The Scene Viewer Application

About the Project

This is an old, discontinued Project.
It is one of the very first graphical scene editors for Java3D.

Related URLs

Here are some URLs related with the Project: Java3D, the 3D API for Java enables 3D applications with new features like Java 3D on the Web, and a high level approach to 3D programming. This package is one of the first developed for this API and represents the core of a library of classes aimed at developing a fully Java-implemented Java3D editor facility. This is anyway a basic release and most of its functionalities are just sketched or even not yet fully available from Javasoft. Future releases will come as soon as new features will be provided.
Here is a screenshot from the Viewer class, as you can see nodes by now are tagged laconically with their toString() method.

a screenshot from the program

figure 1. a screenshot from the Viewer
A Java package for visualizing VirtualUniverse instances with a tree-like interface using the Swing JTree class. A set of classes that build a tree model out of a Java3D scene graph. This not just for looking at it, but also for editing, building and generating full working scenes (The model is bidirectional).
This current release anyway has not editing features because of not yet resolved problems with the 1.1 Java3D API.

Installation

Unzip the file in a new directory and be sure to have Java 2 1.3 with Java3D properly installed and launch the Viewer class for a GUI front end.

Using It With Existing Scenes

When you use it pay attention to obtain all the needed capabilities from every node, otherwise it won't work; for instance, just after a objNode object statement, write also: objNode.setCapability(objNode.ALLOW_CHILDREN_READ);

That is unpractical in this basic release, because you need to code it for every Node instance in your code! As soon as serialization and robust cloning will be available (and documented) this boundary will be overcome.

As a simple procedure, following these steps to see the SceneGraph from your Java3D scene:

make sure every node has its property set for being readable from the tree model
call one of the classes described below, the one that better matches your needs, or even MainFrame as well, giving as the constructor parameter your VirtualUniverse instance, fully readable or editable as you need.

In the package is also shipped a HelloTree class modified, so just launch it.

A Brief Class Description

AbstractTreeModela convenience class for implementing the TreeModel (see the Java Swing Tutorial)
TreeModelSupport a convenience class for implementing the TreeModel (see the Java Swing Tutorial)
SceneTreeModel the model itself, given a VirtualUniverse instance creates a TreeModel's one to be drawn as a 2D, tree-like representation. As described by the Swing team (last month) a tree model can be either build anew or just created adapting a pre-existing tree data structure. The latter was the simplest solution in this case, even if it needed more code and some ad-hoc solutions that will be expanded in next releases.
SceneTreePanel the (scrollable) panel where the JTree is layed out. You can use this class to put the panel on your own frames.
Viewer an example frame that uses the SceneTreePanel that uses itself the core SceneTreeModel.
InfoDialog an utility class for MainFrame
SerializeVU an utility class for serializing VirtualUniverses. Just use it in your code when your VirtualUniverse is ready, the constructor serializes it with the toString() for a file name (instanceof@HashCode).

known problems

ViewerSplitPanel is an utility class that displays a tree and the VirtualUniverse that it represents near it. It has not been fully implemented because when you select different nodes in the JTree you expect to see the scene from that node down in the hierarchy but this implied cloning it for a clean design, and without this feature you need to detach branches (so do maiming the JTree!) because they can have only one father, etc. Hence, for sake of simplicity it was all postponed to next, sounder API releases.

To summarize, TreeModelSupport handles the Listeners, those classes responsible for handling specialized events in the Swing architecture model (a modified MVC ).It's just a matter of visiting each of them, stored in a list and fire their notification methods. Its work is general and could be used and reused for different tree model needs.
Then comes SceneTreeModel that implements all the remaining methods needed for carving out a tree of any object, in Swing's programmer's view: getRoot, getChild, getChildCount, isLeaf, indexOfChild, valueForPathChanged

After you have had a tree model of your data structure (here the VirtualUniverse class, any VirtualUniverse) it's just a layering exercise, to make from it a JTree , and with the JTree a JPanel, and with the JPanel a JFrame, each class providing more and more accessory methods suited for their respective levels. Of course you can get rid of all this proliferation and make it out with one or two classes, but you know...

Release Notes

First Release

Sept.1998 written the essential classes and the UI fully working.
the I/O operations (loading especially) are not working due to unresolved problems

Known Problems

the cloneTree methods seems to be bound throwing nullPointer exceptions on leaf nodes in all the examples classes bundled with this release.This problem needs further work.

their

serialization is not implemented yet from Javasoft and this makes useless the input/output facilities unless next releases will be available.
sadly, being serialization still unavailable the only way to load in VirtualUniverses is hard coding it in the source file, using the VU class that provides easy connection, being an Applet subclass. Future release will provide dinamic loading via ClassLoader.
Also another temporary bug is accessing the nodes up to the ViewingPlatform one (the node selected in figure 1), because for easy of development all the examples subclass SimpleUniverse making unaccessible the capabilities bits of this node.
Finally, documentation lacks. As this is a basic version and will be changed in the future, but being also a very useful library both for Swing JTree's and Java3D's learning I decided to publish this right now. For any question please email me.