FWIW, I take back my most recent post. Upon further research, and consultation with those on the forum for my GUI (wxWidgets), the timer event call is NOT asynchronous; (it is handled in the same thread as the key event). So there should be no concurrency problems.
Anyway, I will have to do more debugging to solve this. Thanks to all for your recent suggestions. On Wed, Oct 8, 2008 at 4:25 PM, Chris <[EMAIL PROTECTED]> wrote: > Well, looks like I am wrong. I had assumed that wxWidgets managing these > timer events and executing the callbacks whenever it could from within its > message dispatch thread. I did a quick test, and indeed my key event is > getting called while my timer callback is active. I guess the wxTimer is > actually a wrapper over the Win32 asychronous timer API or something like > that. > > OK, I feel foolish...but yes, I did understand that unmanaged, concurrent > acess to data is bad . Thanks for pointing this out. :) > > What's very strange is this was never a problem before, as I've made many > scene changes this way in the 4-year history of my app. > > > On Wed, Oct 8, 2008 at 3:54 PM, Chris <[EMAIL PROTECTED]> wrote: > >> 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 >>>>> > >>>>> > >>>>> _______________________________________________ >>>>> 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 >>>> >>>> >>> >>> >>> -- >>> www.sketch3.com >>> >>> _______________________________________________ >>> osg-users mailing list >>> [email protected] >>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >>> >>> >> >> >> -- >> www.sketch3.com >> > > > > -- > www.sketch3.com > -- www.sketch3.com
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