> Am 27.01.2011 11:22, schrieb Jaime Vives Piqueres:
>> Can anyone think of a better (more suited) operation than simple
>> multiplication?
>
> No ;)
>
> I think just *one* multiplication should do it.
>
> Actually it looks to me like the saved lightmap file is not linear. Or
> maybe it gets gamma corrected when loading it back?

   I think it is linear, as I'm using assumed_gamma 1 and the output is 
PNG, but I'm never sure about anything if gamma is involved. ;)

> Have you used OpenEXR files for the lightmap or something else?

   Unfortunately I cannot use OpenEXR, as POV-Ray doesn't supports alpha 
output on these... and I need it for the trick which "grows" the UV maps 
to avoid the visible seams (of course, HDR output will be the best 
solution).

> And that min() bothers me as it defeats the idea of HDR lighting.

  Well, as I'm not using HDR, I guess it shouldn't matter.

> What kind of artefacts do you get?

   Dot-artifacts, exactly them same ones that FlyerX was describing on 
this thread:

http://news.povray.org/povray.general/thread/%3C4ca53804$1@news.povray.org%3E/?ttop=355419&toff=50


   In the mean time, I got slighty better results using the 
multiplication and then applying to the result the formula for the Gimp 
"overlay" mode. Also, I'm not sure if baking lightmaps with white 
pigments on the objects was the best choice... perhaps a medium grey 
would get better results? (trying it now...)

   Regards,

-- 
Jaime Vives Piqueres
		
La Persistencia de la Ignorancia
http://www.ignorancia.org

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