Robert is saying you should create your scene graph such that it replicates a quad tree and separate the billboards in to geo-spatially partitioned groups
See http://www.vis-sim.com/imgdp/dbpart1.jpg, your tree is like the last one 'Root B' which is a very bad tree for a scene graph The middle diagram shows a slightly better partioned tree ( although not a quad its better than 'B') as you know what a quad tree is then you should be able to create a much more balanced tree -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Michele Bosi Sent: Friday, May 23, 2008 11:27 AM To: OpenSceneGraph Users Subject: Re: [osg-users] Small object frustum culling On Fri, May 23, 2008 at 5:06 PM, Robert Osfield <[EMAIL PROTECTED]> wrote: > Hi Michele, > > On Fri, May 23, 2008 at 3:58 PM, Michele Bosi <[EMAIL PROTECTED]> wrote: >> Thank you Robert, >> v-sync is off, I get around 90-100 FPS, when enabled OSG stats I get >> 3.4 for "cull" and 6.4 for "draw", also in this case the frame rate >> basically does not change but floats around the same range 90-100. >> Since the performances are already very good I wont dig more into the >> "problem", which might not be a "problem" but rather a lack of >> understanding of what's going on. >> >> Another thing: I instance a single Geometry (my quad billboard) then >> add it 4000 times to a Billboard node. I looked in the archives for >> "quadtree" but coulnd't find any info. How can I use the quadtrees >> you mentioned with OSG? Did you mean quadtrees to speedup frustum >> culling or a particular parent/child layout for OSG nodes? > > I'm afraid I can't teach you about general real-time graphics work I > have enough on my plate. > Thank you Robert, I know you are swamped of work and deliver for free a great service to the list, but I am afraid you don't need to teach me anything about quadtrees, I regularly work with quadtrees and octrees and implemented several of them. > There are lots of books and online resources on items like quad trees. > Lots in the archives too. > I looked in the archives through this web page: http://lists.openscenegraph.org/pipermail/osg-users-openscenegraph.org/ and there are exactly 0 results for "quadtree" and "quad-tree". My question was very clear, and it has to do a lot with OSG and a few with quadtrees but probably it was a misunderstanding. In your mail you said: "Also with your scene graph, make sure you build a quad tree to store all those billboards, and avoid large flat node contains lots of children/drawables". Did you mean, "OSG has a quadtree class somewhere, use it" or "implement your own quadtree scene graph management, integrate it with OSG culling mechanics, and put your billboards in it"? Michele > Robert. > _______________________________________________ > 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 _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
