Navigation, Input Devices, and Collision - Interactive Web-Based Virtual Reality with Java 3D - page 226

Similar to other utility classes, using the mouse behavior classes is quite straightforward
and requires the following steps:

• Create an appropriate MouseBehavior object.

• Set the target transform group.

• Define bounds for the MouseBehavior object.

• Add the MouseBehavior object to the scene graph.

The code segment listed in Figure 9 exemplifies instances where the three mouse be-
havior classes are used for navigational. Note that MouseBehavior.INVERT_INPUTS is
selected and the target transform group is the ViewPlatform transform.

Figure 9. Code segment for MouseInteractionUtil.java

1. public class MouseInteractionUtil extends Applet

2. {

3. SimpleUniverse universe = null;

4.

5. public BranchGroup createSceneGraph(SimpleUniverse universe, Canvas3D c)

6. {

7. BranchGroup objRoot = new BranchGroup(); // create root of the branch graph

8.

9. TransformGroup viewTrans = new TransformGroup();

10. viewTrans = universe.getViewingPlatform().getViewPlatformTransform();

11.
12. MouseRotate Rotate = new MouseRotate(MouseBehavior.INVERT_INPUT); // rotate

13. Rotate.setTransformGroup(viewTrans);

14. Rotate.setSchedulingBounds(new BoundingSphere());

15. objRoot.addChild(Rotate);

16.
17. MouseTranslate Translate = new MouseTranslate(MouseBehavior.INVERT_INPUT); // translate

18. Translate.setTransformGroup(viewTrans);

19. Translate.setSchedulingBounds(new BoundingSphere());

20. objRoot.addChild(Translate);

21.
22. MouseZoom Zoom = new MouseZoom(MouseBehavior.INVERT_INPUT); // zoom

23. Zoom.setTransformGroup(viewTrans);

24. Zoom.setSchedulingBounds(new BoundingSphere());

25. objRoot.addChild(Zoom);

26.
27. objRoot.addChild(new ColorCube(0.1f));

28. objRoot.addChild(createFloor());

29.
30. objRoot.compile(); // Java optimization

31. return objRoot;

32. }