HI Ravi, No matter what approach you take there will be separate OpenGL program object built and need to be bound. You can do this explicitly by creating your own osg::Program and assigning them to the scene graph or have this done implicitly by the OSG's backend by the utilising the #pragmatic shader composition. The later approach adds convenience if you have dozens of different possible shader combinations but adds a small CPU overhead in maintaining which GL program objects to apply.
Sharing osg::Shader between osg::Program won't add any significant performance gain, just avoid a bit of shader compilation during the compilation phase of the scene graph at application start up. In general I'd recommend going for a solution that is simple to manage in your application and then do benchmarking to see if you've got the performance you need for your application, if you have job done, if not start looking at where the bottlenecks are. Robert. On 4 September 2016 at 02:14, Ravi Mathur <[email protected]> wrote: > Thank you Robert! Can you speak to the performance of using multiple > osg::Programs vs shader composition? > > Another question: suppose I use a separate osg::Program for each > osg::Drawable. Each Program would use the same Vertex osg::Shader object, but > have its own Fragment osg::Shader object. This is the straightforward answer > you mentioned. In this case, do you know if there's any performance benefit > to sharing an osg::Shader object among multiple osg::Program objects? Or is > it the same (performance-wise) as having separate Vertex & Fragment > osg::Shader objects for each osg::Program? > > Thanks! > Ravi > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=68511#68511 > > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
