Hi Deniz, yes I read Jan has mentioned this. Have a look in the osgdb_txp loader in TXPNode::traverse() for inspiration if helps a bit
Nick On Thu, Nov 7, 2013 at 9:40 AM, Deniz Koçak <lend...@gmail.com> wrote: > Hi Trajce, > > I think Jan's answer [1] in the first mail mentions a similar > solution. Setting a flag (by using userdata of the drawable may be) > and updating the drawable in the osg::Drawable::UpdateCallback (of > course by checking the flag) MAY solve the problem. It seems that, > thrusting the Qt's Signal/Slot mechanism is not a good option as Jan > pointed. > > Cheers, > Deniz > > > > [1] One way to solve this is to use the slot to only modify a buffer/set a > flag and then use e.g. an update callback on the affected OSG node to > pick up the changes and implement them in the scene graph when it is > safe (during update traversal). > > On Thu, Nov 7, 2013 at 10:35 AM, Trajce Nikolov NICK > <trajce.nikolov.n...@gmail.com> wrote: > > Hi Jan, > > > > You can modify the scenegraph in the update traversal as well. Like I > did in > > the TerraPage (txp) loader. In the Cull traversall I collect info for > what > > is to be modified and then in the update traversal I update the > scenegraph > > safely. > > > > Just a note > > > > Nick > > > > > > On Thu, Nov 7, 2013 at 9:33 AM, Trajce Nikolov NICK > > <trajce.nikolov.n...@gmail.com> wrote: > >> > >> Hi Jan, > >> > >> > Your approach isn't safe. OSG is *not threadsafe*. Or, rather, it is > >> not threadsafe from arbitrary modifications. If you want to be safe, > >> the only time when modifications to the scene graph may happen is > >> before or after the frame() is invoked, not while frame() is running. > >> > >> > >> > >> On Wed, Nov 6, 2013 at 9:19 PM, Jan Ciger <jan.ci...@gmail.com> wrote: > >>> > >>> -----BEGIN PGP SIGNED MESSAGE----- > >>> Hash: SHA1 > >>> > >>> Hello Deniz, > >>> > >>> On 11/06/2013 07:07 PM, Deniz Koçak wrote: > >>> > This is already a long mail, still I have more to say, many code to > >>> > post, but I am not sure where should I begin. I can provide as > >>> > much as possible. However, before ending my e-mail, I would like to > >>> > ask if this approach is safe or not? I mean, I call frame() method > >>> > within a Qt slot and again update related datas within another Qt > >>> > slot. Qt has a main loop (GUI thread) of course, and is it possible > >>> > to cause a race-condition with OSG, because it has its own > >>> > threading model? Please ask if you need more information and of > >>> > course you will, I would be glad to tell more. > >>> > >>> Your approach isn't safe. OSG is *not threadsafe*. Or, rather, it is > >>> not threadsafe from arbitrary modifications. If you want to be safe, > >>> the only time when modifications to the scene graph may happen is > >>> before or after the frame() is invoked, not while frame() is running. > >>> > >>> If your GUI is modifying the vertex array from the Qt slot, that is, > >>> by definition, asynchronous - you have no idea when the user presses > >>> that button. Which may well be during the rendering when OSG is using > >>> that data structure. If you are clearing the vertex array while the > >>> size of the array is still set, it will go boom. > >>> > >>> One way to solve this is to use the slot to only modify a buffer/set a > >>> flag and then use e.g. an update callback on the affected OSG node to > >>> pick up the changes and implement them in the scene graph when it is > >>> safe (during update traversal). > >>> > >>> Regards, > >>> > >>> J. > >>> -----BEGIN PGP SIGNATURE----- > >>> Version: GnuPG v1.4.14 (GNU/Linux) > >>> Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ > >>> > >>> iD8DBQFSeqRWn11XseNj94gRAuBdAKDuE2rxjaXltXEWg4g2Mka1ZBqVIgCfbKju > >>> vGG9MllrwxlDZjkUd1HHg+8= > >>> =S3At > >>> -----END PGP SIGNATURE----- > >>> _______________________________________________ > >>> osg-users mailing list > >>> osg-users@lists.openscenegraph.org > >>> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > >> > >> > >> > >> > >> -- > >> trajce nikolov nick > > > > > > > > > > -- > > trajce nikolov nick > > > > _______________________________________________ > > osg-users mailing list > > osg-users@lists.openscenegraph.org > > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > -- trajce nikolov nick
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