fixes #13 by using a non multisampled FBO for picking

widgets/glWidget/QtBaseViewer.cc

@@ -1563,12 +1563,19 @@ void glViewer::contextMenuEvent(QGraphicsSceneContextMenuEvent* _e)
 
 void glViewer::mousePressEvent(QGraphicsSceneMouseEvent* _e)
 {
+  makeCurrent();
   QPoint p (_e->scenePos().x(), _e->scenePos().y());
   QMouseEvent me(QEvent::MouseButtonPress ,p, _e->screenPos(), _e->button(),
                  _e->buttons(), _e->modifiers());
   _e->accept ();
 
   emit signalMakeActive();
+  const GLuint prevFBO = ACG::GLState::getFramebufferDraw();
+  QFramebufferObject* nonMultisampledFBO;
+  GLuint fboHandle;
+  int samples = 0;
+  createQFBO(nonMultisampledFBO,&fboHandle,glWidth(),glHeight(),&samples);
+  ACG::GLState::bindFramebuffer(GL_FRAMEBUFFER_EXT, fboHandle);
   glScene_->update ();
 
   // right button pressed => popup menu (ignore here)
@@ -1608,6 +1615,10 @@ void glViewer::mousePressEvent(QGraphicsSceneMouseEvent* _e)
         break;
     }
   }
+  //restore old FBO
+  ACG::GLState::bindFramebuffer(GL_FRAMEBUFFER_EXT,prevFBO);
+  //cleanup
+  deleteQFBO(nonMultisampledFBO);
 }
 
 
@@ -1894,7 +1905,7 @@ void glViewer::handleNormalNavigation( QMouseEvent* _event ) {
   switch (_event->type()) {
 
     case QEvent::MouseButtonPress: {
-      
+
       // Get the depth at the current mouse position ( projected )
       // This is used to do the translation in world coordinates
       // As the scene is rendered, we can get the depth directly from the framebuffer.