Javadoc
This Filter does basically the same as a PointLightShadowRenderer except it
renders the post shadow pass as a fullscreen quad pass instead of a geometry
pass. It's mostly faster than PointLightShadowRenderer as long as you have
more than a about ten shadow receiving objects. The expense is the draw back
that the shadow Receive mode set on spatial is ignored. So basically all and
only objects that render depth in the scene receive shadows. See this post
for more details
http://jmonkeyengine.org/groups/general-2/forum/topic/silly-question-about-shadow-rendering/#post-191599
API is basically the same as the PssmShadowRenderer;