To LUGNET HomepageTo LUGNET News HomepageTo LUGNET Guide Homepage
 Help on Searching
 
Post new message to lugnet.cad.dev.org.ldrawOpen lugnet.cad.dev.org.ldraw in your NNTP NewsreaderTo LUGNET News Traffic PageSign In (Members)
 CAD / Development / Organizations / LDraw / 1917
1916  |  1918
Subject: 
Re: [Parts Tracker] More BFC Primitives
Newsgroups: 
lugnet.cad.dev.org.ldraw
Date: 
Sat, 6 Apr 2002 01:22:59 GMT
Viewed: 
3877 times
  
In lugnet.cad.dev.org.ldraw, Steve Bliss writes:
> In lugnet.cad.dev.org.ldraw, Tony Hafner writes:
> > In lugnet.cad.dev.org.ldraw, Steve Bliss writes:
> > > > Um... Not to stir the pot or anything but I was reading the BFC proposal on
> > > > your website and noticed that the BFC specification says that all primitves
> > > > must be certified CCW.  Did this get revised via discussion and not updated?
> > 
> > For starters, I recently tried to track down the BFC specification but
> > couldn't find it (on ldraw.org or on Steve's site).  Could someone post the
> > link please?
> 
> <http://www.geocities.com/partsref/bfc/>
> 
> > > At this point, I'm as inclined to delete the clause from the spec as to
> > > keep it (and modify the primitives specified as CW).
> > 
> > If it doesn't matter from a performance perspective, I vote you kill the
> > clause.
> 
> I think the only way it would matter for performance is if we decided that
> the *entire* library would be CW or CCW, and so rendering programs wouldn't
> have to check the winding direction at all.  And that would be a very small
> difference in speed.

Given the fact that they have to check whether or not a given file has been
mirrored, I can't see that the directionality would make a large difference.
If everything used CCW, then only mirrored ones would need to be reordered
(assuming the renderer is going to reorder them).  In any event, I can only
see this having an effect on load time, since I would expect a renderer that
is making use of BFC information to reorder all BFC'd polygons to have the
same winding, after taking mirroring into account.

--Travis Cobbs (tcobbs@REMOVE.halibut.com)



Message has 1 Reply:
  Re: [Parts Tracker] More BFC Primitives
 
Hello, Comments below... Travis Cobbs wrote: > In lugnet.cad.dev.org.ldraw, Steve Bliss writes: > >>In lugnet.cad.dev.org.ldraw, Tony Hafner writes: >> >>>In lugnet.cad.dev.org.ldraw, Steve Bliss writes: >>> >>>>>Um... Not to stir the pot or (...) (24 years ago, 6-Apr-02, to lugnet.cad.dev.org.ldraw)

Message is in Reply To:
  Re: [Parts Tracker] More BFC Primitives
 
(...) (URL) (...) I think the only way it would matter for performance is if we decided that the *entire* library would be CW or CCW, and so rendering programs wouldn't have to check the winding direction at all. And that would be a very small (...) (24 years ago, 5-Apr-02, to lugnet.cad.dev.org.ldraw)

21 Messages in This Thread:





Entire Thread on One Page:
Nested:  All | Brief | Compact | Dots
Linear:  All | Brief | Compact

This Message and its Replies on One Page:
Nested:  All | Brief | Compact | Dots
Linear:  All | Brief | Compact
    

©2005 LUGNET. All rights reserved. - hosted by steinbruch.info GbR