Hi Nick, I don't know much about PSSM. I am na author of LispSM implementation. However, many osgShadow techniques use shaders and they will not work out of the box for all the applications that also use shaders. In this case one have to 1) subsitute shadow shaders to add aplication shader functionality or 2) override shadow shaders at the scene root with application shaders that were modified to include shadow term computation (using the uniforms theat shadow technique sets). Check forums there was a lot on the subject recently.
Both cases are advanced topics, so one trying to do this usually must have good knowledge of C++ (to read and understand the Technique code), GLSL (to modify shaders), shadow map algorithm (to know whats important is shaders, NVidia has nice presentations). Its steep path but implementing CSM technique in OSG for multithreaded/multimonitor from scratch will be much much steeper. Wojtek From: Trajce Nikolov Sent: Wednesday, December 09, 2009 12:11 PM To: OpenSceneGraph Users Subject: Re: [osg-users] osgShadows I tried both. PSSM gives some artifacts (see the attached image) - the white in the background, also, some flickering of the shadow on the models. Nick http://www.linkedin.com/in/tnikolov Sent from G�m��suyu, �stanbul, Turkey On Wed, Dec 9, 2009 at 12:27 PM, Wojciech Lewandowski <lewandow...@ai.com.pl> wrote: Hi, � Cascaded Shadow Maps is�the same as Parallel Split Shadow Map. PSSM is implemented in osgShadow. Also LispSM�could�work for you scenario. � Cheers, Wojtek Lewandowski � � � � From: Trajce Nikolov Sent: Wednesday, December 09, 2009 10:19 AM To: OpenSceneGraph Users Subject: Re: [osg-users] osgShadows Hi Harold, yes, my light source is the "sun". No other lights in the scene yet. And the results are not good. I will do research on the "cascade shadowmaps" and will try to implement it. Thanks for the hint Nick http://www.linkedin.com/in/tnikolov Sent from G�m��suyu, �stanbul, Turkey On Wed, Dec 9, 2009 at 11:13 AM, Harold Comere <harold.com...@gmail.com> wrote: Hi Nike, There is many way to get shadows and the shadowing technique choice shall depend of your scene data. The two basic shadowing techniques are : - shadow maps ( image based ) - shadow volumes ( geometry based ) Shadow maps are very cheap and easy to implement but will works good only if your light is not far from what you are shadowing due to the image approach. So if you have a large terrain with an unique directional light ( as sun ), simple shadowmaps should do an ugly result. You could try "cascade shadowmaps" which is a technique used a lot in video games. It uses a kind of shadowmap LOD to avoid image based algorithms issues and stay cheap. Shadow volumes generate very accurate shadows but as it is based on geometry, if your scene geometry is complex you will experience some perf issues. Again, the shadowing technique choice depends of how many lights you have, where they are, what you are shadowing etc. Give a bit more details of your goal and i'm sure some osg pro will bring to you the ideal solution using osg :) Regards, Harold _______________________________________________ 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 _______________________________________________ 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
_______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
