Hello Georg,
Georg Wünsch wrote:
> Other topic: I am still on the way of trying to use OpenSG in a
> multithreaded environment.
>
>>From my understanding, the classes use a so called thread aspect. Does that
> have something to do with any of the native thread ids or how would I match
> them against each other to tell both open sg and the other apps parts which
> thread they are on?
aspects and threads are two different things, you associate a thread
with an aspect so that it knows on which copy of the scenegraph data it
should work. Every aspect holds a copy of every container in the system
(contents of fields are shared until a beginEditCP() requires an unshare
to keep the overhead low).
When you create a thread you can associate it with an aspect (if you use
some external library to create the thread you need to use the
ExternalThread class to establish that association).
> I am having several models that have to be calculating some simulation in
> the background and manipulate open sg nodes and cores etc in one aspect, a
> background threads aspect.
right, those changes can be done in one aspect (say A1) as long as they
don't touch the same containers concurrently. The rendering can keep
running on a different aspect (A0) and is not affected by the changes
until you apply the changes from the per thread (!) changelists to A0.
> In the mean time the gui thread might be trying to draw the scene in another
> aspect as I understand it. The aspects btw are numbered as 1 and 2, right?!
no, they are numbered 0,1,... In OpenSG 1.x their number is a compile
time constant that defaults to 2.
> Every time I am switching the aspects something is crashing around a
> beginEditCP or endEditCP. What might I be doing wrong? Any Clue?
what do you mean by switching aspects? You should not be changing the
aspect that a specific thread is associated with after it has done any
work. Have you seen Doc/tutorial/progs/13multithreading2.cpp? The
tutorial program is a highly simplified variant of something similar to
what you are doing: Aspect 0 keeps rendering images while aspect 1
updates the scene.
Cheers,
Carsten
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