Hi, I have a lot of questions for you! But, there is one really more critical than the others. Let me just introduce the problem :). (I am sorry if I bother, but I searched on the net, in the doc and examples and didn't find answers. I apologize if this is because I badly searched.)
I want to cut my primitives along the frustum of a camera. 1) To do this I first have to get my planes equations. I have found a page dealing about this problem in OpenGL: http://www2.ravensoft.com/users/ggribb/plane%20extraction.pdf I think I'll use it, replacing in OSG conventions. I also found this: http://markmail.org/message/eeolcuruqpsbgrgu#query:osg%20frustum+page:1+mid:eeolcuruqpsbgrgu+state:results >From famous Paul ;). Well, it draws the frustum, but it can be used to get the planes equations. (for whom it may interest) 2) Then I have my equations. Thus I can declare many osg::Plane. Question If the plane is a Vec4d (a,b,c,d) does it well represent the equation ax+by+cz+d = 0 ? I would like to use a PolytopeIntersector. In the doc it's written planes normals have to point the inside of the polytope. Question How are the normals set when the plane is initialized? Question Is there any problem declaring a non-closed (also called opened) polytope? I don't mind about the far plane. 3) Once I have a polytope, I would like to intersect the polytope with the scene. Thus I declare a PolytopeIntersector I associate to an IntersectionVisitor. The BIG Question How do I associate the IntersectionVisitor to a model? I saw for a LineIntersector it is possible to associate it to a view via computeIntersections(), but it doesn't seem possible to do the same with polytope. 4) Question Having the intersected points, is it possible to "easily" get the primitive or do I have to use this (it is in french, sorry): http://www.enseignement.polytechnique.fr/profs/informatique/Philippe.Chassignet/03-04/INF_431/td_16.html (exercise 4) Thank you a lot! Cheers, Maxime ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=14070#14070 _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
