Hi Robert, On Wednesday, 29 June 2022 10:33:43 BST Robert Osfield wrote: > Hi James, > > For performance improvements with VR applications it may be best to have a > look at the OpenGL MultiView extension. These are integrated with the > MultiView branch of the OSG that is built off the 3.6 branch.
Thanks. Yes, I need to have a proper look at this. > The MultiView functionality requires use of shaders, but if your scene > graph is already shader based these could be tweaked to include the extra > uniforms required for the multiview. Since most OSG/OpenGL applications > are CPU limited it's possible to add stereo rendering with very low > overhead, in the tests I've done with my Geforce 2060 system it's possible > to do stereo with negligible slow down over normal rendering. > > There also some work I've done on the VSG that could potentially backported > to the OSG that would improve CPU performance such as the vsg::Allocator > work. > > These approaches will likely give far better performance improvements that > trying to be clever about traversals. Also, I eventually figured out that my flightgear LOD distances were dumb, which seemed to be the cause of most of the cull traversal time. Resetting those to default did improve things a bit and I was able to get it playable on a newish PC, but I'm sure there's plenty more improvements to make. I think I understand a bit more about the dependencies between frames now too. The issue I think is that there are quite a few dynamic objects which delay the next frame from starting until all dynamic objects have been drawn. Probably quite invasive to fix so I'll drop that idea for now. I wonder whether VSG takes the same approach to them? I imagine a buffered / RCU style approach to dynamic draw data would be ideal for parallelism but perhaps its not necessary since command buffers can be generated in parallel anyway. Cheers James -- You received this message because you are subscribed to the Google Groups "OpenSceneGraph Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/osg-users/3182385.44csPzL39Z%40saruman.
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