Killer Game Programming in Java

Creating the Scene

As with previous Wrap classes, WrapLoader3D creates the scene (the checkerboard, the lights, the background, the mouse controls and viewpoint). It offers methods that Loader3D can call to set and get the model's coordinates.

Figure 16-20 shows the methods defined in WrapLoader3D.

Figure 16-20. WrapLoader3D methods

The public methods pass requests sent from the GUI through to a PropManager object, propMan:

    // global
    private PropManager propMan;

    public void movePos(int axis, int change)
    {  propMan.move(axis, change);  }

PropManager manipulates the model. WrapLoader3D is acting as a facade, hiding implementation details from the application's GUI layer. This coding approach allows WrapLoader3D to carry out its own checking on the GUI inputs though it currently doesn't do that.

The PropManager object is created in WrapLoader3D's constructor:

    propMan = new PropManager(filename, hasCoordsInfo);

The call includes the model's filename and a Boolean indicating if a coords datafile is available.

The top-level TransformGroup for the model is accessed in createSceneGraph():

    sceneBG.addChild( propMan.getTG() );