Chris Cason wrote:
> what is known as the 'document/view' model

Also, in the early days commonly known as model-view-controller concept 
(whereas the controller is not directly mentioned in modern paradigms, it is 
assumed to be part of the view).  The model really is the "model" aka scene 
in POV-Ray, the view is the frontend, actually two views, the rendered image 
and the scene source.  Ideally the text editor would also allow direct 
control over the image view (a WYSIWYG paradigm), but of course in POV-Ray 
that isn't possible (Moray gets close to that though afaics) as the parser 
is in between :-)

As Chris mentions, the complexities in the code POV-Ray are now mostly 
hammered out, but the real topic is to get it in a nice, still easy to use 
GUI.  Hiding the complexities of distributed computers is not trivial, in 
particular to do it right, and if possible the first time is really difficult.

Another benefit Chris did not mention explicitly is that finally we can have 
the GUIs evolve at a different rate than the rendering core. Previously 
extending the GUI always required rather complicated render core changes if 
the GUI needed new data.  Now we can just say that if a message passes data 
from the backend and a particular piece of information is not there, well, 
we don't display it, while before it meant a different internal call 
structure with different parameters and a whole mess.

In fact, this design process did start with POV-Ray 3.5 already, and it has 
been making smaller steps with every release of POV-Ray since then.  Now 
with POV-ray 3.7 all these internal changes for the message-driven control 
that have been going on for five years now finally show results and 
*improvements* for users.  Especially for POV-Ray 3.6 a lot was done already 
in cleaning up the early 3.5 implementation of this.  So anybody who had a 
look at the 3.6 or 3.5 source code and thought "Why do they do all this 
complicated message passing abstraction just to turn it into text again ten 
calls down the call chain ?" has their answer - it was of tremendous help to 
get clean SMP support working to some extend within less than one month!

Nevertheless, as you can see, doing proper and clean SMP support is a 
massive task and nothing a simple patch could ever have established (the 
existing patches for distributed rendering just run multiple copies of 
POV-Ray and duplicate *all* scene data).  In the end, we will probably have 
"invested" two full-time developer years into getting the POV-Ray 3.7 core 
to do SMP, and that doesn't even include any new features or the GUI frontends!

	Thorsten

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