Hi Wojtek, the idea of PSSM is to split the view frustum into n-parts. then for each of such sub volume (frustum) we have to render one shadow map and apply the shadow for such a volume. or in other words, we like to get one texture (shadow map) for one sub-frustum starting at near (plane : split i) and end at far (plane : split i + 1). in this sub frustum the shadow map [i,i+1] is active, and this map is used to render the shadow. so if we can define in the Lispsm a range [i,i+1] /// [near,far] then we have one split for the pssm. next we need many such splits, and finally we get the pssm working (many for n splits from near_frustum = near_0, far_frustum = far_n [near_0, far_0][near_1=far_0,far_1] [far_1,...] [far_n-1,far_n = far_frustum]
would this be easy to do? multiple shadow technic nodes in one scene to get such maps. /adrian 2008/10/6 Wojciech Lewandowski <[EMAIL PROTECTED]> > Adrian, > > I am afraid I don't understand what you want to do. Could you provide bit > more explicit explanation ? At higher level of abstraction using LispSM with > PSSM should be possible but I am not that familiar with PSSM implementations > to judge whether it is easy or difficult task to merge two approaches. > > If you closely look at LightPerspectiveShadowMap class you will find that > it basicaly overrides one method of ProjectionShadowMap template class. Rest > of heavy work is done by underlying MinimalXXXShadowMaps. These classes > attempt to compute minimal shadowed volume (as ConvexPolyhedron - polytope > like object). This volume could be used by modified PSSM instead of view > frustum. This computed volume is passed as one of the input arguments to > the method that LispSM overrrides. > > Cheers, > Wojtek > > > ----- Original Message ----- > *From:* Adrian Egli OpenSceneGraph (3D) <[EMAIL PROTECTED]> > *To:* OpenSceneGraph Users <[email protected]> > *Sent:* Monday, October 06, 2008 11:40 AM > *Subject:* [osg-users] Lispsm / PSSM merge ? > > Hi all > > The osgShadow lib becomes a really nice shadow toolkit, thanks all to work > out on different shadow technics. As we all understand is that the PSSM > would be one of the most > robust shadowing technic for large terrain, now we should be able to merge > the lispsm with the pssm idea: > > would it be possible to add one feature to lispsm: > > start shadow at near plane and stop shadow at far plane, then we will need > a combiner of the lispsm shadow, then we gets pssm idea back. would this be > possible to do, or do we need to rewrite the whole pssm stuff? > > would it be possible to add some filter into the GLSL shader code for > shadows: pcf ... ? > > adrian > > > > -- > ******************************************** > Adrian Egli > > ------------------------------ > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > -- ******************************************** Adrian Egli
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