SbRotation Class Reference
[Basics]

Class for representing a rotation. More...

#include <Inventor/SbRotation.h>

List of all members.

Public Member Functions
	SbRotation ()
	SbRotation (const float v[4])
	SbRotation (float q0, float q1, float q2, float q3)
	SbRotation (const SbMatrix &m)
	SbRotation (const SbMatrix3 &m)
	SbRotation (const SbVec3f &axis, float radians)
	SbRotation (const SbVec3f &rotateFrom, const SbVec3f &rotateTo)
const float *	getValue () const
void	getValue (float &q0, float &q1, float &q2, float &q3) const
void	getValue (SbVec3f &axis, float &radians) const
void	getValue (SbMatrix &matrix) const
void	getValue (SbMatrix3 &matrix) const
void	getValue (SbMatrixd &matrix) const
SbRotation &	invert ()
SbRotation	inverse () const
SbRotation &	setValue (const float q[4])
SbRotation &	setValue (float q0, float q1, float q2, float q3)
SbRotation &	setValue (const SbMatrix &m)
SbRotation &	setValue (const SbMatrix3 &m)
SbRotation &	setValue (const SbVec3f &axis, float radians)
SbRotation &	setValue (const SbVec3f &rotateFrom, const SbVec3f &rotateTo)
SbRotation &	setValue (const SbRotationd &rotated)
SbRotation &	setValue (const SbMatrixd &md)
SbRotation &	operator*= (const SbRotation &q)
SbBool	equals (const SbRotation &r, float tolerance) const
void	multVec (const SbVec3f &src, SbVec3f &dst) const
void	scaleAngle (float scaleFactor)
Static Public Member Functions
static SbRotation	slerp (const SbRotation &rot0, const SbRotation &rot1, float t)
static SbRotation	identity ()
Friends
int	operator== (const SbRotation &q1, const SbRotation &q2)
int	operator!= (const SbRotation &q1, const SbRotation &q2)
SbRotation	operator* (const SbRotation &q1, const SbRotation &q2)

---

Detailed Description

Class for representing a rotation.

Object that stores a rotation. There are several ways to specify a rotation: quaternion (4 floats, in the order x, y, z, w), 4x4 rotation matrix, or axis and angle. All angles are in radians and all rotations are right-handed.

The rotation value is stored internally as a quaternion. Quaternion representation is more compact, faster to compute and more numerically stable than rotation matrices. Quaternion representation allows smooth rotation (spherical linear interpolation) and avoids the problem of "gimbal lock" associated with Euler angles. It is not necessary to deal directly with quaternions. Many convenience methods are provided to set and get rotations using matrix and axis/angle representations.

Rotations are most commonly specified using an axis and an angle in radians. A common mistake is to use the constructor or setValue method that takes four float values, when intending to set an axis and angle. The methods that take four float values directly specify the quaternion value, which is probably not the intended result. For example:

     // Create a rotation of PI/2 radians around the Z axis:

     // Incorrect.
     // (Compiles, but actually sets the quaternion value directly!)
     SbRotation rotation(0, 0, 1, 1.5707963f);

     // This is the correct rotation.
     SbRotation rotation( SbVec3f(0, 0, 1), 1.5707963f);

SEE ALSO

SbRotationd, SbVec2d, SbVec2f, SbVec2i32, SbVec2s, SbVec3d, SbVec3f, SbVec3i32, SbVec3s, SbVec4b, SbVec4d, SbVec4f, SbVec4i32, SbVec4s, SbVec4ub, SbVec4ui32, SbVec4us

---

Constructor & Destructor Documentation

SbRotation::SbRotation

(

)

[inline]

Default constructor.

The initial value is no rotation.

SbRotation::SbRotation

(

const float

v[4]

)

[inline]

Constructor.

The quaternion constructor takes four floats that define a quaternion.
Note this is NOT the same as an axis/radian definition.

SbRotation::SbRotation	(	float	q0,
		float	q1,
		float	q2,
		float	q3
	)			[inline]

Constructor.

The quaternion constructor takes four floats that define a quaternion.
Note this is NOT the same as an axis/radian definition.

SbRotation::SbRotation

(

const SbMatrix &

m

)

[inline]

Constructor.

The matrix constructor takes a valid rotation matrix.

SbRotation::SbRotation

(

const SbMatrix3 &

m

)

[inline]

Constructor.

The matrix constructor takes a valid 3x3 rotation matrix.

SbRotation::SbRotation	(	const SbVec3f &	axis,
		float	radians
	)			[inline]

Constructor.

The axis/radians constructor creates a rotation of angle radians about the given axis.

SbRotation::SbRotation	(	const SbVec3f &	rotateFrom,
		const SbVec3f &	rotateTo
	)			[inline]

Constructor.

The rotateFrom/To constructor defines a rotation that rotates from one vector into another. The rotateFrom and rotateTo vectors are normalized by the constructor before calculating the rotation.

---

Member Function Documentation

SbBool SbRotation::equals	(	const SbRotation &	r,
		float	tolerance
	)			const

Equality comparison within given tolerance - the square of the length of the maximum distance between the two quaternion vectors.

void SbRotation::getValue

(

SbMatrixd &

matrix

)

const

Returns corresponding 4x4 rotation matrix.

void SbRotation::getValue

(

SbMatrix3 &

matrix

)

const

Returns corresponding 3x3 rotation matrix.

void SbRotation::getValue

(

SbMatrix &

matrix

)

const

Returns corresponding 4x4 rotation matrix.

void SbRotation::getValue	(	SbVec3f &	axis,
		float &	radians
	)			const

Returns corresponding 3D rotation axis vector and angle in radians.

void SbRotation::getValue	(	float &	q0,
		float &	q1,
		float &	q2,
		float &	q3
	)			const

Returns 4 individual components of rotation quaternion.

const float* SbRotation::getValue

(

)

const [inline]

Returns pointer to array of 4 components defining quaternion.

static SbRotation SbRotation::identity

(

)

[inline, static]

Returns a null rotation.

SbRotation SbRotation::inverse

(

)

const [inline]

Returns the inverse of a rotation.

SbRotation& SbRotation::invert

(

)

Changes a rotation to be its inverse.

void SbRotation::multVec	(	const SbVec3f &	src,
		SbVec3f &	dst
	)			const

Multiplies the given vector by the matrix of this rotation.

SbRotation& SbRotation::operator*=

(

const SbRotation &

q

)

Multiplies by another rotation; results in product of rotations.

void SbRotation::scaleAngle

(

float

scaleFactor

)

Keep the axis the same.

Multiply the angle of rotation by the amount scaleFactor.

SbRotation& SbRotation::setValue

(

const SbMatrixd &

md

)

Sets rotation from a double precision rotation matrix.

SbRotation& SbRotation::setValue

(

const SbRotationd &

rotated

)

Sets rotation from a double precision rotation.

SbRotation& SbRotation::setValue	(	const SbVec3f &	rotateFrom,
		const SbVec3f &	rotateTo
	)

Sets rotation to rotate one direction vector to another.

The rotateFrom and rotateTo arguments are normalized before the rotation is calculated.

SbRotation& SbRotation::setValue	(	const SbVec3f &	axis,
		float	radians
	)

Sets value of vector from 3D rotation axis vector and angle in radians.

SbRotation& SbRotation::setValue

(

const SbMatrix3 &

m

)

Sets rotation from a 3x3 rotation matrix.

SbRotation& SbRotation::setValue

(

const SbMatrix &

m

)

Sets value of rotation from a rotation matrix.

SbRotation& SbRotation::setValue	(	float	q0,
		float	q1,
		float	q2,
		float	q3
	)

Sets value of rotation from 4 individual components of a quaternion.

SbRotation& SbRotation::setValue

(

const float

q[4]

)

Sets value of rotation from array of 4 components of a quaternion.

static SbRotation SbRotation::slerp	(	const SbRotation &	rot0,
		const SbRotation &	rot1,
		float	t
	)			[static]

Spherical linear interpolation: as t goes from 0 to 1, returned value goes from rot0 to rot1.

---

Friends And Related Function Documentation

int operator!=	(	const SbRotation &	q1,
		const SbRotation &	q2
	)			[friend]

Inequality comparison operator.

SbRotation operator*	(	const SbRotation &	q1,
		const SbRotation &	q2
	)			[friend]

Multiplication of two rotations; results in product of rotations.

int operator==	(	const SbRotation &	q1,
		const SbRotation &	q2
	)			[friend]

Equality comparison operator.

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

• Inventor/SbRotation.h