POV-Ray : Newsgroups : povray.advanced-users : Gamma and light sources : Re: Gamma and light sources Server Time
23 Jun 2021 05:45:00 EDT (-0400)
  Re: Gamma and light sources  
From: Alain
Date: 31 Aug 2015 16:04:27
Message: <55e4b34b$1@news.povray.org>
Le 15-08-31 11:55, Mike Horvath a écrit :
> Do light sources in POV 3.7 use srgb or rgb? Do the colors need to be
> adjusted to the new system? For instance:
> light_source
> {
>      -z * 40960
>      <pow(light_color.red,2.2),pow(light_color.green,2.2),pow(light_color.blue,2.2)>
>      rotate        -x * 60
>      rotate        +y * 45
>      parallel
> }

By default, they use rgb unless you explicitely use srgb.

light_source{Location rgb<1,0.5,0.4>} use the rgb colour space.
light_source{Location srgb<1,0.5,0.4>} use the srgb colour space.

Your sample don't translate from rgb to srgb but, instead, adjust for a 
gamma of 2.2.

You should use assumed_gamma 1 in your global_settings section and set 
display_gamma 2.2 in the master .ini file. Once it's done, you should 
never need to perform that kind of gamma "magic" in your scenes.

By the way, rotate<-60, 45> or rotate<-60, 45, 0> will give you exactly 
the same result as your pair of rotates.

Post a reply to this message

Copyright 2003-2021 Persistence of Vision Raytracer Pty. Ltd.