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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. More...

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

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

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

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

Quaternion interpolate (Real t)
 Returns an interpolated point based on a parametric value over the whole series. More...

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

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

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


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.


Constructor & Destructor Documentation

Ogre::RotationalSpline::RotationalSpline  
 

Ogre::RotationalSpline::~RotationalSpline  
 


Member Function Documentation

void Ogre::RotationalSpline::addPoint const Quaternion   p
 

Adds a control point to the end of the spline.

void Ogre::RotationalSpline::clear void   
 

Clears all the points in the spline.

unsigned short Ogre::RotationalSpline::getNumPoints void    const
 

Gets the number of control points in the spline.

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

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

Quaternion Ogre::RotationalSpline::interpolate unsigned int    fromIndex,
Real    t
 

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

Quaternion Ogre::RotationalSpline::interpolate Real    t
 

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.

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.

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.

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.


Member Data Documentation

bool Ogre::RotationalSpline::mAutoCalc [protected]
 

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

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

Copyright © 2002 by The OGRE Team