POV-Ray : Newsgroups : povray.news-submissions : Spectral Rendering with POV-Ray : Re: Spectral Rendering with POV-Ray: comments on the tutorial Server Time
10 Jun 2023 07:30:48 EDT (-0400)
  Re: Spectral Rendering with POV-Ray: comments on the tutorial  
From: Ive
Date: 25 Sep 2012 14:10:05
Message: <5061f37d@news.povray.org>
Am 24.09.2012 16:02, schrieb Thomas de Groot:
> Done a new render with finish{} added to the gold.
Hm, I fail to notice any improvement :(

Having not used any of the standard texture include files myself since 
decades I took a quick look at golds.inc and assume you did replace the 
P_Gold statements by
#declare P_Gold1 = srgb CVect1;
...and so on, right?

Well, I have sworn to keep my mouth shut on this topic but I simply 
can't help it. As I have stated multiple times all "color math" works 
only as expected within a linear color space (and doing this kind of 
math myself very often is one of the reasons I advocate for 
assumed_gamma 1.0 since decades).
Now the author of golds.inc does apply a lot of mathematical operations 
on this declared color vectors afterwards - but when this vectors are 
already defined as non-linear srgb values all these operations are 
pretty pointless and the final textures will never look like expected.

And to get even a bit on topic ;) you might find the M_Gold macro with 
its sub-macro calls that are used for *Preview* rendering useful (and 
with a high reflective value like M_Gold(0.9) ) as they give under all 
lighting conditions fairly realistic results.


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