On Wed, Jun 20, 2018 at 8:14 AM, Robert Osfield <robert.osfi...@gmail.com> wrote:
> Hi Scott, > > On Wed, 20 Jun 2018 at 08:09, Scott Bailey <bai...@insanegenius.org> > wrote: > > Wow is this ever good news! I'm glad to see OSG will move into the > future, albeit as VSG. I'm especially excited to see modern c++ targeted. > Personally, my preference is for c++14 if only for std::make_unique<>(), > but I'll take c++11 any day! > > I guess there is chance I'll use std::unique_ptr<> and associated > std::make_unique<>() at some point. The scene graph itself will be > managed using intrusive reference counting just like the OSG does for > performance reasons, so I've prototyped equivalents of osg::ref_ptr<> > and osg::Referenced for this purpose. I guess one could also write a > vsg::make_ref<> equivalent to std::make_unique<> if one so desired. > > Before you move on, the big advantage of std::shared_ptr over intrusive reference counting is that support for weak pointers is rock solid. In the intrusive model, you can't implement thread-safe weak pointers without an auxiliary data structure, which complicates the implementation a lot. I know that one historic OSG performance win for osg::ref_ptr was the ability to not do the reference counting if it isn't needed, but with atomic increment / decrement implemented everywhere, do you think there is really much performance advantage for intrusive counting? Also, std::make_shared<>() allocates the shared_ptr control block in the same memory allocation as the shared object, so there need not be a memory fragmentation hit for using shared_ptr. Tim > For now I'm wider design issues, doing experiments with more modern > C++ along the way to see what is possible. My general guide is that > modern C++ features deployed needs to make the code easier to read and > maintain than not using it, or provide significant flexibility/power > that justifies any possible complexities in following the code. So > far so good on this count - I've been able to make the VSG equivalents > of OSG much simpler thanks to modern C++ features. > > I won't make any decision on C++11 vs 14 vs 17 until the end of > Exploration Phase. If we can do everything we'll need with just C++11 > and there are few features of 14 and 17 that offer significant > benefits then I'll likely just stick with C++11 for better backwards > compatibility to older compilers. The backwards compatibility with > older compilers isn't a priority though, just something worth > maintaining if it comes at no cost to the integrity/quality of the > scene graph. > > I have to admit, I *really* like working with modern C++, looking back > to some OSG code is bit painful now. This isn't just C++ features > though, my skills as programmer have slowly advanced over the years so > now can spot better ways of solving problems. Once VSG is established > there may be a few areas of the OSG that could be updated to do > similar things to what the VSG will do, though backwards compatibility > for the OSG is crucial - it'll be a case of asking the question what > can make OSG users lives better without risking breaking things. > > These possibilities are all a way off yet. Through to the end of > August I'll be just learning, thinking, experimenting with C++, Vulkan > and ideas for improving scene graphs, and also getting OSG-3.6.2 out > the door :-) > > Robert. > > > > > > If you haven't already seen it, check out the Magnum Graphics Engine. > It's the only example I've found of anything close to a scene graph with a > modern c++ interface. > > > > Best luck and Thanks! > > SB > > [/url] > > > > ------------------ > > Read this topic online here: > > http://forum.openscenegraph.org/viewtopic.php?p=74083#74083 > > > > > > > > > > > > _______________________________________________ > > osg-users mailing list > > osg-users@lists.openscenegraph.org > > http://lists.openscenegraph.org/listinfo.cgi/osg-users- > openscenegraph.org > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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