Hi Frederic, I have a quick look up on the GL primitive restart and understand it a bit better now. As this feature has to be enabled/disabled using glEnable/glDisable it naturally would be an StateSet::setMode() rather than something embedded in a DrawElements. The glPrimitiveRestartIndex call is also something I would be inclined to put in it's own dedicate StateAttribute as it's likely to be something that one would set to a particular value for a subgraph and not change it. When working to get the best performance out of OpenGL is crucial to minimize the number of separate glEnable/glDisable and other OpenGL calls that change the state machine, the OSG manages this by having fine grained lazy state updating so the setMode and custom StateAttribute suggestion here would take advantage of this - whereas putting these in DrawElements work break this lazy state updating facility and lower performance. Putting the mode changes into an DrawElements would also leave the door open to mode changes being done within a display list which will break the lazy state updating mechanism and lead to state leakage.
Using a custom StateAttribute for glPrimitiveRestartIndex would however cause problems for code that parses DrawElements without knowing that there is a special index embedded it in. To handle this one would need to watch out for this custom state attribute and mode in the parental path and then it's it's value when parsing the DrawElements. Robert. _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
