Shadow maps unable to properly project shadows in some situations?

Question

In the shadow map sample provided by Microsoft I've noticed an issue where shadows are not properly projected when thin geometry is projected at high angles, see here the shadows being projected, notice the poles from the lights are not projected: http://imgur.com/QwOBa.png

And in this screenshot we see things from the lights perspective, not ethe poles are clearly visible: http://imgur.com/k2woZ.png

So two questions really, is this an actual bug or a limitation with shadow mapping and if it's a bug how can I fix it?

The source is directly from the Microsoft DirectX Sample Browser 'ShadowMap' sample from July 2004, the sample browser is the latest August 2009 one.

Answer 1

Have a look at your shadow buffer (use Pix or write it to disk).