Sajjadul Islam wrote:
> Hello,
>
> It is specified that every OpenSG specific class relatd to data storage
> is derived from FieldContainer.
>
> What kind of data are we meaning here ? - Does that mean the node 
> created and all  the geometry related information and other attributes
> regarding to  the just created node?
>   
Usually we mean member variables of a class, i.e. a Node's children 
_pointers_, the normals of a geometry, the color in a solidbackground.

There is a difference between node and core, but that's pretty clear 
from the tutorials. Nodes make up the tree of the scene graph, while 
cores define a Node's semantics (i.e. what it does, such as 
material/geometry/transform cores).
> Every node created with  a create() method is also a Field, but Field is
> very abstract that gets concrete down  the hierarchy  - is that so ?
>   
Not really right. A node is not a field. A node is a field container. It 
has a trav mask field, a child pointers field, etc.

A field is a wrapper/decorator for a regular value (float, string, 
std::vector<osg::NodePtr>, etc.). The field-wrapper provides some useful 
things to the data, such as read/write from string/binary, dynamic-name 
& type checking.

The wrapper is essential for the multi-thread & cluster-capability of 
OpenSG, as it allows any type to be sent over the network. The cluster 
system only concerns itself about the Field, not about what it wraps.

The multi-threading tutorial page explains a bit more about how it 
works: http://www.opensg.org/doc-1.6.0/Multithreading.html

I think the tutorial writer tried to hide most of this complexity until 
later, because you don't really need to know it to create osgHelloWorld.
> I believe the a concrete example with the functions specified in the
> Tutorial regarding FieldContainer of different type and different
> accessor functions could have elaborated more.
>   
Yup.
> Would somebody do that or show me the way to try that by myself?
>   
Not sure. We'll see if anyone picks up this thread, otherwise I can't 
see why not. :)

/Marcus

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
Opensg-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/opensg-users

Reply via email to