[Opensim-users] Question out of curiosity Re:Prim Data Formats

[Toni Alatalo]

LaeMing kirjoitti:
> I am curious about the format of prim attribute data, particularly whether it 
> is fixed length, or if there is potential to expand the types of prims and/or 
> attributes for existing prims. Obviously this would require expanding the 
>   

The data as it is in the sludp protocol is declared in the message 
template, 
http://secondlife.com/app/message_template/master_message_template.msg 
(that is not viewer source, i think used in the server as well, reading 
that is not in violation of the opensim contributors agreement).

Search for "ObjectUpdate - Sent by objects from the simulator to the 
viewer" there to see the data.

It is pretty hardcoded for the SL features and not really extensible, at 
the protocol level - in the server code you can do things.

> mesher server-side and the renderer (and edit tools) client-side, but I am 
> more interested here in whether the database entries themselves can be 
> expanded this way without breaking the defined storage/transmission formats.
>   

At least you can have additional storage where store your own 
information about objects, I think many modules that people have written 
for their applications do that. I guess that's done both by just having 
separate data that is somehow connected to the prims, and also by 
subclassing/extending it to have more (like Diva mentioned recently here 
that their stuff subclasses SceneObjectPart, right?)

In the realXtend project we've extended the data model in opensim to 
have data like meshes and materials, that is implemented in a module 
where the data is in a object properties class - see 
http://forge.opensimulator.org/gf/project/modrex/scmsvn/?action=browse&path=%2Ftrunk%2FModularRex%2FRexFramework%2FRexObjectProperties.cs&view=markup

I actually haven't touched the server much 'cause have been so busy with 
the new viewer, so was just reading a bit there now. Adam Frisby and 
Mikko Pallari know all about that example, and the code seemed to 
explain itself pretty nicely as well.

In the networking we've so far used the GenericMessage packet that SLUDP 
provides for arbitrary data.

You should also note that Adam is just about to start a major 
refactoring in opensim to change exactly this area: how scene objects 
are in the code, and how data to them is attached. The goal of the new 
model is exactly to allow apps to add any kind of custom data to scene.
https://lists.berlios.de/pipermail/opensim-dev/2009-December/008095.html 
is his post about it, and the plan was attached there, "Components and 
SceneObject.pdf" 
https://lists.berlios.de/pipermail/opensim-dev/attachments/20091211/6e190ca7/attachment-0001.pdf

Cheers,

> Lae
>   

~Toni