Hi Robert,
> The most general approach is the best, and the performance differences> will
> almost certainly be negligible between your suggest> SwitchStateSetNode and
> my suggest Layer node with nodemask. Feel free> to implement both and test
> them against each other w.r.t cull> traversal time and overall framerate.>
I implemented the LayerNode approach and tested both versions using a composite
viewer.
The StateSetSwitchNode is a tiny bit faster as predicted, but I agree with you
that the difference is negligible.
The other penalty that I worte about earlier is however large.
My scene:==========- My scene contains 40308 nodes. - A full traverse results
in visiting 380941 nodes (lot of reused geometry).
Pre-processing the scene with
LayerNodes:==========================================- 2356 LayerNodes are
inserted. - Each LayerNode is one Group node with 5 child Group nodes. -
Each child node share the same children as the other child nodes.- I apply
optimizations from osgUtil::Optimizer.- Result: - 54444 nodes totally in the
scene. - 11446441 visits during a full traverse.
Pre-processing the scene with
StateSetSwitchNode:==================================================- 2356
StateSetSwitchNodes are inserted. - This is one Group node that has 5 Group
nodes embedded. - All 5 embedded nodes share the same children as the
StateSetSwitchNode. - None of the 5 embedded nodes has any parents.- I use
the same optimizations as above.- Result: - 42664 nodes totally in the scene.
- 540844 visits during a full traverse.
The penalty:=============Our viewer is a osgViewer::CompositeViewer.Calling the
run function of the osgViewer::CompositeViewer is quite dramatically different
from the LayerNode to the StateSetSwitchNode approach.The LayerNode approach
use approximately 20 times longer time from we call run until the scene appears
on screen.11446441 divided by 540844 = 21.
Conclusion after this testing:===============================- We do not need
the StateSetSwitchNode if the viewer initialization penalty is somehow fixed.
New questions:===============- What does the osgViewer::CompositeViewer do when
we call run and until render starts?- Is this something that would be possible
to do in a pre-processor and save in a .ive file?- Other ways to get around
this problem?
Regards,Viggo
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