Re: [osg-users] computeIntersections performance
Hi Robert,
thanks for your reply. :)
The stats of my scene are as follows:
Stateset: 17
Group: 7
Transform: 5
LOD: 0
Switch: 0
Geode: 57
Drawable: 175
Geometry: 175
Vertices: 10508
Primitives: 3993
I guess the model isn't as simple as described it. ;)
However, I really thinks it still isn't a very complex model, compared to 3D
buildings or industrial gadgets.
I tested it also with the dumptruck and cow osg files and the speed outcome is
quite similiar.
I made an example programm using the cow:
Code:
#include windows.h
#include iostream
#include vector
#include osgViewer/Viewer
#include osgViewer/ViewerEventHandlers
#include osg/io_utils
#include osg/MatrixTransform
#include osg/Geode
#include osg/Group
#include osgDB/ReadFile
int width = 640;
int height = 480;
std::string modelFile = cow.osg;
int main(int , char **){
//KD-Tree usage
osgDB::Registry::instance()-setBuildKdTreesHint(osgDB::ReaderWriter::Options::BUILD_KDTREES);
osg::ref_ptrosgViewer::Viewer viewer = new osgViewer::Viewer();
osg::ref_ptrosg::Group root = new osg::Group;
osg::ref_ptrosg::Node loadedModel =
osgDB::readNodeFile(modelFile.c_str());
osg::ref_ptrosg::MatrixTransform arTransform = new
osg::MatrixTransform();
arTransform-getOrCreateStateSet()-setRenderBinDetails(100,
RenderBin);
arTransform-addChild(loadedModel);
root-addChild(arTransform.get());
viewer-setSceneData(root.get());
viewer-addEventHandler(new osgViewer::StatsHandler);
viewer-setUpViewInWindow(200, 200, width, height);
osg::Matrix trans;
trans.makeTranslate( 0., 0., -12. );
osg::Matrix rot;
rot.makeRotate(
osg::DegreesToRadians(-90.0), osg::Vec3(1,0,0),
osg::DegreesToRadians(0.0), osg::Vec3(0,1,0) ,
osg::DegreesToRadians(0.0), osg::Vec3(0,0,1) );
viewer-getCamera()-setViewMatrix(rot * trans);
// generate random image points -
struct ImgPoint{
double x;
double y;
};
int numImagePoints = 800;
srand((unsigned)time(0));
std::vectorImgPoint points;
for (int i = 0; i numImagePoints; i++) {
ImgPoint p = {(rand()/(double)RAND_MAX)*width,
(rand()/(double)RAND_MAX)*height };
points.push_back(p);
}
// intersections -
std::vectorImgPoint intersectionPoints;
std::vectorosg::Vec3d modelPoints;
//necessary so that Y values won't be inverted if there hasn't been
mouse interaction yet
viewer-getEventQueue()-getCurrentEventState()-setMouseYOrientation(
osgGA::GUIEventAdapter::Y_INCREASING_UPWARDS );
//time start
LONGLONG g_Frequency, g_CurentCount, g_LastCount;
if (!QueryPerformanceFrequency((LARGE_INTEGER*)g_Frequency))
printf(%s\n, Performance Counter nicht vorhanden);
QueryPerformanceCounter((LARGE_INTEGER*)g_CurentCount);
osgUtil::LineSegmentIntersector::Intersections intersections;
std::vectorImgPoint::iterator myPointVectorIterator;
for(myPointVectorIterator = points.begin(); myPointVectorIterator !=
points.end(); myPointVectorIterator++){
if(viewer-computeIntersections(myPointVectorIterator-x,
myPointVectorIterator-y, intersections)){
intersectionPoints.push_back(*myPointVectorIterator);
osgUtil::LineSegmentIntersector::Intersection
first = *(intersections.begin());
modelPoints.push_back(first.getWorldIntersectPoint());
}
}
//time stop
QueryPerformanceCounter((LARGE_INTEGER*)g_LastCount);
double dTimeDiff =
(((double)(g_LastCount-g_CurentCount))/((double)g_Frequency));
dTimeDiff = dTimeDiff * 1000;
printf(%s %s %f \n, Intersection:, (ms): \n, dTimeDiff);
std::coutNumber Image Points: points.size()std::endl;
std::coutNumber Model Points intersected :
modelPoints.size()std::endl;
while (!viewer-done()){
viewer-frame();
}
}
Maybe I do something wrong. The only line I use for KD Tree usage is the first
line in main. Is that correct?
Or is geometry like the model I have or cow or dumptruck already to complex too
use for realtime intersection testing with ~800 points?
Thanks!
Cheers,
Jen
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http://forum.openscenegraph.org/viewtopic.php?p=44668#44668
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Re: [osg-users] computeIntersections performance
Hi Dakota, Without knowing more about your model we can't say too much about what is actually causing the performance to be so poor. KdTree normally help with intersection performance in a massive way, and will typically be hundreds or even thousands of times faster depending on the nature of the model. Since you aren't getting speed and slow in the first place I can't help wonder if there isn't something particular about your model that is causing problem. Could it be that you have many long thin triangles in your scene? Run you model with osgviewer and bring up the on screen stats by pressing 's' three times - the will list the scene stats. How many geometry, primitives and vertices do you have in the scene? Robert. On 14 December 2011 09:40, Jen Hunter jenr...@web.de wrote: Hi, I'm curious about the time it takes to do intersection testing. I have roughly 800 Image points that I need to check for intersection with my model. My model isn't really complicated, it's basically just a huge box with a few rectangular elements that stand out a bit. It was created using Sketchup and is in Collada file format. I use the method computeIntersections. I'm working with OSG 2.8.2. However, even with kdtree support it takes about 120 to 190 ms to test for the 800 intersections. Without kdtrees it takes up to above 400 ms. I'm confused that it varies so much when the setup of the scene I tested was always the same. I am by no means an expert in computer graphics, so I ask you. Is it normal that it takes so long even for kdtrees, or is it likely that I do something terribly wrong? Thank you! Cheers, Dakota -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=44379#44379 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] computeIntersections performance
Robert, I've also seen minimal speedup with KdTree usage (in my case with terrain). Is there an example where this feature (KdTree usage) is employed? Perhaps the way it's being used (at least by me) isn't correct... -Shayne -Original Message- From: osg-users-boun...@lists.openscenegraph.org [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Robert Osfield Sent: Thursday, January 05, 2012 1:14 PM To: osg-users@lists.openscenegraph.org Subject: Re: [osg-users] computeIntersections performance Hi Dakota, Without knowing more about your model we can't say too much about what is actually causing the performance to be so poor. KdTree normally help with intersection performance in a massive way, and will typically be hundreds or even thousands of times faster depending on the nature of the model. Since you aren't getting speed and slow in the first place I can't help wonder if there isn't something particular about your model that is causing problem. Could it be that you have many long thin triangles in your scene? Run you model with osgviewer and bring up the on screen stats by pressing 's' three times - the will list the scene stats. How many geometry, primitives and vertices do you have in the scene? Robert. On 14 December 2011 09:40, Jen Hunter jenr...@web.de wrote: Hi, I'm curious about the time it takes to do intersection testing. I have roughly 800 Image points that I need to check for intersection with my model. My model isn't really complicated, it's basically just a huge box with a few rectangular elements that stand out a bit. It was created using Sketchup and is in Collada file format. I use the method computeIntersections. I'm working with OSG 2.8.2. However, even with kdtree support it takes about 120 to 190 ms to test for the 800 intersections. Without kdtrees it takes up to above 400 ms. I'm confused that it varies so much when the setup of the scene I tested was always the same. I am by no means an expert in computer graphics, so I ask you. Is it normal that it takes so long even for kdtrees, or is it likely that I do something terribly wrong? Thank you! Cheers, Dakota -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=44379#44379 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.or g ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.or g ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] computeIntersections performance
Hi, I'm curious about the time it takes to do intersection testing. I have roughly 800 Image points that I need to check for intersection with my model. My model isn't really complicated, it's basically just a huge box with a few rectangular elements that stand out a bit. It was created using Sketchup and is in Collada file format. I use the method computeIntersections. I'm working with OSG 2.8.2. However, even with kdtree support it takes about 120 to 190 ms to test for the 800 intersections. Without kdtrees it takes up to above 400 ms. I'm confused that it varies so much when the setup of the scene I tested was always the same. I am by no means an expert in computer graphics, so I ask you. Is it normal that it takes so long even for kdtrees, or is it likely that I do something terribly wrong? Thank you! Cheers, Dakota -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=44379#44379 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
