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From: Tim Nikias
Subject: Using images in density-medias?
Date: 5 Feb 2002 13:58:06
Message: <3C602B2E.39A4AA9F@gmx.de>
I wanted to create an emission-media which actually uses
an image as base, simulating a glowing image.

Before, all I did, was use image-map right inside
the density-statement, but I don't get it to work.

Anyone know how to?

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html


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From: Warp
Subject: Re: Using images in density-medias?
Date: 5 Feb 2002 14:04:10
Message: <3c602caa@news.povray.org>
Already tried image_pattern?

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -


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From: Lutz-Peter Hooge
Subject: Re: Using images in density-medias?
Date: 5 Feb 2002 14:12:09
Message: <MPG.16ca4ce65d03bb809896da@news.povray.org>
In article <3C602B2E.39A4AA9F@gmx.de>, tim### [at] gmxde says...

> Before, all I did, was use image-map right inside
> the density-statement, but I don't get it to work.

What exactly was the problem? When I tried this some time ago it worked 
without probs.

Lutz-Peter


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From: Tim Nikias
Subject: Re: Using images in density-medias?
Date: 5 Feb 2002 14:17:02
Message: <3C602F9E.846E21E2@gmx.de>
>   Already tried image_pattern?
>

I only get a gray-scale image then.

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html


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From: Tim Nikias
Subject: Re: Using images in density-medias?
Date: 5 Feb 2002 14:18:00
Message: <3C602FD7.A4A4928@gmx.de>
>
> What exactly was the problem? When I tried this some time ago it worked
> without probs.

It returns error message and points at the image_map statement inside
the density.

Some time ago, this way worked for me as well...

I'm stuck!
--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html


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From: Lutz-Peter Hooge
Subject: Re: Using images in density-medias?
Date: 5 Feb 2002 14:28:41
Message: <MPG.16ca50b3e22f3aa69896db@news.povray.org>
In article <MPG.16ca4ce65d03bb809896da@news.povray.org>, lpv### [at] gmxde 
says...

> What exactly was the problem? When I tried this some time ago it worked 
> without probs.

Oh, I just tried re-render it, and it didn't work anymore.
So propably i created that one in MegaPov...

However, using image_pattern or a function makes it work but without 
color, so you will have to use 3 medias (one for each color component).

Is there a reason why Pov 3.5 doesn't accept an image_map inside a 
density?

Lutz-Peter


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From: Tim Nikias
Subject: Re: Using images in density-medias?
Date: 5 Feb 2002 14:33:19
Message: <3C60336F.830840EF@gmx.de>
Thanks for your testing, but I guess I'll have to stick to a "normal"
image (not glowing).

Also, while testing, I've found that using a contrast-adjusted and
shadow-midtone-highlight-adjusted image, I can achieve something
pretty realistic.

It was meant for a dark room, without much light, and the adjustments
to the image-map made if appear more like an in-scene radiosity-affected
image-map (though it isn't, of course).

I'll post a version of that on my homepage WIP sometime this night.

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html


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From: Warp
Subject: Re: Using images in density-medias?
Date: 5 Feb 2002 15:31:55
Message: <3c60413a@news.povray.org>
Tim Nikias <tim### [at] gmxde> wrote:
:>   Already tried image_pattern?

: I only get a gray-scale image then.

  It's difficult to tell what is wrong without seeing any code.

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -


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From: Jaime Vives Piqueres
Subject: Re: Using images in density-medias?
Date: 5 Feb 2002 16:33:04
Message: <3c604f8f@news.povray.org>
Lutz-Peter Hooge wrote:


> Oh, I just tried re-render it, and it didn't work anymore.
> So propably i created that one in MegaPov...

  Same case here... I used it on my IRTC entry for "LABORATORY", but that 
was MegaPOV. I don't know right now if it was posible with 3.1, but I 
doon't think so. Anyhow, I don't remember to have seen this specified as a 
MegaPOV feature.... hmmmm. 

  Indeed, this was very handy for "luminous" objetcs with global ambient 
set to 0.... I'm also curious about why this does not work on 3.5. Must 
investigate...

-- 
Jaime Vives Piqueres

La Persistencia de la Ignorancia
http://www.ignorancia.org


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From: Tim Nikias
Subject: Re: Using images in density-medias?
Date: 5 Feb 2002 16:40:24
Message: <3C605138.2B584D4C@gmx.de>
In basic, its like this:

object{ Area hollow pigment{rgbt <0,0,0,1>}
 interior{media{emission 1 intervals 1 method 3 samples 1,5
 density{image_map{tga "image.tga"} translate -.5 /*centers the image*/}
}}
}

It does create some sort of emission, based on the calculated grayness
of a colored pixel, but the colors get lost. That's not the behaviour of
POV-Ray 3.1g, and probably MegaPOV (I don't use MegaPOV).


--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html


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