[osg-users] [3rdparty] OSG + Qt on Android

Alistair Baxter alistair at mve.com
Mon Apr 3 01:24:57 PDT 2017

When I had to make an app integrate osg and Qt on Android (and other portable platforms) , I based it off the osg / Qt Quick example here:


Since then, other osg / Qt quick examples have been put forward, if you search the mailing list archives.

Qt widgets isn't really intended to work well with mobile platforms, and that's what the old osgQt library is based on.

-----Original Message-----
From: osg-users [mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Coach Treazy
Sent: 31 March 2017 23:45
To: osg-users at lists.openscenegraph.org
Subject: [osg-users] [3rdparty] OSG + Qt on Android


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 have seen this question posted on the forums before but I do not think it has been solved. This is my first post and therefore I cannot post URL links to the previous answers but you can search for the title "OSG with Qt on Android fails to render anything" on the forums

I have posted my example code below and any help will be appreciated.

#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 {
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.

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_sd-"setColor(osg::Vec4(0, 0, 1.0, 1.0));

osg::Geode* earth_geode = new osg::Geode; earth_geode-"setName("EarthGeode");

// 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;

// 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);
	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-"addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::LINES,0,6));

// Earth orbit
osg::Geode * earthOrbitGeode = new osg::Geode; earthOrbitGeode-"addDrawable(unitCircle);

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);

osg::Group* scene = new osg::Group;

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(); }


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;
osgViewer::ViewerBase::ThreadingModel threadingModel = osgViewer::ViewerBase::CullDrawThreadPerContext;

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 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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