LoopShrink

VTKEx/Cxx/Visualization/LoopShrink

Description¶

A network with a loop. VTK 5.0 and later do not allow you to execute a looping visualization network; this was possible in previous versions of VTK.

Info

See Figure 4-22 in Chapter 4 the VTK Textbook.

Other languages

See (Python), (Java)

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

Code¶

LoopShrink.cxx

#include <vtkActor.h>
#include <vtkCullerCollection.h>
#include <vtkDataSetMapper.h>
#include <vtkElevationFilter.h>
#include <vtkNamedColors.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkShrinkFilter.h>
#include <vtkSphereSource.h>


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

  vtkSmartPointer<vtkRenderer> renderer =
    vtkSmartPointer<vtkRenderer>::New();
  renderer->GetCullers()->RemoveAllItems();

  vtkSmartPointer<vtkRenderWindow> renWin =
    vtkSmartPointer<vtkRenderWindow>::New();
  renWin->AddRenderer(renderer);
  vtkSmartPointer<vtkRenderWindowInteractor> iren =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  iren->SetRenderWindow(renWin);

  vtkSmartPointer<vtkSphereSource> sphere =
    vtkSmartPointer<vtkSphereSource>::New();
  sphere->SetThetaResolution(12); sphere->SetPhiResolution(12);

  vtkSmartPointer<vtkShrinkFilter> shrink =
    vtkSmartPointer<vtkShrinkFilter>::New();
  shrink->SetInputConnection(sphere->GetOutputPort());
  shrink->SetShrinkFactor(0.9);

  vtkSmartPointer<vtkElevationFilter> colorIt =
    vtkSmartPointer<vtkElevationFilter>::New();
  colorIt->SetInputConnection(shrink->GetOutputPort());
  colorIt->SetLowPoint(0,0,-.5);
  colorIt->SetHighPoint(0,0,.5);

  vtkSmartPointer<vtkDataSetMapper> mapper =
    vtkSmartPointer<vtkDataSetMapper>::New();
  mapper->SetInputConnection(colorIt->GetOutputPort());

  vtkSmartPointer<vtkActor> actor =
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);

  renderer->AddActor(actor);
  renderer->SetBackground(colors->GetColor3d("White").GetData());
  renWin->SetSize(640, 480);

  renWin->Render();

  // interact with data
  iren->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt¶

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(LoopShrink)

find_package(VTK COMPONENTS 
  vtkvtkCommonColor
  vtkvtkFiltersCore
  vtkvtkFiltersGeneral
  vtkvtkFiltersSources
  vtkvtkInteractionStyle
  vtkvtkRenderingContextOpenGL2
  vtkvtkRenderingCore
  vtkvtkRenderingFreeType
  vtkvtkRenderingGL2PSOpenGL2
  vtkvtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping LoopShrink: ${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(LoopShrink MACOSX_BUNDLE LoopShrink.cxx )
  target_link_libraries(LoopShrink PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(LoopShrink MACOSX_BUNDLE LoopShrink.cxx )
  target_link_libraries(LoopShrink PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS LoopShrink
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build LoopShrink¶

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

cd LoopShrink/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:

./LoopShrink

WINDOWS USERS

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