Hi Pablo,
Pablo Carneiro Elias wrote:
> Thanks for the post Reiche,
>
> So, basically it works pretty much as the basic example at starterGuide,
> only that SortLastWindow is used instead of the basic ClusterWindow and
> a composer must be set.
Correct. We tried to abstract the details of how to cluster as much as
we could.
> So, let me see if I understand correctly what is
> happening behind the code you sent (the same at Tutorial28):
>
> -> SortLastWindow will take care of sending each node to a different
> rendering server, instead of sending everything to all servers
No, it doesn't go that far. Because the Nodes are not self-contained
(they can reference arbitrary other objects) figuring out what you need
to send to be able to render a subtree would be a fairly expensive
operation. It's not impossible, but quite a bit of effort. So right now
all servers have a full copy of the scenegraph.
One reason why we haven't spent time on changing that is that even we
did do that, the master machine would still have to be able to store the
whole scene, which limits the size to its memory.
To handle really large scenes we have the ProxyGroup. The idea is that
you create a ProxyGroup (or you use a tool like the ProxyBuilder or the
OOCProxyBuilder). The ProxyGroup just contains complexity and bounding
box information, and a filename that references the actual object. The
actual object is only loaded when the ProxyGroup is really rendered. On
the master, only the Proxies are loaded, which take practically no
memory. Based on their information they are distributed amongst the
renderers, where they are loaded and rendered.
> -> After each server has rendered it nodes, the scene fragments are
> composed accordingly with the composer strategy.
Yup.
> -> What happens behind is that each node of geometry is a fieldContainer
> itself, and so it has it own ChangeList for tracking any changes at each
> different Thread. So, what really happens is that some how
> SortLastWindow can send each ChangeList entries to a specific server
> instead of sending every time for all servers.. Is that right?
Nope, see above. It would be an interesting extension, but not something
that we have.
> Please correct me if I made any mistake and please post any
> complementary explanation if possible ;)
Hope it helps
Dirk
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