= osgShadow =
[[TracNav(TracNav/CommunityTOC)]]

The osgShadow !NodeKit  is now underway and will be integrated into core !OpenSceneGraph and all going well will be part of the next release - OpenSceneGraph-1.3.  We don't have a release date for this release, so if your impatient, check up on progress by sending a querry to the osg-users mailing list.  The code will first be available in the CVS version of the !OpenSceneGraph.

Deliverables for the first release of osgShadow are:

== MUST HAVE ==
 * !NodeKit  containing nodes and helper classes for specify:
   - light sources
   - the parts of the scene being shadowed
   - the parts of the scene which cast shadows
   - a mechansim for specifying the shadow techniques/implementations
   - a mechansim for specifying the options required to configure the different shadow techniques
 * Shadow techniques:
   - stencil volume shadows

== Could have ==
 * Shadow techniques:
   - shadow textures
   - shadow maps
   - parallel split shadow maps

== Existing implementations that can be used as source material ==
Stencil Shadow Volumes implementations:
 * ChangzhiLi's osgShadow [http://openscenegraph.org/osgwiki/uploads/NodeKits/osgShadow.zip implementation]
 * Shi Jazheng and Anders Backman´s (VRlab) [http://www.vrlab.umu.se/research/colosseum3d/osgshadowvolumes/shadow_volume_thesis.pdf Shadow Volume Thesis] and osgShadowVolume [http://www.vrlab.umu.se/research/colosseum3d/osgshadowvolumes/osgshadowvolume-060906.tgz implementation]

Parallel Split Shadow Map implementations:
 * Terry Welsh's Parallel Split Shadow Map [http://www.reallyslick.com/~terry/stuff/PSSMdemo.tar.gz implementation]
  * Adrian Egli's Parallel Split Shadow Map [attachment:PSSM.zip implementation]

Simple Depth Shadow implementations:
 * osgdepthshadow from OpenSceneGraph/examples/osgdepthshadow
 * Mihai Radu's version of the above, separated in classes and added a small scene manager [[Attach:depthShadow.zip implementation]

== Online resource that are a good source of information about the various shadow techniques ==
 *  [http://www.gamedev.net/community/forums/topic.asp?topic_id=399014  GameDev Parallel-Split Shadow Maps demo ]
 *  [http://www.gamedev.net/reference/articles/article1873.asp The Theory of Stencil Shadow Volumes (GameDev)]
 *  [http://www.devmaster.net/articles/shadow_volumes/ An Introduction to Stencil Shadow Volumes (DevMaster)]
 *  [http://developer.nvidia.com/object/robust_shadow_volumes.html  Practical and Robust Shadow Volumes (Nvidia)]
 *  [http://developer.nvidia.com/object/fast_shadow_volumes.html Fase Shadow Volumes (NVidia)]
 *  [http://en.wikipedia.org/wiki/Stencil_shadow_volume Shadow volume (Wikipedia)]
 *  [http://artis.inrialpes.fr/Publications/2005/HHLH05/ ZP+: correct Z-pass stencil shadows]
 *  [http://www.flipcode.com/articles/article_shadowvextrude.shtml Accelerated Stencil Shadow Extrusion via Vertex Blending (flipcode) ] [[BR]] - note Shi Jazheng's work above suggest that GPU compute of the shadow volume is slower than CPU..
==  Recent mailing list threads on shadows ==
 * Terry Welsh -  [http://openscenegraph.net/pipermail/osg-users/2006-September/068417.html osg-users Parallel-Split Shadow Map with osg PSSM]
 * Terry Welsh -  [http://openscenegraph.net/pipermail/osg-users/2006-September/068544.html osg-users Parallel-Split Shadow Map with osg PSSM]
 * Adrian Egli -  [http://openscenegraph.net/pipermail/osg-users/2006-September/068278.html osg-users Parallel-Split Shadow Map with osg PSSM]