[osg-users] The importance of using Camera::setDrawBuffer()+setReadBuffer() in application setup

[Julien Valentin]

Sorry, false alarm (shouldn't post when tired)
It was my fault forgot to rebuild my nodekits... 


mp3butcher wrote:
> I haven't followed recent developpement this last 15 days but after merging my fork with master todya, all my rtt stuff saved as osgb doesn't work anymore(freeze).
> You said using using osgviewer would be okay but it doesn't seams to work 
> I had setted all my view and rtt cam Read/Draw buffer to GL_BACK but nothing help...
> Any idea why?
> 
> 
> robertosfield wrote:
> > Hi All,
> > 
> > A recent investigation into a bug a user was seeing in their
> > application revealed that some applications that use 3rd party
> > windowing toolkits aren't setting up the viewer Camera's correctly,
> > and I've traced this back to the examples that the OSG provides.  To
> > fix these I checked in the followinig commit that patches the various
> > osgviewer* examples:
> > 
> > https://github.com/openscenegraph/OpenSceneGraph/commit/ee3e8202779f370501a1a27c83cb9a72ad009439
> > 
> > These fixes are now checked into the OpenSceneGraph-3.4 branch and
> > master.  The changes are all in form:
> > 
> > // set the draw and read buffers up for a double buffered
> > window with rendering going to back buffer
> > camera->setDrawBuffer(GL_BACK);
> > camera->setReadBuffer(GL_BACK);
> > 
> > This explicitly tells the OSG that you wish it to render to the back
> > buffer, rather than just leave it to OpenGL defaults.  Not having
> > these calls causes problems when you do RTT work where the draw/read
> > buffer state has to be toggled between different states.  You can
> > think this of a classic uninitialized variable issue - if you don't
> > set the value you can get undefined results.
> > 
> > If you are using native osgViewer windowing it's likely that you won't
> > need to make any changes as the code in osgViewer for setting up
> > various viewer configurations do the neccessary
> > setDrawBuffer+setReadBuffer() calls.  If you are are creating the
> > graphics context and setting up the Camera's yourself then you'll need
> > to above calls.
> > 
> > If you are using a Pixel Buffer then you'd set the values to GL_FRONT,
> > or if you are using stereo buffer then you'll won't to use
> > GL_BACK_LEFT, GL_BACK_RIGHT.
> > 
> > Cheers,
> > Robert.
> > _______________________________________________
> > osg-users mailing list
> > 
> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> > 
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> 


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