Hi, On Sat, 2004-12-11 at 11:37, Jo Bard wrote: > Hello, > > first of all, thanks for the answers you gave me before, it was very > useful. But I have a new problem right with the performances of my > application now, and I don't think it comes from the application > itself. Let me explain. > > I'm currently finishing a project using OpenSG and VRjuggler, and it's > supposed to run into a virtual reality environment (a CAVE) within 4 > days... It's a kind of game with some spaceships flying everywhere and > shooting at you. We use some vrml files for the spaceships and all the > objects. Everything worked fine with our tests until the day we > introduced some home-made vrml models, which use textures. Before, the > only object which used textures was the decor and it also worked fine. > But now, we want to use textures with spaceships, which can be very > numerous (almost 20 spaceships) in our scene, compared to the decor. > The problem is that as soon as we did this, the performance > dramatically decreased in the CAVE. The CAVE uses a cluster of 5 > machines with GeForce Quadro graphic card so this should be largely > sufficient to render 20 objects composed of 400 polygons and 2 or 3 MB > of tga and png textures. And also, when we make the application run in > simulation mode, on a single PC, the frame rate is perfect. So we > deleted the textures of the spaceship model and everything worked fine > in the CAVE then... > So we would like to know where this problem can come from and we would > like to know what does the simple vrml loader do when we load a model > : are some OpenGL display lists created? > In fact, all our spaceships use the same model : the model is loaded > separately first, and not inserted in the graph, and then, when a > spaceship is added to the scene, we call a shallowCopy on the model > node (in fact we call the shallowCopy on the model node and all its > children nodes) and we add the new node to the graph. Is this a good > way to make all the objects share the same model? > And have you ever heard about performance issues specefically in an > environment like a CAVE or some compatibility problems with VRjuggler? > > Sorry for this long message but we are a little overstressed with this > problem as the deadline approaches...
one general observation, known problem with PC Clusters, try to cache your scene in the first frame on all cluster nodes (basically render without frustum culling), so that everything is downloaded to the gfx board at the beginning. When we started working with cluster it was a big issue that things that got visible for the first time on a node stalled the whole system as all the downloads were triggered at this point in time. The first thing to try is to use models without texture and disable display list caching, if this runs smoothly, but it does not with display lists enabled, it is a good hint that this 'download when visible for the first time' might be the problem. regards, gerrit ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/ _______________________________________________ Opensg-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/opensg-users
