vtkQuaternionInterpolator Class Reference

#include <vtkQuaternionInterpolator.h>

Inheritance diagram for vtkQuaternionInterpolator:

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Collaboration diagram for vtkQuaternionInterpolator:

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List of all members.

Detailed Description

interpolate a quaternion

This class is used to interpolate a series of quaternions representing the rotations of a 3D object. The interpolation may be linear in form (using spherical linear interpolation SLERP), or via spline interpolation (using SQUAD). In either case the interpolation is specialized to quaternions since the interpolation occurs on the surface of the unit quaternion sphere.

To use this class, specify at least two pairs of (t,q[4]) with the AddQuaternion() method. Next interpolate the tuples with the InterpolateQuaternion(t,q[4]) method, where "t" must be in the range of (t_min,t_max) parameter values specified by the AddQuaternion() method (t is clamped otherwise), and q[4] is filled in by the method.

There are several important background references. Ken Shoemake described the practical application of quaternions for the interpolation of rotation (K. Shoemake, "Animating rotation with quaternion curves", Computer Graphics (Siggraph '85) 19(3):245--254, 1985). Another fine reference (available on-line) is E. B. Dam, M. Koch, and M. Lillholm, Technical Report DIKU-TR-98/5, Dept. of Computer Science, University of Copenhagen, Denmark.

Warning:: Note that for two or less quaternions, Slerp (linear) interpolation is performed even if spline interpolation is requested. Also, the tangents to the first and last segments of spline interpolation are (arbitrarily) defined by repeating the first and last quaternions.
There are several methods particular to quaternions (norms, products, etc.) implemented interior to this class. These may be moved to a separate quaternion class at some point.

Definition at line 60 of file vtkQuaternionInterpolator.h.


Public Types
typedef vtkObject	Superclass

enum	{ INTERPOLATION_TYPE_LINEAR = 0, INTERPOLATION_TYPE_SPLINE }
Public Member Functions
virtual const char *	GetClassName ()
virtual int	IsA (const char *type)
void	PrintSelf (ostream &os, vtkIndent indent)
int	GetNumberOfQuaternions ()
void	Initialize ()
void	AddQuaternion (double t, double q[4])
void	RemoveQuaternion (double t)
void	InterpolateQuaternion (double t, double q[4])

double	GetMinimumT ()
double	GetMaximumT ()

virtual void	SetInterpolationType (int)
virtual int	GetInterpolationType ()
void	SetInterpolationTypeToLinear ()
void	SetInterpolationTypeToSpline ()
Static Public Member Functions
static int	IsTypeOf (const char *type)
static vtkQuaternionInterpolator *	SafeDownCast (vtkObject *o)
static vtkQuaternionInterpolator *	New ()
Protected Member Functions
	vtkQuaternionInterpolator ()
virtual	~vtkQuaternionInterpolator ()
void	Slerp (double t, double q0[4], double q1[4], double q[4])
Static Protected Member Functions
static void	InnerPoint (double q0[4], double q1[4], double q2[4], double q[4])
Protected Attributes
int	InterpolationType
vtkQuaternionList *	QuaternionList

Member Typedef Documentation

typedef vtkObject vtkQuaternionInterpolator::Superclass

Reimplemented from vtkObject.

Definition at line 63 of file vtkQuaternionInterpolator.h.

Member Enumeration Documentation

anonymous enum

Enums to control the type of interpolation to use.

Enumerator:

INTERPOLATION_TYPE_LINEAR
INTERPOLATION_TYPE_SPLINE

Definition at line 104 of file vtkQuaternionInterpolator.h.

Constructor & Destructor Documentation

vtkQuaternionInterpolator::vtkQuaternionInterpolator ( ) [protected]

virtual vtkQuaternionInterpolator::~vtkQuaternionInterpolator ( ) [protected, virtual]

Member Function Documentation

virtual const char* vtkQuaternionInterpolator::GetClassName ( ) [virtual]

Reimplemented from vtkObject.

static int vtkQuaternionInterpolator::IsTypeOf ( const char * name ) [static]

Return 1 if this class type is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeRevisionMacro found in vtkSetGet.h.

Reimplemented from vtkObject.

virtual int vtkQuaternionInterpolator::IsA ( const char * name ) [virtual]

Return 1 if this class is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeRevisionMacro found in vtkSetGet.h.

Reimplemented from vtkObject.

static vtkQuaternionInterpolator* vtkQuaternionInterpolator::SafeDownCast ( vtkObject * o ) [static]

Reimplemented from vtkObject.

void vtkQuaternionInterpolator::PrintSelf	(	ostream &	os,
		vtkIndent	indent
	)			`[virtual]`

Methods invoked by print to print information about the object including superclasses. Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.

Reimplemented from vtkObject.

static vtkQuaternionInterpolator* vtkQuaternionInterpolator::New ( ) [static]

Instantiate the class.

Reimplemented from vtkObject.

int vtkQuaternionInterpolator::GetNumberOfQuaternions ( )

Return the number of quaternions in the list of quaternions to be interpolated.

double vtkQuaternionInterpolator::GetMinimumT ( )

Obtain some information about the interpolation range. The numbers returned (corresponding to parameter t, usually thought of as time) are undefined if the list of transforms is empty. This is a convenience method for interpolation.

double vtkQuaternionInterpolator::GetMaximumT ( )

Obtain some information about the interpolation range. The numbers returned (corresponding to parameter t, usually thought of as time) are undefined if the list of transforms is empty. This is a convenience method for interpolation.

void vtkQuaternionInterpolator::Initialize ( )

Reset the class so that it contains no data; i.e., the array of (t,q[4]) information is discarded.

void vtkQuaternionInterpolator::AddQuaternion	(	double	t,
		double	q[4]
	)

Add another quaternion to the list of quaternions to be interpolated. Note that using the same time t value more than once replaces the previous quaternion at t. At least one quaternions must be added to define an interpolation functios.

void vtkQuaternionInterpolator::RemoveQuaternion ( double t )

Delete the quaternion at a particular parameter t. If there is no quaternion tuple defined at t, then the method does nothing.

void vtkQuaternionInterpolator::InterpolateQuaternion	(	double	t,
		double	q[4]
	)

Interpolate the list of quaternions and determine a new quaternion (i.e., fill in the quaternion provided). If t is outside the range of (min,max) values, then t is clamped to lie within the range.

virtual void vtkQuaternionInterpolator::SetInterpolationType ( int ) [virtual]

Specify which type of function to use for interpolation. By default (SetInterpolationFunctionToSpline()), cubic spline interpolation using a modifed Kochanek basis is employed. Otherwise, if SetInterpolationFunctionToLinear() is invoked, linear spherical interpolation is used between each pair of quaternions.

virtual int vtkQuaternionInterpolator::GetInterpolationType ( ) [virtual]

Specify which type of function to use for interpolation. By default (SetInterpolationFunctionToSpline()), cubic spline interpolation using a modifed Kochanek basis is employed. Otherwise, if SetInterpolationFunctionToLinear() is invoked, linear spherical interpolation is used between each pair of quaternions.

void vtkQuaternionInterpolator::SetInterpolationTypeToLinear ( ) [inline]

Specify which type of function to use for interpolation. By default (SetInterpolationFunctionToSpline()), cubic spline interpolation using a modifed Kochanek basis is employed. Otherwise, if SetInterpolationFunctionToLinear() is invoked, linear spherical interpolation is used between each pair of quaternions.

Definition at line 119 of file vtkQuaternionInterpolator.h.

void vtkQuaternionInterpolator::SetInterpolationTypeToSpline ( ) [inline]

Specify which type of function to use for interpolation. By default (SetInterpolationFunctionToSpline()), cubic spline interpolation using a modifed Kochanek basis is employed. Otherwise, if SetInterpolationFunctionToLinear() is invoked, linear spherical interpolation is used between each pair of quaternions.

Definition at line 121 of file vtkQuaternionInterpolator.h.