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Qt + OpenSceneGraph on Android



  • All,

    I'm trying to run an open scene graph+qt example on my Samsung Galaxy S2 tablet. I'm using Qt 5.8, OpenSceneGraph 3.5.6, Android NDK-r13b and Android 6.0 (API Level 23). FYI - I compiled open scene graph on Android and did not download binaries.

    I cannot even get the open scene graph examples to work. Code compiles fine but when I deploy it on my tablet all I see is a blue screen. I realize that this might be an open scene graph but am at my wits end and 'am posting it on this forum just in case if anyone here has found a solution to my problem. I have posted my code below.

    #include <QTimer>
    #include <QApplication>
    #include <QGridLayout>
    
    #include <osgViewer/CompositeViewer>
    #include <osgViewer/ViewerEventHandlers>
    #include <osg/PositionAttitudeTransform>
    #include <osgGA/MultiTouchTrackballManipulator>
    #include <osg/ShapeDrawable>
    #include <osgDB/ReadFile>
    #include <osgQt/GraphicsWindowQt>
    
    #include <iostream>
    
    class ViewerWidget : public QWidget, public osgViewer::CompositeViewer
    {
    public:
        ViewerWidget(QWidget* parent = 0, Qt::WindowFlags f = 0, osgViewer::ViewerBase::ThreadingModel threadingModel=osgViewer::CompositeViewer::SingleThreaded) : QWidget(parent, f)
        {
            setThreadingModel(threadingModel);
    
            // disable the default setting of viewer.done() by pressing Escape.
            setKeyEventSetsDone(0);
    
            const double r_earth = 6378.137;
            const double r_sun = 695990.0;
            const double AU = 149697900.0;
    
            // Create the Earth, in blue
            osg::ShapeDrawable *earth_sd = new osg::ShapeDrawable;
            osg::Sphere* earth_sphere = new osg::Sphere;
            earth_sphere->setName("EarthSphere");
            earth_sphere->setRadius(r_earth);
            earth_sd->setShape(earth_sphere);
            earth_sd->setColor(osg::Vec4(0, 0, 1.0, 1.0));
    
            osg::Geode* earth_geode = new osg::Geode;
            earth_geode->setName("EarthGeode");
            earth_geode->addDrawable(earth_sd);
    
            // Create the Sun, in yellow
            osg::ShapeDrawable *sun_sd = new osg::ShapeDrawable;
            osg::Sphere* sun_sphere = new osg::Sphere;
            sun_sphere->setName("SunSphere");
            sun_sphere->setRadius(r_sun);
            sun_sd->setShape(sun_sphere);
            sun_sd->setColor(osg::Vec4(1.0, 0.0, 0.0, 1.0));
    
            osg::Geode* sun_geode = new osg::Geode;
            sun_geode->setName("SunGeode");
            sun_geode->addDrawable(sun_sd);
    
            // Move the sun behind the earth
            osg::PositionAttitudeTransform *pat = new osg::PositionAttitudeTransform;
            pat->setPosition(osg::Vec3d(0.0, AU, 0.0));
            pat->addChild(sun_geode);
    
            osg::Geometry * unitCircle = new osg::Geometry();
            {
                osg::Vec4Array * colours = new osg::Vec4Array(1);
                (*colours)[0] = osg::Vec4d(1.0,1.0,1.0,1.0);
                unitCircle->setColorArray(colours, osg::Array::BIND_OVERALL);
                const unsigned int n_points = 1024;
                osg::Vec3Array * coords = new osg::Vec3Array(n_points);
                const double dx = 2.0*osg::PI/n_points;
                double s,c;
                for (unsigned int j=0; j<n_points; ++j) {
                    s = sin(dx*j);
                    c = cos(dx*j);
                    (*coords)[j].set(osg::Vec3d(c,s,0.0));
                }
                unitCircle->setVertexArray(coords);
                unitCircle->getOrCreateStateSet()->setMode(GL_LIGHTING,osg::StateAttribute::OFF);
                unitCircle->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::LINE_LOOP,0,n_points));
            }
    
            osg::Geometry *axes = new osg::Geometry;
            {
                osg::Vec4Array *colours = new osg::Vec4Array(1);
                (*colours)[0] = osg::Vec4d(1.0,0.0,0.0,1.0);
                axes->setColorArray(colours, osg::Array::BIND_OVERALL);
                osg::Vec3Array *coords = new osg::Vec3Array(6);
                (*coords)[0].set(osg::Vec3d(0.0, 0.0, 0.0));
                (*coords)[1].set(osg::Vec3d(0.5, 0.0, 0.0));
                (*coords)[2].set(osg::Vec3d(0.0, 0.0, 0.0));
                (*coords)[3].set(osg::Vec3d(0.0, 0.5, 0.0));
                (*coords)[4].set(osg::Vec3d(0.0, 0.0, 0.0));
                (*coords)[5].set(osg::Vec3d(0.0, 0.0, 0.5));
                axes->setVertexArray(coords);
                axes->getOrCreateStateSet()->setMode(GL_LIGHTING,osg::StateAttribute::OFF);
                axes->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::LINES,0,6));
            }
    
            // Earth orbit
            osg::Geode * earthOrbitGeode = new osg::Geode;
            earthOrbitGeode->addDrawable(unitCircle);
            earthOrbitGeode->addDrawable(axes);
            earthOrbitGeode->setName("EarthOrbitGeode");
    
            osg::PositionAttitudeTransform * earthOrbitPAT = new osg::PositionAttitudeTransform;
            earthOrbitPAT->setScale(osg::Vec3d(AU,AU,AU));
            earthOrbitPAT->setPosition(osg::Vec3d(0.0, AU, 0.0));
            earthOrbitPAT->addChild(earthOrbitGeode);
            earthOrbitPAT->setName("EarthOrbitPAT");
    
            osg::Group* scene = new osg::Group;
            scene->setName("SceneGroup");
            scene->addChild(earth_geode);
            scene->addChild(pat);
            scene->addChild(earthOrbitPAT);
    
            QWidget* widget1 = addViewWidget(createGraphicsWindow(0,0,100,100),scene);
    
            QGridLayout* grid = new QGridLayout;
            grid->addWidget( widget1, 0, 0 );
            setLayout( grid );
    
            connect( &_timer, SIGNAL(timeout()), this, SLOT(update()) );
            _timer.start( 10 );
        }
    
        QWidget* addViewWidget( osgQt::GraphicsWindowQt* gw, osg::ref_ptr<osg::Node> scene )
        {
            osgViewer::View* view = new osgViewer::View;
            addView( view );
    
            osg::Camera* camera = view->getCamera();
            camera->setGraphicsContext( gw );
    
            const osg::GraphicsContext::Traits* traits = gw->getTraits();
    
            //camera->setClearColor( osg::Vec4(1.0, 0.0, 0.0, 0.0) );
            camera->setViewport( new osg::Viewport(0, 0, traits->width, traits->height) );
            camera->setProjectionMatrixAsPerspective(30.0f, static_cast<double>(traits->width)/static_cast<double>(traits->height), 1.0f, 10000.0f );
    
            view->setSceneData( scene.get() );
            view->addEventHandler( new osgViewer::StatsHandler );
            view->setCameraManipulator( new osgGA::MultiTouchTrackballManipulator );
            gw->setTouchEventsEnabled( true );
            return gw->getGLWidget();
        }
    
        osgQt::GraphicsWindowQt* createGraphicsWindow( int x, int y, int w, int h, const std::string& name="Planets", bool windowDecoration=false )
        {
            osg::DisplaySettings* ds = osg::DisplaySettings::instance().get();
            osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits;
            traits->windowName = name;
            traits->windowDecoration = windowDecoration;
            traits->x = x;
            traits->y = y;
            traits->width = w;
            traits->height = h;
            traits->doubleBuffer = true;
            traits->alpha = ds->getMinimumNumAlphaBits();
            traits->stencil = ds->getMinimumNumStencilBits();
            traits->sampleBuffers = ds->getMultiSamples();
            traits->samples = ds->getNumMultiSamples();
    
            return new osgQt::GraphicsWindowQt(traits.get());
        }
    
        virtual void paintEvent( QPaintEvent* /*event*/ )
        { frame(); }
    
    protected:
    
        QTimer _timer;
    };
    
    int main( int argc, char** argv )
    {
        osg::ArgumentParser arguments(&argc, argv);
    
    #if QT_VERSION >= 0x050000
        // Qt5 is currently crashing and reporting "Cannot make QOpenGLContext current in a different thread" when the viewer is run multi-threaded, this is regression from Qt4
        osgViewer::ViewerBase::ThreadingModel threadingModel = osgViewer::ViewerBase::SingleThreaded;
    #else
        osgViewer::ViewerBase::ThreadingModel threadingModel = osgViewer::ViewerBase::CullDrawThreadPerContext;
    #endif
    
        while (arguments.read("--SingleThreaded")) threadingModel = osgViewer::ViewerBase::SingleThreaded;
        while (arguments.read("--CullDrawThreadPerContext")) threadingModel = osgViewer::ViewerBase::CullDrawThreadPerContext;
        while (arguments.read("--DrawThreadPerContext")) threadingModel = osgViewer::ViewerBase::DrawThreadPerContext;
        while (arguments.read("--CullThreadPerCameraDrawThreadPerContext")) threadingModel = osgViewer::ViewerBase::CullThreadPerCameraDrawThreadPerContext;
    
    #if QT_VERSION >= 0x040800
        // Required for multithreaded QGLWidget on Linux/X11, see http://blog.qt.io/blog/2011/06/03/threaded-opengl-in-4-8/
        if (threadingModel != osgViewer::ViewerBase::SingleThreaded)
            QApplication::setAttribute(Qt::AA_X11InitThreads);
    #endif
    
        QApplication app(argc, argv);
        ViewerWidget* viewWidget = new ViewerWidget(0, Qt::Widget, threadingModel);
        viewWidget->realize();
        viewWidget->setGeometry( 100, 100, 800, 600 );
        viewWidget->show();
        return app.exec();
    }
    
    

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