Hi Sonya, I faced the same challenge while back and was able to resolve it by using the OpenGL selection buffer. Here it is described how:
http://www.opengl.org/archives/resources/faq/technical/selection.htm Nick On Sat, Jul 5, 2014 at 9:00 AM, Sonya Blade <[email protected]> wrote: > Dear All, > > I noticed that when one tries to pick an object from scene there is a > critera for that, > I directly started the example from osgPicking example shown at the > officail Osg site. > The code which generates the grids in scene are as follow, problem with > this is that PickHandler > doesn't detect each line as individual entity. > > I can understand the behaviour of having all the vertices and lines > stuffed under the > DrawImplementation to increase the performance and PickHandler not > detecting them, > But If you create each line as individual osg::Geometry then PickHandler > must detect them > which will result in obvious performance penalty. > > I tried both osgUtil::LineSegmentIntersector > and view->computeIntersections(x,y,intersections) > functions if any of them intersects with scene objects, but none of them > worked. > > osg::Geode* CreateGrid(osg::Group* gr, int x, int y, int step) > { > osg::Geode* gode = new osg::Geode(); > > for (int j=1; j<2000; j++) > { > osg::Geometry* linesGeom = new osg::Geometry(); > osg::Vec3Array* vertices = new osg::Vec3Array(100 ); > for (int i=0;i<50 ;i++ ) > { > (*vertices)[2*i].set(-100, step+i*10, 40); > (*vertices)[2*i+1].set(100, step+i*10, 40); > }; > > linesGeom->setVertexArray(vertices); > // set the colors as before, plus using the above > osg::Vec4Array* colors = new osg::Vec4Array; > colors->push_back(osg::Vec4(1.0f,1.0f,0.0f,1.0f)); > linesGeom->setColorArray(colors); > linesGeom->setColorBinding(osg::Geometry::BIND_OVERALL); > > // set the normal in the same way color. > osg::Vec3Array* normals = new osg::Vec3Array; > normals->push_back(osg::Vec3(0.0f,-1.0f,0.0f)); > linesGeom->setNormalArray(normals); > linesGeom->setNormalBinding(osg::Geometry::BIND_OVERALL); > > linesGeom->addPrimitiveSet(new > osg::DrawArrays(osg::PrimitiveSet::LINES,0,100)); > gode->addDrawable(linesGeom); > } > return gode; > } > > Regards, > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > -- trajce nikolov nick
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