[osg-users] OSG Performance Issues

Paul Martz pmartz at skew-matrix.com
Fri Oct 26 14:07:37 PDT 2007

Not really enough information.
When "SLOW CODE" is enabled, did you run a profiler to determine whether the
bulk of your time is being spent in "SLOW CODE" or elsewhere in OSG? If
elsewhere in OSG, did you determine where? What kind of stats output did you
get when you enable the osgviewer statistics view? Is it possible that your
Geometry object was inadvertently left with display lists enabled (which you
would certainly want to disable in such a case)? What is the value of
"test_load_resolution"? Do you see the same performance hit when you
eliminate the doubly-nested loops and simply do a straight replace of the
vertex array with new data? Can you describe the structure and organization
of your scene graph? Are you using buffer objects? Are you displaying on
multiple screens/pipes?
Etc. (Hard to debug remotely, as you can see.)


From: osg-users-bounces at lists.openscenegraph.org
[mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Shawn Cook
Sent: Friday, October 26, 2007 2:20 PM
To: osg-users at lists.openscenegraph.org
Subject: [osg-users] OSG Performance Issues

Hi, I'm back to whine about my performance issues in OpenSceneGraph.  Look
at this main loop: 
while( !viewer.done() && !timeToDie)
//*** SLOW CODE ***
osg::Vec3Array *vecs = dynamic_cast<osg::Vec3Array*>
if( vecs ) {
for(int i=0; i<test_load_resolution; i++ ){
for(int j=0; j<test_load_resolution; j++ ) {
float left = unit_size*i;
float right = unit_size*(i+1);
float bottom = unit_size*j;
float top = unit_size*(j+1);
int quadIndex = (i*4*test_load_resolution) + (j*4);
vecs->at(quadIndex+0).set(left, bottom, 0.0);
vecs->at(quadIndex+1).set(right, bottom, 0.0);
vecs->at(quadIndex+2).set(right, top, 0.0);
vecs->at(quadIndex+3).set(left, top, 0.0);
//^^^ SLOW CODE ^^^^
When I comment out "SLOW CODE" my framerate is a few hundred frames a
second.  But when I uncomment "SLOW CODE" my frame rate won't go above
20fps.  I need dynamic vertices in my application - how do I acheive this
with OpenSceneGraph?
Thanks folks!


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