Hi,
When i use LineSegmentIntersector in the following code.
there must be 8 lines. but after I run the code, only 7 lines exist.
int main( int argc, char** argv ){
float height = 5.f;
osg::ref_ptr<osg::TessellationHints> hints;
hints = new osg::TessellationHints;
hints->setDetailRatio(0.5f);
hints->setCreateBody(true);
hints->setCreateBottom(false);
hints->setCreateTop(false);
osg::ref_ptr<osg::Geode> mynode = new osg::Geode;
osg::ref_ptr<osg::ShapeDrawable> drawable = new osg::ShapeDrawable(new
osg::Cylinder(osg::Vec3(0.0f,0.0f,0.0f),1.0f,height),hints);
osg::ref_ptr<osg::ShapeDrawable> drawable2 = new osg::ShapeDrawable(new
osg::Cylinder(osg::Vec3(0.0f,0.0f,0.0f),4.0f,height),hints);
mynode->addDrawable(drawable.get()); // geom.get() or gemo. both
are ok.
mynode->addDrawable(drawable2.get());
osg::ref_ptr<osg::Group> root = new osg::Group;
root->addChild(mynode.get() );
float angle = 0.0;
float angleDelta = 2.0f*osg::PI/8;
for(int i=0; i<8;i++){
float c = cosf(angle);
float s = sinf(angle);
osg::ref_ptr<osgUtil::LineSegmentIntersector> intersector = new
osgUtil::LineSegmentIntersector( osg::Vec3(0.0f,0.0f,0.0f),
osg::Vec3(10.0f*c,10.0f*s,0.0f) );
osgUtil::IntersectionVisitor iv( intersector.get() );
mynode->accept( iv );
if ( intersector->containsIntersections() )
{
osgUtil::LineSegmentIntersector::Intersections
&intersections =
intersector->getIntersections();
std::cout <<"intersection size
"<<intersections.size()<<std::endl;
osg::ref_ptr<osg::Geode> geode=new osg::Geode;
osg::ref_ptr<osg::Geometry> geom=new osg::Geometry;
osg::ref_ptr<osg::Vec3Array> v3a=new osg::Vec3Array;
osg::ref_ptr<osg::Vec4Array> colors = new
osg::Vec4Array;
colors->push_back( osg::Vec4(1.0, 0.0, 0.0, 1.0) );
osgUtil::LineSegmentIntersector::Intersections::iterator itr;
for ( itr = intersections.begin(); itr !=
intersections.end(); ++itr ) {
std::cout <<" X" <<
itr->getWorldIntersectPoint().x()
<< " Y" <<
itr->getWorldIntersectPoint().y()
<< " Z" <<
itr->getWorldIntersectPoint().z();
if(itr == intersections.begin())
v3a->push_back(
itr->getWorldIntersectPoint());
}
itr--;
v3a->push_back( itr->getWorldIntersectPoint());
std::cout<<std::endl;
geom->setVertexArray(v3a);
geom->setColorArray(colors.get() );
geom->setColorBinding(osg::Geometry::BIND_OVERALL);
for(int k=0; k<v3a->size(); k++){
std::cout<<"vectex: "<<v3a->at(k).x()<<"
"<<v3a->at(k).y()<<" "<<v3a->at(k).z();
}
std::cout<<std::endl;
geom->addPrimitiveSet(new
osg::DrawArrays(osg::PrimitiveSet::LINES,0,v3a->size()));
geode->addDrawable(geom);
root->addChild(geode);
}else{
std::cout<<"no intersection for i="<<i<<std::endl;
std::cout<<"x "<<intersector->getStart().x()<<" y
"<<intersector->getStart().y()<<" z "<<intersector->getStart().z()<<std::endl;
std::cout<<"x "<<intersector->getEnd().x()<<" y
"<<intersector->getEnd().y()<<" z "<<intersector->getEnd().z()<<std::endl;
}
angle+=angleDelta;
}
osgViewer::Viewer viewer;
viewer.setSceneData(root.get());
viewer.addEventHandler(new osgViewer::WindowSizeHandler);
return viewer.run();
}
Thanks._______________________________________________
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