I've just got variance shadow maps working in my game (I'm using XNA) but something
curious occurs to me. I'm using what I assume is the standard algorithm:
http://fabiensanglard.net/shadowmappingVSM/
http://electronicmeteor.wordpress.com/2011/11/06/xna-4-0-variance-shadow-mapping-sample/
I don't see why it's necessary to use the moments to calculate the variance, use chebyshev's upper
bound etc etc. Assuming you've already blurred the shadow map, why can you just use read each
pixel's occlusion directly from the r component?
It seems to work fine (if anything it looks better). I assume it's gonna cause a problem further down the line
though or people wouldn't have bothered with all those extra lines of code??
Thanks