Hi Rui, Artifacts can be caused by a number of different reasons, as I have seen the models, screenshots of the artefacts I don't feel comfortable pointing at any particular cause or solution.
Having a public model we can test against would be very useful. Also modifying the osgshadow example to have a unit test for these case would also be useful. Given a unit test we as group can start refining things for the problem cases. As a more general note ViewDependentShadowMap doesn't yet provide shaders that resolve the issue correct lighting of shadows, the thread you link to discusses this topic. Introducing the required shaders as an option into ViewDependentShadowMap would address one of the areas that artefacts can be seen when users don't provide their own shaders that do the lighting correctly. This won't solve all the potential artefacts that we see when doing shadow mapping but it would at least discount one possible set of problems. Robert. On 12 March 2012 09:38, Wang Rui <wangra...@gmail.com> wrote: > Hi all, > > I'm currently working on an example that uses > osgShadow::ViewDependentShadowMap for generating dynamic shadows on a large > area of buildings. It can work correctly on a huge city which is created by > CityEngine and then converted to OSG styled scene graph. It also generates > aliasing issues as expected, but I'm still looking for some good solutions > to reduce such problem and want to discuss them in this thread if possible. > My test program and a simple shader file can be found in attachement. > > I've already read a similar topic at: > http://lists.openscenegraph.org/htdig.cgi/osg-users-openscenegraph.org/2011-August/053731.html > And I believe it is necessary to apply some filters on the shadow map (the > test shader file simply uses PCF here) and increase the texture resolution > as well. But for huge scene, a 4096-sized RTT texture will be a heavy > burden. So I wonder if there are some more methods to choose, for example, > is it possible to change the internal format of the texture to > GL_DEPTH_COMPONENT32 to improve the shadow comparision process? > > Meanwhile, is it necessary to perform a screen space blurring to reduce the > aliasing effect? It is a serious problem for my scene now as I can't use a > very high resolution. Could anyone suggest some other possible methods on > the post-processing level? To be honest, the ViewDependentShadowMap is the > best shadow solution for me at present as it is easy to be integrated with > custom shaders and embedded into a deferred shading framework. > > The test city models are about 180MB. If any of you think it important for > digging into the problem. I'd like to share them freely, too, as I believe > these automatically generated models should not have any copyrights with > them. :-) > > Cheers, > > Wang Rui > > > _______________________________________________ > 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
