Hi Terry, I'm just working through my submissions inbox and have done another review of your proposed changes the DrawElements to add a setCount() option. I valuably remember discussing this before and suspect I had the same view as I do now - that adding an optional Count value is not appropriate for DrawElements, doing so would add an extra bool check for every glDrawElements call to give an option that only a tiny minority of OSG users might ever find a use for.
For niche features like this I feel that they are based implementation by users own subclasses from osg::DrawElements. Cheers, Robert. On 17 July 2013 at 20:57, Terry Welsh <[email protected]> wrote: > I was interested in drawing less than all of the data in DrawElements as I > stated in this mailing list thread: > http://lists.openscenegraph.org/pipermail/osg-users-openscenegraph.org/2013-July/063950.html > > Looking at DrawElements* in PrimitiveSet.cpp, they seem to be hardwired to > draw all the data. I added a _count variable like in DrawArrays to let the > user draw only a subset of the data. I also added a _countDefined flag to > be set when the user actually defines a count. If it's not set, the old > behavior of drawing all the data is used. I'm not sure if this is the best > solution, but I don't see another way to do it without changing the API > because, unlike DrawArrays, DrawElements can be initialized with no count > specified. > > However it ends up being implemented, this seems like good functionality > to have. Not allowing a count to be specified removes access to an OpenGL > feature that should be exposed. > -- > Terry Welsh > www.reallyslick.com > > _______________________________________________ > osg-submissions mailing list > [email protected] > > http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org > >
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