[David Neubelt <david@re...>]

Looks like you want to normalize the 3d vector made from the basis
coefficients (-f[1,1], -f[1,-1], f[1,0]). Section 3.3 ZH Error Analysis
paragraph 2.

 

-= Dave

 

From: Dan Treble [mailto:daniel.treble@...] 
Sent: Thursday, February 02, 2012 3:22 PM
To: gdalgorithms-list@...
Subject: [Algorithms] Pick dominant light from sh coeffs

 

I have 9 red, 9 green and 9 blue sh coefficients (packed using the
method in appendix 10 of
http://www.ppsloan.org/publications/StupidSH36.pdf).

 

I want to pick a single dominant light to use for specular. How would I
go about efficiently extracting the direction and color of that light
from the coefficients?

 

Looks like I need to calculate the "optimal linear direction" which is
supposedly in this paper
http://research.microsoft.com/en-us/um/people/johnsny/papers/ldprt.pdf,
however I can't see it. Worse still, if it is in there, it is probably
an integral that I will struggle to turn into code!

 

Thanks

 

Dan