[Bf-committers] Re: Minnaert shader

[Jean-Luc Peuriere]

Le 9 avr. 05, à 11:04, Jonathan Merritt a écrit :

> I've been extremely busy, so have only just been able to get around to
> responding to the discussion on the Minneart shader.  I've got to say
> that I think most of the discussion about the "correctness" of the
> shader has been a bit silly..

i will quote myself on that :

> The issue is the following :
>
>  On the net and in other apps, Minnaert refer to a defined shader 
> (less used than lambert agreed but still well known), and the 
> parameter for it is k also known as darkness. For k = 1, gives same 
> result as standard Lambert.
>
> NVidia diffused a different version of this shader, where results are 
> similar but  inversed. it is known on several internet referral pages 
> as Minnaert-B or NV-Minnaert.
>
> The problem is only there, same name, same parameter name but gives 
> different result ! Not good in my book.

Your own links say that k=1 ==> Lambert.

Jorge said you mixed the 2 versions, it appears it is only base one.

the issue is not silly at all, but leads to confuse an user who would 
try to follow some documentation or tutorial on the net.

There is 2 solutions to correct that :

- changing the parameter name to something else (eg obscuring) while 
stating in the doc the relation with k
- using the same range as the others.

No change of code is needed, it is only a matter of UI.

We are of course free to make changes but should be very wary about 
doing things our own different way when it is unneeded.
-- 
Jean-Luc
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: text/enriched
Size: 1585 bytes
Desc: not available
Url : http://projects.blender.org/pipermail/bf-committers/attachments/20050409/55fb1ffe/attachment.bin