Qt + OpenSceneGraph on Android

[Treazy]

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();
}