POV-Ray : Newsgroups : povray.beta-test : Media densities Server Time
1 Nov 2024 23:16:38 EDT (-0400)
  Media densities (Message 1 to 3 of 3)  
From: Slime
Subject: Media densities
Date: 3 Feb 2002 15:07:09
Message: <3c5d986d$1@news.povray.org>
Media densities are clipped to the region [0,1]. (Simple proof: make a media
with a density of function{1.01} and the media will be the same as though it
were just function{.01}.) Is this the intended behavior? It seems to me that
it's perfectly logical to specify a media that's higher than 1. In fact, if
I want to keep the same average density, but create a little noise in it, I
have to do something like function{f_noise3d(x,y,z)+.5}, which doesn't work
as expected with the current behavior.

- Slime
[ http://www.slimeland.com/ ]
[ http://www.slimeland.com/images/ ]


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From: Christopher James Huff
Subject: Re: Media densities
Date: 3 Feb 2002 15:49:12
Message: <chrishuff-CF61B8.15503503022002@netplex.aussie.org>
Media densities are specified by the color_map, not by the pattern. The 
default color_map goes from black to white, you need to change it if you 
want a larger range.
I don't know if the function pattern values are still clipped...you may 
just be able to specify a color_map using values outside the [0, 1] 
range, like:

color_map {
    [0 rgb 0]
    [10 rgb 10]
}

If not, you will need to scale the function value down to the [0, 1] 
range and specify a brighter color in the color_map.

-- 
Christopher James Huff <chr### [at] maccom>
POV-Ray TAG e-mail: chr### [at] tagpovrayorg
TAG web site: http://tag.povray.org/


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From: Thorsten Froehlich
Subject: Re: Media densities
Date: 3 Feb 2002 17:39:06
Message: <3c5dbc0a@news.povray.org>
In article <chr### [at] netplexaussieorg> , Christopher
James Huff <chr### [at] maccom>  wrote:

> Media densities are specified by the color_map, not by the pattern. The
> default color_map goes from black to white, you need to change it if you
> want a larger range.
> I don't know if the function pattern values are still clipped...

Almost all patterns are clipped to 0-1, or at least they are only defined
within that range.

Using a function pattern that returns values outside the range of 0-1 may be
different from version to version.  One should not depend on it (just like
with the other patterns).

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

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