I don't believe there is any concurrency going on. The "on timer" is in the
same thread as the key press. AFAIK it is the main app thread, i.e. the one
that receives window messages. I"m using wxWidgets' wxTimer class for the
timer. There is only one thread, and as I read the docs, it could only
work from the main thread anyway (see
http://docs.wxwidgets.org/stable/wx_wxtimer.html#wxtimer).
In any event, I am reviewing the wxWidgets docs to see if there is a chance
the timer callback is in it's own thread, but the docs so far don't mention
that.
On Wed, Oct 8, 2008 at 3:32 PM, Tomlinson, Gordon <
[EMAIL PROTECTED]> wrote:
> It seems from the information presented that your Basically running a
> multi-threaded GUI app like MFC/ WInd32 and trying to changing something
> that is being accessed concurrently ( which is bad)
>
> So as your key press happens in your application GUI event thread your on
> timer is also firing in its thread and drawing your text, this means your
> changing the text at the same time your trying to draw it
>
> its like getting your tires changed and trying to drive at the same time,
> your gonna come a cropper ;)
>
> You need to do your text changes in the void render() or in an update
> traversal callback, you need be able to pass data from your key press
> thread in a thread safe manner to your rendering thread to indicate a key
> was pressed and then act on that in void render() function
>
>
>
>
> *Gordon*
>
> __________________________________________________________
> *Gordon Tomlinson*
>
> *Product Manager 3D
> **Email * : gtomlinson @ overwatch.textron.com
> __________________________________________________________
> *(C): (+1) 571-265-2612
> (W)**: (+1) 703-437-7651*
>
> "Self defence is not a function of learning tricks
> but is a function of how quickly and intensely one
> can arouse one's instinct for survival"
> - *Master Tambo Tetsura*
>
>
>
> ------------------------------
> *From:* [EMAIL PROTECTED] [mailto:
> [EMAIL PROTECTED] *On Behalf Of *Chris
> *Sent:* Wednesday, October 08, 2008 3:22 PM
>
> *To:* OpenSceneGraph Users
> *Subject:* Re: [osg-users] osgText crash
>
> Sorry if I don't quite understand the GUI/render thread
> distinction...(learning as I go :)
>
> Pseudo code for adding/deleting is as follows, (all in the same (and only)
> thread,which receives GUI events)
>
> on_key_press()
> {
> toggle = ! toggle
> if (toggle)
> addTextToScene()
> else
> removeAndDeleteTextFromScene()
> }
>
> on_timer_event() // timer event occurs 30 times a second
> {
> renderScene() (calls the render function I quoted earlier)
> }
>
> On Wed, Oct 8, 2008 at 3:05 PM, Tomlinson, Gordon <
> [EMAIL PROTECTED]> wrote:
>
>> Were are you changing, adding, removing etc the text.
>>
>> You need to ensure you are updating only in the APP thread ( not a gui
>> thread )
>> From the snippet below, you need to do this in the Render function ( or
>> that thread ) or in the Update traversal
>>
>>
>> *Gordon*
>>
>> __________________________________________________________
>> *Gordon Tomlinson*
>>
>> *Product Manager 3D
>> **Email * : gtomlinson @ overwatch.textron.com
>> __________________________________________________________
>> *(C): (+1) 571-265-2612
>> (W)**: (+1) 703-437-7651*
>>
>> "Self defence is not a function of learning tricks
>> but is a function of how quickly and intensely one
>> can arouse one's instinct for survival"
>> - *Master Tambo Tetsura*
>>
>>
>>
>> ------------------------------
>> *From:* [EMAIL PROTECTED] [mailto:
>> [EMAIL PROTECTED] *On Behalf Of *Chris
>> *Sent:* Wednesday, October 08, 2008 2:48 PM
>> *To:* OpenSceneGraph Users
>> *Subject:* Re: [osg-users] osgText crash
>>
>> Thanks Robert,
>>
>> I do realize it's tough to tell without seeing the code. Up to yesterday I
>> used osg 2.1, but just upgrade to 2.7.1 (bug still occurs). FWIW, I'm not
>> using the viewer setup in the examples, I use my own osgUtil::SceneView and
>> use cull & draw directly. Note I setup my viewport properties on each
>> rendered frame, as these are animated. The basic code is like:
>>
>> void render()
>> {
>> osgProducer::OsgSceneHandler *sh =
>> dynamic_cast<osgProducer::OsgSceneHandler *> ( _cam.getSceneHandler() );
>> osgUtil::SceneView* sv = sh->getSceneView();
>> sv->setSceneData( (osg::Node *) getSceneNode(0) );
>> osg::State* state = sv->getState();
>> state-> dirtyColorPointer();
>>
>> sv->setProjectionMatrix( projection );
>> sv->setViewMatrix( *_viewMatrix );
>> sv->setViewport( clippedViewport.x, clippedViewport.y,
>> clippedViewport.xdim, clippedViewport.ydim );
>>
>> //sv->update(); no anims, no need to update ?
>> sv->cull();
>> sv->draw();
>> }
>>
>>
>> On Wed, Oct 8, 2008 at 2:13 PM, Robert Osfield <[EMAIL PROTECTED]>wrote:
>>
>>> Hi Chris,
>>>
>>> With so few details about your viewer setup and scene graph usage the
>>> best we can do is guess what you might have done wrong given other
>>> common mistakes we see pop up - have the DataVariance recommendation.
>>>
>>> Another thing you could try setting the threading model on the viewer
>>> by calling
>>>
>>> viewer.setThreadingMode(osgViewer::Viewer::SingleThreaded);
>>>
>>> Again it's a long shot given we really don't know enough about the OSG
>>> version you are using, which viewer library/classes and the fact
>>> you're trying to control everything thing through swig wrappers.
>>>
>>> Robert.
>>>
>>> On Wed, Oct 8, 2008 at 7:04 PM, Chris <[EMAIL PROTECTED]> wrote:
>>> > I had just read the osg archive and set the text DataVariance to
>>> DYNAMIC,
>>> > with high hopes..unfortunately still crashes :(
>>> >
>>> > _text->setDataVariance(osg::Object::DYNAMIC);
>>> >
>>> > I create my Text in response to a keystroke, and add it to the scene.
>>> The
>>> > next keystroke removes and deletes it. Each time I create it, the
>>> initial
>>> > rendered text string does not change.
>>> >
>>> > ( Also set my loaded osgText::Font to DYNAMIC DataVariance, doesn't
>>> help. )
>>> >
>>> > BTW I noticed there were some nvidia problems in the archives; I do
>>> have an
>>> > NVidia driver (my machine is a Toshiba Tecra M4, Geforge Go 6200 (three
>>> > years old), driver date 3/14/2005, version 7.1.4.1 )
>>> >
>>> > as per your StateSet DataVariance comment, should i do that as well ?
>>> I'm
>>> > not familiar with osg's thread models, but I just call render within my
>>> > app's main thread, and I dont' explicitly create other threads myself.
>>> >
>>> > On Wed, Oct 8, 2008 at 1:21 PM, Paul Melis <[EMAIL PROTECTED]>
>>> wrote:
>>> >>
>>> >> Robert Osfield wrote:
>>> >>>
>>> >>> Are you dynamically updating the text each frame? If so set the
>>> >>> DataVariance to DYNAMIC.
>>> >>>
>>> >>
>>> >> Hmmm, if setting it to STATIC causes a crash like this, might that be
>>> a
>>> >> design flaw?
>>> >>
>>> >> Paul
>>> >>
>>> >>> Robert.
>>> >>>
>>> >>> On Wed, Oct 8, 2008 at 6:09 PM, Chris <[EMAIL PROTECTED]> wrote:
>>> >>>
>>> >>>>
>>> >>>> Hi,
>>> >>>>
>>> >>>> I'm having semi-random crash bugs when I add an osgText drawable to
>>> my
>>> >>>> scene. The actual error is a mem access violation, and it occurs
>>> after
>>> >>>> I've
>>> >>>> added & removed the node containing the drawable from the scene a
>>> random
>>> >>>> number of times' (usually from 1 to 10 times)
>>> >>>>
>>> >>>> The exception occurs in the same place in the call stack, apparently
>>> >>>> somewhere in my open gl .dll (nvoglnt.dll). One thing that puzzles
>>> me is
>>> >>>> that I'm using SWIG, and from the call stack the function
>>> >>>> PySwigObject_Check(PyObject *op) ) seems to call into the osgUtil
>>> .dll,
>>> >>>> which in about 10 stack layers ends up calling nvoglnt.dll. I don't
>>> know
>>> >>>> why
>>> >>>> 'PySwigObject_Check' would be caling the osg .dll, (see func copied
>>> >>>> below),
>>> >>>> but maybe some sort of wierd thread confusion ?
>>> >>>>
>>> >>>> SWIGRUNTIMEINLINE int
>>> >>>> PySwigObject_Check(PyObject *op) {
>>> >>>> return ((op)->ob_type == PySwigObject_type())
>>> >>>> || (strcmp((op)->ob_type->tp_name,"PySwigObject") == 0);
>>> >>>> }
>>> >>>>
>>> >>>> The crash does NOT occur if I repeatedly create/delete the osgText
>>> >>>> drawable
>>> >>>> but don't add it to my scene. It does not crash during the render
>>> but
>>> >>>> seems
>>> >>>> to corrupt something that fails elsewhere (apparently in
>>> >>>> 'PySwigObject_Check' )
>>> >>>>
>>> >>>> While I can't be certain it's not my code, I have been running the
>>> same
>>> >>>> render code (which uses osg) now for a few years without problems.
>>> Note
>>> >>>> that I dont explictly create extra threads in my code, beyond what
>>> osg
>>> >>>> might
>>> >>>> be doing.
>>> >>>>
>>> >>>> I thought this looked like some thread/mutex problem, or pehaps a
>>> VC++
>>> >>>> STL
>>> >>>> problem (anyone had these issues with osg Text before?) I created
>>> a
>>> >>>> new
>>> >>>> version of osgText that hacks out the STL-based 'String' class used
>>> to
>>> >>>> 'setText', but no dice.
>>> >>>>
>>> >>>> I was running on WinXP, using compiler: Visual Studio .net 2002. I
>>> just
>>> >>>> installed Osg 2.7.1, and Visual Studio Express 9.0; but the crash
>>> still
>>> >>>> occurs.
>>> >>>>
>>> >>>> TIA,
>>> >>>> Chris
>>> >>>>
>>> >>>> --
>>> >>>> www.sketch3.com
>>> >>>>
>>> >>>> _______________________________________________
>>> >>>> osg-users mailing list
>>> >>>> [email protected]
>>> >>>>
>>> >>>>
>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>>> >>>>
>>> >>>>
>>> >>>>
>>> >>>
>>> >>> _______________________________________________
>>> >>> osg-users mailing list
>>> >>> [email protected]
>>> >>>
>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>>> >>>
>>> >>
>>> >> _______________________________________________
>>> >> osg-users mailing list
>>> >> [email protected]
>>> >>
>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>>> >
>>> >
>>> >
>>> > --
>>> > www.sketch3.com
>>> >
>>> > _______________________________________________
>>> > osg-users mailing list
>>> > [email protected]
>>> >
>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>>> >
>>> >
>>> _______________________________________________
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>>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>>>
>>
>>
>>
>> --
>> www.sketch3.com
>>
>> _______________________________________________
>> osg-users mailing list
>> [email protected]
>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>>
>>
>
>
> --
> www.sketch3.com
>
> _______________________________________________
> osg-users mailing list
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>
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