org.j3d.geom.spline
Class PatchGenerator

java.lang.Object
  org.j3d.geom.GeometryGenerator
      org.j3d.geom.spline.PatchGenerator

Direct Known Subclasses:

BezierPatchGenerator, BSplinePatchGenerator

public abstract class PatchGenerator
extends GeometryGenerator

Base geometry generator defintion for all forms of spline-based patches.

Patches of all orders are permitted. Order information is derived from the provided controlPoint coordinates. When generating a patch, the values for the coordinates are nominally provided in the X and Z plane although no explicit checking is performed to ensure that controlPoint coordinates do not self-intersect or do anything nasty. Normals are always generated as the average between the adjacent faces.

A user may optionally provide a weighting for each control point to make for rational patches. By default, all control points start with a weight of one. The implementation automatically resets the weights back to one each time the control points are changed, unless otherwise specified. If the patch coordinate size changes, then the weights will always be reset, otherwise if the size is the same as previously set, then the weights are left alone.

Version:

$Revision: 1.8 $

Author:

Justin Couch

Field Summary

protected float[][]	controlPointCoordinates ControlPoint values used to generate patches
protected float[][]	controlPointWeights The control point weightings on the patch.
protected int	depthFacetCount The number of sections used around the patch depth
protected boolean	normalsChanged Flag indicating base values have changed
protected int	numDepthControlPoints The number of control points in the depth
protected int	numNormalValues The number of patch coordinates in depth
protected int	numPatchValues The number of patch coordinates in depth
protected int	numTexcoordValues The number of patch coordinates in depth
protected int	numWidthControlPoints The number of control points in the width
protected boolean	patchChanged Flag indicating base values have changed
protected float[][]	patchCoordinates The points on the patch.
protected float[][]	patchNormals The smoothed normal for each point on the patch.
protected float[][]	patchTexcoords The texture coordinate for each point on the patch.
protected boolean	texCoordsChanged Flag indicating base values have changed
protected boolean	useControlPointWeights Should we use control point weights.
protected int	widthFacetCount The number of sections used around the patch width

Constructor Summary

protected

PatchGenerator() Construct a new generator with no control points set.

Method Summary

void	enableControlPointWeights(boolean state) Set the flag to say that calculations should be using the control point weights.
void	generate(GeometryData data) Generate a new set of geometry items patchd on the passed data.
int	getVertexCount(GeometryData data) Get the number of vertices that this generator will create for the shape given in the definition.
boolean	hasControlPointWeights() Get the current setting of the control point weight usage flag.
protected void	regenerateNormals() Convenience method to regenerate the smoothed normals for the patch.
protected abstract void	regeneratePatch() Regenerate the patch coordinate points in accordance with the derived classes algorithm type.
protected void	regenerateTexcoords() Regenerate the texture coordinate points.
void	setFacetCount(int widthFacets, int depthFacets) Change the number of facets used to create this cone.
void	setPatchControlPoints(double[][] controlPoints) Set the patch control points.
void	setPatchControlPoints(double[][] controlPoints, double[][] weights) Set the patch control points and weights at the same time.
void	setPatchControlPoints(double[] controlPoints, int numWidth, int numDepth) Set the patch controlPoints.
void	setPatchControlPoints(double[] controlPoints, int numWidth, int numDepth, double[] weights) Set the patch controlPoints.
void	setPatchControlPoints(float[][] controlPoints) Set the patch control points.
void	setPatchControlPoints(float[][] controlPoints, float[][] weights) Set the patch control points and weights at the same time.
void	setPatchControlPoints(float[] controlPoints, int numWidth, int numDepth) Set the patch controlPoints.
void	setPatchControlPoints(float[] controlPoints, int numWidth, int numDepth, float[] weights) Set the patch controlPoints.
void	setPatchWeights(double[][] weights) Set the patch control point weights.
void	setPatchWeights(double[] weights, int numWidth, int numDepth) Set the patch controlPoints.
void	setPatchWeights(float[][] weights) Set the patch control point weights.
void	setPatchWeights(float[] weights, int numWidth, int numDepth) Set the patch controlPoints.

Methods inherited from class org.j3d.geom.GeometryGenerator

createFaceNormal, createFaceNormal, createRadialNormal, createRadialNormal

Methods inherited from class java.lang.Object

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

Field Detail

controlPointCoordinates

protected float[][] controlPointCoordinates

ControlPoint values used to generate patches

controlPointWeights

protected float[][] controlPointWeights

The control point weightings on the patch. This will be the same size as controlPointCoordinates.

numWidthControlPoints

protected int numWidthControlPoints

The number of control points in the width

numDepthControlPoints

protected int numDepthControlPoints

The number of control points in the depth

patchCoordinates

protected float[][] patchCoordinates

The points on the patch.

patchNormals

protected float[][] patchNormals

The smoothed normal for each point on the patch.

patchTexcoords

protected float[][] patchTexcoords

The texture coordinate for each point on the patch.

numPatchValues

protected int numPatchValues

The number of patch coordinates in depth

numNormalValues

protected int numNormalValues

The number of patch coordinates in depth

numTexcoordValues

protected int numTexcoordValues

The number of patch coordinates in depth

patchChanged

protected boolean patchChanged

Flag indicating base values have changed

normalsChanged

protected boolean normalsChanged

Flag indicating base values have changed

texCoordsChanged

protected boolean texCoordsChanged

Flag indicating base values have changed

widthFacetCount

protected int widthFacetCount

The number of sections used around the patch width

depthFacetCount

protected int depthFacetCount

The number of sections used around the patch depth

useControlPointWeights

protected boolean useControlPointWeights

Should we use control point weights. Defaults to false.

Constructor Detail

PatchGenerator

protected PatchGenerator()

Construct a new generator with no control points set.

Method Detail

regeneratePatch

protected abstract void regeneratePatch()

Regenerate the patch coordinate points in accordance with the derived classes algorithm type.

setFacetCount

public void setFacetCount(int widthFacets,
                          int depthFacets)

Change the number of facets used to create this cone. This will cause the geometry to be regenerated next time they are asked for. The minimum number of facets is 3.

Parameters:

widthFacets - The number of facets on the width of the patch

depthFacets - The number of facets on the width of the patch

Throws:

java.lang.IllegalArgumentException - The number of facets is less than 3

enableControlPointWeights

public void enableControlPointWeights(boolean state)

Set the flag to say that calculations should be using the control point weights. Initially this starts as false, so if the user wants to create a rational surface then they should call this method with a value of true.

Parameters:

state - true if the weights should be used

hasControlPointWeights

public boolean hasControlPointWeights()

Get the current setting of the control point weight usage flag.

Returns:

true if the control point weights are in use

setPatchWeights

public void setPatchWeights(float[][] weights)

Set the patch control point weights. The array is presented as [width][depth] with the coordinates flattened as [Xn, Yn, Zn] in the depth array.

If the arrays are not of minimum length 3 and equal length an exception is generated.

Parameters:

weights - The weight values to use

setPatchWeights

public void setPatchWeights(double[][] weights)

Set the patch control point weights. The array is presented as [width][depth] with the coordinates flattened as [Xn, Yn, Zn] in the depth array.

If the arrays are not of minimum length 3 and equal length an exception is generated.

Parameters:

weights - The weight values to use

setPatchWeights

public void setPatchWeights(float[] weights,
                            int numWidth,
                            int numDepth)

Set the patch controlPoints. The array is presented as a flat array where coordinates are [depth * width Xn, Yn, Zn] in the array. The order of the patch is determined by the passed array. If the arrays are not of minimum length 3 and equal length an exception is generated.

Parameters:

weights - The weight values to use

numWidth - The number of points in the width

numDepth - The number of points in the depth

setPatchWeights

public void setPatchWeights(double[] weights,
                            int numWidth,
                            int numDepth)

Set the patch controlPoints. The array is presented as a flat array where coordinates are [depth * width Xn, Yn, Zn] in the array. The order of the patch is determined by the passed array. If the arrays are not of minimum length 3 and equal length an exception is generated.

Parameters:

weights - The weight values to use

numWidth - The number of points in the width

numDepth - The number of points in the depth

setPatchControlPoints

public void setPatchControlPoints(float[][] controlPoints)

Set the patch control points. The array is presented as [width][depth] with the coordinates flattened as [Xn, Yn, Zn] in the depth array. The order of the patch is determined by the passed array. If the arrays are not of minimum length 3 and equal length an exception is generated.

Parameters:

controlPoints - The controlPoint coordinate values

setPatchControlPoints

public void setPatchControlPoints(double[][] controlPoints)

Set the patch control points. The array is presented as [width][depth] with the coordinates flattened as [Xn, Yn, Zn] in the depth array. The order of the patch is determined by the passed array. If the arrays are not of minimum length 3 and equal length an exception is generated.

Parameters:

controlPoints - The controlPoint coordinate values

setPatchControlPoints

public void setPatchControlPoints(float[][] controlPoints,
                                  float[][] weights)

Set the patch control points and weights at the same time. The array is presented as [width][depth] with the coordinates flattened as [Xn, Yn, Zn] in the depth array. The order of the patch is determined by the passed array. If the arrays are not of minimum length 3 and equal length an exception is generated.

Parameters:

controlPoints - The controlPoint coordinate values

weights - The weight values to use

setPatchControlPoints

public void setPatchControlPoints(double[][] controlPoints,
                                  double[][] weights)

Set the patch control points and weights at the same time. The array is presented as [width][depth] with the coordinates flattened as [Xn, Yn, Zn] in the depth array. The order of the patch is determined by the passed array. If the arrays are not of minimum length 3 and equal length an exception is generated.

Parameters:

controlPoints - The controlPoint coordinate values

weights - The weight values to use

setPatchControlPoints

public void setPatchControlPoints(float[] controlPoints,
                                  int numWidth,
                                  int numDepth)

Set the patch controlPoints. The array is presented as a flat array where coordinates are [depth * width Xn, Yn, Zn] in the array. The order of the patch is determined by the passed array. If the arrays are not of minimum length 3 and equal length an exception is generated.

Parameters:

controlPoints - The controlPoint coordinate values

numWidth - The number of points in the width

numDepth - The number of points in the depth

setPatchControlPoints

public void setPatchControlPoints(double[] controlPoints,
                                  int numWidth,
                                  int numDepth)

Set the patch controlPoints. The array is presented as a flat array where coordinates are [depth * width Xn, Yn, Zn] in the array. The order of the patch is determined by the passed array. If the arrays are not of minimum length 3 and equal length an exception is generated.

Parameters:

controlPoints - The controlPoint coordinate values

numWidth - The number of points in the width

numDepth - The number of points in the depth

setPatchControlPoints

public void setPatchControlPoints(float[] controlPoints,
                                  int numWidth,
                                  int numDepth,
                                  float[] weights)

Set the patch controlPoints. The array is presented as a flat array where coordinates are [depth * width Xn, Yn, Zn] in the array. The order of the patch is determined by the passed array. If the arrays are not of minimum length 3 and equal length an exception is generated.

Parameters:

controlPoints - The controlPoint coordinate values

numWidth - The number of points in the width

numDepth - The number of points in the depth

setPatchControlPoints

public void setPatchControlPoints(double[] controlPoints,
                                  int numWidth,
                                  int numDepth,
                                  double[] weights)

Set the patch controlPoints. The array is presented as a flat array where coordinates are [depth * width Xn, Yn, Zn] in the array. The order of the patch is determined by the passed array. If the arrays are not of minimum length 3 and equal length an exception is generated.

Parameters:

controlPoints - The controlPoint coordinate values

numWidth - The number of points in the width

numDepth - The number of points in the depth

getVertexCount

public int getVertexCount(GeometryData data)
                   throws UnsupportedTypeException

Get the number of vertices that this generator will create for the shape given in the definition.

Specified by:

getVertexCount in class GeometryGenerator

Parameters:

data - The data to patch the calculations on

Returns:

The vertex count for the object

Throws:

UnsupportedTypeException - The generator cannot handle the type of geometry you have requested.

generate

public void generate(GeometryData data)
              throws UnsupportedTypeException,
                     InvalidArraySizeException

Generate a new set of geometry items patchd on the passed data. If the data does not contain the right minimum array lengths an exception will be generated. If the array reference is null, this will create arrays of the correct length and assign them to the return value.

Specified by:

generate in class GeometryGenerator

Parameters:

data - The data to patch the calculations on

Throws:

InvalidArraySizeException - The array is not big enough to contain the requested geometry

UnsupportedTypeException - The generator cannot handle the type of geometry you have requested

regenerateNormals

protected void regenerateNormals()

Convenience method to regenerate the smoothed normals for the patch. It assumes that the patch has been regenerated just before this call.

regenerateTexcoords

protected final void regenerateTexcoords()

Regenerate the texture coordinate points. Assumes regenerateBase has been called before this