Subject:
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Re: Line in the Sand
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Newsgroups:
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lugnet.cad.dev
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Date:
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Tue, 9 Nov 1999 11:17:47 GMT
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Viewed:
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2980 times
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[ Still discussing http://www.geocities.com/partsref/bfcspec.txt ]
Rui:
> > > Allows a mix of extended and unextended files in one rendering, but
> > > to allow clipping, all files, have to be certified !?!?
> >
> > All the files in the relevant _branch_ of the rendering
> > tree.
>
> of course, but all files start on one root, if that is no BFC certified,
> then no acceleration.
Yes, but generally it is no big deal to certify a model file
- and there is the suggested option for the renderers
mentioned further down for the lazy.
> > If you certify your model, then every certified primitive
> > will be drawn with back-face-culling when it is used for a
> > certified part.
> but a certified part can have sub parts not certified ! hence another
> no-go.
Yes, but we aren't all that stupid. We will of cause start
certifying the primitives and critical sub-parts.
> > As soon as all the primitives are certified and people start
> > to insert certification flags in their models, all certified
> > parts will be drawn with back-face-culling.
>
> That will take a lot of time. we should see progress (acceleration)
> as soon as we start implementing it.
You can't eat a cake before you've baked it!
[...]
> > The renderers are allowed to give the user the _option_ of
> > bending the rules slightly.
>
> These things makes me remember the word 'hacking', until you get your
> code running.
It is an indirect way of accepting the files in the PARTS
directory as something special. Some of us feel that it is
important that all DAT files are equal (even though it, at
the moment, is practical that some are more equal than
others).
> > > In my opinion the language extensions should be written with curly
> > > braces '{' '}' instead of '[' ']', because the later means optional
> > > parameter and the previous means compulsory parameter with possible
> > > options if the pipe '|' is used.
I got it wrong first time.
I remember to have learnt that
( ... ) - means one copy of "...". This is just used to
group alternatives.
[ ... ] - means zero or one copy of "...".
{ ... } - means zero or more copies of "...".
According to that grammar, the production rules should be
written:
certification = "0" "CERTIFY" ( "BFC" | "NOBFC" ) { certification_flag }
winding = "0" "WINDING" ( "CW" | "CCW" | "UNKNOWN" )
clipping = "0" "CLIPPING" ( "ON" | "OFF" )
invert = "0" "INVERT"
> > This sounds correct, but do we want to eliminate this
> > syntactic sugar?
>
> why not ?
I like it.
Play well,
Jacob
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Message has 2 Replies:
 | | Re: Line in the Sand
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| (...) You'll pardon me if I use an abbreviated notation, and skip the " characters. (...) It's hard to argue with that. Steve (25 years ago, 9-Nov-99, to lugnet.cad.dev)
| | | Re: Line in the Sand
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| (...) ---...--- (...) Don't take this so personally, it's not worth it. I am only trying to contribute to a worthy cause (LEGO). Everyone can have different opinions. I don't need to jump on the other guys traught. Anyway, I apologise if I have (...) (25 years ago, 10-Nov-99, to lugnet.cad.dev)
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Message is in Reply To:
| | Re: Line in the Sand
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| (...) Agreed, it's logical. Should is too strong ! not like must, but strong anyway. (...) of course, but all files start on one root, if that is no BFC certified, than no acceleration. (...) but a certified part can have sub parts not certified ! (...) (25 years ago, 8-Nov-99, to lugnet.cad.dev)
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