Re: [Maya2osg-users] Discussion of next changes

[Javier T. <jav...@gm...>]

  Hi J-S

On Sun, May 29, 2011 at 5:15 AM, Jean-Sébastien Guay
<jea...@cm...> wrote:
>
> OK, I'll do it the hard way, it doesn't matter that much because it's
> not performance-critical code but I would have throught there was a
> way... It feels like I'm doing a series of dynamic_casts to find out the
> true concrete type of an object...

  It *should* be a way. Maybe it is. But I don't know it.

>>    However, I don't think that exporting all extra attributes is a good
>> idea. There are utilities that generate lots of attributes. I would
>> focus on the attributes defined by the exporter, maybe naming them
>> with a prefix to identify them (tough we can remove the prefix when
>> creating the OSG descriptions).
>
> A prefix is a good idea. I just don't want to have to hard-code
> attribute names in the plugin. But if I export any attribute that starts
> with say "maya2osg_" that would be ok, is that ok for you?

  Perfect!

>>    I don't know if I am understanding you correctly. Is exporting all
>> "Extra attributes" what you are proposing? How do you identify what
>> attributes are "extra attributes", btw?
>
>  From an MFnDependencyNode, I can do:
>
> unsigned int count = dnodefn.attributeCount();
> for (unsigned int i = 0; i < count; ++i)
> {
>     MObject attr = dnodefn.attribute(i);
>     MAttrClass attrClass = dnodefn.attributeClass(attr);
>     if (attrClass == MFnDependencyNode::kLocalDynamicAttr)
>     {
>         // This is a custom attribute (i.e. not part of the normal list
>         // of attributes for this type of node).
>         // Also the notes attribute is one of these.
>     }
> }
>
> So the MFnDependencyNode::MAttrClass enum gives the type of an attribute
> when iterating through all attributes of a node. kLocalDynamicAttr is
> documented as "Dynamically added, applies to this specific node." and I
> verified that when iterating through attributes of a node in a maya
> scene being exported, this was the class returned for custom attributes
> (added by addAttr or the Attributes menu) as well as the notes. Other
> attributes (there were almost 200 on the node I checked) did not have
> this class.

  Interesting. I didn't know that. Quite useful.


  Regards,

-- 
Javier Taibo