NOTE: I also posted this in the OSG mailing list.

Hi,

I have mixed Qt and OSG to create a viewer for the PCL library OutOfCore trees (using the wrapper classes of osgpcl written by Adam Stambler: https://github.com/adasta/osgpcl).

I started with the osgQtViewer example and changed it accordingly with my needs. Using Windows 7 64 bits, the viewer works great.
Now, I tried to run the viewer in 32 bits and got an assertion error from Eigen that I could overpass including this in my class:

EIGEN_MAKE_ALIGNED_OPERATOR_NEW

But then I got a new error about constructing a QWidget before a QApplication when creating the graphics context:

Qt Code: 
  1. osg::ref_ptr<osgQt::GraphicsWindowQt> gc = new osgQt::GraphicsWindowQt(traits.get());
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This was due to mixing debug and release libraries.

Now, using only release libraries I got rid of that error and the viewer widget window appears, but when it is about to show the OutOfCore tree, the app segfaults with this error:

Qt Code: 
  1. QWidget::releaseDC(): failed to release HDC (El identificador del contexto de dispositivo (DC) no es v?lido.)
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My viewer class inherits both from QWidget and from osg::CompositeViewer. Here is how the widget is called:

Qt Code: 
  1. // The widget already exists. It is created in the main thread with some default values. No camera, no graphics context.
  2. widget->AddCloud();   
  3.  
  4. osg::Vec3d eye, up;
  5.  
  6. widget->getCameraManipulator()->getHomePosition(eye, center, up);
  7.  
  8. distance = widget->getCameraManipulator()->getFusionDistanceValue();
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And the involved methods from the OSG+Qt Viewer:

Qt Code: 
  1. void QOSGViewer::AddCloud(void) {
  2.  
  3.   std::cout << "Loading cloud from file: " << cloud_file.c_str() << "\n";
  4.  
  5.   int fileformat_idx( cloud_filepath.find(".pcd") );
  6.  
  7.   std::string aux( cloud_filepath.substr(0, fileformat_idx) );
  8.  
  9.   aux += "_octree/tree.oct_idx";
  10.  
  11.   QWidget* widget = AddViewWidget(
  12.  
  13.     CreateCamera(0,0,100,100),
  14.  
  15.     ReadOctree(aux)
  16.  
  17.   );
  18.  
  19.   qDebug() << "YAY";   // REACHES THIS
  20.  
  21.   QGridLayout* grid = new QGridLayout;
  22.  
  23.   grid->setContentsMargins(1,1,1,1);
  24.  
  25.   grid->addWidget( widget, 0, 0 );
  26.  
  27.   this->setLayout( grid );
  28.  
  29. }
  30.  
  31.  
  32. osg::Camera* QOSGViewer::CreateCamera(
  33.  
  34.   int x,
  35.  
  36.   int y,
  37.  
  38.   int w,
  39.  
  40.   int h,
  41.  
  42.   const std::string &name,
  43.  
  44.   bool windowDecoration
  45.  
  46. ) {
  47.  
  48.   osg::DisplaySettings* ds = osg::DisplaySettings::instance().get();
  49.  
  50.   osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits;
  51.  
  52.   traits->windowName = name;
  53.  
  54.   traits->windowDecoration = windowDecoration;
  55.  
  56.   traits->x = x;
  57.  
  58.   traits->y = y;
  59.  
  60.   traits->width = w;
  61.  
  62.   traits->height = h;
  63.  
  64.   traits->doubleBuffer = true;
  65.  
  66.   traits->alpha = ds->getMinimumNumAlphaBits();
  67.  
  68.   traits->stencil = ds->getMinimumNumStencilBits();
  69.  
  70.   traits->sampleBuffers = ds->getMultiSamples();
  71.  
  72.   traits->samples = ds->getNumMultiSamples();
  73.  
  74.   osg::ref_ptr<osg::Camera> camera = new osg::Camera;
  75.  
  76. //  camera = new osg::Camera;
  77.  
  78.   osg::ref_ptr<osgQt::GraphicsWindowQt> gc = new osgQt::GraphicsWindowQt(traits.get());
  79.  
  80.   camera->setGraphicsContext( gc.get() );
  81.  
  82.   camera->setClearColor( osg::Vec4(0,0,0,1) );
  83.  
  84.   camera->setViewport( new osg::Viewport(0, 0, traits->width, traits->height) );
  85.  
  86.   camera->setProjectionMatrixAsPerspective(
  87.  
  88.     30.0f,
  89.  
  90.     static_cast<double>(traits->width)/static_cast<double>(traits->height),
  91.  
  92.     1.0f,
  93.  
  94.     10000.0f
  95.  
  96.   );
  97.  
  98.   return camera.release();
  99.  
  100. }
  101.  
  102. osg::Node* QOSGViewer::ReadOctree(const std::string &file) {
  103.  
  104.   osg::Group* group = new osg::Group;
  105.  
  106.   group->addChild( osgDB::readNodeFile(file, options) );
  107.  
  108.   return group;
  109.  
  110. }
  111.  
  112. QWidget* QOSGViewer::AddViewWidget(
  113.  
  114.   osg::Camera *camera,
  115.  
  116.   osg::Node *scene
  117.  
  118. ) {
  119.  
  120.   osgViewer::View* view = new osgViewer::View;
  121.  
  122. //  view = new osgViewer::View;
  123.  
  124.   view->setCamera( camera );
  125.  
  126.   view->setSceneData( scene );
  127.  
  128.   addView( view );
  129.  
  130.   view->addEventHandler( new osgViewer::StatsHandler );
  131.  
  132.   view->setCameraManipulator( new osgGA::TrackballManipulator );
  133.  
  134.   osgQt::GraphicsWindowQt* gw = dynamic_cast<osgQt::GraphicsWindowQt*>(
  135.  
  136.     camera->getGraphicsContext()
  137.  
  138.   );
  139.  
  140.   return gw ? gw->getGLWidget() : 0;
  141.  
  142. }
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Can you please tell me where I'm failing? I'm clueless about this crash.

Best regards,
Adrián.