[osg-users] VBO Bug with 3.6.1 and Normal Arrays

[Robert Osfield]

Hi Dan,

Oopps, like I was using another VBO bug test program earlier, and
fixed an entirely separate bug.... The one I was testing had a issue
with normals on the cessna model.

Still another bug fixed, that's good.

Trying your test program out with the latest OpenSceneGraph-3.6
default build (so GL2) I get a crash:

 ./arraybug
Warning: detected OpenGL error 'invalid operation' at after
drawable.compileGLObjects() call in
GLObjectsVisitor::apply(osg::Drawable& drawable)
Segmentation fault (core dumped)

I haven't tried GLCORE build yet.

Robert.


On Wed, 13 Jun 2018 at 16:59, Daniel Emminizer, Code 5773
<dan.emminizer at nrl.navy.mil> wrote:
>
> Hi Robert,
>
> Thanks for this change.  Unfortunately it does not look like it fixes my issue.
>
> I'm building GL3 core profile mode against OpenSceneGraph-3.6.  I use the main.cpp and CMakeLists.txt from my 6/1/18 email.  I'm using NVidia card with NVS 510, driver 388.19, OpenGL version 3.3.0 (due to core profile flag).  It is Windows 10.
>
> I still see the error:
> Warning: detected OpenGL error `invalid operation` at after drawable.compileGLObjects() call in GLObjectsVisitor::apply(osg::Drawable& drawable)
>
> I have no modifications to OSG.  I did a full rebuild from scratch on OSG.
>
>
> > What I believe is the problem is that the the VertexArrayState object
> > gets initialized by the realizer operation and uses the
> > State::getUseVertexAttributeAliasing() that was current at the time of
> > the realizer operation, then code then calls
> > State::setUseVertexAttributeAliasing() afterwards to a different
> > value, so the rest of the OSG assumes that is now the current value
> > but the global VertexArrayState is still set up against the original
> > value so is passing using GL vertex array settings that are
> > inconsistent with the shaders.
>
> This is the second email you've mentioned the realizer operation.  I do not understand what you're referring to; this is very likely my inexperience with the depth of OSG.  Do you mean the code that eventually calls and includes Geometry::drawVertexArraysImplementation()?
>
> I do not see any code that calls State::setUseVertexAttributeAliasing() in osg/src/*/*, or in osg/include/*/*.  I don't call it in main.cpp either (and if I did, I would only call it at startup, not on each geometry creation).
>
> Are we running the same main.cpp?  I'm attaching my original just in case.
>
> Thanks,
>
>  - Dan
>
>
>
> > -----Original Message-----
> > From: osg-users [mailto:osg-users-bounces at lists.openscenegraph.org] On
> > Behalf Of Robert Osfield
> > Sent: Wednesday, June 13, 2018 7:45 AM
> > To: OpenSceneGraph Users
> > Subject: Re: [osg-users] VBO Bug with 3.6.1 and Normal Arrays
> >
> > Hi Dan et. al,
> >
> > I have had another look into this issue, looked at Dan's workaround
> > and used Dan's test example to see investigate what might be going on.
> > I have checked in a fix:
> >
> >
> > https://github.com/openscenegraph/OpenSceneGraph/commit/673292b995
> > 115c6ca9a3cc82c26e05023f504774
> >
> > This allows the test example to work correctly in all different
> > combinations with the realizer operation on/off etc.
> >
> > What I believe is the problem is that the the VertexArrayState object
> > gets initialized by the realizer operation and uses the
> > State::getUseVertexAttributeAliasing() that was current at the time of
> > the realizer operation, then code then calls
> > State::setUseVertexAttributeAliasing() afterwards to a different
> > value, so the rest of the OSG assumes that is now the current value
> > but the global VertexArrayState is still set up against the original
> > value so is passing using GL vertex array settings that are
> > inconsistent with the shaders.
> >
> > The solution is simple reassign the VertexArrayState for each call to
> > State::setUseVertexAttributeAliasing().
> >
> > I have only tested with Dan's test program, there is chance that other
> > usage cases might tease out the issue in a different way, fingers
> > crossed the just solves all these issue.
> >
> > Could users who've seen issues with the arrays being used correctly
> > update to the head of the OpenSceneGraph-3.6 branch and let me know
> > how you get on.
> >
> > If this all works fine then we can start looking at a release of 3.6.2
> > this month.
> >
> > Cheers,
> > Robert.
> > _______________________________________________
> > osg-users mailing list
> > osg-users at lists.openscenegraph.org
> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> _______________________________________________
> osg-users mailing list
> osg-users at lists.openscenegraph.org
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org