Robert, Sorry it has been long giving feedback on this. I've been working other issues.
I did try the KdTrees stuff you suggested without any improvement in performance. I called osgDB::Registry::instance()->setBuildKdTreesHint(osgDB::ReaderWriter::Option s::BUILDKDTREES); before I load my terrain database. Is this the correct way to do this? Is there anything else I need to do to enable this or get this to work? In some respects things got even slower than before when I try LOS intersection calculations via the osgSim::LineOfSight class... -Shayne -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Robert Osfield Sent: Wednesday, July 28, 2010 2:47 AM To: OpenSceneGraph Users Subject: Re: [osg-users] osgSim HeightAboveTerrain performance... Hi Shyane, I've not been at my desk too consistently this last few weeks due to school holidays, so not able to dig down into all threads. A couple of general comments. If intersections are slow then consider enabling the building KdTree's on your scene graph, this will greatly improve performance. In osgDB::Options and osgDB::Registry there is a setBuildKdTreesHint(..) method that you can use. Robert. On Tue, Jul 27, 2010 at 7:25 PM, Tueller, Shayne R Civ USAF AFMC 519 SMXS/MXDEC <[email protected]> wrote: > Since I didn't receive any input or feedback on my previous inquiry, I'm > assuming no one has used osgSim very much in an extensive setting.?.? > > At any rate, I've done some further investigation. It appears that > performance is very poor when HAT inquiries are randomly called in different > portions of the code via the > osgSim::HeightAboveTerrain::computeHeightAboveTerrain(.) method. On the > other hand, if HAT points via hat.addPoint() are collected up and then > computed (intersections) in one place, performance improves. I'm assuming > that this is the correct usage for OSG? If this is true, I must say that > this is a major problem since HAT inquiries need to be done at different > times throughout the application due to dependencies on HAT for other > calculations. > > I would like some feedback from someone in the know on osgSim so I know what > the proper usage is for maximum performance. If it is true that all HAT > points in OSG need to be consolidated for intersection calculation, then I > will attempt to refactor the code to support what OSG wants. > > Thanks, > -Shayne > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of > Tueller,Shayne R Civ USAF AFMC 519 SMXS/MXDEC > Sent: Friday, July 23, 2010 10:57 AM > To: OpenSceneGraph Users > Subject: [osg-users] osgSim HeightAboveTerrain performance... > > All, > > > > I was wanting some feedback for those who have used osgSim in querying VPB > database info such has HAT, LOS, etc., during runtime. > > > > I'm seeing some performance issues when using > osgSim::HeightAboveTerrain::computeHeightAboveTerrain(.) to get the HAT > value for a particular location in the database. At times, we need multiple > HAT values per frame which seems to bog the performance down. I would > surmise that LOS calculations are probably worse since multiple > intersections are computed. > > > > My question is, is how efficient is the osgSim HAT function? Is the process > of retrieving HAT a slow one? If so, is there a way to improve performance > if one or more HAT requests are issued on a per frame basis? > > > > Thanks in advance, > > -Shayne > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
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