Hi Jason, On Wed, 24 Mar 2021 at 15:22, Jason Beverage <[email protected]> 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 [email protected]. 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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