[Fwd: RE: [Openvrml-develop] Using OpenVrml for a simulation]

[Peter M. <me...@iw...>]

-------- Original Message --------
Subject: RE: [Openvrml-develop] Using OpenVrml for a simulation
Date: Wed, 1 Aug 2001 06:24:19 -0700
From: "luca regini" <luc...@li...>
Reply-To: "luca regini" <luc...@li...>
To: me...@iw...

This message was sent from Geocrawler.com by "luca regini"
<luc...@li...>

Ur Answer is clearing some points and is very 
helpful.
Anyway probably my first question is not well 
formulated: I should have the ability to parse 
all nodes in the Vrml scene graph , not just 
DEFined nodes.

Taking a look at this code:

VrmlMFNode * VrmlScene::readWrl(Doc2 * tryUrl, 
VrmlNamespace * ns)
{
    VrmlMFNode * result = 0;
    
    theSystem->debug("readWRL %s\n", tryUrl->url
());
    
    // Should verify MIME type...
    istream & istm = tryUrl->inputStream();
    if (istm) {
        
        Vrml97Scanner scanner(istm);
        Vrml97Parser parser(scanner);
        
        //
        // If the caller is not interested in 
PROTO defs, use a local namespace.
        //
        // Note: Can we displace the 
responsibility for this to the caller? Here
        // we instantiate a VrmlNamespace whether 
or not we need it. That could
        // be avoided with new/delete, but the 
resulting code would be awkward
        // and hard to follow. Why not instead 
have the caller pass in a
        // reference to a namespace, and let the 
caller decide whether or not a
        // new namespace should be instantiated?
        // -- Braden McDaniel 
<br...@en...>, 30 Mar, 2000
        //
        VrmlNamespace nodeDefs;
        VrmlNamespace * rootNamespace = ns ? ns : 
&nodeDefs;
        
        result = new VrmlMFNode();
        try {
            parser.vrmlScene(*result, 
*rootNamespace, tryUrl);
        } catch (std::exception & ex) {
            cerr << ex.what() << endl;
        }
    }
    
    return result;
}

it seems to me that all the parsed scene graph is 
collected in VrmlMFNode * result so i would like 
to know how to parse the resulting tree.

I dont know if i am right since i didnt have the 
time to dig deeply in the library code ( and this 
is an hard task given the amount of code ) but to 
me this ipothesis makes sense even if probably i 
am wrong.
So put in a few word the question is:

if i run something like this:

parser.vrmlScene(*result, *rootNamespace, tryUrl);

is all the World scene graph returned in *result?
How to traverse the resulting object graph?


Greets
Luca