[osg-users] Distributed rendering of scene graph

[Stefan Eilemann]

Benjamin, Jan,

Let me jump in with some definite answers on Equalizer.

On 1. Mar 2008, at 20:54, Benjamin Eikel wrote:

> On Saturday 01 March 2008 at 20:18:19, Jan Ciger wrote:
>> Hello Benjamin,
>>
>> Benjamin Eikel wrote:
>>> Hello Jan,
>>>
>>> thank you for your suggestion. Equalizer looks like a prebuilt  
>>> framework
>>> for simple, high-performance parallel rendering. This is not what  
>>> we are
>>> searching for, because we want to/have to implement our own  
>>> specialized
>>> rendering system.
>>
>> As far as I remember, you can plug in your own rendering and  
>> compositing
>> stages into Equalizer.
> Hello Jan,
>
> okay, this might be something that we could use. I have only skimmed  
> through
> the web page and the programming guide so maybe I missed something.  
> The
> problem that I see is that maybe other functions which are provided by
> OpenSceneGraph are not supported by Equalizer (loading from  
> different file
> formats, picking/dragging, animation pathes).

Equalizer is a parallel rendering framework, in the same sense as MPI  
is a parallel programming framework. File loading, picking, etc. are  
application-specific problema, and outside of the scope of Equalizer.  
Equalizer does not prevent implementing these, and where it makes  
sense it will aid these functions.

File loading for example would be done, as I understand, on your  
application node. The resulting scenegraph will then be distributed to  
your render clients. This is something we have already done with  
another scene graph.

Picking and event handling in general are areas where Equalizer helps  
the application. For example, events are sent to the application node  
by default.

Data distribution for OSG is something which has been requested a  
number of times, just nobody stepped forward and did it so far (or  
paid for it). I am sure this work would give you a good reward, and I  
can help with the details.

Equalizer gives you a framework into which you plug your  
applications' (rendering) code. If you have something which doesn't  
fit, let us know and we'll find a solution.

> Furthermore if we want to write
> our own rendering and composition algorithm what is left for  
> Equalizer to do
> for us?

What exactly do you have in mind? It seems that if you want to  
implement your own parallel rendering algorithms, the right way would  
be to modify Equalizer. You are of course welcome to contribute.

> I think the effort getting used to it and integrating it in our
> system would be too high in comparison to the earnings.

The effort to relearn the lessons we learned by doing two parallel  
rendering frameworks is high as well.

>> Sometimes it is better to start from something working than from
>> scratch, even though it is tempting to reinvent the wheel (I am/was  
>> in
>> academia too).
> Yes that is right. That is why we want to use OpenSceneGraph.

An integration of OSG with Equalizer is a new thing. Furthermore it  
builds new value (rather than redoing existing things), and would add  
value to both projects.

Cross-posting to eq-dev. Feel free to direct Equalizer-specific  
questions to this list.


Cheers,

Stefan.
-- 
http://www.eyescale.ch
http://www.equalizergraphics.com
http://www.linkedin.com/in/eilemann