On Monday 08 February 2010 09:38:53 pm Paul Martz wrote: > Ricardo Ruiz wrote: > > Thanks. > > > > Just one question, OSG renders at the maximun amount of FPS it can, but > > ODE requires a fixed time step. How do you solve this problem? Thanks a > > lot. > > Is there a reason you're not synced to vertical swap? If you were to > enable that, then OSG would render at the refresh rate of the monitor > (unless you have a huge rendering load). Assuming you use the monitor > refresh rate as the ODE simulation interval, then the two sample rates > would match. End of problem. > > I'm not sure my Bullet work will help here, as Bullet doesn't require a > fixed time interval. You just pass an arbitrary elapsed time interval to > stepSimulation and Bullet produces sim results accordingly. > > osgBullet (at http://osgbullet.googlecode.com) includes a mechanism to > share transform data between separate rendering and physics threads, > allowing both to run at whichever rate they choose (not to mention take > advantage of multicore systems). So if you can't find any way for ODE > and OSG to use the same sample rate, then a mechanism like this might help. > > I seem to recall someone making some changes to osgViewer a while back > to control the frame rate. I didn't really follow that change or > discussion. Maybe just looking at the source code would be revealing. > -Paul > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > Hi,
I'm working on a project (work in progress, still growing) which combines bullet and osg. Currently there are only rigid bodies and I'm not using osgBullet or osgPhysics. What I've done so far: - separate threads for bullet and osg - usage of btDiscreteDynamicsWorld - a loader which loads 3d objects and calculates simplified collision bodies Any loaded 3d object is attached to the OSG-graph and its collision body is attached to the DynamicsWorld. The physics thread runs at a high frequency while the gfx-thread is synced to the vertical swap. Even if vsync is off you can implement a frame limiter by measuring the time a single frame needs to be calculated. You can then put the gfx thread to sleep (OpenThreads::Thread::microSleep()). You can calculate the frame-time in the same way for the physics-thread. Use this value as simulation step. The high update rate of the physics thread prevents punch-through effects for fast moving objects. The transform data of the collision bdoy is read from the gfx-thread in an OSG update callback. You may have to sync both threads here. Greetings Mathias Buhr -- _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
