Quaternion (jMonkeyEngine3)

java.lang.Object
- com.jme3.math.Quaternion

All Implemented Interfaces:

Savable, java.io.Serializable, java.lang.Cloneable
```
public final class Quaternion
extends java.lang.Object
implements Savable, java.lang.Cloneable, java.io.Serializable
```
Quaternion defines a single example of a more general class of hypercomplex numbers. Quaternions extends a rotation in three dimensions to a rotation in four dimensions. This avoids "gimbal lock" and allows for smooth continuous rotation. Quaternion is defined by four floating point numbers: {x y z w}.

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`static Quaternion`	`DIRECTION_Z`
`static Quaternion`	`IDENTITY` Represents the identity quaternion rotation (0, 0, 0, 1).
`protected float`	`w`
`protected float`	`x`
`protected float`	`y`
`protected float`	`z`
`static Quaternion`	`ZERO`

Constructor Summary

Constructors
Constructor and Description
`Quaternion()` Constructor instantiates a new `Quaternion` object initializing all values to zero, except w which is initialized to 1.
`Quaternion(float[] angles)` Constructor instantiates a new `Quaternion` object from a collection of rotation angles.
`Quaternion(float x, float y, float z, float w)` Constructor instantiates a new `Quaternion` object from the given list of parameters.
`Quaternion(Quaternion q)` Constructor instantiates a new `Quaternion` object from an existing quaternion, creating a copy.
`Quaternion(Quaternion q1, Quaternion q2, float interp)` Constructor instantiates a new `Quaternion` object from an interpolation between two other quaternions.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Quaternion`	`add(Quaternion q)` `add` adds the values of this quaternion to those of the parameter quaternion.
`Quaternion`	`addLocal(Quaternion q)` `add` adds the values of this quaternion to those of the parameter quaternion.
`void`	`apply(Matrix3f matrix)` `apply` multiplies this quaternion by a parameter matrix internally.
`Quaternion`	`clone()`
`float`	`dot(Quaternion q)` `dot` calculates and returns the dot product of this quaternion with that of the parameter quaternion.
`boolean`	`equals(java.lang.Object o)` `equals` determines if two quaternions are logically equal, that is, if the values of (x, y, z, w) are the same for both quaternions.
`Quaternion`	`fromAngleAxis(float angle, Vector3f axis)` `fromAngleAxis` sets this quaternion to the values specified by an angle and an axis of rotation.
`Quaternion`	`fromAngleNormalAxis(float angle, Vector3f axis)` `fromAngleNormalAxis` sets this quaternion to the values specified by an angle and a normalized axis of rotation.
`Quaternion`	`fromAngles(float[] angles)` `fromAngles` builds a quaternion from the Euler rotation angles (x,y,z) aka (pitch, yaw, roll).
`Quaternion`	`fromAngles(float xAngle, float yAngle, float zAngle)` `fromAngles` builds a Quaternion from the Euler rotation angles (x,y,z) aka (pitch, yaw, roll)).
`Quaternion`	`fromAxes(Vector3f[] axis)` `fromAxes` creates a `Quaternion` that represents the coordinate system defined by three axes.
`Quaternion`	`fromAxes(Vector3f xAxis, Vector3f yAxis, Vector3f zAxis)` `fromAxes` creates a `Quaternion` that represents the coordinate system defined by three axes.
`Quaternion`	`fromRotationMatrix(float m00, float m01, float m02, float m10, float m11, float m12, float m20, float m21, float m22)`
`Quaternion`	`fromRotationMatrix(Matrix3f matrix)` `fromRotationMatrix` generates a quaternion from a supplied matrix.
`Vector3f`	`getRotationColumn(int i)` `getRotationColumn` returns one of three columns specified by the parameter.
`Vector3f`	`getRotationColumn(int i, Vector3f store)` `getRotationColumn` returns one of three columns specified by the parameter.
`float`	`getW()`
`float`	`getX()`
`float`	`getY()`
`float`	`getZ()`
`int`	`hashCode()` `hashCode` returns the hash code value as an integer and is supported for the benefit of hashing based collection classes such as Hashtable, HashMap, HashSet etc.
`Quaternion`	`inverse()` `inverse` returns the inverse of this quaternion as a new quaternion.
`Quaternion`	`inverseLocal()` `inverse` calculates the inverse of this quaternion and returns this quaternion after it is calculated.
`boolean`	`isIdentity()`
`boolean`	`isSimilar(Quaternion other, float epsilon)` Returns true if this quaternion is similar to the specified quaternion within some value of epsilon.
`void`	`loadIdentity()` Sets this Quaternion to {0, 0, 0, 1}.
`Quaternion`	`lookAt(Vector3f direction, Vector3f up)` `lookAt` is a convienence method for auto-setting the quaternion based on a direction and an up vector.
`Quaternion`	`mult(float scalar)` `mult` multiplies this quaternion by a parameter scalar.
`Quaternion`	`mult(Quaternion q)` `mult` multiplies this quaternion by a parameter quaternion.
`Quaternion`	`mult(Quaternion q, Quaternion res)` `mult` multiplies this quaternion by a parameter quaternion.
`Vector3f`	`mult(Vector3f v)` `mult` multiplies this quaternion by a parameter vector.
`Vector3f`	`mult(Vector3f v, Vector3f store)` `mult` multiplies this quaternion by a parameter vector.
`Quaternion`	`multLocal(float scalar)` `mult` multiplies this quaternion by a parameter scalar.
`Quaternion`	`multLocal(float qx, float qy, float qz, float qw)` Multiplies this Quaternion by the supplied quaternion.
`Quaternion`	`multLocal(Quaternion q)` Multiplies this Quaternion by the supplied quaternion.
`Vector3f`	`multLocal(Vector3f v)` `mult` multiplies this quaternion by a parameter vector.
`void`	`negate()` `negate` inverts the values of the quaternion.
`void`	`nlerp(Quaternion q2, float blend)` Sets the values of this quaternion to the nlerp from itself to q2 by blend.
`float`	`norm()` `norm` returns the norm of this quaternion.
`Quaternion`	`normalizeLocal()` `normalize` normalizes the current `Quaternion`.
`Quaternion`	`opposite()`
`Quaternion`	`opposite(Quaternion store)` FIXME: This seems to have singularity type issues with angle == 0, possibly others such as PI.
`Quaternion`	`oppositeLocal()`
`void`	`read(JmeImporter e)`
`void`	`readExternal(java.io.ObjectInput in)` `readExternal` builds a quaternion from an `ObjectInput` object.
`Quaternion`	`set(float x, float y, float z, float w)` sets the data in a `Quaternion` object from the given list of parameters.
`Quaternion`	`set(Quaternion q)` Sets the data in this `Quaternion` object to be equal to the passed `Quaternion` object.
`void`	`slerp(Quaternion q2, float changeAmnt)` Sets the values of this quaternion to the slerp from itself to q2 by changeAmnt
`Quaternion`	`slerp(Quaternion q1, Quaternion q2, float t)` `slerp` sets this quaternion's value as an interpolation between two other quaternions.
`Quaternion`	`subtract(Quaternion q)` `subtract` subtracts the values of the parameter quaternion from those of this quaternion.
`Quaternion`	`subtractLocal(Quaternion q)` `subtract` subtracts the values of the parameter quaternion from those of this quaternion.
`float`	`toAngleAxis(Vector3f axisStore)` `toAngleAxis` sets a given angle and axis to that represented by the current quaternion.
`float[]`	`toAngles(float[] angles)` `toAngles` returns this quaternion converted to Euler rotation angles (x,y,z) aka (pitch, yaw, roll). Note that the result is not always 100% accurate due to the implications of euler angles.
`void`	`toAxes(Vector3f[] axis)` `toAxes` takes in an array of three vectors.
`Matrix3f`	`toRotationMatrix()` `toRotationMatrix` converts this quaternion to a rotational matrix.
`Matrix3f`	`toRotationMatrix(Matrix3f result)` `toRotationMatrix` converts this quaternion to a rotational matrix.
`Matrix4f`	`toRotationMatrix(Matrix4f result)` `toRotationMatrix` converts this quaternion to a rotational matrix.
`java.lang.String`	`toString()` `toString` creates the string representation of this `Quaternion`.
`Matrix4f`	`toTransformMatrix(Matrix4f store)` `toTransformMatrix` converts this quaternion to a transform matrix.
`void`	`write(JmeExporter e)`
`void`	`writeExternal(java.io.ObjectOutput out)` `writeExternal` writes this quaternion out to a `ObjectOutput` object.

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - IDENTITY
```
public static final Quaternion IDENTITY
```
    Represents the identity quaternion rotation (0, 0, 0, 1).
  - DIRECTION_Z
```
public static final Quaternion DIRECTION_Z
```
  - ZERO
```
public static final Quaternion ZERO
```
  - x
```
protected float x
```
  - y
```
protected float y
```
  - z
```
protected float z
```
  - w
```
protected float w
```
- Constructor Detail
  - Quaternion
```
public Quaternion()
```
    Constructor instantiates a new Quaternion object initializing all values to zero, except w which is initialized to 1.
  - Quaternion
```
public Quaternion(float x,
                  float y,
                  float z,
                  float w)
```
    Constructor instantiates a new Quaternion object from the given list of parameters.
    
    Parameters:
    
    x - the x value of the quaternion.
    
    y - the y value of the quaternion.
    
    z - the z value of the quaternion.
    
    w - the w value of the quaternion.
  - Quaternion
```
public Quaternion(float[] angles)
```
    Constructor instantiates a new Quaternion object from a collection of rotation angles.
    
    Parameters:
    
    angles - the angles of rotation (x, y, z) that will define the Quaternion.
  - Quaternion
```
public Quaternion(Quaternion q1,
                  Quaternion q2,
                  float interp)
```
    Constructor instantiates a new Quaternion object from an interpolation between two other quaternions.
    
    Parameters:
    
    q1 - the first quaternion.
    
    q2 - the second quaternion.
    
    interp - the amount to interpolate between the two quaternions.
  - Quaternion
```
public Quaternion(Quaternion q)
```
    Constructor instantiates a new Quaternion object from an existing quaternion, creating a copy.
    
    Parameters:
    
    q - the quaternion to copy.
- Method Detail
  - getX
```
public float getX()
```
  - getY
```
public float getY()
```
  - getZ
```
public float getZ()
```
  - getW
```
public float getW()
```
  - set
```
public Quaternion set(float x,
                      float y,
                      float z,
                      float w)
```
    sets the data in a Quaternion object from the given list of parameters.
    
    Parameters:
    
    x - the x value of the quaternion.
    
    y - the y value of the quaternion.
    
    z - the z value of the quaternion.
    
    w - the w value of the quaternion.
    
    Returns:
    
    this
  - set
```
public Quaternion set(Quaternion q)
```
    Sets the data in this Quaternion object to be equal to the passed Quaternion object. The values are copied producing a new object.
    
    Parameters:
    
    q - The Quaternion to copy values from.
    
    Returns:
    
    this
  - loadIdentity
```
public void loadIdentity()
```
    Sets this Quaternion to {0, 0, 0, 1}. Same as calling set(0,0,0,1).
  - isIdentity
```
public boolean isIdentity()
```
    Returns:
    
    true if this Quaternion is {0,0,0,1}
  - fromAngles
```
public Quaternion fromAngles(float[] angles)
```
    fromAngles builds a quaternion from the Euler rotation angles (x,y,z) aka (pitch, yaw, roll).
    
    Parameters:
    
    angles - the Euler angles of rotation (in radians).
  - fromAngles
```
public Quaternion fromAngles(float xAngle,
                             float yAngle,
                             float zAngle)
```
    fromAngles builds a Quaternion from the Euler rotation angles (x,y,z) aka (pitch, yaw, roll)). Note that we are applying in order: (y, z, x) aka (yaw, roll, pitch) but we've ordered them in x, y, and z for convenience.
    
    Parameters:
    
    xAngle - the Euler pitch of rotation (in radians). (aka Attitude, often rot around x)
    
    yAngle - the Euler yaw of rotation (in radians). (aka Heading, often rot around y)
    
    zAngle - the Euler roll of rotation (in radians). (aka Bank, often rot around z)
    
    See Also:
    
    http://www.euclideanspace.com/maths/geometry/rotations/conversions/eulerToQuaternion/index.htm
  - toAngles
```
public float[] toAngles(float[] angles)
```
    toAngles returns this quaternion converted to Euler rotation angles (x,y,z) aka (pitch, yaw, roll).
    Note that the result is not always 100% accurate due to the implications of euler angles.
    
    Parameters:
    
    angles - the float[] in which the angles should be stored, or null if you want a new float[] to be created
    
    Returns:
    
    the float[] in which the angles are stored.
    
    See Also:
    
    http://www.euclideanspace.com/maths/geometry/rotations/conversions/quaternionToEuler/index.htm
  - fromRotationMatrix
```
public Quaternion fromRotationMatrix(Matrix3f matrix)
```
    fromRotationMatrix generates a quaternion from a supplied matrix. This matrix is assumed to be a rotational matrix.
    
    Parameters:
    
    matrix - the matrix that defines the rotation.
  - fromRotationMatrix
```
public Quaternion fromRotationMatrix(float m00,
                                     float m01,
                                     float m02,
                                     float m10,
                                     float m11,
                                     float m12,
                                     float m20,
                                     float m21,
                                     float m22)
```
  - toRotationMatrix
```
public Matrix3f toRotationMatrix()
```
    toRotationMatrix converts this quaternion to a rotational matrix. Note: the result is created from a normalized version of this quat.
    
    Returns:
    
    the rotation matrix representation of this quaternion.
  - toRotationMatrix
```
public Matrix3f toRotationMatrix(Matrix3f result)
```
    toRotationMatrix converts this quaternion to a rotational matrix. The result is stored in result.
    
    Parameters:
    
    result - The Matrix3f to store the result in.
    
    Returns:
    
    the rotation matrix representation of this quaternion.
  - toTransformMatrix
```
public Matrix4f toTransformMatrix(Matrix4f store)
```
    toTransformMatrix converts this quaternion to a transform matrix. The result is stored in result. Note this method won't preserve the scale of the given matrix.
    
    Parameters:
    
    store - The Matrix3f to store the result in.
    
    Returns:
    
    the transform matrix with the rotation representation of this quaternion.
  - toRotationMatrix
```
public Matrix4f toRotationMatrix(Matrix4f result)
```
    toRotationMatrix converts this quaternion to a rotational matrix. The result is stored in result. 4th row and 4th column values are untouched. Note: the result is created from a normalized version of this quat. Note that this method will preserve the scale of the given matrix
    
    Parameters:
    
    result - The Matrix4f to store the result in.
    
    Returns:
    
    the rotation matrix representation of this quaternion.
  - getRotationColumn
```
public Vector3f getRotationColumn(int i)
```
    getRotationColumn returns one of three columns specified by the parameter. This column is returned as a Vector3f object.
    
    Parameters:
    
    i - the column to retrieve. Must be between 0 and 2.
    
    Returns:
    
    the column specified by the index.
  - getRotationColumn
```
public Vector3f getRotationColumn(int i,
                                  Vector3f store)
```
    getRotationColumn returns one of three columns specified by the parameter. This column is returned as a Vector3f object. The value is retrieved as if this quaternion was first normalized.
    
    Parameters:
    
    i - the column to retrieve. Must be between 0 and 2.
    
    store - the vector object to store the result in. if null, a new one is created.
    
    Returns:
    
    the column specified by the index.
  - fromAngleAxis
```
public Quaternion fromAngleAxis(float angle,
                                Vector3f axis)
```
    fromAngleAxis sets this quaternion to the values specified by an angle and an axis of rotation. This method creates an object, so use fromAngleNormalAxis if your axis is already normalized.
    
    Parameters:
    
    angle - the angle to rotate (in radians).
    
    axis - the axis of rotation.
    
    Returns:
    
    this quaternion
  - fromAngleNormalAxis
```
public Quaternion fromAngleNormalAxis(float angle,
                                      Vector3f axis)
```
    fromAngleNormalAxis sets this quaternion to the values specified by an angle and a normalized axis of rotation.
    
    Parameters:
    
    angle - the angle to rotate (in radians).
    
    axis - the axis of rotation (already normalized).
  - toAngleAxis
```
public float toAngleAxis(Vector3f axisStore)
```
    toAngleAxis sets a given angle and axis to that represented by the current quaternion. The values are stored as follows: The axis is provided as a parameter and built by the method, the angle is returned as a float.
    
    Parameters:
    
    axisStore - the object we'll store the computed axis in.
    
    Returns:
    
    the angle of rotation in radians.
  - slerp
```
public Quaternion slerp(Quaternion q1,
                        Quaternion q2,
                        float t)
```
    slerp sets this quaternion's value as an interpolation between two other quaternions.
    
    Parameters:
    
    q1 - the first quaternion.
    
    q2 - the second quaternion.
    
    t - the amount to interpolate between the two quaternions.
  - slerp
```
public void slerp(Quaternion q2,
                  float changeAmnt)
```
    Sets the values of this quaternion to the slerp from itself to q2 by changeAmnt
    
    Parameters:
    
    q2 - Final interpolation value
    
    changeAmnt - The amount difference
  - nlerp
```
public void nlerp(Quaternion q2,
                  float blend)
```
    Sets the values of this quaternion to the nlerp from itself to q2 by blend.
    
    Parameters:
    
    q2 -
    
    blend -
  - add
```
public Quaternion add(Quaternion q)
```
    add adds the values of this quaternion to those of the parameter quaternion. The result is returned as a new quaternion.
    
    Parameters:
    
    q - the quaternion to add to this.
    
    Returns:
    
    the new quaternion.
  - addLocal
```
public Quaternion addLocal(Quaternion q)
```
    add adds the values of this quaternion to those of the parameter quaternion. The result is stored in this Quaternion.
    
    Parameters:
    
    q - the quaternion to add to this.
    
    Returns:
    
    This Quaternion after addition.
  - subtract
```
public Quaternion subtract(Quaternion q)
```
    subtract subtracts the values of the parameter quaternion from those of this quaternion. The result is returned as a new quaternion.
    
    Parameters:
    
    q - the quaternion to subtract from this.
    
    Returns:
    
    the new quaternion.
  - subtractLocal
```
public Quaternion subtractLocal(Quaternion q)
```
    subtract subtracts the values of the parameter quaternion from those of this quaternion. The result is stored in this Quaternion.
    
    Parameters:
    
    q - the quaternion to subtract from this.
    
    Returns:
    
    This Quaternion after subtraction.
  - mult
```
public Quaternion mult(Quaternion q)
```
    mult multiplies this quaternion by a parameter quaternion. The result is returned as a new quaternion. It should be noted that quaternion multiplication is not commutative so q * p != p * q.
    
    Parameters:
    
    q - the quaternion to multiply this quaternion by.
    
    Returns:
    
    the new quaternion.
  - mult
```
public Quaternion mult(Quaternion q,
                       Quaternion res)
```
    mult multiplies this quaternion by a parameter quaternion. The result is returned as a new quaternion. It should be noted that quaternion multiplication is not commutative so q * p != p * q. It IS safe for q and res to be the same object. It IS NOT safe for this and res to be the same object.
    
    Parameters:
    
    q - the quaternion to multiply this quaternion by.
    
    res - the quaternion to store the result in.
    
    Returns:
    
    the new quaternion.
  - apply
```
public void apply(Matrix3f matrix)
```
    apply multiplies this quaternion by a parameter matrix internally.
    
    Parameters:
    
    matrix - the matrix to apply to this quaternion.
  - fromAxes
```
public Quaternion fromAxes(Vector3f[] axis)
```
    fromAxes creates a Quaternion that represents the coordinate system defined by three axes. These axes are assumed to be orthogonal and no error checking is applied. Thus, the user must insure that the three axes being provided indeed represents a proper right handed coordinate system.
    
    Parameters:
    
    axis - the array containing the three vectors representing the coordinate system.
  - fromAxes
```
public Quaternion fromAxes(Vector3f xAxis,
                           Vector3f yAxis,
                           Vector3f zAxis)
```
    fromAxes creates a Quaternion that represents the coordinate system defined by three axes. These axes are assumed to be orthogonal and no error checking is applied. Thus, the user must insure that the three axes being provided indeed represents a proper right handed coordinate system.
    
    Parameters:
    
    xAxis - vector representing the x-axis of the coordinate system.
    
    yAxis - vector representing the y-axis of the coordinate system.
    
    zAxis - vector representing the z-axis of the coordinate system.
  - toAxes
```
public void toAxes(Vector3f[] axis)
```
    toAxes takes in an array of three vectors. Each vector corresponds to an axis of the coordinate system defined by the quaternion rotation.
    
    Parameters:
    
    axis - the array of vectors to be filled.
  - mult
```
public Vector3f mult(Vector3f v)
```
    mult multiplies this quaternion by a parameter vector. The result is returned as a new vector.
    
    Parameters:
    
    v - the vector to multiply this quaternion by.
    
    Returns:
    
    the new vector.
  - multLocal
```
public Vector3f multLocal(Vector3f v)
```
    mult multiplies this quaternion by a parameter vector. The result is stored in the supplied vector
    
    Parameters:
    
    v - the vector to multiply this quaternion by.
    
    Returns:
    
    v
  - multLocal
```
public Quaternion multLocal(Quaternion q)
```
    Multiplies this Quaternion by the supplied quaternion. The result is stored in this Quaternion, which is also returned for chaining. Similar to this *= q.
    
    Parameters:
    
    q - The Quaternion to multiply this one by.
    
    Returns:
    
    This Quaternion, after multiplication.
  - multLocal
```
public Quaternion multLocal(float qx,
                            float qy,
                            float qz,
                            float qw)
```
    Multiplies this Quaternion by the supplied quaternion. The result is stored in this Quaternion, which is also returned for chaining. Similar to this *= q.
    
    Parameters:
    
    qx - - quat x value
    
    qy - - quat y value
    
    qz - - quat z value
    
    qw - - quat w value
    
    Returns:
    
    This Quaternion, after multiplication.
  - mult
```
public Vector3f mult(Vector3f v,
                     Vector3f store)
```
    mult multiplies this quaternion by a parameter vector. The result is returned as a new vector.
    
    Parameters:
    
    v - the vector to multiply this quaternion by.
    
    store - the vector to store the result in. It IS safe for v and store to be the same object.
    
    Returns:
    
    the result vector.
  - mult
```
public Quaternion mult(float scalar)
```
    mult multiplies this quaternion by a parameter scalar. The result is returned as a new quaternion.
    
    Parameters:
    
    scalar - the quaternion to multiply this quaternion by.
    
    Returns:
    
    the new quaternion.
  - multLocal
```
public Quaternion multLocal(float scalar)
```
    mult multiplies this quaternion by a parameter scalar. The result is stored locally.
    
    Parameters:
    
    scalar - the quaternion to multiply this quaternion by.
    
    Returns:
    
    this.
  - dot
```
public float dot(Quaternion q)
```
    dot calculates and returns the dot product of this quaternion with that of the parameter quaternion.
    
    Parameters:
    
    q - the quaternion to calculate the dot product of.
    
    Returns:
    
    the dot product of this and the parameter quaternion.
  - norm
```
public float norm()
```
    norm returns the norm of this quaternion. This is the dot product of this quaternion with itself.
    
    Returns:
    
    the norm of the quaternion.
  - normalizeLocal
```
public Quaternion normalizeLocal()
```
    normalize normalizes the current Quaternion. The result is stored internally.
  - inverse
```
public Quaternion inverse()
```
    inverse returns the inverse of this quaternion as a new quaternion. If this quaternion does not have an inverse (if its normal is 0 or less), then null is returned.
    
    Returns:
    
    the inverse of this quaternion or null if the inverse does not exist.
  - inverseLocal
```
public Quaternion inverseLocal()
```
    inverse calculates the inverse of this quaternion and returns this quaternion after it is calculated. If this quaternion does not have an inverse (if its normal is 0 or less), nothing happens
    
    Returns:
    
    the inverse of this quaternion
  - negate
```
public void negate()
```
    negate inverts the values of the quaternion.
  - toString
```
public java.lang.String toString()
```
    toString creates the string representation of this Quaternion. The values of the quaternion are displaced (x, y, z, w), in the following manner:
    (x, y, z, w)
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    the string representation of this object.
    
    See Also:
    
    Object.toString()
  - equals
```
public boolean equals(java.lang.Object o)
```
    equals determines if two quaternions are logically equal, that is, if the values of (x, y, z, w) are the same for both quaternions.
    
    Overrides:
    
    equals in class java.lang.Object
    
    Parameters:
    
    o - the object to compare for equality
    
    Returns:
    
    true if they are equal, false otherwise.
  - isSimilar
```
public boolean isSimilar(Quaternion other,
                         float epsilon)
```
    Returns true if this quaternion is similar to the specified quaternion within some value of epsilon.
  - hashCode
```
public int hashCode()
```
    hashCode returns the hash code value as an integer and is supported for the benefit of hashing based collection classes such as Hashtable, HashMap, HashSet etc.
    
    Overrides:
    
    hashCode in class java.lang.Object
    
    Returns:
    
    the hashcode for this instance of Quaternion.
    
    See Also:
    
    Object.hashCode()
  - readExternal
```
public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException
```
    readExternal builds a quaternion from an ObjectInput object.
    NOTE: Used with serialization. Not to be called manually.
    
    Parameters:
    
    in - the ObjectInput value to read from.
    
    Throws:
    
    java.io.IOException - if the ObjectInput value has problems reading a float.
    
    See Also:
    
    Externalizable
  - writeExternal
```
public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException
```
    writeExternal writes this quaternion out to a ObjectOutput object. NOTE: Used with serialization. Not to be called manually.
    
    Parameters:
    
    out - the object to write to.
    
    Throws:
    
    java.io.IOException - if writing to the ObjectOutput fails.
    
    See Also:
    
    Externalizable
  - lookAt
```
public Quaternion lookAt(Vector3f direction,
                         Vector3f up)
```
    lookAt is a convienence method for auto-setting the quaternion based on a direction and an up vector. It computes the rotation to transform the z-axis to point into 'direction' and the y-axis to 'up'.
    
    Parameters:
    
    direction - where to look at in terms of local coordinates
    
    up - a vector indicating the local up direction. (typically {0, 1, 0} in jME.)
  - write
```
public void write(JmeExporter e)
           throws java.io.IOException
```
    Specified by:
    
    write in interface Savable
    
    Throws:
    
    java.io.IOException
  - read
```
public void read(JmeImporter e)
          throws java.io.IOException
```
    Specified by:
    
    read in interface Savable
    
    Throws:
    
    java.io.IOException
  - opposite
```
public Quaternion opposite()
```
    Returns:
    
    A new quaternion that describes a rotation that would point you in the exact opposite direction of this Quaternion.
  - opposite
```
public Quaternion opposite(Quaternion store)
```
    FIXME: This seems to have singularity type issues with angle == 0, possibly others such as PI.
    
    Parameters:
    
    store - A Quaternion to store our result in. If null, a new one is created.
    
    Returns:
    
    The store quaternion (or a new Quaternion, if store is null) that describes a rotation that would point you in the exact opposite direction of this Quaternion.
  - oppositeLocal
```
public Quaternion oppositeLocal()
```
    Returns:
    
    This Quaternion, altered to describe a rotation that would point you in the exact opposite direction of where it is pointing currently.
  - clone
```
public Quaternion clone()
```
    Overrides:
    
    clone in class java.lang.Object

Class Quaternion

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

IDENTITY

DIRECTION_Z

ZERO

x

y

z

w

Constructor Detail

Quaternion

Quaternion

Quaternion

Quaternion

Quaternion

Method Detail

getX

getY

getZ

getW

set

set

loadIdentity

isIdentity

fromAngles

fromAngles

toAngles

fromRotationMatrix

fromRotationMatrix

toRotationMatrix

toRotationMatrix

toTransformMatrix

toRotationMatrix

getRotationColumn

getRotationColumn

fromAngleAxis

fromAngleNormalAxis

toAngleAxis

slerp

slerp

nlerp

add

addLocal

subtract

subtractLocal

mult

mult

apply

fromAxes

fromAxes

toAxes

mult

multLocal

multLocal

multLocal

mult

mult

multLocal

dot

norm

normalizeLocal

inverse

inverseLocal

negate

toString

equals

isSimilar

hashCode

readExternal

writeExternal

lookAt

write

read

opposite

opposite

oppositeLocal