[osg-users] PagedLOD and page in/out detection

[Trajce Nikolov NICK]

Hi Robert,

thanks for the *hints* :) ... Reading the code is always the best option
:-). I found the thing while reading the code you pointed me to. It is this
thing that when set up properly per the database, then it works nicely ..

viewer->getDatabasePager()->setTargetMaximumNumberOfPageLOD(...);

Thanks again!

Cheers,
Nick

p.s. I still like my simple hack :-). I will keep it and not do it the
proper way this time ;-)

On Fri, Jun 3, 2016 at 7:51 PM, Robert Osfield <robert.osfield at gmail.com>
wrote:

> Hi Nick,
>
> It's *really* inefficient to use an update callback to do this type of
> task, I can not recommend going this path, it's waste of both our time
> trying to coax it to do something useful.
>
> The right way of doing it is by overriding the
> DatabasePager::updateSceneGraph() method or implementing you own
> equivalent method in the Viewer::updateTraversak() in place of current
> calls to updateceneSceneGraph().
>
> Robert.
>
> On 3 June 2016 at 18:28, Trajce Nikolov NICK
> <trajce.nikolov.nick at gmail.com> wrote:
> > Hi Robert,
> >
> > this is my update callback .. And I know for sure it was working. I just
> did
> > a clean app (modified osgviewer with only this callback installed in the
> > root PagedLODs) and I never see a Paged Out tile ... I am limited to not
> > having the possibility to make a custom DatabasePager or it will go
> really
> > complicated. The root PagedLOD can have only one or zero children (that
> is
> > the test database I am testing it against)
> >
> > struct UpdateCallback : public osg::NodeCallback
> > {
> > UpdateCallback()
> > : _numChildren(0)
> > {
> >
> > }
> > virtual void operator()(osg::Node* node, osg::NodeVisitor* nv)
> > {
> > osg::PagedLOD* plod = dynamic_cast<osg::PagedLOD*>(node);
> > if (plod)
> > {
> > if (plod->getNumChildren() != _numChildren)
> > {
> > _numChildren = plod->getNumChildren();
> >
> > if (_numChildren)
> > std::cout << "Paged in" << std::endl;
> > else
> > std::cout << "Paged out" << std::endl;
> >
> > }
> > }
> > traverse(node, nv);
> > }
> > protected:
> > int _numChildren;
> > };
> >
> > On Fri, Jun 3, 2016 at 6:49 PM, Robert Osfield <robert.osfield at gmail.com
> >
> > wrote:
> >>
> >> Hi Nick,
> >>
> >> There isn't a feature directly built into osg::PageLOD or
> >> DatabasePager for this.
> >>
> >> What you could do is look at the  creating a custom DatabasePager that
> >> overrides the following method:
> >>
> >>        /** Merge the changes to the scene graph by calling calling
> >> removeExpiredSubgraphs then addLoadedDataToSceneGraph.
> >>           * Note, must only be called from single thread update phase.
> */
> >>         virtual void updateSceneGraph(const osg::FrameStamp&
> frameStamp);
> >>
> >> Within this you could add your own tracking of when things are merge or
> >> removed.
> >>
> >> Robert.
> >>
> >>
> >>
> >> On 3 June 2016 at 17:15, Trajce Nikolov NICK
> >> <trajce.nikolov.nick at gmail.com> wrote:
> >> > Hi Community,
> >> >
> >> > I was looking for a way to detect when PagedLOD gets its children
> paged
> >> > in/out. So I installed an update callback and based on a difference in
> >> > the
> >> > children number I was able to know when such change occurred. And this
> >> > was
> >> > working with a code an year ago.
> >> >
> >> > Now it doesn't .. Any clue or hint how to detect such changes?
> >> >
> >> > Thanks a bunch as always!
> >> >
> >> > Cheers,
> >> > Nick
> >> >
> >> > --
> >> > trajce nikolov nick
> >> >
> >> > _______________________________________________
> >> > osg-users mailing list
> >> > osg-users at lists.openscenegraph.org
> >> >
> >> >
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> >> >
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> >
> >
> >
> >
> > --
> > trajce nikolov nick
> >
> > _______________________________________________
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> >
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> >
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-- 
trajce nikolov nick
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