Hi Mike,
I have an OSG application where I am using osg::Shapedrawable(new
osg::Sphere(...)) to represent errors ellipsoids (all have various sizes
and locations) for targets on a terrain. Prior to their introduction
into the scene, I am getting around 40 frames per second. After
introducing 1000 of them, my frame rate goes down to 4-5 frames per
second.
[...]
My viewer is set up in an overhead view, so I see them all every frame
(i.e., I don't think culling will help here). And also, their PATs have
to occassionally be updated (i.e., not static size, orientation, position).
If you see 1000 spheres in the window at the same time, I'm guessing
that even if they don't look like spheres up close it won't make much
difference from afar. So you could look into the osg::TessellationHints
class which you pass to osg::ShapeDrawable when constructing your
spheres. Setting the detail ratio to 0.5 for example would reduce the
number of polygons. See how low you can go before it becomes
unacceptable. Perhaps you can even set up an LOD structure where close
up you would have a sphere with detail ratio 1.0, but further away it
would have 0.5, then 0.2, then 0.1...
As a general note, osg::ShapeDrawable is intended for quick prototyping,
not for heavy use. If you want some more optimal geometry, you could for
example create a sphere in any 3D modeling program, run that through the
Optimizer with the TRISTRIP_GEOMETRY option (which is not enabled by
default) and you would have better-performing geometry, and it would be
more customizable to what you need (detail level).
If you want to know more about how osg::ShapeDrawable constructs the
geometry from osg::Shapes, have a look at src/osg/ShapeDrawable.cpp.
Hope this helps,
J-S
--
______________________________________________________
Jean-Sebastien Guay [EMAIL PROTECTED]
http://www.cm-labs.com/
http://whitestar02.webhop.org/
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