VTK/Examples/Cxx/Widgets/SphereWidget2

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VTK Examples Baseline Widgets TestSphereWidget2.png

The spherical coordinates of the widget's handle match the coordinates that it displays in the window. The world coordinates of the handle are also shown.

SphereWidget2.cxx

#include <vtkCommand.h>
#include <vtkMath.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkSmartPointer.h>
#include <vtkSphere.h>
#include <vtkSphereRepresentation.h>
#include <vtkSphereWidget2.h>

// Callback that displays the sphere widget's spherical handle postion
// in both sphercial (relative to the widget's center) and cartesian global coordinates
class vtkSphereCallback : public vtkCommand
{
public:
  static vtkSphereCallback *New()
    {
    return new vtkSphereCallback;
    }
 
  virtual void Execute(vtkObject *caller, unsigned long, void*)
    {
    vtkSphereWidget2 *sphereWidget = 
      reinterpret_cast<vtkSphereWidget2*>(caller);

    double center[3], handlePosition[3];
    vtkSphereRepresentation* sphereRepresentation = 
      vtkSphereRepresentation::SafeDownCast( sphereWidget->GetRepresentation() );
    sphereRepresentation->GetHandlePosition( handlePosition );
    sphereRepresentation->GetSphere( this->Sphere );

    this->Sphere->GetCenter( center );

    double radius = sqrt( static_cast<double>(vtkMath::Distance2BetweenPoints( center, handlePosition ) ) );
    radius = (radius <= 0.0 ? 1.0 : radius );
    double theta = vtkMath::DegreesFromRadians( atan2( ( handlePosition[1] - center[1] ), ( handlePosition[0] - center[0] ) ) );
    double phi   = vtkMath::DegreesFromRadians( acos( ( handlePosition[2] - center[2] ) / radius ) );

    std::cout << "r, theta, phi: ("
              << std::setprecision(3)
              << radius << ", " << theta << ", " << phi << ") "
              << "x, y, z: ("
              << handlePosition[0] << ", "
              << handlePosition[1] << ", " 
              << handlePosition[2] << ") "
              << std::endl;
   }

  vtkSphereCallback(){ this->Sphere = vtkSphere::New(); }
  ~vtkSphereCallback(){ this->Sphere->Delete(); }

  vtkSphere* Sphere;
};

int main( int, char *[] )
{
  // Create a renderer and a render window
  vtkSmartPointer<vtkRenderer> renderer =
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow = 
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);

  // Create an interactor
  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = 
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);

  // Create a sphere widget
  vtkSmartPointer<vtkSphereWidget2> sphereWidget = 
    vtkSmartPointer<vtkSphereWidget2>::New();
  sphereWidget->SetInteractor(renderWindowInteractor);
  sphereWidget->CreateDefaultRepresentation();

  vtkSphereRepresentation* sphereRepresentation = 
    vtkSphereRepresentation::SafeDownCast( sphereWidget->GetRepresentation() );
  sphereRepresentation->HandleVisibilityOn();

  vtkSmartPointer<vtkSphereCallback> sphereCallback = 
    vtkSmartPointer<vtkSphereCallback>::New();

  sphereWidget->AddObserver( vtkCommand::InteractionEvent, sphereCallback );

  renderWindow->Render();

  renderWindowInteractor->Initialize();
  renderWindow->Render();
  sphereWidget->On();

  // Begin mouse interaction
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

Please try the new VTKExamples website.

CMakeLists.txt

cmake_minimum_required(VERSION 2.8)

PROJECT(SphereWidget2)

find_package(VTK REQUIRED)
include(${VTK_USE_FILE})

add_executable(SphereWidget2 MACOSX_BUNDLE SphereWidget2.cxx)

if(VTK_LIBRARIES)
  target_link_libraries(SphereWidget2 ${VTK_LIBRARIES})
else()
  target_link_libraries(SphereWidget2 vtkHybrid vtkWidgets)
endif()

Download and Build SphereWidget2

Click here to download SphereWidget2. and its CMakeLists.txt file.

Once the tarball SphereWidget2.tar has been downloaded and extracted,

cd SphereWidget2/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:

./SphereWidget2

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