Subject:
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Re: LDraw color codes needed for rendering program
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Newsgroups:
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lugnet.cad.dev
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Date:
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Tue, 9 Jan 2001 00:53:33 GMT
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Viewed:
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442 times
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----- Original Message -----
From: "Lars C. Hassing" <lch@ccieurope.com>
To: <lugnet.cad.dev@lugnet.com>
Sent: Monday, January 08, 2001 5:32 PM
Subject: Re: LDraw color codes needed for rendering program
> Gary Williams wrote...
> > Apparently not all LDraw color codes are specified in the LDraw FAQ ... • and
> > some that are, are missing the RGB assignments (for instance: 11, 3, 12, • 5).
> > Code 39 is used by the car.dat file that is included with LDraw, but it
> > seems to be missing from the FAQ.
> >
> > Is there a definitive list of color code assignments somewhere that I • can
> > use?
>
> You may have a look in this L3Lab generated table:
> http://home16.inet.tele.dk/hassing/ldcolors.html
> which has colors 0..63 for LDraw, LDLite+MLCad and L3P.
> I'm working on adding more colors and more color schemes.
Thanks, this is helpful.
> LDraw draws transparent colors (32 + 0..15) by dithering,
> i.e. it only paints every other pixel in a checker board pattern.
> It uses the 0..15 color for that.
>
> Other programs may use different colors for the transparent color
> and the non-transparent color.
> E.g. LDLite+MLCad use (153,153,153) for the transparent grey 39 (32+7)
> and (170,170,170) for the non-transparent grey 7.
>
> How are you going to implement transparent colors?
I have several algorithms in mind, that I want to test them before I commit.
However, in a CAD program, I think blazing rendering speed is more important
than having true transparency. In other words, transparent parts might
appear as brightly-colored solid parts in the initial releases, or I might
fake them in some other way.
Eventually I envision assigning an opacity of 0 to 255 to every transparent
color code. There would be a rendering option that the user could use to
control the level of photorealism.
> Blending is rather difficult if it has to support multiple transparent
> layers correctly...
> In L3Lab you may try out blending (which is not perfect...)
>
> I can offer you a C subroutine, Color2RGB, which
> converts any valid LDraw color into RGB according to
> various color schemes. It also supports extended colors,
> see http://home16.inet.tele.dk/hassing/l3p.html#extcol
I would like to take a look at your function.
Up till now I've been planning to store the color assignments in a simple
text file that would be parsed upon running the program. This way users can
create custom colors, specifying the Red/Green/Blue/Opacity components of
each.
-Gary
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Message has 1 Reply:
 | | Re: LDraw color codes needed for rendering program
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| (...) Me too! I was just about to say he could get a copy of the function from the L3 parser code in ldglite but it wasn't there. Even worse, it turns out I just commented out the call to Color2RGB() in L3Input.cpp when I couldn't find a copy of (...) (23 years ago, 9-Jan-01, to lugnet.cad.dev)
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Message is in Reply To:
| | Re: LDraw color codes needed for rendering program
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| Gary Williams wrote... (...) You may have a look in this L3Lab generated table: (URL) has colors 0..63 for LDraw, LDLite+MLCad and L3P. I'm working on adding more colors and more color schemes. LDraw draws transparent colors (32 + 0..15) by (...) (23 years ago, 8-Jan-01, to lugnet.cad.dev)
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