Hi Robert, When i pick e.g. a 3d model of a table my result looks like taht:
intersection.ratio 0.298972 intersection.localIntersectionPoint -37.4626 -162.331 25 intersection.localIntersectionNormal -0 0 1 intersection.getWorldIntersectionPoint() 2187.54 -1787.33 750 intersection.getWorldIntersectionNormal() 0 0 1 intersection.primitiveIndex 11 BUT: intersection.indexList.size() 0 intersection.ratioList.size() 0 intersection.drawable.library/className osg::Geometry geometry->getNumPrimitiveSets() 1 geometry->getVertexArray()->getNumPrimitiveSets() 8 Simon Robert Osfield schrieb: > Hi Simon, > > The LineSegmentIntersector records the indices of the vertices of the > primitive that has been hit. The > LineSegmentIntersector::Intersection::indexList and ratioList provide > the indices and barycentric coords. > > Robert. > > On Tue, Sep 2, 2008 at 8:54 AM, Simon Notheis <[EMAIL PROTECTED]> wrote: >> Hi everyone, >> >> I want to use mouse events to pick an object of the 3D scene. Instead of >> working with the intersection point, I want to find the nearest vertex >> or edge of the polygon that was hit. >> Until now I used code similar to the following one: >> >> // Get the hitlist by using osg::Viewer::computeIntersection(...) >> const osgUtil::LineSegmentIntersector::Intersection& >> intersection = *(hitlist.begin()) >> osg::Geometry* geometry = intersection.drawable->asGeometry() >> >> Then i used intersection.indexList and the geometry's VertexArray to >> iterate through all vertices to find the closest vertex (vx) wrt the >> intersection point. >> Then I calculated the angles between vx and the both neighbouring >> vertices in the indexList to determine which one belongs to the closest >> edge. Finally, the nodePath gave me the local=>world transformation. >> >> All of that only worked because we had some bad code to load/convert our >> own scene format into OSG. This code generated seperate triangles or >> quads, so actually I always hit a polygon with 3 or 4 vertices, what >> made it easy to determinie the neighbours of vx. >> >> Now that we're using some optimization steps (e.g. triangle strips), I >> can't use the above code (e.g. the indexList is empty). I tried to use >> the geometry's IndexArray instead, but the problem is that without >> knowing the exact primitive type, it is hard to determine which vertices >> are the neighbouring ones to find the edge. E.g. in case of an triangle >> strip I would have to check the last 2 and next 2 vertices in the >> index/vertex list. Also the code won't work if the drawable can't be >> cast to a Geometry. >> >> So my question is, if there's a more easy or flexible way to determine >> the closest vertex and edge of the intersected polygon/primitve? >> >> Looking forward to your ideas or solutions, if something similar was >> already discussed here..... >> >> Simon >> >> _______________________________________________ >> 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
