gnu.gleem.linalg
Class Rotf

java.lang.Object
  |
  +--gnu.gleem.linalg.Rotf

public class Rotf

extends java.lang.Object

Represents a rotation with single-precision components

Constructor Summary

Rotf()
Default constructor initializes to the identity quaternion

Rotf(Rotf arg)

Rotf(Vec3f axis, float angle)
Axis does not need to be normalized but must not be the zero vector.

Method Summary

void	fromMatrix(Mat4f mat) Turns the upper left 3x3 of the passed matrix into a rotation.
float	get(Vec3f axis) Returns angle (in radians) and mutates the given vector to be the axis.
void	init() Re-initialize this quaternion to be the identity quaternion "e" (i.e., no rotation)
Rotf	inverse() Returns inverse of this rotation; creates new rotation
void	invert() Mutate this quaternion to be its inverse.
float	length() Length of this quaternion in four-space
float	lengthSquared() This dotted with this
void	mul(Rotf a, Rotf b) Compose two rotations: this = A * B in that order.
void	normalize() Make this quaternion a unit quaternion again.
Vec3f	rotateVector(Vec3f src) Rotate a vector by this quaternion, returning newly-allocated result.
void	rotateVector(Vec3f src, Vec3f dest) Rotate a vector by this quaternion.
void	set(Rotf arg)
void	set(Vec3f axis, float angle) Axis does not need to be normalized but must not be the zero vector.
Rotf	times(Rotf b) Returns this * b, in that order; creates new rotation
void	toMatrix(Mat4f mat) Turns this rotation into a 3x3 rotation matrix.
java.lang.String	toString()
boolean	withinEpsilon(Rotf arg, float epsilon) Test for "approximate equality" -- performs componentwise test to see whether difference between all components is less than epsilon.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Rotf

public Rotf()

Default constructor initializes to the identity quaternion

Rotf

public Rotf(Rotf arg)

Rotf

public Rotf(Vec3f axis,
            float angle)

Axis does not need to be normalized but must not be the zero vector. Angle is in radians.

Method Detail

init

public void init()

Re-initialize this quaternion to be the identity quaternion "e" (i.e., no rotation)

withinEpsilon

public boolean withinEpsilon(Rotf arg,
                             float epsilon)

Test for "approximate equality" -- performs componentwise test to see whether difference between all components is less than epsilon.

set

public void set(Vec3f axis,
                float angle)

Axis does not need to be normalized but must not be the zero vector. Angle is in radians.

set

public void set(Rotf arg)

get

public float get(Vec3f axis)

Returns angle (in radians) and mutates the given vector to be the axis.

inverse

public Rotf inverse()

Returns inverse of this rotation; creates new rotation

invert

public void invert()

Mutate this quaternion to be its inverse. This is equivalent to the conjugate of the quaternion.

length

public float length()

Length of this quaternion in four-space

lengthSquared

public float lengthSquared()

This dotted with this

normalize

public void normalize()

Make this quaternion a unit quaternion again. If you are composing dozens of quaternions you probably should call this periodically to ensure that you have a valid rotation.

times

public Rotf times(Rotf b)

Returns this * b, in that order; creates new rotation

mul

public void mul(Rotf a,
                Rotf b)

Compose two rotations: this = A * B in that order. NOTE that because we assume a column vector representation that this implies that a vector rotated by the cumulative rotation will be rotated first by B, then A. NOTE: "this" must be different than both a and b.

toMatrix

public void toMatrix(Mat4f mat)

Turns this rotation into a 3x3 rotation matrix. NOTE: only mutates the upper-left 3x3 of the passed Mat4f. Implementation from B. K. P. Horn's _Robot Vision_ textbook.

fromMatrix

public void fromMatrix(Mat4f mat)

Turns the upper left 3x3 of the passed matrix into a rotation. Implementation from Watt and Watt, _Advanced Animation and Rendering Techniques_.

See Also:

gnu.gleem.linalg.Mat4f.getRotation

rotateVector

public void rotateVector(Vec3f src,
                         Vec3f dest)

Rotate a vector by this quaternion. Implementation is from Horn's _Robot Vision_. NOTE: src and dest must be different vectors.

rotateVector

public Vec3f rotateVector(Vec3f src)

Rotate a vector by this quaternion, returning newly-allocated result.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object