Hi,

I'm trying to create a wall with a graffiti image on it. To that
end, I downloaded a grafitti image from a website, converted it to a
.png, made some part of it transparent, and layered it over a brick
pattern. That didn't work, however; the transparent pixels in the .png
caused the brick pattern to become transparent as well.

Thus, I converted the .png to a .gif, and would want to use the
transmit bitmap modifier to get the desired effect, but I can't seem
to guess the right color number, and I'm reluctant to try all 256
possibilities; I'm not even sure whether what I'm doing is the right
way.

Could any kind soul tell me what the best way to layer a
partially-transparent image map over a patterned pigment is? And if
I'm doing the best possible thing with those "transmit" modifiers, how
I can efficiently determine the right color index to make it work?

TIA,

-- 
Wouter Verhelst
Debian GNU/Linux -- http://www.debian.org
Nederlandstalige Linux-documentatie -- http://nl.linux.org
"Stop breathing down my neck." "My breathing is merely a simulation."
"So is my neck, stop it anyway!"
  -- Voyager's EMH versus the Prometheus' EMH, stardate 51462.

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Wouter Verhelst <wou### [at] grepbe> wrote:
> I'm trying to create a wall with a graffiti image on it. To that
> end, I downloaded a grafitti image from a website, converted it to a
> .png, made some part of it transparent, and layered it over a brick
> pattern. That didn't work, however; the transparent pixels in the .png
> caused the brick pattern to become transparent as well.

  That's not because there would be something wrong with using a png.
It's because you defined your texture wrong.
  You should post a small (but complete, ie. renderable) piece of code
demonstrating what you are doing.

-- 
plane{-x+y,-1pigment{bozo color_map{[0rgb x][1rgb x+y]}turbulence 1}}
sphere{0,2pigment{rgbt 1}interior{media{emission 1density{spherical
density_map{[0rgb 0][.5rgb<1,.5>][1rgb 1]}turbulence.9}}}scale
<1,1,3>hollow}text{ttf"timrom""Warp".1,0translate<-1,-.1,2>}//  - Warp -

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In article <400c3aa6@news.povray.org>,
	Warp <war### [at] tagpovrayorg> writes:
> Wouter Verhelst <wou### [at] grepbe> wrote:
>> I'm trying to create a wall with a graffiti image on it. To that
>> end, I downloaded a grafitti image from a website, converted it to a
>> .png, made some part of it transparent, and layered it over a brick
>> pattern. That didn't work, however; the transparent pixels in the .png
>> caused the brick pattern to become transparent as well.
> 
>   That's not because there would be something wrong with using a png.
> It's because you defined your texture wrong.

Ah.

>   You should post a small (but complete, ie. renderable) piece of code
> demonstrating what you are doing.

Heh. Well, trying to reconstruct what I did with the .png file before
(I had since switched to a different setup using a .gif) didn't work.
Instead, I accidentally seem to have done the right thing; it now
nicely gives me the graffiti image on a background of a brick pattern,
which is what it should be doing.

I don't even remember how it was when it didn't work; but as it now
does what I want it to do, I'd say we can consider this issue
fixed. Thanks!

-- 
Wouter Verhelst
Debian GNU/Linux -- http://www.debian.org
Nederlandstalige Linux-documentatie -- http://nl.linux.org
"Stop breathing down my neck." "My breathing is merely a simulation."
"So is my neck, stop it anyway!"
  -- Voyager's EMH versus the Prometheus' EMH, stardate 51462.

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