mingfx::Quaternion Class Reference

Detailed Description

A quaternion to represent rotations in 3D space.

The main use of quaternions within the library is to support smooth interpolation between rotations, since this is not possible using Euler angles or rotation matrices. The class includes a Slerp routine for spherical interpolation between rotations. Example use:

// find a rotation 1/2 way between r1 and r2, both originally expressed in Euler angles
 
Vector3 euler1 = GfxMath::ToRadians(Vector3(0,0,60));
Vector3 euler2 = GfxMath::ToRadians(Vector3(45,45,60));
 
Quaternion q1 = Quaternion::FromEulerAnglesZYX(euler1);
Quaternion q2 = Quaternion::FromEulerAnglesZYX(euler2);
 
float alpha = 0.5;
Quaternion q_half_way = q1.Slerp(q2, alpha);
Vector3 new_euler_angles = GfxMath::ToDegrees(q_half_way.ToEulerAnglesZYX());

Definition at line 41 of file quaternion.h.

#include <quaternion.h>

Public Member Functions
	Quaternion ()
	Creates a quat with the identity rotation. More...
	Quaternion (float qx, float qy, float qz, float qw)
	Creates a quat from the 4 parameters. More...
	Quaternion (float *ptr)
	Creates a quate from a pointer to 4 floating point numbers in the order qx, qy, qz, qw. More...
	Quaternion (const Quaternion &other)
	Copy constructor. More...
virtual	~Quaternion ()
bool	operator== (const Quaternion &q) const
	Check for "equality", taking floating point imprecision into account. More...
bool	operator!= (const Quaternion &q) const
	Check for "inequality", taking floating point imprecision into account. More...
Quaternion &	operator= (const Quaternion &q)
	Assignment operator. More...
float	operator[] (const int i) const
	Read only access to the ith coordinate of the quaternion (qx, qy, qz, qw). More...
float &	operator[] (const int i)
	Writable access the ith coordinate of the quaternion (qx, qy, qz, qw). More...
float	x () const
	Read only access to the x coordinate of the imaginary part of the quaternion. More...
float	y () const
	Read only access to the y coordinate of the imaginary part of the quaternion. More...
float	z () const
	Read only access to the z coordinate of the imaginary part of the quaternion. More...
float	w () const
	Read only access to the w, real part, of the quaternion. More...
const float *	value_ptr () const
	Returns a const pointer to the raw data array, stored in the order qx, qy, qz, qw. More...
float	Dot (const Quaternion &q) const
	Returns the dot product of this quaternion with another. More...
float	Length () const
	Returns the length of the quaternion. More...
void	Normalize ()
	Normalizes the quat by making it unit length. More...
Quaternion	ToUnit () const
	Returns a normalized (i.e., unit length) version of the quaternion without modifying the original. More...
Quaternion	Conjugate () const
	Returns the conjugate of the quaternion. More...
Vector3	ToEulerAnglesZYX () const
	Converts the rotation specified by the quaternion into Euler angles. More...
Quaternion	Slerp (const Quaternion &other, float alpha) const
	Uses spherical interpolation to interpoloate between the rotation stored in this quaternion and the rotation stored in another. More...

Static Public Member Functions
static Quaternion	FromAxisAngle (const Vector3 &axis, float angle)
	Creates a new quaternion that describes a rotation by angle radians about. More...
static Quaternion	FromEulerAnglesZYX (const Vector3 &angles)
	Creates a new quaternion from a rotation defined in Euler angles. More...
static Quaternion	Slerp (const Quaternion &a, const Quaternion &b, float alpha)
	Uses spherical interpolation to interpoloate between the rotations specified by two quaternions. More...

Constructor & Destructor Documentation

Quaternion() [1/4]

mingfx::Quaternion::Quaternion

(

)

Creates a quat with the identity rotation.

Quaternion() [2/4]

mingfx::Quaternion::Quaternion	(	float	qx,
		float	qy,
		float	qz,
		float	qw
	)

Creates a quat from the 4 parameters.

Quaternion() [3/4]

mingfx::Quaternion::Quaternion

(

float *

ptr

)

Creates a quate from a pointer to 4 floating point numbers in the order qx, qy, qz, qw.

Quaternion() [4/4]

mingfx::Quaternion::Quaternion

(

const Quaternion &

other

)

Copy constructor.

~Quaternion()

virtual mingfx::Quaternion::~Quaternion ( )

virtual

Member Function Documentation

Conjugate()

Quaternion mingfx::Quaternion::Conjugate

(

)

const

Returns the conjugate of the quaternion.

Dot()

float mingfx::Quaternion::Dot

(

const Quaternion &

q

)

const

Returns the dot product of this quaternion with another.

FromAxisAngle()

static Quaternion mingfx::Quaternion::FromAxisAngle ( const Vector3 &  axis, float  angle  )

static

Creates a new quaternion that describes a rotation by angle radians about.

FromEulerAnglesZYX()

static Quaternion mingfx::Quaternion::FromEulerAnglesZYX ( const Vector3 &  angles )

static

Creates a new quaternion from a rotation defined in Euler angles.

Length()

float mingfx::Quaternion::Length

(

)

const

Returns the length of the quaternion.

Normalize()

void mingfx::Quaternion::Normalize

(

)

Normalizes the quat by making it unit length.

operator!=()

bool mingfx::Quaternion::operator!=

(

const Quaternion &

q

)

const

Check for "inequality", taking floating point imprecision into account.

operator=()

Quaternion& mingfx::Quaternion::operator=

(

const Quaternion &

q

)

Assignment operator.

operator==()

bool mingfx::Quaternion::operator==

(

const Quaternion &

q

)

const

Check for "equality", taking floating point imprecision into account.

operator[]() [1/2]

float& mingfx::Quaternion::operator[]

(

const int

i

)

Writable access the ith coordinate of the quaternion (qx, qy, qz, qw).

operator[]() [2/2]

float mingfx::Quaternion::operator[]

(

const int

i

)

const

Read only access to the ith coordinate of the quaternion (qx, qy, qz, qw).

Slerp() [1/2]

static Quaternion mingfx::Quaternion::Slerp ( const Quaternion &  a, const Quaternion &  b, float  alpha  )

static

Uses spherical interpolation to interpoloate between the rotations specified by two quaternions.

Slerp() [2/2]

Quaternion mingfx::Quaternion::Slerp	(	const Quaternion &	other,
		float	alpha
	)		const

Uses spherical interpolation to interpoloate between the rotation stored in this quaternion and the rotation stored in another.

ToEulerAnglesZYX()

Vector3 mingfx::Quaternion::ToEulerAnglesZYX

(

)

const

Converts the rotation specified by the quaternion into Euler angles.

ToUnit()

Quaternion mingfx::Quaternion::ToUnit

(

)

const

Returns a normalized (i.e., unit length) version of the quaternion without modifying the original.

value_ptr()

const float* mingfx::Quaternion::value_ptr

(

)

const

Returns a const pointer to the raw data array, stored in the order qx, qy, qz, qw.

w()

float mingfx::Quaternion::w ( ) const

inline

Read only access to the w, real part, of the quaternion.

Definition at line 83 of file quaternion.h.

x()

float mingfx::Quaternion::x ( ) const

inline

Read only access to the x coordinate of the imaginary part of the quaternion.

Definition at line 74 of file quaternion.h.

y()

float mingfx::Quaternion::y ( ) const

inline

Read only access to the y coordinate of the imaginary part of the quaternion.

Definition at line 77 of file quaternion.h.

z()

float mingfx::Quaternion::z ( ) const

inline

Read only access to the z coordinate of the imaginary part of the quaternion.

Definition at line 80 of file quaternion.h.

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

• src/quaternion.h