Introduction - If you have any usage issues, please Google them yourself
		 
Shadows are an important visual cue.  Unfortunately, most real-time techniques f
computing shadows generate hard and, in the case of shadow-maps, aliased 
shadows.  We can soften the edges of the shadows by employing percentage-clos
filtering.  In fact, a sufficiently large percentage-closer filter approximates soft 
shadow boundaries well.  High quality soft shadows, however, require a large 
number of samples.