[osg-users] Using PolytopeIntersector from the root of the scene graph instead of camera
Hi, I'm trying to use a PolytopeIntersector in my scene and so far I have succeeded but only by using the camera (i.e. mCamera-accept(PolyVisitor)) with a PolytopeIntersector built from x and y coordinates in window frame. However I would rather pass the visitor the root of my scene. I am doing this in a virtual reality project, and using the camera seems to complicate things a fair bit because we modify projection matrices and viewports a whole lot. For my LineSegmentIntersector I have used 3D points in model space, which worked fine when visiting the root of the scene. For the PolytopeIntersector I am unsure how to do this... Only examples I have found so far used either coordinates in projection space or coordinates in window space. Now I have seen the CoordinateFrame MODEL or VIEW in the PolytopeIntersector constructor, but I am unsure as how to use it. I have seen that the Znear plane is fixed to 0 for MODEL and VIEW coordinate frames.. Does this mean that any object behind Z=0 could not be intersected? I also have a bad feeling that building and using the PolytopeIntersector in MODEL and VIEW coordinate frames will make it just rectangular instead of pyramidal. To recapitulate : I am trying to build a polytpe intersector from one 3d point in model space (or world space) and it's orientation. I would prefer this polytope intersector to be independent from the cameras or viewports. I am stuck at this point. Am I assuming something wrong? Did I miss something that could make this simpler? Do you have any clue that could help me? Am I even making sense? :D Thank a lot, Sincerely, Julien-Charles -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=23242#23242 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] LineSegmentIntersector, IntersectionVisitor and children
Hi, I am using LineSegmentIntersectors with IntersectionVisitor to do some ray casting in my architecture. Everything works fine to select and move objects. However I want to implement a drag-and-drop interaction, where I can move an object onto another and have something different happen. I want to obtain this object using the ray casting as well, so I cast a ray and check to get the first object in Intersections that is not my current object (which I saved in a member variable at the beginning of my drag-and-drop). It all works fine until I start interacting with parent/child objects. I have a sphere and a cube, the sphere is the parent of the cube. When I drag-and-drop my cube over black space, the IntersectionVisitor returns me the sphere (the parent) as the second object intersected even though there is nothing behind the cube at the place I dropped it. Now I believe this has something to do with the parent's bounding sphere including it's children and thus being counted as an intersection, but I'm not sure how I can deal with this kind of stuff. Then again, I could be mistaken. I tried reading about bounding spheres in the reference guide and did not see much, neither could I get much information (or enough information ;) about IntersectionVisitors.. any help would be strongly appreciated ! Thanks in advance ! Sincerely, Julien-Charles -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=17395#17395 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] Preventing scale from being transmitted to children
Hi, I'm currently working with PositionAttitudeTransform controlled objects in my environment. Some objects are clearly too big, some too small. So I set their scale using the setScale function. Problem is that this scale is transmitted automatically to children of the Transforms, and I do not want that. Sure I could apply the inverse of the scale factor to each children, but that doesn't seem like a clean solution to me. I want my children to receive the position and orientation modifications, alas not the scale modifications. There must be a simple way to do this, right ? Anyone has a clue? Thanks in advance! Cheers, JC -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=17354#17354 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
