[osg-users] Intersection with a boundingBox
Hello, I have a scene and i would like to clip considering a bounding box (i.e cut the polygon at the border and eliminate the outside elements). Does there already exist in osg an implementation to calculate the interesection with a boudingbox (or a plane) or must I implement it? I have found PolytopeIntersector but I don't know if it calculate the intersection or just return the vertex in the boundingbox). Thanks. Aerkis. -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=29772#29772 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Intersection with a boundingBox
Hi Aerkis, There is a osgUtil::PlaneIntersector that gives you the intersection polygon between a plane and a scene, there is also the PolytopIntersector but this tells you whether the scene contains any geometry that has at least part of it in the polytop - it doesn't give the intersection. However, given your email I'm not sure either of these is what you are after, and if you actually want to cut the polygons and create a whole new geometry from the result then the OSG doesn't support this. However, if you just want to do this for rendering then there is OpenGL support for clip planes in the OSG so perhaps this is sufficient. Might I suggest explaining what you are after as a result rather than focusing too much on the low level as doing so doesn't give us an idea of what you are trying to do and why - advice for you will be much more useful if you can provide a clearer to others. Robert. On Wed, Jul 7, 2010 at 9:14 AM, Baptiste Souli aer...@hotmail.fr wrote: Hello, I have a scene and i would like to clip considering a bounding box (i.e cut the polygon at the border and eliminate the outside elements). Does there already exist in osg an implementation to calculate the interesection with a boudingbox (or a plane) or must I implement it? I have found PolytopeIntersector but I don't know if it calculate the intersection or just return the vertex in the boundingbox). Thanks. Aerkis. -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=29772#29772 ___ 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] Intersection with a boundingBox
Hi Aerkis, all the intersection routines you find under osgUtil are meant just to find intersection (picking being the most common usage), not to clip polygons. For that purpose you should instead look at osg::ClipPlane/ClipNode which implement GL clipping. I don't think there's a routine which clips by a bb extents, you should implement that by using 6 different clipping planes yourself. See osgClip example for a reference. HTH, Ricky On Wed, Jul 7, 2010 at 10:14, Baptiste Souli aer...@hotmail.fr wrote: Hello, I have a scene and i would like to clip considering a bounding box (i.e cut the polygon at the border and eliminate the outside elements). Does there already exist in osg an implementation to calculate the interesection with a boudingbox (or a plane) or must I implement it? I have found PolytopeIntersector but I don't know if it calculate the intersection or just return the vertex in the boundingbox). Thanks. Aerkis. -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=29772#29772 ___ 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
