add osgWidget::Viewer subclass to keep OSG from setting the CPU affinity

OSGWidget.cpp

@@ -67,6 +67,21 @@ QRect makeRectangle( const QPoint& first, const QPoint& second )
 
 }
 
+namespace osgWidget {
+  void Viewer::setUpThreading()
+  {
+    if(_threadingModel == SingleThreaded) {
+      if(_threadsRunning) {
+        stopThreading();
+      }
+    } else {
+      if(!_threadsRunning) {
+        startThreading();
+      }
+    }
+  }
+}
+
 OSGWidget::OSGWidget( QWidget* parent,
                       Qt::WindowFlags f )
   : QOpenGLWidget( parent,
@@ -75,7 +90,7 @@ OSGWidget::OSGWidget( QWidget* parent,
                                                             this->y(),
                                                             this->width(),
                                                             this->height() ) )
-  , viewer_( new osgViewer::CompositeViewer )
+  , viewer_( new osgWidget::Viewer )
   , selectionActive_( false )
   , selectionFinished_( true )
 {

OSGWidget.h

@@ -9,6 +9,19 @@
 #include <osgViewer/GraphicsWindow>
 #include <osgViewer/CompositeViewer>
 
+namespace osgWidget {
+  //! The subclass of osgViewer::CompositeViewer we use
+  /*!
+   * This subclassing allows us to remove the annoying automatic
+   * setting of the CPU affinity to core 0 by osgViewer::ViewerBase,
+   * osgViewer::CompositeViewer's base class.
+   */
+  class Viewer : public osgViewer::CompositeViewer
+  {
+    public:
+	    virtual void setUpThreading();
+  };
+}
 class OSGWidget : public QOpenGLWidget
 {
   Q_OBJECT
@@ -43,7 +56,7 @@ class OSGWidget : public QOpenGLWidget
   osgGA::EventQueue* getEventQueue() const;
 
   osg::ref_ptr<osgViewer::GraphicsWindowEmbedded> graphicsWindow_;
-  osg::ref_ptr<osgViewer::CompositeViewer> viewer_;
+  osg::ref_ptr<osgWidget::Viewer> viewer_;
 
   QPoint selectionStart_;
   QPoint selectionEnd_;