The old shadow kernel formula is not "wrong" per se, as the only judge
is if it looks good. However, the formula used is not really gaussian.
Also, the kernel size calculation doesn't really make sense to me.
This commit change the kernel formula to actually use a gaussian
distribution. As far as I can tell, there is no perceivable difference.
Except now the effective shadow radius is smaller for the same config.
Also, made that part of code a bit more mordern.
Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
dffde065b1