINDOWS USERS

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