Hi,
I've got a pretty large terrain database in the OpenFlight format. I've written
an algorithm that samples the elevation at various/lots of points throughout
the entire database. To accomplish this I'm wrapping a LineSegmentIntersector
inside an IntersectionVisitor.
This first iteration of the algorithm took forever seemingly because each
height query would page in one of the OpenFlight tiles, perform the height
query, and discard that data. So the next height query would have to page in
the same data again. To address this issue I started giving the
IntersectionVisitor a reference to my DatabaseCacheReadCallback.
This second iteration of my algorithm sped up performance dramatically.
However, if I set the maximum number of files to cache to too high a number it
will crash OSG. Presumably, because I'm running out of memory before the cache
is full.
Any suggestions on how to handle this? It would be nice if I could set a memory
size on the cache file as opposed to the number of files. It would be nice if I
could somehow tell OSG to gracefully handle this error. I'm sure the API
address this issue and I'm just missing it, any suggestions?
Here is a code sample of what I'm doing...
Code:
osg::Vec3d lineStart(xyPoint.x(), xyPoint.y(), -1000000);
osg::Vec3d lineEnd(xyPoint.x(), xyPoint.y(), 1000000);
osg::ref_ptr<osgUtil::LineSegmentIntersector> lineSegmentIntersector =
new osgUtil::LineSegmentIntersector(lineStart, lineEnd);
osg::ref_ptr<osgUtil::IntersectionVisitor> intersectionVisitor = new
osgUtil::IntersectionVisitor(lineSegmentIntersector,
mDatabaseCacheReadCallback);
mRootNode->accept(*(intersectionVisitor.get()));
osgUtil::LineSegmentIntersector::Intersections& intersections =
lineSegmentIntersector->getIntersections();
if(intersections.size() > 0)
{
const osg::Vec3d& intersectionPoint =
intersections.begin()->getLocalIntersectPoint();
}
Thank you!
Cheers,
Ed[/code]
------------------
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http://forum.openscenegraph.org/viewtopic.php?p=45223#45223
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