OpenSceneGraph/examples/osgviewerQt/osgviewerQt.cpp
Robert Osfield 6a67be2e32 Introduced CMake option OSG_PROVIDE_READFILE option that defaults to ON, but when switched to OFF disables the building of the osgDB::read*File() methods,
forcing users to use osgDB::readRef*File() methods.  The later is preferable as it closes a potential threading bug when using paging databases in conjunction
with the osgDB::Registry Object Cache.  This threading bug occurs when one thread gets an object from the Cache via an osgDB::read*File() call where only
a pointer to the object is passed back, so taking a reference to the object is delayed till it gets reassigned to a ref_ptr<>, but at the same time another
thread calls a flush of the Object Cache deleting this object as it's referenceCount is now zero.  Using osgDB::readREf*File() makes sure the a ref_ptr<> is
passed back and the referenceCount never goes to zero.

To ensure the OSG builds when OSG_PROVIDE_READFILE is to OFF the many cases of osgDB::read*File() usage had to be replaced with a ref_ptr<> osgDB::readRef*File()
usage.  The avoid this change causing lots of other client code to be rewritten to handle the use of ref_ptr<> in place of C pointer I introduced a serious of
templte methods in various class to adapt ref_ptr<> to the underly C pointer to be passed to old OSG API's, example of this is found in include/osg/Group:

    bool addChild(Node* child); // old method which can only be used with a Node*

    tempalte<class T> bool addChild(const osg::ref_ptr<T>& child) { return addChild(child.get()); } // adapter template method

These changes together cover 149 modified files, so it's a large submission. This extent of changes are warrent to make use of the Object Cache
and multi-threaded loaded more robust.



git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/branches/OpenSceneGraph-3.4@15165 16af8721-9629-0410-8352-f15c8da7e697
2015-10-22 14:14:53 +00:00

120 lines
4.9 KiB
C++

#include <QTimer>
#include <QApplication>
#include <QGridLayout>
#include <osgViewer/CompositeViewer>
#include <osgViewer/ViewerEventHandlers>
#include <osgGA/MultiTouchTrackballManipulator>
#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);
QWidget* widget1 = addViewWidget( createGraphicsWindow(0,0,100,100), osgDB::readRefNodeFile("cow.osgt") );
QWidget* widget2 = addViewWidget( createGraphicsWindow(0,0,100,100), osgDB::readRefNodeFile("glider.osgt") );
QWidget* widget3 = addViewWidget( createGraphicsWindow(0,0,100,100), osgDB::readRefNodeFile("axes.osgt") );
QWidget* widget4 = addViewWidget( createGraphicsWindow(0,0,100,100), osgDB::readRefNodeFile("fountain.osgt") );
QWidget* popupWidget = addViewWidget( createGraphicsWindow(900,100,320,240,"Popup window",true), osgDB::readRefNodeFile("dumptruck.osgt") );
popupWidget->show();
QGridLayout* grid = new QGridLayout;
grid->addWidget( widget1, 0, 0 );
grid->addWidget( widget2, 0, 1 );
grid->addWidget( widget3, 1, 0 );
grid->addWidget( widget4, 1, 1 );
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(0.2, 0.2, 0.6, 1.0) );
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 );
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="", 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->setGeometry( 100, 100, 800, 600 );
viewWidget->show();
return app.exec();
}