Hi David, On 13 June 2013 15:31, David Callu <[email protected]> wrote: > As you say, we need to carefully choose what we add in OSG, > but I think OpenGL feature have to be add before we need it, > to be sure that OSG is a fine layer over OpenGL and not a fine > layer over a subset of OpenGL.
I don't believe the OSG should try and map all features OpenGL, rather just focus on the key features that all OSG will rely upon, and niche features that a fair number of OSG users will rely upon. For niche features that used by few users we still need to be able to provide a path to implementing these features on the user side. For instance osg::StateAttribute system is extensible as is osg::Drawable allow users to integrate the OSG with NVidia specific extensions in the case of the osgNV library, and OpenCL etc. Know where to keep the niche features is something we have to continuously evaluate - once niche features can become mainstream, while once mainstream features can and sometimes should fall out of use. An example of the later is OpenGL slow paths such as BIND_PER_PRIMITIVE and vertex indices that aren't even supported by modern OpenGL. The fixed function pipeline will eventually go this way too. Being able to migrate things from external to the OSG to core OSG and back out again is something we will need to do. Sometimes just making a feature usage may require modifications of the core OSG, even when the actual feature is implemented external to the OSG. I believe this flexibility has helped the OSG over years stay relevant, unfortunately we've also accumulated a bit of cruft that needs weeding out - like the slow path stuff in osg::Geometry. Avoiding cruft building up is also part of why I don't just accept any feature addition to the OSG, and why you see me pushing back on threads like this. Often times when I have to easily accepted feature additions to the OSG it's come back to bite us - with extra NodeKits that have never quite fulfilled that original purpose and are now largely orphaned. Robert. _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
