POV-Ray : Newsgroups : povray.binaries.images : Colors from golds.inc and metals.inc : Re: Colors from golds.inc and metals.inc Server Time
1 Mar 2024 16:57:49 EST (-0500)
  Re: Colors from golds.inc and metals.inc  
From: Alain Martel
Date: 23 Feb 2022 10:01:52
Message: <62164c60$1@news.povray.org>
Le 2022-02-22 à 10:48, Thomas de Groot a écrit :
> Op 22-2-2022 om 14:36 schreef Cousin Ricky:
>> When Thomas de Groot challenged Alain and me to write improved
>> metals.inc, one of my first thoughts was "Why bother? It's a lost
>> cause."  Alain's solution was to just replace all the ambients with 0,
>> but I think that's too simplistic.  That file and golds.inc were written
>> before POV-Ray had metallic reflection.  File golds.inc goes through an
>> elaborate ritual to compensate for this deficiency, while metals.inc
>> ignores the problem completely.  Everything about those two files
>> screams "OBSOLETE!"  But the challenge still gnaws at me.
>>
>> One question that must be answered is should we assume that the colors
>> are gamma pre-encoded?  Image stock_metal_gamma-srgb.jpg assumes that
>> they are, and uses the srgbft keyword to decode them.  Image
>> stock_metal_gamma-linear.jpg assumes they are not, and just uses the
>> colors as-is.  Comparing them, it seems to me that the colors were not
>> pre-encoded, unlike those in colors.inc.
>>
>> Both images use assumed_gamma 1, and the spheres use this finish:
>>
>>    finish
>>    { ambient 0 diffuse 0
>>      reflection { 1 metallic }
>>      specular albedo 1 metallic
>>      roughness 1 / 3000
>>    }
>>
>> Of course, any improvements to these files will cause old scenes to look
>> different.  Better, but different.
> 
> I truly appreciate your thoughts and efforts. To address your last 
> comment: I am increasingly convinced that trying at all costs to find 
> solutions, at the same time preserving the aspect of old scenes, is a 
> dead end. I would strongly be in favour of making those textures up to 
> date, whatever the costs. For older scenes, there still are the older 
> POV-Ray versions available if necessary.
> 

Why struggle to keep old scenes to render identically when the change 
make them better ?


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