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Ogre::RotationalSpline Class Reference

This class interpolates orientations (rotations) along a spline using derivatives of quaternions. More...

#include <OgreRotationalSpline.h>

List of all members.

Public Methods

 RotationalSpline ()
 ~RotationalSpline ()
void addPoint (const Quaternion &p)
 Adds a control point to the end of the spline.

const QuaterniongetPoint (unsigned short index) const
 Gets the detail of one of the control points of the spline.

unsigned short getNumPoints (void) const
 Gets the number of control points in the spline.

void clear (void)
 Clears all the points in the spline.

void updatePoint (unsigned short index, const Quaternion &value)
 Updates a single point in the spline.

Quaternion interpolate (Real t, bool useShortestPath=true)
 Returns an interpolated point based on a parametric value over the whole series.

Quaternion interpolate (unsigned int fromIndex, Real t, bool useShortestPath=true)
 Interpolates a single segment of the spline given a parametric value.

void setAutoCalculate (bool autoCalc)
 Tells the spline whether it should automatically calculate tangents on demand as points are added.

void recalcTangents (void)
 Recalculates the tangents associated with this spline.


Protected Attributes

bool mAutoCalc
std::vector< QuaternionmPoints
std::vector< QuaternionmTangents


Detailed Description

This class interpolates orientations (rotations) along a spline using derivatives of quaternions.

Remarks:
Like the SimpleSpline class, this class is about interpolating values smoothly over a spline. Whilst SimpleSpline deals with positions (the normal sense we think about splines), this class interpolates orientations. The theory is identical, except we're now in 4-dimensional space instead of 3.

In positional splines, we use the points and tangents on those points to generate control points for the spline. In this case, we use quaternions and derivatives of the quaternions (i.e. the rate and direction of change at each point). This is the same as SimpleSpline since a tangent is a derivative of a position. We effectively generate an extra quaternion in between each actual quaternion which when take with the original quaternion forms the 'tangent' of that quaternion.

Definition at line 48 of file OgreRotationalSpline.h.


Constructor & Destructor Documentation

Ogre::RotationalSpline::RotationalSpline  
 

Definition at line 33 of file OgreRotationSpline.cpp.

Ogre::RotationalSpline::~RotationalSpline  
 

Definition at line 37 of file OgreRotationSpline.cpp.


Member Function Documentation

void Ogre::RotationalSpline::addPoint const Quaternion   p
 

Adds a control point to the end of the spline.

Definition at line 41 of file OgreRotationSpline.cpp.

References mPoints, and recalcTangents().

Referenced by Ogre::AnimationTrack::buildInterpolationSplines().

void Ogre::RotationalSpline::clear void   
 

Clears all the points in the spline.

Definition at line 192 of file OgreRotationSpline.cpp.

References mPoints, and mTangents.

Referenced by Ogre::AnimationTrack::buildInterpolationSplines().

unsigned short Ogre::RotationalSpline::getNumPoints void    const
 

Gets the number of control points in the spline.

Definition at line 187 of file OgreRotationSpline.cpp.

References mPoints.

const Quaternion & Ogre::RotationalSpline::getPoint unsigned short    index const
 

Gets the detail of one of the control points of the spline.

Definition at line 180 of file OgreRotationSpline.cpp.

References mPoints.

Quaternion Ogre::RotationalSpline::interpolate unsigned int    fromIndex,
Real    t,
bool    useShortestPath = true
 

Interpolates a single segment of the spline given a parametric value.

Parameters:
fromIndex  The point index to treat as t=0. fromIndex + 1 is deemed to be t=1
t  Parametric value
useShortestPath  Defines if rotation should take the shortest possible path

Definition at line 62 of file OgreRotationSpline.cpp.

References mPoints, mTangents, and Ogre::Real.

Quaternion Ogre::RotationalSpline::interpolate Real    t,
bool    useShortestPath = true
 

Returns an interpolated point based on a parametric value over the whole series.

Remarks:
Given a t value between 0 and 1 representing the parametric distance along the whole length of the spline, this method returns an interpolated point.
Parameters:
t  Parametric value.
useShortestPath  Defines if rotation should take the shortest possible path

Definition at line 50 of file OgreRotationSpline.cpp.

References mPoints, and Ogre::Real.

Referenced by Ogre::AnimationTrack::getInterpolatedKeyFrame().

void Ogre::RotationalSpline::recalcTangents void   
 

Recalculates the tangents associated with this spline.

Remarks:
If you tell the spline not to update on demand by calling setAutoCalculate(false) then you must call this after completing your updates to the spline points.

Definition at line 98 of file OgreRotationSpline.cpp.

References Ogre::Quaternion::Exp(), Ogre::Quaternion::Inverse(), Ogre::Quaternion::Log(), mPoints, and mTangents.

Referenced by addPoint(), Ogre::AnimationTrack::buildInterpolationSplines(), and updatePoint().

void Ogre::RotationalSpline::setAutoCalculate bool    autoCalc
 

Tells the spline whether it should automatically calculate tangents on demand as points are added.

Remarks:
The spline calculates tangents at each point automatically based on the input points. Normally it does this every time a point changes. However, if you have a lot of points to add in one go, you probably don't want to incur this overhead and would prefer to defer the calculation until you are finished setting all the points. You can do this by calling this method with a parameter of 'false'. Just remember to manually call the recalcTangents method when you are done.
Parameters:
autoCalc  If true, tangents are calculated for you whenever a point changes. If false, you must call reclacTangents to recalculate them when it best suits.

Definition at line 209 of file OgreRotationSpline.cpp.

References mAutoCalc.

Referenced by Ogre::AnimationTrack::buildInterpolationSplines().

void Ogre::RotationalSpline::updatePoint unsigned short    index,
const Quaternion   value
 

Updates a single point in the spline.

Remarks:
This point must already exist in the spline.

Definition at line 198 of file OgreRotationSpline.cpp.

References mPoints, and recalcTangents().


Member Data Documentation

bool Ogre::RotationalSpline::mAutoCalc [protected]
 

Definition at line 111 of file OgreRotationalSpline.h.

Referenced by setAutoCalculate().

std::vector<Quaternion> Ogre::RotationalSpline::mPoints [protected]
 

Definition at line 115 of file OgreRotationalSpline.h.

Referenced by addPoint(), clear(), getNumPoints(), getPoint(), interpolate(), recalcTangents(), and updatePoint().

std::vector<Quaternion> Ogre::RotationalSpline::mTangents [protected]
 

Definition at line 116 of file OgreRotationalSpline.h.

Referenced by clear(), interpolate(), and recalcTangents().


The documentation for this class was generated from the following files:

Copyright © 2002-2003 by The OGRE Team
Last modified Fri May 14 23:27:06 2004