Hi Chris, I'm not going to bother telling your the same over and over. The problem is elsewhere, the error code won't help anymore than crash. What will help is my advice which you seem determined to ignore.
Robert. On Fri, Sep 19, 2008 at 7:39 PM, Chris Denham <[EMAIL PROTECTED]> wrote: > Hi Robert, > Well, if you can convince me that a NULL pointer exception and a crashing, > is in any way more helpful than reporting OpenGL error code 0x502, then I > would agree with you. But in any case, if gluErrorString returning NULL > represents such a deep failure, why not report that, rather than waiting > until ostream inserter blows a wobbler and crashes the app? It gives you > nothing unless you happen to be running a debugger an can look at a stack > trace. > Chris. > > ----- Original Message ----- From: "Robert Osfield" > <[EMAIL PROTECTED]> > To: "Chris Denham" <[EMAIL PROTECTED]> > Cc: "OpenSceneGraph Submissions" <[email protected]> > Sent: Friday, September 19, 2008 5:56 PM > Subject: Re: [osg-submissions] SceneView OpenGL error trap succeptable to > null pointer exception in OSG2.6. > > >> Hi Chris, >> >> If the get string is null, then it suggests that you don't have a >> valid graphics context, so the error code you'd get would be complete >> nonsense. Hiding this crash does nothing to help you. >> >> Robert. >> >> On Fri, Sep 19, 2008 at 5:35 PM, Chris Denham <[EMAIL PROTECTED]> >> wrote: >>> >>> Hi Robert, >>> Surely the purpose of the code that reports the GL error is intended to >>> help >>> users fix the problem. >>> It it not helpful if the application crashes while it is merely trying to >>> output the "pretty string" version of the error code. >>> My suggested change does NOT hide the bug. On the contary, it helps you >>> find >>> the bug because it tells you the error code rather than bombing out >>> trying >>> to display the error. >>> Chris. >>> >>> ----- Original Message ----- From: "Robert Osfield" >>> <[EMAIL PROTECTED]> >>> To: "Chris Denham" <[EMAIL PROTECTED]> >>> Cc: "OpenSceneGraph Submissions" >>> <[email protected]> >>> Sent: Friday, September 19, 2008 5:14 PM >>> Subject: Re: [osg-submissions] SceneView OpenGL error trap succeptable to >>> null pointer exception in OSG2.6. >>> >>> >>>> Hi Chris, >>>> >>>> The submission isn't problematic, but the suggestion that it might fix >>>> a crash is, as the app is broken and is likely just to crash somewhere >>>> else that access OpenGL. The crash you have is symptom of problem >>>> elsewhere, the fix really is not really a fix, it's just a recording >>>> to hide a bug elsewhere. >>>> >>>> Robert. >>>> >>>> On Fri, Sep 19, 2008 at 5:06 PM, Chris Denham <[EMAIL PROTECTED]> >>>> wrote: >>>>> >>>>> Hi Robert, >>>>> You may be right about the cause of the GL error as I am currently >>>>> doing >>>>> horrible things experimenting with code to try and support an SVI >>>>> display. >>>>> However, I stand by this submission, as it was not really about the >>>>> cause >>>>> of >>>>> the GL error, more about how it is reported and the re-use of the GL >>>>> error >>>>> reporting code in State.cpp. >>>>> Basically, <<gluErrorString(errorNo)<<" goes bang! if there is no error >>>>> string for the code passed in. >>>>> It seemed to me that the original code makes an assumption the return >>>>> value >>>>> of gluErrorString(errorCode) being non NULL. >>>>> An assumption that is not made by the code in State::checkGLErrors(), >>>>> so >>>>> it >>>>> makes sense to reuse that code in any case. >>>>> >>>>> Hope that explains my reasoning for submitting this trivial little >>>>> change. >>>>> And it might stop an app crashing unnecessarily when it gets a GLerror >>>>> for >>>>> which there is no 'pretty string' available.. >>>>> >>>>> Chris. >>>>> >>>>> ----- Original Message ----- From: "Robert Osfield" >>>>> <[EMAIL PROTECTED]> >>>>> To: "Chris Denham" <[EMAIL PROTECTED]>; "OpenSceneGraph Submissions" >>>>> <[email protected]> >>>>> Sent: Friday, September 19, 2008 4:43 PM >>>>> Subject: Re: [osg-submissions] SceneView OpenGL error trap succeptable >>>>> to >>>>> null pointer exception in OSG2.6. >>>>> >>>>> >>>>>> Hi Chris, >>>>>> >>>>>> If glGetError() is crashing then it suggests that you are calling this >>>>>> code from a thread that doesn't have valid graphics context, which is >>>>>> a bug at the application level, rather than SceneView itself. >>>>>> >>>>>> Robert. >>>>>> >>>>>> On Fri, Sep 19, 2008 at 4:09 PM, Chris Denham <[EMAIL PROTECTED]> >>>>>> wrote: >>>>>>> >>>>>>> Just found a little problem with SceneView.cpp crashing with NULL >>>>>>> pointer >>>>>>> exception because it tried to use a NULL returned by >>>>>>> gluErrorString(). >>>>>>> I noticed that there is GL error reporting code in State.cpp that >>>>>>> probably >>>>>>> should have be used here. >>>>>>> Mods shown below, and I have attached modified osg2.6 SceneView.cpp >>>>>>> >>>>>>> //////////////////BEFORE////////////////////// >>>>>>> GLenum errorNo = glGetError(); >>>>>>> if (errorNo!=GL_NO_ERROR) >>>>>>> { >>>>>>> osg::notify(WARN)<<"Warning: detected OpenGL error >>>>>>> '"<<gluErrorString(errorNo)<<"'"<< std::endl; >>>>>>> >>>>>>> // go into debug mode of OGL error in a fine grained way to >>>>>>> help >>>>>>> // track down OpenGL errors. >>>>>>> state->setCheckForGLErrors(osg::State::ONCE_PER_ATTRIBUTE); >>>>>>> } >>>>>>> } >>>>>>> /////////////AFTER//////////////////////////// >>>>>>> if (state->checkGLErrors("end of SceneView::draw()")) >>>>>>> { >>>>>>> // go into debug mode of OGL error in a fine grained way to >>>>>>> help >>>>>>> // track down OpenGL errors. >>>>>>> state->setCheckForGLErrors(osg::State::ONCE_PER_ATTRIBUTE); >>>>>>> } >>>>>>> ////////////////////////////////////////////////////// >>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>>> osg-submissions mailing list >>>>>>> [email protected] >>>>>>> >>>>>>> >>>>>>> >>>>>>> http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org >>>>>>> >>>>>>> >>>>> >>>>> >>> >>> > > _______________________________________________ osg-submissions mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org
