AlBlendCurve

Synopsis

#include <AlBlendCurve.h>

class AlBlendCurve :	public AlObject

enum AlKnotSpacingType {

	kChord,

	kUniform

};

AlBlendCurve();

virtual	~AlBlendCurve();

virtual statusCode	deleteObject();

virtual AlObject*	copyWrapper() const;

statusCode	create( int , AlKnotSpacingType , int , const double[][3] );

statusCode	create( int , AlKnotSpacingType );

virtual AlObjectType	type() const;

int	degree();

statusCode	setDegree( int );

statusCode	knotSpacingType( AlKnotSpacingType& );

statusCode	setKnotSpacingType( AlKnotSpacingType );

int	numberOfPoints();

statusCode param( int, double& );

AlBlendPoint*	getPoint( int );

statusCode	points( int, double[] );

statusCode	insert( int, double, double, double );

statusCode	append( double, double, double );

boolean	isPicked();

AlBlendCurve*	next();

statusCode	nextD( AlBlendCurve * );

AlBlendCurve*	prev();

statusCode	prevD( AlBlendCurve * );

AlCurveNode*	curveNode();

Description

An Alias Blend Curve is a normal NURBS curve with construction history. This class allows blend curves to be created and intersected with other curves, curves on surfaces, blend curves and surfaces. Note that intersection with clouds is not currently supported. Blend Curves contain Blend Points so it is necessary to use the AlBlendPoint class to make use of all of the Blend Curve functionality. To find the curve node which is the output of the Blend Curve command, use the curveNode() method.

Notes:

1. If a blend curve is active and the API is used to create another blend curve, the first blend curve will become inactive.

2. Blend curves can be made active or inactive by finding the curveNode() method and calling pick() on unpick() with the AlCurveNode.

AlBlendCurve::AlBlendCurve()

Description

NULL constructor.

AlBlendCurve::~AlBlendCurve()

Description

NULL destructor.

statusCode AlBlendCurve::deleteObject()

Description

This method deletes a blend curve object and any points it has. In addition, the output AlCurve of the blend curve object is deleted.

Return Codes

sSuccess - the object was successfully deleted

sFailure - the method failed

sInvalidObject - the object was invalid

AlObject *AlBlendCurve::copyWrapper() const

Description

Returns an exact copy of the blend curve wrapper. NULL is returned if this method failed.

statusCode AlBlendCurve::create( int degree, AlKnotSpacingType ks )

Description

Create a blend curve based on a specified degree and knot spacing. Points are added to the blend curve using the insertPoint() or appendPoint() methods.

Arguments

< degree - one of 1, 2, 3, 5, or 7

< ks - kChord or kUniform

Return Codes

sSuccess - a blend curve was created

sFailure - blend curve is currently valid, or other internal error occurred

sInvalidArgument - degree is not one of 1, 2, 3, 5, 7

statusCode AlBlendCurve::create( int degree, AlKnotSpacingType ks, int numPoints, const double points[][3])

Description

Create a blend curve based on a specified degree, knot spacing and points. More points can be added to the blend curve using the insertPoint() or appendPoint() methods. Note: a new point is initially not connected to any object, has a location interpolation direction, and has a parallel direction type.

Arguments

< degree - one of 1, 2, 3, 5, or 7

< ks - kChord or kUniform

< numPoints - number of points in the point[] array

< points[] - array of 3D points

Return Codes

sSuccess - a blend curve was created

sFailure - blend curve is currently valid, or other internal error occurred

sInvalidArgument - degree is not one of 1, 2, 3, 5, 7, or points are too close together (tolerance = 0.01).

AlObjectType AlBlendCurve::type() const

Description

Returns the class identifier kBlendCurveType.

int AlBlendCurve::degree()

Description

Returns the degree of the blend curve. Note that -1 is returned if the blend curve is invalid or if an internal error occurs.

statusCode AlBlendCurve::setDegree( int degree )

Description

Sets the degree of the blend curve.

Arguments

< degree - one of 1, 2, 3, 5, or 7

Return Codes

sSuccess - the method succeeded

sFailure - internal failure

sInvalidArgument - degree was not one of 1, 2, 3, 5 or 7

sInvalidObject - invalid blend curve

statusCode AlBlendCurve::knotSpacingType( AlKnotSpacingType& kst )

Description

Returns the knot spacing setting of the blend curve.

Arguments

> kst - knot spacing of the curve

Return Codes

sSuccess - the method succeeded

sFailure - internal failure

sInvalidObject - invalid blend curve

statusCode AlBlendCurve::setKnotSpacingType( AlKnotSpacingType kst )

Description

Sets the knot spacing of the blend curve.

Arguments

< kst - kChord or kUniform

Return Codes

sSuccess - the method succeeded

sFailure - internal failure

sInvalidObject - invalid blend curve

int AlBlendCurve::numberOfPoints()

Description

Returns the number of points in a blend curve. If this method fails, -1 is returned. This method will fail if the blend curve is invalid.

statusCode AlBlendCurve::param( int index, double& param )

Description

Returns the param or ’t’ value of the blend point at the index specified in the blend curve. The first blend point is at index = 0.

Arguments

index - the index of the point on the blend curve to return the param for param - the blend point’s param value

Return Codes

sSuccess - the method succeeded

sFailure - internal failure,

sInvalidObject - the blend point is invalid

AlBlendPoint* AlBlendCurve::getPoint( int index )

Description

Returns the Nth point of the blend curve. NULL is returned if this method fails. This method will fail if index is less than 0 or greater than the number of points in the blend curve. The first blend curve point is at index = 0.

statusCode AlBlendCurve::points( int numPoints, double points[] )

Description

Returns the world position of the points of a blend curve.

Example code:

int num = blendCurve->numberOfPoints();       double *points = (double *) malloc( sizeof(double) * num * 3 );       if ( points == NULL )           	return;       if ( blendCurve->points( num, points ) != sSuccess )           	return;       double *pt = points; for ( int i = 0 ; i < num ; i++ )       {           	pt[0] += x;  	pt[1] += y;  	pt[2] += z;           	pt += 3;       }

Note: numPoints can be less than the actual number of points. The method will place as many points as possible into the array and then return successfully.

Arguments

< numPoints - size of the points array, must be a value greater than 0. For every n points, you need to allocate n * 3 elements

> points - array to return points in

Return Codes

sSuccess - the method succeeded

sFailure - internal failure

sInvalidObject - the blend curve is invalid

sInvalidArgument - numPoints < 1

statusCode AlBlendCurve::insert( int index, double x, double y, double z )

Description

Inserts a new blend point before the blend point at the index specified. Note: a new point is initially not connected to any object, has a location interpolation direction, and has a parallel direction type.

Arguments

< index - position to insert the point before

< x,y,z - world space location of the new point

Return Codes

sSuccess - method succeeded

sFailure - internal failure

sInvalidObject - the blend curve is invalid

sInvalidArgument - index < 0 or falls after the last point

statusCode AlBlendCurve::append( double x, double y, double z)

Description

Appends a new blend point to the end of the blend curve. Note: a new point is initially not connected to any object, has a location interpolation direction, and has a parallel direction type.

Arguments

x,y,z - the world space coordinates of the new blend point

Return Codes

sSuccess - the method succeeded

sFailure - internal failure

sInvalidObject - the blend curve is invalid

AlCurveNode* AlBlendCurve::curveNode()

Description

Returns the construction history curve that is the output of the blend curve.

boolean AlBlendCurve::isPicked()

Description

Returns TRUE is the blend curve is currently picked. FALSE is returned if the blend curve is invalid or if an internal error occurs.

lBlendCurve* AlBlendCurve::next()

Description

Returns the next blend curve in the Universe.

statusCode AlBlendCurve::nextD( AlBlendCurve *blendCurve )

Description

Destructive method for returning the next blend curve in the universe. sFailure is returned if there is no next blend curve in the universe.

Arguments

< blendCurve - the blend curve to obtain the next blend curve from

Return Codes

sSuccess - the method worked sFailure - the method failed, could be due to there being no next blend curve sInvalidObject - this blend curve is invalid

AlBlendCurve* AlBlendCurve::prev()

Description

Returns the previous blend curve in the Universe.

statusCode AlBlendCurve::prevD( AlBlendCurve *blendCurve )

Description

Destructive method for returning the previous blend curve in the universe. sFailure is returned if there is no previous blend curve in the universe.

Arguments

< blendCurve - the blend curve to obtain the previous blend curve from

Return Codes

sSuccess - the method worked sFailure - the method failed, could be due to there being no previous blend curve sInvalidObject - this blend curve is invalid