Geometry Objects - Interactive Web-Based Virtual Reality with Java 3D - page 58

Figure 35. Code segment and result of LineTrapez.java

1. public class Axis

2. {

3. private BranchGroup axisBG;

4.

5. public Axis()

6. {

7. axisBG = new BranchGroup();

8. IndexedLineArray array =

9. new IndexedLineArray(8,LineArray.COORDINATES|LineArray.COLOR_3,24);

10.
11. Point3f []pts = new Point3f[8];

12. pts[0] = new Point3f(0.5f, 0.75f, 0.5f); pts[1] = new Point3f(-0.5f, 0.75f, 0.5f);

13. pts[2] = new Point3f(0.5f, 0.75f, -0.5f); pts[3] = new Point3f(-0.5f, 0.75f, -0.5f);

14. pts[4] = new Point3f(0.75f, -0.25f, 0.75f); pts[5] = new Point3f(-0.75f, -0.25f, 0.75f);

15. pts[6] = new Point3f(0.75f, -0.25f, -0.75f); pts[7] = new Point3f(-0.75f, -0.25f, -0.75f);

16.
17. int []indices = {0,1,0,2,2,3,1,3,4,5,4,6,6,7,5,7,0,4,2,6,3,7,1,5};

18. array.setCoordinates(0,pts);

19. array.setCoordinateIndices(0, indices);

20.
21. Color3f []color = new Color3f[8];

22. color[0] = new Color3f(1f, 0f, 1f); color[1] = new Color3f(1f, 0f, 0f);

23. color[2] = new Color3f(0f, 1f, 0f); color[3] = new Color3f(0f, 0f, 1f);

24. color[4] = new Color3f(0f, 1f, 1f); color[5] = new Color3f(0.5f, 0.5f, 0.5f);

25. color[6] = new Color3f(0.5f, 0.5f,0f); color[7] = new Color3f(1f, 1f, 1f);

26.
27. int []colorIndices = {0,1,0,2,2,3,1,3,4,5,4,6,6,7,5,7,0,4,2,6,3,7,1,5};

28. array.setColors(0,color);

29. array.setColorIndices(0, colorIndices);

30.
31. axisBG.addChild(new Shape3D(array));

32. }

33.
34. public BranchGroup getBG() return axisBG;

35.
36.

vertices, and joining two appropriate vertices will give a line forming one side of the object
which has a total of 12 sides.
When the constructor of Axis is invoked, a BranchGroup object axisBG will be created
in line 7. Lines 8 and 9 then create an IndexedLineArray object named array in the code
segment. This object has a vertex count of eight and an index count of 24 to construct the