// Some light is added to the scene here.
public void addLight(SimpleUniverse su) {
BranchGroup bgLight = new BranchGroup();
BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0, 0.0),
100.0);
Color3f lightColour1 = new Color3f(1.0f, 1.0f, 1.0f);
Vector3f lightDir1 = new Vector3f(-1.0f, 0.0f, -0.5f);
DirectionalLight light1 = new DirectionalLight(lightColour1, lightDir1);
light1.setInfluencingBounds(bounds);