[osg-users] osgText::Text dissapears when reparent container window on qt

[Diego Mancilla]

Hello,

 This is a mixed OSG/Qt question. I asked first here due to previous experiences with the community. 

 I'm following a minimal example of embedding OSG into a Qt5 application from https://gist.github.com/vicrucann/874ec3c0a7ba4a814bd84756447bc798. When I modify that example, and add a simple osgText::Text to the base Geode everything works as expected. But If I ,additionally, encapsulate the OSG Widget (a widget derived from QOpenGLWidget) on a QDockWidget and undock it, the text dissapears.

 Can someone point me out what could be the problem?

The code:


Code:
#include<QApplication>
#include<QMainWindow>
#include<QOpenGLWidget>
#include<QMouseEvent>
#include<QWheelEvent>
#include<QDesktopWidget>
#include<QScreen>
#include<QtGlobal>
#include<QWindow>
#include<QWidget>
#include<QDockWidget>
#include<QVBoxLayout>

#include<osg/ref_ptr>
#include<osgViewer/GraphicsWindow>
#include<osgText/Text>
#include<osgViewer/Viewer>
#include<osg/Camera>
#include<osg/ShapeDrawable>
#include<osg/StateSet>
#include<osg/Material>
#include<osgGA/EventQueue>
#include<osgGA/TrackballManipulator>

#include <iostream>
#include <stdio.h>

class QtOSGWidget : public QOpenGLWidget
{
public:
  QtOSGWidget(qreal scaleX, qreal scaleY, QWidget* parent = 0)
      : QOpenGLWidget(parent)
        , _mGraphicsWindow(new osgViewer::GraphicsWindowEmbedded( this->x(), this->y(),
                                                                 this->width(), this->height() ) )
        , _mViewer(new osgViewer::Viewer)
      , m_scaleX(scaleX)
      , m_scaleY(scaleY)
      {
        osg::Cylinder* cylinder    = new osg::Cylinder( osg::Vec3( 0.f, 0.f, 0.f ), 0.25f, 0.5f );
        osg::ShapeDrawable* sd = new osg::ShapeDrawable( cylinder );
        sd->setColor( osg::Vec4( 0.8f, 0.5f, 0.2f, 1.f ) );
        osg::Geode* geode = new osg::Geode;
        geode->addDrawable(sd);

		// adding text to the visualization
		osgText::Text * test = new osgText::Text();
		test->setDataVariance(osg::Object::DYNAMIC);
		
		test->setCharacterSize(1.0);
		test->setColor(osg::Vec4(0.0, 0.0, 0.0, 1.0));
		test->setAlignment(osgText::Text::CENTER_BOTTOM);
		test->setAxisAlignment(osgText::TextBase::SCREEN);
		test->setCharacterSizeMode(osgText::Text::OBJECT_COORDS);
		test->setText("CYLINDER");
		geode->addDrawable(test);
		// end adding text

        osg::Camera* camera = new osg::Camera;
        camera->setViewport( 0, 0, this->width(), this->height() );
        camera->setClearColor( osg::Vec4( 0.9f, 0.9f, 1.f, 1.f ) );
        float aspectRatio = static_cast<float>( this->width()) / static_cast<float>( this->height() );
        camera->setProjectionMatrixAsPerspective( 30.f, aspectRatio, 1.f, 1000.f );
        camera->setGraphicsContext( _mGraphicsWindow );

        _mViewer->setCamera(camera);
        _mViewer->setSceneData(geode);
        osgGA::TrackballManipulator* manipulator = new osgGA::TrackballManipulator;
        manipulator->setAllowThrow( false );
        this->setMouseTracking(true);
        _mViewer->setCameraManipulator(manipulator);
        _mViewer->setThreadingModel(osgViewer::Viewer::SingleThreaded);
       // _mViewer->realize();
      }


  virtual ~QtOSGWidget(){}

  void setScale(qreal X, qreal Y)
  {
      m_scaleX = X;
      m_scaleY = Y;
      this->resizeGL(this->width(), this->height());
  }

protected:

  virtual void paintGL() {
    _mViewer->frame();
  }

  virtual void resizeGL( int width, int height ) 
  {
      this->getEventQueue()->windowResize(this->x()*m_scaleX, this->y() * m_scaleY, width*m_scaleX, height*m_scaleY);
      _mGraphicsWindow->resized(this->x()*m_scaleX, this->y() * m_scaleY, width*m_scaleX, height*m_scaleY);
      osg::Camera* camera = _mViewer->getCamera();
      camera->setViewport(0, 0, this->width()*m_scaleX, this->height()* m_scaleY);
  }

  virtual void initializeGL(){
      osg::Geode* geode = dynamic_cast<osg::Geode*>(_mViewer->getSceneData());
      osg::StateSet* stateSet = geode->getOrCreateStateSet();
      osg::Material* material = new osg::Material;
      material->setColorMode( osg::Material::AMBIENT_AND_DIFFUSE );
      stateSet->setAttributeAndModes( material, osg::StateAttribute::ON );
      stateSet->setMode( GL_DEPTH_TEST, osg::StateAttribute::ON );
  }

  virtual void mouseMoveEvent(QMouseEvent* event)
  {
      this->getEventQueue()->mouseMotion(event->x()*m_scaleX, event->y()*m_scaleY);
  }

  virtual void mousePressEvent(QMouseEvent* event)
  {
      unsigned int button = 0;
      switch (event->button()){
      case Qt::LeftButton:
          button = 1;
          break;
      case Qt::MiddleButton:
          button = 2;
          break;
      case Qt::RightButton:
          button = 3;
          break;
      default:
          break;
      }
      this->getEventQueue()->mouseButtonPress(event->x()*m_scaleX, event->y()*m_scaleY, button);
  }

  virtual void mouseReleaseEvent(QMouseEvent* event)
  {
      unsigned int button = 0;
      switch (event->button()){
      case Qt::LeftButton:
          button = 1;
          break;
      case Qt::MiddleButton:
          button = 2;
          break;
      case Qt::RightButton:
          button = 3;
          break;
      default:
          break;
      }
      this->getEventQueue()->mouseButtonRelease(event->x()*m_scaleX, event->y()*m_scaleY, button);
  }

  virtual void wheelEvent(QWheelEvent* event)
  {
      int delta = event->delta();
      osgGA::GUIEventAdapter::ScrollingMotion motion = delta > 0 ?
                  osgGA::GUIEventAdapter::SCROLL_UP : osgGA::GUIEventAdapter::SCROLL_DOWN;
      this->getEventQueue()->mouseScroll(motion);
  }

  virtual bool event(QEvent* event)
  {
      bool handled = QOpenGLWidget::event(event);
      this->update();
      return handled;
  }

private:

  osgGA::EventQueue* getEventQueue() const {
    osgGA::EventQueue* eventQueue = _mGraphicsWindow->getEventQueue();
    return eventQueue;
  }

  osg::ref_ptr<osgViewer::GraphicsWindowEmbedded> _mGraphicsWindow;
  osg::ref_ptr<osgViewer::Viewer> _mViewer;
  qreal m_scaleX, m_scaleY;
};

int main(int argc, char** argv)
{
	// This was necessary for keeping the context when undocking
	QApplication::setAttribute(Qt::AA_ShareOpenGLContexts);

    QApplication qapp(argc, argv);

    QMainWindow window;

	// Here starts code to put the QtOSGWidget inside a dock area
	QDockWidget * visDock = new QDockWidget(&window);
	visDock->setFloating(false);
	visDock->setFeatures(QDockWidget::DockWidgetFloatable | QDockWidget::DockWidgetMovable);
	visDock->setAllowedAreas(Qt::TopDockWidgetArea);

	QWidget * dockWidgetContent = new QWidget();

	QVBoxLayout * verticalLayout = new QVBoxLayout(dockWidgetContent);
	verticalLayout->setSpacing(6);
	verticalLayout->setContentsMargins(11, 11, 11, 11);

	QWidget * containerWidget = new QWidget(dockWidgetContent);
	QHBoxLayout * horizontalLayout = new QHBoxLayout(containerWidget);
	horizontalLayout->setSpacing(0);
	horizontalLayout->setContentsMargins(11, 11, 11, 11);
	horizontalLayout->setContentsMargins(0, 0, 0, 0);
	
	
	QtOSGWidget* widget = new QtOSGWidget(1, 1, containerWidget);

	horizontalLayout->addWidget(widget);


	verticalLayout->addWidget(containerWidget);

	visDock->setWidget(dockWidgetContent);
		
	window.addDockWidget(static_cast<Qt::DockWidgetArea>(4), visDock);

	// No central widget is used for the example
    window.setCentralWidget(Q_NULLPTR);
    window.show();

    return qapp.exec();
}





Thank you!

Cheers,

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http://forum.openscenegraph.org/viewtopic.php?p=75733#75733