Hi D.J., (please use your name so we know how to address you)
I am in the same business as you, solar system simulations and such. And I too use DPN happily, but not much experience with osgShadow. One advice is to make sure you're running single thread with OSG, I think it is a strong requirement of DPN so far, it might get better with future. As for the eclipses, it's hard to model them correctly with regular shadows, so I opted to just draw transparent cones (one for the penumbra, one for the umbra) see i.e.: http://orsa.sourceforge.net/screenshots/misc/eclipse.png Cheers, Pasquale On Tue, Jul 21, 2009 at 2:30 PM, D.J. Caldwell<dlcaldwel...@gmail.com> wrote: > I am a developer for a program that visualizes large scale (solar > system) and small scale (desktop) scenes. We would like to be able to > visualize shadows in our scenes for things like solar/lunar eclipses, > and ground vehicles with headlights traveling over terrain in and out of > sun light. > > We started using OpenSceneGraph around version 2.2 or 2.4. We are now > moving from version 2.6 to version 2.8. We have been using an > adaptation of the DepthPartitionNode from the osgdepthpartition example > to help with rendering since we often operate in a solar system scene, > with orbits, trajectories and lines of sight displayed as lines. > We also keep the camera positioned at the origin and move the scene > (by way of a transform) to help cut down on jitter in the near view > caused by floating point error. > > The problem is... > > While trying to make use of osgShadow, I have discovered apparent > interference between shadowing and the depth partition node (see two > images attached). It would seem that the depth partition node causes > the shadow to move with the camera viewing direction, rather than > staying with the light direction. In other words, moving the camera > causes the shadow to move in an unexpected and undesired manner. > > My questions are... > > Is there a way to get osgShadow and a depth partition node to play nice > together, or are they at odds by design? Is that, in fact, what I am > seeing, or have I set my test case up incorrectly? Perhaps there is > some other way to get the benefits of depth partitioning that will not > interfere with shadows? > > I have searched the archives for discussion of using shadows with a > depth partition node, but I seem to be missing it (or it just isn't > there). I did find one reference > > http://www.mail-archive.com/osg-users@lists.openscenegraph.org/msg11218.html > > which says to follow the source code. I looked under the hood for > ParallelSplitShadowMap, ShadowMap, and LightSpacePerspectiveShadowMap to > try to get a feel for how best to proceed, but I'm not seeing a clear > path to a solution which allows use of shadowing with a depth partition > node. I was hoping to avoid a custom solution, either that combines > the two, or maybe goes in a totally different direction, but my gut > reaction is that it may be unavoidable. > > In addition to the images, I have also attached my test environment > source code, so that you can interact with the test environment which > produced the two attached images. The source code represents a > simplified model of our use of OSG in our program. I have it set up so > that, if --noUpdate is specified on the command line at run time, the > home position of the camera manipulator is set to show the problem I am > seeing. It may be easiest to see with --no-base-texture on the command > line (which is what I used for the images). > > My development environment is currently: > > OpenSceneGraph 2.8.1 > Visual Studio 2005 Professional Edition SP1 > Microsoft .NET Framework Version 2.0 SP2 > Microsoft Windows XP Professional Service Pack 3 (win32) > NVIDIA GeForce Go 7950 GTX (nv4_disp.dll version 6.14.10.9422) > > Thanks in advance! > > D.J. Caldwell > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
