Geometry Objects - Interactive Web-Based Virtual Reality with Java 3D - page 70

Figure 46. Code segment and result of DiamondIndexedTriangleFanArray.java

1. public class Diamond extends Shape3D

2. {

3. public Diamond()

4. {

5. this.setGeometry(DiamondGeometry());

6. this.setAppearance(DiamondAppearance());

7. }

8.

9. private Geometry DiamondGeometry()

10. {

11. int N=5; //number of vertices in one fan

12. int totalN = 2*(N+1); //total number of vertices

13. int stripVertexCount[] = {N+1,N+1};

14. IndexedTriangleFanArray Tri = new IndexedTriangleFanArray

15. (totalN, IndexedGeometryArray.COORDINATES, 12, stripVertexCount);

16.
17. Tri.setCoordinate( 0, new Point3f(0f, 0.8f, 0f));
Tri.setCoordinate( 1, new Point3f(0f, 0f, 0.5f));
18. Tri.setCoordinate( 2, new Point3f(0.5f, 0f, 0f));
Tri.setCoordinate( 3, new Point3f(0f, 0f, -0.5f));
19. Tri.setCoordinate( 4, new Point3f(-0.5f, 0f, 0f));
Tri.setCoordinate( 5, new Point3f(0f, -0.8f, 0f));
20.
21. //Top Diamond
22. Tri.setCoordinateIndex( 0, 0); Tri.setCoordinateIndex( 1, 1);
Tri.setCoordinateIndex( 2, 2);
23. Tri.setCoordinateIndex( 3, 3); Tri.setCoordinateIndex( 4, 4);
Tri.setCoordinateIndex( 5, 1);
24.
25. //Bottom Diamond
26. Tri.setCoordinateIndex( 6, 5); Tri.setCoordinateIndex( 7, 4);
Tri.setCoordinateIndex( 8, 3);
27. Tri.setCoordinateIndex( 9, 2); Tri.setCoordinateIndex( 10, 1);
Tri.setCoordinateIndex( 11, 4);
28.
29.

return Tri;

30. }

31. }

Specifically, the constructor for the Exhibit class shown in Figure 47 is an extension
of a Shape3D class. Line 3 invokes an Artefact() method which returns a geometry object
for the creation of the artifact, with the setGeometry method placing the created geometry
object as a geometry component at index 0. Similarly, the next line invokes a Glass_case()