Steve Baker (sbaker++at++link.com)
Thu, 16 Oct 1997 15:10:33 -0500 (CDT)
> Hi,
>
> Are there some good reasons not to have given direct access to members
> of Performer C++API classes (reasons more important than performance!)
>
> 2 examples:
>
> 1) the only way to access the pfPlanes of a pfPolytope (without a copy)
> is to subclass it (the "facets" member is protected),
> 2) there is no way to access the culling pfPolytopes of a pfChannel
> (without a copy) (the "cullVol" and "nomCullVol" members are privates).
What's wrong with:
int pfPolytope::getFacet(int i, pfPlane *facet);
and
void pfChannel::getPtope(pfPolytope *ptope);
???
I understand that you'd like to avoid a copy - but if the channel object
gave you the address of the pfPolytope then you'd be able to *write* to
it without pfChannel knowing that you'd done that - if the channel caches
other information related to the Polytope (or more likely - passes it on
to daughter processes in a mp-safe manner) then the fact that you could
change it at any time *might* be a very bad thing.
Hence it's a private/protected member to be on the safe side.
Since you say that you need this access for reasons *other* than
performance - and a copy is for some reason no use to you - then it seems
like it must be that you were planning just such a dangerous access
and the protection afforded by the pfChannel class was warranted.
Steve Baker 817-619-8776 (Vox/Vox-Mail)
Hughes Training Inc. 817-619-4028 (Fax)
2200 Arlington Downs Road SBaker++at++link.com (eMail)
Arlington, Texas. TX 76005-6171 SJBaker1++at++airmail.net (Personal eMail)
http://www.hti.com http://web2.airmail.net/sjbaker1 (personal)
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