I totally understand your prorities (further it's release time:/) and your position on VASSharing... (I began coding VAS-that i think you refer to VertexArrayBlock- and perContextVAS to do so) I will not bother you until it's not (too) controversal...
But i'm not agree with you calling basevertex drawcall a hack.. The sacrosaint 0 draw overhead is not hacking, it's the (unreachable) absolute that drove the GL evolution this 20 last years!? ( if basevertex is hacking, what about indirectdraw? lol) I would be glad to help you with the shader_pipeline branch but I'm afraid not to have a view of osg macro enough to help in anyway:/ Cheers robertosfield wrote: > Hi Julian, > > I don't have the time right now to dive in to a complex discussion. A > few general feelings on the topic so you know where I stand: > > First up sharing VAO's would be best done by shading a > VertexArrayBlock container class for per vertex arrays, that > osg::Geomertry objects would share. The VertexArrayBlock would map to > VAO's. At this point in time I don't think the performance benefit of > adding this extra level of complexity into the OSG is probably not > justified - in tests I did with your early VAO sharing code > performance was worse than the non shader VAO implementation that is > now in the core OSG. You may have improved your VAO sharing > implementation to avoid the CPU overhead that was limiting > performance, but I wouldn't expect it'll make a big difference for > most OSG usage cases. > > The BaseVertex extension to OpenGL is something that looks like a hack > for lazy OpenGL application developers that don't wish to update their > index and draw array offsets. The osg::PrimitiveSet class has an > ofsetIndices(int) method makes it easy to readjust primitive sets when > vertex array are merged, so it's essentially the same feature, just > implemented on the OSG side and in a way that is compatible with all > OpenGL versions and compatible with scene graph code that traverses > the scene graph for things like intersection tests. I am not aware of > any real benefit of base vertex for OSG users. > > We are now not far from making the next stable OSG release, I still > have shader_pipeline functionality to complete for it, this is my > focus. The shader_pipeline functionality will benefit the majority of > OSG users so in terms of bang for the buck this is where I need to > spend my time working on rather on niche areas of the OSG/OpenGL > usage. > > Are there are small and uncontroversial changes to the OSG that will > help your usage case then please put them forward. > > Robert. > _______________________________________________ > osg-users mailing list > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > ------------------ > Post generated by Mail2Forum ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=70615#70615 _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org