POV-Ray : Newsgroups : povray.newusers : Using PNG's alpha for transparency... Server Time
28 Nov 2024 11:29:21 EST (-0500)
  Using PNG's alpha for transparency... (Message 1 to 4 of 4)  
From: Simon Lemieux
Subject: Using PNG's alpha for transparency...
Date: 18 Nov 2000 01:16:13
Message: <3A162CD8.C98A884E@yahoo.com>
Hi,
	I'm pretty new with textures...

I have a PNG image that is composed of white shapes on transparent background...
and the white fades to transparent...

Now, can I put this PNG and use its alpha channel in povray for transparency?
I tried "transmit all 1" and "filter all 1", didn't work... maybe I'm not using
it correctly?...

Please help!

Thanks,
	Simon
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+-------------------------+----------------------------------+
| Simon Lemieux           | Website : http://www.666Mhz.net  |
| Email : Sin### [at] 666Mhznet | POV-Ray, OpenGL, C++ and more... |
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From: Dawn McKnight
Subject: Re: Using PNG's alpha for transparency...
Date: 18 Nov 2000 03:26:47
Message: <3A163D49.6E3CAA45@mac.com>
Simon Lemieux wrote:
> Now, can I put this PNG and use its alpha channel in povray for transparency?
> I tried "transmit all 1" and "filter all 1", didn't work... maybe I'm not using
> it correctly?...

Simon, if I understand correctly, you can only use transparency with a
paleted color graphic.  Filter all and transmit all make /all/ of the
colors in your graphic transparent or translucent.

You need to use a graphics program such as draw or paintshop to convert
the image coloring scheme to paletted, determine which palette number
the color you want not to appear is, and set /that/ to transmit.

-- 
Dawn McKnight      | "Who cares what the hipbone's connected to? I'm in Neurology!"
McK### [at] maccom   |					-- Justine Devlin, M.D.


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From: Rune
Subject: Re: Using PNG's alpha for transparency...
Date: 18 Nov 2000 08:52:36
Message: <3a1689a4@news.povray.org>
"Simon Lemieux" wrote:
> I have a PNG image that is composed of white shapes on
> transparent background... and the white fades to transparent...
>
> Now, can I put this PNG and use its alpha channel in povray
> for transparency? I tried "transmit all 1" and "filter all 1",
> didn't work... maybe I'm not using it correctly?...

If I recall correctly, POV-Ray always use the alpha channel if present. You
shouldn't use transmit all 1 or filter all 1, since those keywords are
related to images with palettes only.

Rune
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From: Simon Lemieux
Subject: Re: Using PNG's alpha for transparency...
Date: 18 Nov 2000 17:17:45
Message: <3A170E28.AEA9369@yahoo.com>
> If I recall correctly, POV-Ray always use the alpha channel if present. You
> shouldn't use transmit all 1 or filter all 1, since those keywords are
> related to images with palettes only.

Yes it's true... it wasn't working but then I got the keywords out and there it
worked!

Thanks,
	Simon

-- 
+-------------------------+----------------------------------+
| Simon Lemieux           | Website : http://www.666Mhz.net  |
| Email : Sin### [at] 666Mhznet | POV-Ray, OpenGL, C++ and more... |
+-------------------------+----------------------------------+


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