Package com.jme3.math

Class Matrix3f

java.lang.Object

com.jme3.math.Matrix3f

All Implemented Interfaces:

Serializable, Cloneable

public final class Matrix3f
extends Object
implements Cloneable, Serializable

A 3x3 matrix composed of 9 single-precision elements, used to represent linear transformations of 3-D coordinates, such as rotations, reflections, and scaling.

Element numbering is (row, column), so m01 is the element in row 0, column 1.

For pure rotations, the Quaternion class provides a more efficient representation.

With one exception, the methods with names ending in "Local" modify the current instance. They are used to avoid creating garbage.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final Matrix3f	IDENTITY	Shared instance of the identity matrix (diagonals = 1, other elements = 0).
protected float	m00	The element in row 0, column 0.
protected float	m01	The element in row 0, column 1.
protected float	m02	The element in row 0, column 2.
protected float	m10	The element in row 1, column 0.
protected float	m11	The element in row 1, column 1.
protected float	m12	The element in row 1, column 2.
protected float	m20	The element in row 2, column 0.
protected float	m21	The element in row 2, column 1.
protected float	m22	The element in row 2, column 2.
static final Matrix3f	ZERO	Shared instance of the all-zero matrix.

Constructor Summary

Constructors

Constructor	Description
Matrix3f()	Instantiates an identity matrix (diagonals = 1, other elements = 0).
Matrix3f(float m00, float m01, float m02, float m10, float m11, float m12, float m20, float m21, float m22)	Instantiates a matrix with specified elements.

Method Summary

Modifier and Type	Method	Description
Matrix3f	clone()	Creates a copy.
float	determinant()	Returns the determinant.
boolean	equals(Object o)	Tests for exact equality with the argument, distinguishing -0 from 0.
void	fromAxes(Vector3f uAxis, Vector3f vAxis, Vector3f wAxis)	Configures from the specified column vectors.
float	get(int i, int j)	Returns the element at the specified position.
int	hashCode()	Returns a hash code.
Matrix3f	invert(Matrix3f store)	Returns the multiplicative inverse in the specified storage.
boolean	isIdentity()	Tests for exact identity.
void	loadIdentity()	Configures as an identity matrix (diagonals = 1, other elements = 0).
Matrix3f	mult(Matrix3f mat, Matrix3f product)	Multiplies with the specified matrix and returns the product in a 3rd matrix.
Vector3f	mult(Vector3f vec, Vector3f product)	Applies the linear transformation to specified vector and stores the result in another vector.
Matrix3f	multLocal(float scale)	Multiplies by the scalar argument and returns the (modified) current instance.
Matrix3f	set(int i, int j, float value)	Sets the specified element.
Matrix3f	set(Matrix3f matrix)	Copies the matrix argument.
Matrix3f	set(Quaternion quaternion)	Configures as a rotation matrix equivalent to the argument.
String	toString()	Returns a string representation of the matrix, which is unaffected.
Matrix3f	zero()	Sets all elements to zero.

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

m00

protected float m00

The element in row 0, column 0.

m01

protected float m01

The element in row 0, column 1.

m02

protected float m02

The element in row 0, column 2.

m10

protected float m10

The element in row 1, column 0.

m11

protected float m11

The element in row 1, column 1.

m12

protected float m12

The element in row 1, column 2.

m20

protected float m20

The element in row 2, column 0.

m21

protected float m21

The element in row 2, column 1.

m22

protected float m22

The element in row 2, column 2.

ZERO

public static final Matrix3f ZERO

Shared instance of the all-zero matrix. Do not modify!

IDENTITY

public static final Matrix3f IDENTITY

Shared instance of the identity matrix (diagonals = 1, other elements = 0). Do not modify!

Constructor Details

Matrix3f

public Matrix3f()

Instantiates an identity matrix (diagonals = 1, other elements = 0).

Matrix3f

public Matrix3f(float m00,
 float m01,
 float m02,
 float m10,
 float m11,
 float m12,
 float m20,
 float m21,
 float m22)

Instantiates a matrix with specified elements.

Parameters:

m00 - the desired value for row 0, column 0

m01 - the desired value for row 0, column 1

m02 - the desired value for row 0, column 2

m10 - the desired value for row 1, column 0

m11 - the desired value for row 1, column 1

m12 - the desired value for row 1, column 2

m20 - the desired value for row 2, column 0

m21 - the desired value for row 2, column 1

m22 - the desired value for row 2, column 2

Method Details

set

public Matrix3f set(Matrix3f matrix)

Copies the matrix argument. If the argument is null, the current instance is set to identity (diagonals = 1, other elements = 0).

Parameters:

matrix - the matrix to copy (unaffected) or null for identity

Returns:

the (modified) current instance (for chaining)

get

public float get(int i,
 int j)

Returns the element at the specified position. The matrix is unaffected.

Parameters:

i - the row index (0, 1, or 2)

j - the column index (0, 1, or 2)

Returns:

the value of the element at (i, j)

Throws:

IllegalArgumentException - if either index isn't 0, 1, or 2

set

public Matrix3f set(int i,
 int j,
 float value)

Sets the specified element.

Parameters:

i - the row index (0, 1, or 2)

j - the column index (0, 1, or 2)

value - desired value for the element at (i, j)

Returns:

the (modified) current instance (for chaining)

Throws:

IllegalArgumentException - if either index isn't 0, 1, or 2

fromAxes

public void fromAxes(Vector3f uAxis,
 Vector3f vAxis,
 Vector3f wAxis)

Configures from the specified column vectors. If the vectors form an orthonormal basis, the result will be a pure rotation matrix.

Parameters:

uAxis - the desired value for column 0 (not null, unaffected)

vAxis - the desired value for column 1 (not null, unaffected)

wAxis - the desired value for column 2 (not null, unaffected)

set

public Matrix3f set(Quaternion quaternion)

Configures as a rotation matrix equivalent to the argument.

Parameters:

quaternion - the input quaternion (not null, unaffected)

Returns:

the (modified) current instance (for chaining)

loadIdentity

public void loadIdentity()

Configures as an identity matrix (diagonals = 1, other elements = 0).

isIdentity

public boolean isIdentity()

Tests for exact identity. The matrix is unaffected.

Returns:

true if all diagonals = 1 and all other elements = 0 or -0, otherwise false

mult

public Matrix3f mult(Matrix3f mat,
 Matrix3f product)

Multiplies with the specified matrix and returns the product in a 3rd matrix. The current instance is unaffected unless it's product.

Note that matrix multiplication is noncommutative, so generally q * p != p * q.

It is safe for mat and product to be the same object.

Parameters:

mat - the right factor (not null, unaffected unless it's product)

product - storage for the product, or null for a new Matrix3f

Returns:

this times mat (either product or a new Matrix3f)

mult

public Vector3f mult(Vector3f vec,
 Vector3f product)

Applies the linear transformation to specified vector and stores the result in another vector. The matrix is unaffected.

This can also be described as multiplying the matrix by a column vector.

It is safe for vec and product to be the same object.

Parameters:

vec - the coordinates to transform (not null, unaffected unless it's product)

product - storage for the result, or null for a new Vector3f

Returns:

either product or a new Vector3f

multLocal

public Matrix3f multLocal(float scale)

Multiplies by the scalar argument and returns the (modified) current instance.

Parameters:

scale - the scaling factor

Returns:

the (modified) current instance (for chaining)

invert

public Matrix3f invert(Matrix3f store)

Returns the multiplicative inverse in the specified storage. If the current instance is singular, an all-zero matrix is returned. In either case, the current instance is unaffected.

If this and store are the same object, the result is undefined.

Parameters:

store - storage for the result, or null for a new Matrix3f

Returns:

either store or a new Matrix3f

determinant

public float determinant()

Returns the determinant. The matrix is unaffected.

Returns:

the determinant

zero

public Matrix3f zero()

Sets all elements to zero.

Returns:

the (modified) current instance (for chaining)

toString

public String toString()

Returns a string representation of the matrix, which is unaffected. For example, the identity matrix is represented by:

 Matrix3f
 [
  1.0  0.0  0.0
  0.0  1.0  0.0
  0.0  0.0  1.0
 ]
 

Overrides:

toString in class Object

Returns:

the string representation (not null, not empty)

hashCode

public int hashCode()

Returns a hash code. If two matrices have identical values, they will have the same hash code. The matrix is unaffected.

Overrides:

hashCode in class Object

Returns:

a 32-bit value for use in hashing

See Also:

• Object.hashCode()

equals

public boolean equals(Object o)

Tests for exact equality with the argument, distinguishing -0 from 0. If o is null, false is returned. Either way, the current instance is unaffected.

Overrides:

equals in class Object

Parameters:

o - the object to compare (may be null, unaffected)

Returns:

true if this and o have identical values, otherwise false

clone

public Matrix3f clone()

Creates a copy. The current instance is unaffected.

Overrides:

clone in class Object

Returns:

a new instance, equivalent to the current one