[LSC] Ambiguities in the draft BFC spec

[Lars C. Hassing]

Travis Cobbs wrote:
> Thanks for bringing the first part up.  I had forgotten about that.  I 
> believe that LDView is the only tool that spits out warnings when 0 BFC 
> CERTIFY is used as the start text for every single BFC command.

The unreleased L3P and L3Lab also spit out these warnings.
Here are all warnings:

"BFC CERTIFY already met"
the second time CERTIFY is met

"BFC NOCERTIFY already met"
the second time NOCERTIFY is met

"Already BFC certified implicitly"
if CERTIFY is met later and e.g. "0 BFC CW" is already met

"BFC CERTIFY must appear before the first operational command-line"
"BFC NOCERTIFY must appear before the first operational command-line"
"This BFC is ignored because no BFC appeared before the first operational command-line"
I guess these are self-explanatory


> I personally think that we shouldn't care about winding changes at all.  
> LDView performs the swap at load-time, which prevents there from being 
> any performance hit.

So does L3Lab.
L3P doesn't use BFC, however, since L3P and L3Lab use the same input routines
L3P spits out warnings too.


>  It might be 
> a good idea to mention in the spec that the best way for a renderer to 
> handle multiple windings is to swap the winding at load time for all the 
> polygons that don't match its expected winding.

Yes.
/Lars