John VanZwieten wrote:
> 
> Is it necessary for POV-Ray to parse a file separately for each view of the
> same scene?  Is there any way to "save" the result of the parsing to use in
> repeated raytracings from different views?
> 
> Thanks in advance for any help with this.
> 
> -John VanZwieten

Hi there,
my default insertion here, like some folks always say 'visit my links
page' I use to say the following:

I object to the statement that POV-Ray is slow in parsing. All that POV
is doing, is saying that it parsed some 1.5h, but most of the time it
did run your code.
It just doesn't tell you 
'your $%*&ing codes runtime: 1.49Hrs
parsing time: 60 sec'

What do we have? By the grace of the POV-Ray Team we have one and only
one interface to the rendering engine, and thats the Scene Description
Language.
Like that name says, it's a language defined to describe a scene. It's
not designed to do heavy numerics or business-transactions.
Throughout it's history (which I experienced not so much of) it has been
extended by more and more programming constructs, giving the users more
and more possibilities. Thanx, guys.
But that stuff doesn't only have to be coded, but it has to be paid for.
And that's simply speed.
Short: the parser is fine, the interpreter is slow. That's fine, I do
prefer a good renderer to yet another interpreter.
Could someone speed it up? No, because there are way too many backdoors,
like pre- and postframe shellouts and #read, so one rarely knows, what
content changed at what time.
So, if you want to stick to portable and simple coding for the users,
you stick to the speed.

More speed would require a serious breaking of compatibility, and in my
opinion, another interface to the engine. POVLegal won't like it, and
most probably the POV-Ray Team won't code it.
(I think of something like a DOM-based CORBA interface)

A short remark on the binary format. It was implemented, but provided
the heterogeneous tree structure of the scene in memory, you have a lot
of work putting all those pointers back into place, and most objects
will be created one by one, so not that much of speedup to expect.

Axel

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