Viewing the Scene Graph

Viewer Movement

The user is able to move through the scene by utilizing the Java 3D OrbitBehavior utility class in the view graph. A combination of control keys and mouse button presses move and rotate (or orbits) the viewer's position.

The behavior is set up in orbitControls( ) in WrapCheckers3D:

     OrbitBehavior orbit = new OrbitBehavior(c, OrbitBehavior.REVERSE_ALL);     orbit.setSchedulingBounds(bounds);     ViewingPlatform vp = su.getViewingPlatform( );     vp.setViewPlatformBehavior(orbit);

The REVERSE_ALL flag ensures that the viewpoint moves in the same direction as the mouse.

Numerous other flags and methods affect the rotation, translation, and zooming characteristics, explained in the OrbitBehavior class documentation.

MouseRotate, MouseTranslate, and MouseZoom are similar behavior classes that appear in many Java 3D examples; their principal difference from OrbitBehavior is that they affect the objects in the scene rather than the viewer.

Most games, such as first-person shooters (FPS), require greater control over the viewer's movements than these utility behaviors can offer, so I'll be implementing my own behaviors in later chapters.