org.j3d.geom
Class MobiusGenerator

java.lang.Object
  org.j3d.geom.GeometryGenerator
      org.j3d.geom.MobiusGenerator

public class MobiusGenerator
extends GeometryGenerator

A mobius strip geometry generator with specified number of divisions per strip, number of strips, position, and appearance.

The generator is used to create Mobius strip shapes as geometry. The output are coordinates as quads suitable for use in an unindexed-quad array. The number of faces (polygons) generated is derived from the number of divisions times.

When normals are calculated, they are only generated for one side of the strip. When you create the Java3D geometry from this you should make sure to set the rendering attributes to be double sided.

The algorithm was adapted from Tore Nordstrand's Math Image Gallery: http://www.uib.no/people/nfytn/mathgal.htm (This algorithm is not perfect yet: The strips are slightly out of alignment. This is easy to see with a small number of strips

The current algorithm does not have control over the diameter of the strip created. I'd like to fix it but don't know where to start yet.

Version:

$Revision: 1.2 $

Author:

Justin Couch (heavily revised version of code from unknown source)

Constructor Summary

MobiusGenerator()
Constructs a mobius strip with 28 divisions per strip, 14 strips.

MobiusGenerator(int divisions, int strips)
Constructs a mobius strip with number of divisions per strip and number of strips.

Method Summary

float[]	generateUnindexedCoordinates() Generates new set of points.
void	setDimensions(int divisions, int strips) Change the dimensions of the cone to be generated.

Methods inherited from class org.j3d.geom.GeometryGenerator

createFaceNormal, createFaceNormal, createRadialNormal, createRadialNormal, generate, getVertexCount

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MobiusGenerator

public MobiusGenerator()

Constructs a mobius strip with 28 divisions per strip, 14 strips.

MobiusGenerator

public MobiusGenerator(int divisions,
                       int strips)

Constructs a mobius strip with number of divisions per strip and number of strips.

Parameters:

divisions - The number of divisions to use

strips - The number of strips to use

Method Detail

setDimensions

public void setDimensions(int divisions,
                          int strips)

Change the dimensions of the cone to be generated. Calling this will make the points be re-calculated next time you as for geometry or normals.

Parameters:

divisions - The number of divisions to use

strips - The number of strips to use

generateUnindexedCoordinates

public float[] generateUnindexedCoordinates()

Generates new set of points. If the dimensions have not changed since the last call, the identical array will be returned. Note that you should make a copy of this if you intend to call this method more than once as it will replace the old values with the new ones and not reallocate the array.

Returns:

An array of points representing the geometry vertices