Re: [JAVA3D] obj loader

[Ewan Borland]

Hi Rob,

 

Hope this is some help. I've been using this on models from various different sources.

 

I simply traverse the scenegraph for the given root node to retrieve all of its Appearance node components. Then I set the indiviual appearance components for each Appearance to attributes which I have previously defined. In this way the attributes are shared between all of the appearances, so that , for example, when I change my polygon attributes all of my models are changed.e.g.

 

polygonAttr.setPolygonMode(PolygonAttributes.POLYGON_LINE);

 

has the effect of changing my models to wireframe.

 

I find that retrieving the different appearance components and keeping references to them before the graph is live makes changing the appearance much  easier once the graph is live, because you don't have to set the necessary capabilities for traversing the live graph (Also means you can compile the scene graph). Obviously you still need to set the capabilities for the appearance components,

e.g. polygonAttr.setCapability(PolygonAttributes.ALLOW_MODE_WRITE);

 

If you prefer to keep the appearance components already associated with each model you can use the Appearance get methods rather than set.

 

Cheers,

 

Ewan

 

 

 

 

// Adds a new model to the scene graph after retrieving its Appearance components

public void addModel(Node model)

{

    // Retrieve all the appearance node components associated with the model

    visitedSharedGroups = new HashSet();
    appearances            = new Vector();

    retrieveAppearances(model);

 

      // Set the rendering attributes for the appearances
      for (int i = 0; i < appearances.size(); i++)
      {
           Appearance app = (Appearance)appearances.elementAt(i);
           app.setPolygonAttributes(polygonAttr);
           app.setTextureAttributes(textureAttr);
           app.setColoringAttributes(colourAttr);
      }

      

    ..... Rest of my code adds model to scene graph

 

} // addModel

 

 

// Retrieve all the Appearance node components in the scene graph which begins at root
private void retrieveAppearances(Node root) throws CapabilityNotSetException

{
      // If this is a null tree then return
      if (root == null)
            return;

 

      // If the root is a shared group then make sure it hasn't already been considered
      if (root instanceof SharedGroup)
      {
           // If it has been visited previously then return
           if (visitedSharedGroups.contains(root))
                return;

 

           // If not then add it to the list of visited shared groups
           else
                  visitedSharedGroups.add(root);
      }

 

      // If the current root node is a Shape3D then retrieve it's appearance node component
      // and place that in the appearances vector
      if (root instanceof Shape3D)
           appearances.add(((Shape3D)root).getAppearance());

 

      // If root is a group then traverse all of its children
      else if (root instanceof Group)
      {
           Enumeration e = ((Group)root).getAllChildren();
           while(e.hasMoreElements())
                retrieveAppearances((Node)e.nextElement());

 

      }

 

      // If root is a link then traverse its shared group
      else if (root instanceof Link)
           retrieveAppearances(((Link)root).getSharedGroup());

 

 } // retrieveAppearances

 

 

 

----- Original Message -----

From: "Rob Brown" <[EMAIL PROTECTED]>

To: <[EMAIL PROTECTED]>

Sent: Monday, March 11, 2002 1:24 PM

Subject: [JAVA3D] obj loader

> Anyone have suggestion:
>
> After, I load in an object from an OBJ file. How can I make it render as
> points, wire frame, flat shaded, etc... basically a quick mod to ObjLoad
> that comes with J3d.
>
>
> Thanks for any help
>
>
> Rob Brown
> Eyetronics Inc
> Developer
> [EMAIL PROTECTED]
>
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