Interpolator Class Reference

#include <Interpolator.h>

Inheritance diagram for Interpolator:


Public Member Functions
	Interpolator (unsigned int dim, unsigned int num_samples, bool use_tangents=false)
virtual	~Interpolator ()
unsigned int	GetDimension () const
unsigned int	GetNumSamples () const
virtual void	Reset ()
virtual void	GetSample (unsigned int i, float p_time, T sample, T *tangent=NULL)
virtual bool	AddSample (float t, const T sample, const T tangent=NULL)
virtual void	Eval (float t, T *value)=0
Protected Member Functions
virtual void	ComputeTangents (unsigned int i)
int	FindNearestSample (float t)
Memory management
T **	AllocateSamples (unsigned int num_samples, unsigned int size_sample)
void	DeallocateSamples (T **vec_samples, unsigned int num_samples, unsigned int size_sample)
void	ShiftSamples (T **vec_samples, unsigned int num_samples, unsigned int size_sample)
Protected Attributes
unsigned int	m_Dimension
unsigned int	m_NumSamples
bool	m_bInitialized
float *	m_vecTimes
T **	m_vecSamples
T **	m_vecTangents

Detailed Description

Interpolator abstract base class.

This class defines the interface of a general purpose interpolator for interpolating a sequence of n samples: { {t_0, S_0} .. {t_n-1, S_n-1} } each one consisting of a vector of dim elements of class T: S_i = [ T_0 .. T_dim-1 ]

The Interpolator class manages the data insertion and memory allocation/deallocation leaving only the Eval() method to be implemented in each subclasses/interpolation scheme.

Todo:

ALLOW the use of externam memory for the samples and the sample times, to avoid unnecessary replication in data stored originally in the correct format. => Maybe putting the time in the first position of the vector of T would help to make it easier (i T is float)

Extend it to handle periodic functions/cyclic animations

The class can be templarized, allowing for interpolation of vectors of T class elements if T is "additive". (no quaternions or rotation matrices here! But works for vectors or euler angles)

Shifting could be avoided using a "circular vector" of samples.

Constructor & Destructor Documentation

Interpolator::Interpolator ( unsigned int dim,

unsigned int num_samples,

bool use_tangents = false

) [inline]

virtual Interpolator::~Interpolator ( ) [inline, virtual]

Member Function Documentation

virtual bool Interpolator::AddSample ( float t,

const T * sample,

const T * tangent = NULL

) [inline, virtual]

Adds a sample to the end of the sample sequence.
Time t must be > than the previously inserted ones (samples should be inserted in chronological order).
Tangents can be specified or not, but they only will be stored if 'use_tangents' was true when the Interpolator was created.
If tangents are needed but not specified for some sample, method ComputeTangents() will be called to initialize it.
Returns false if there was some error.

T** Interpolator::AllocateSamples ( unsigned int num_samples,

unsigned int size_sample

) [inline, protected]

virtual void Interpolator::ComputeTangents ( unsigned int i ) [inline, protected, virtual]

Virtual method to compute/guess the tangent of the new added i-th sample.
MUST be redefined by subclasses that use tangents in order to properly initialize unspecified tangents.
MAY change the tangents of previous samples using the new i-th sample information.
[OSCAR] Currently used for splines only
Reimplemented in InterpolatorCubicSpline.

void Interpolator::DeallocateSamples ( T ** vec_samples,

unsigned int num_samples,

unsigned int size_sample

) [inline, protected]

virtual void Interpolator::Eval ( float t,

T * value

) [pure virtual]

Evaluates the function in t using the specific interpolation method (defined in a subclass).
Implemented in InterpolatorLinear, InterpolatorQuadratic, and InterpolatorCubicSpline.

int Interpolator::FindNearestSample ( float t ) [inline, protected]

Searches the nearest sample S_i with t_i <= t and returns its index. Notice that when the index -1 or N-1 is returned, t is ouside of the sampled interval [t_0..t_N-1). In this case we may want to extrapolate instead of interpolate.

unsigned int Interpolator::GetDimension ( ) const [inline]

unsigned int Interpolator::GetNumSamples ( ) const [inline]

virtual void Interpolator::GetSample ( unsigned int i,

float * p_time,

T * sample,

T * tangent = NULL

) [inline, virtual]

Returns the i-th time, sample and tangent (optional).