Hi Jason, On Wed, 24 Mar 2021 at 15:22, Jason Beverage <jasonbever...@gmail.com> wrote:
> Very impressive Robert! As you said, comparing osgEarth to your example > isn't exactly apples to apples since the implementation under the hood is > quite different but this is still great. > Thanks. Indeed it's apples to oranges comparison so we shouldn't draw too many conclusions. I guess I could rewrite the vsgpagedlod example into an OSG equivalent so all the settings are the same. I'd actually be quite a nice OSG examp[le. My priority for the OSG is support so I'll have to leave this to others. > From what I've seen from your performance reporting, vsg is significantly > faster than osg in most of your tests. Do you have a feel for how much of > that is just Vulkan being faster than OpenGL vs some of the other > improvements you've made in design decisions of VSG vs OSG? Are there any > opportunities for porting some of the structures or concepts from VSG back > to OSG to get some of the performance benefits you've seen in VSG in OSG? > The CPU overhead is much lower in the VSG than the OSG due to architecture changes in the core Object/Node structure to reduce memory footprint/bandwidth load and to avoid conditionals, These could be ported into an OSG lite, but it'd break compatibility with a great many applications - no BoundingSphere on all nodes, no NodeMask, no Callbacks, no ancillary data stored in Object/Node. It would break so many applications and even the OSG itself it wouldn't be a small task to update everything. The differences are fundamental to the VSG delivering on the performance capability that Vulkan provides, without it you'd only see a small % improvement here or there if porting the OSG from OpenGL to Vulkan. I've a few applications and libraries that cite modest improvements when porting to Vulkan, and don't recall any that claim 3 x to 10+ x faster than I'm seeing on OSG vs VSG. I think this either means the OSG is more of CPU hog that we've long assumed or the VSG does a better job of not holding Vulkan back by designing everything from the ground up to not get in the way as much as possible. I suspect it's a bit of both. Cheers, Robert. -- 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 osg-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/osg-users/CAFN7Y%2BV7Wt%2BSD2OWQR8wHd-fWGu9F%3DEdpZjm6cE-cQ0rDQDEtg%40mail.gmail.com.
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