Opacity

VTKEx/Cxx/Visualization/Opacity

Other languages

See (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

Opacity.cxx

#include <vtkSmartPointer.h>
#include <vtkCubeSource.h>
#include <vtkSphereSource.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkActor.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>

int main(int, char *[])
{ 
  // Cube
  vtkSmartPointer<vtkCubeSource> cubeSource = 
    vtkSmartPointer<vtkCubeSource>::New();
  vtkSmartPointer<vtkPolyDataMapper> cubeMapper = 
    vtkSmartPointer<vtkPolyDataMapper>::New();
  cubeMapper->SetInputConnection(cubeSource->GetOutputPort());

  vtkSmartPointer<vtkActor> cubeActor = 
    vtkSmartPointer<vtkActor>::New();
  cubeActor->GetProperty()->SetOpacity(0.5);
  cubeActor->SetMapper(cubeMapper);

  // Sphere
  vtkSmartPointer<vtkSphereSource> sphereSource = 
    vtkSmartPointer<vtkSphereSource>::New();
  vtkSmartPointer<vtkPolyDataMapper> sphereMapper = 
    vtkSmartPointer<vtkPolyDataMapper>::New();
  sphereMapper->SetInputConnection(sphereSource->GetOutputPort());

  vtkSmartPointer<vtkActor> sphereActor = 
    vtkSmartPointer<vtkActor>::New();
  sphereActor->GetProperty()->SetColor(0.5,1,0.5);
  sphereActor->GetProperty()->SetOpacity(0.5);
  sphereActor->SetMapper(sphereMapper);

  // Create renderers and add actors of plane and cube
  vtkSmartPointer<vtkRenderer> renderer = 
    vtkSmartPointer<vtkRenderer>::New();
  renderer->AddActor(cubeActor);
  renderer->AddActor(sphereActor);

  // Add renderer to renderwindow and render
  vtkSmartPointer<vtkRenderWindow> renderWindow = 
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);

  vtkSmartPointer<vtkRenderWindowInteractor> interactor = 
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  interactor->SetRenderWindow(renderWindow);
  renderer->SetBackground(0,0,0);
  renderWindow->Render();

  interactor->Start();
  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(Opacity)

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

Download and Build Opacity

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

cd Opacity/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:

./Opacity

WINDOWS USERS

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