Subject:
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Re: White noise around model with colored background
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Newsgroups:
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lugnet.cad
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Date:
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Wed, 8 Jun 2005 22:47:42 GMT
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Viewed:
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1308 times
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In lugnet.cad, Don Heyse wrote:
> I think I had an idea for an extra rendering pass to fix this but
> never got motivated enough to try it out.
>
> http://news.lugnet.com/cad/dev/?n=9910
>
> Does it sound like it might work? I can barely remember what I was
> thinking.
That won't help. The problem is that OpenGL antialiasing antialises the color
channel based on the background color the original rendering happens over. So
even if you bump the alpha on all those pixels up to 1.0 (fully opaque), you'll
still have the original blended color based on the original background color.
You end up with the same problem with regular alpha-blended transparent items
that sit over the background.
What we need is the ability to tell OpenGL to not blend the color channels if
the destination alpha of the pixel being drawn is 0. (Perhaps the blending
should be proportional to the destination alpha of the existing pixel.) I'm
pretty sure this isn't possible in OpenGL.
--Travis
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Message has 1 Reply:
 | | Re: White noise around model with colored background
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| (...) Ah ha! That explains why I said to set the background color to black. That way the exterior lines alpha blend with zeros. I suspect setting -b0 in the ldglite options window of lpub will give better results. Maybe lpub should always do this if (...) (19 years ago, 8-Jun-05, to lugnet.cad)
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Message is in Reply To:
| | Re: White noise around model with colored background
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| (...) Antialiasing it turned on in ldglite by -q. I'm not sure if this is done automatically by lpub or if it's in the optional settings box. Background color is set by -b and I think it supports ldlite and l3p colors style extended colors. (...) I (...) (19 years ago, 8-Jun-05, to lugnet.cad)
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