Hi Max, Osgparticleeffect is a nice example. I don't see how this example relates to the floating point precision problems introduced by the changes to ModularEmitter.cpp last September? Can you be more specific?
-----Original Message----- From: GMD GammerMaxyandex.ru [mailto:[email protected]] Sent: Wednesday, April 22, 2009 12:43 PM To: [email protected] Subject: Re: [osg-submissions] osgParticle ParticleSystem andModularEmitterin different coordinate systems see osgparticleeffect example ... max. 22.04.09, 21:35, "Jolley, Thomas P" <[email protected]>: > Hi Robert, > A little late but I just noticed this change has broken particle > effects in my application. When I tried to change my application to > work with this change I get problems with floating point precision on > the particles. I don't think this change is the correct solution for > fixing floating point precision problems with particle effects. It's > better done at the application level by separating out non-particle > system nodes, particle processors, and the geodes where particles are placed. > An appropriate MatrixTransform can be placed above each new graph to > resolve the precision issues for the particular frames of reference. > Perhaps Tim Moore can explain further the problem he was trying solve > by giving us an example. > Here are some examples of how this change looks like it might work and > how it doesn't work using the cessnafire.osg model. > 1. How it looks like it might work. Load the cessnafire.osg model > and put it under a MatrixTransform. Using the MatrixTransform, move > the model to about 6M meters. Watch the particle effects when the > model is slowly translated using the MatrixTransform. The precision > of the particles look good. The particles are emitted from the > correct location from the model. The particles once emitted move with > the MatrixTransform when they should stay fixed to the world > coordinate system. > 2. How it doesn't work. Load the cessnafire.osg model and put it > under a MatrixTransform. Put the MatrixTransform under a Group. Move > the Geodes where particles are placed so that they are under the top > Group node. You may as well move the ParticleSystemUpdater under the > top Group node. Moving the model out to 6M meters and slowly > translate the model using the MatrixTransform. The precision of the > particles is bad. > The particles are emitted from the correct location but possibly the > wrong direction due to precision problems. The particles once emitted > stay fixed to the world coordinate system as I would expect. > -----Original Message----- > From: Robert Osfield [mailto:[email protected]] > Sent: Thursday, September 18, 2008 5:12 AM > To: OpenSceneGraph Submissions > Subject: Re: [osg-submissions] osgParticle ParticleSystem and > ModularEmitterin different coordinate systems Thanks Tim, I've merged > your changes, and also added a Drawable::getWorldMatrices(const Node*) > method and tweaked your code to use this rather than needing to use > getParents(0) and then > getWorldMatrices() as getParents(0) could in theory be null (although > in a correctly set up scene it won't be). > Could you do an svn update and test out my changes, Robert. > On Wed, Sep 10, 2008 at 9:39 AM, Tim Moore <[email protected]> wrote: > > Hello, > > This submission fixes a bug when the ModularEmitter and > > ParticleSystem are in different frames of reference. Specifically, > > it supports the case where the ParticleSystem is not in the world > > frame. One way this can come up is if your world coordinate system > > is Earth-centric; the float coordinates of particles don't have > > enough precision to avoid terrible jitter and other rendering > > artifacts, so it's convenient to root the particle systems in a > > local Z-up coordinate system that gets > moved around from time to time. > > > > I haven't touched the rotation and angular velocity properties of > particles. > > IMHO they are pretty broken, dealing in Euler angles and such, and I > > see that they aren't used in the rest of the particle system code. > > > > Tim > > > > _______________________________________________ > > osg-submissions mailing list > > [email protected] > > http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-opensce > > ne > > graph.org > > > > > _______________________________________________ > osg-submissions mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscene > gr > aph.org > _______________________________________________ > osg-submissions mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscene > graph.org -- Яндекс.Открытки на все случаи жизни http://cards.yandex.ru/ _______________________________________________ osg-submissions mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org _______________________________________________ osg-submissions mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org
