POV-Ray : Newsgroups : povray.general : Adding two images via functions...? : Re: Adding two images via functions...? Server Time
4 Aug 2024 08:23:31 EDT (-0400)
  Re: Adding two images via functions...?  
From: Tim Nikias v2 0
Date: 17 Jun 2003 07:17:03
Message: <3eeef8af$1@news.povray.org>
I'm trying to combine all three color componentes
now. So that I might take any image, and black=transparent,
white=non-transparent, and every color in between will
get transparency based on total brightness... Sort of like
a color overlay. Anyone know how to do that?

-- 
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: Tim### [at] gmxde

> I'm doing it like this now:
>
>  #local _I=function{pigment{_ImagePigment}}
>  #local _Image=texture{
>   pigment{function{_I(x,y,z).x}
>    color_map{[0 rgbt <1,1,1,1>][1 rgbt <1,1,1,0>]}
>    poly_wave _Exponent
>    }
>   finish{ambient _Brightness diffuse 0}
>   }
>
> And it works fine. Thanks for the suggestion though,
> even though that one didn't work, it got me to the right
> place.
>
> Regards,
> Tim
> -- 
> Tim Nikias v2.0
> Homepage: http://www.digitaltwilight.de/no_lights
> Email: Tim### [at] gmxde
> "Mark Weyer" <wey### [at] informatikuni-freiburgde> schrieb im Newsbeitrag
> news:3EE### [at] informatikuni-freiburgde...
> > > What I'm trying to do is following:
> > > I've got two images, one in grayscale,
> > > the other just some image. I want to
> > > add the grayscale to the other image, so
> > > that white areas of the grayscale are white
> > > in the combination, and black won't change
> > > the colored image.
> >
> > Let eps be small enough. I usually use
> >
> >    #declare eps = 1e4;
> >
> > Apply the gray picture as a texture to a plane and add:
> >
> >    pigment_map {
> >      [0 rgbt <0,0,0,1-eps>]
> >      [1 rgbt <1,1,1,1-eps>]
> >    }
> >    finish {ambient 1/eps}
> >
> > There should be a way to do that without the pigment_map,
> > but I am unsure enough about above syntax. Hope the idea
> > made it through, though...
> >
> >
> > -- 
> > merge{#local i=-11;#while(i<11)#local
> > i=i+.1;sphere{<i*(i*i*(.05-i*i*(4e-7*i*i+3e-4))-3)10*sin(i)30>.5}#end
> > pigment{rgbt 1}interior{media{emission x}}hollow}//  Mark Weyer
> >
>
>


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