org.instantreality.InstantIO
Class Matrix3d

java.lang.Object
  org.instantreality.InstantIO.Matrix3d

public class Matrix3d
extends java.lang.Object

Helper class for exchanging 3x3 matrices of double values.

Matrix3d is a basic helper class for exchanging matrices of 3x3 double values between different software components. It does not contain any means for matrix arithmetics, only methods for setting and getting the matrix elements. It is not meant to be used directly by software components for matrix representation. Instead, software components should use their own, appropriate classes for handling matrices. Only when sending matrices to an OutSlot, or when receiving matrices from an InSlot, the internal representation of matrices should be converted to Matrix3d's. This ensures the interoperability between different software components that use different internal representations for matrices.

Author:

Patrick Dähne

Field Summary

static Matrix3d

IDENTITY The identity matrix.

Constructor Summary

Matrix3d(double[] matrix)
Creates a new Matrix3d object that gets initialized by a given 9 element double array representing a 3x3 matrix.

Matrix3d(double m11, double m12, double m13, double m21, double m22, double m23, double m31, double m32, double m33)
Creates a new Matrix3d object that gets initialized by given 9 double values representing a 3x3 matrix.

Matrix3d(Matrix3d matrix)
Constructor that initializes the components of the Matrix3d object with the elements taken from another Matrix3d object.

Method Summary

boolean	equals(java.lang.Object obj) Compares the matrix to another object.
void	get(double[] matrix) Returns the matrix elements.
double	get(int index) Returns one element of the matrix.
java.lang.String	toString() Converts the matrix to a string.
static Matrix3d	valueOf(java.lang.String str) Converts a string to a Matrix3d object.

Methods inherited from class java.lang.Object

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

Field Detail

IDENTITY

public static final Matrix3d IDENTITY

The identity matrix.

Constructor Detail

Matrix3d

public Matrix3d(double m11,
                double m12,
                double m13,
                double m21,
                double m22,
                double m23,
                double m31,
                double m32,
                double m33)

Creates a new Matrix3d object that gets initialized by given 9 double values representing a 3x3 matrix.

Parameters:

m11 - The value at row 1, column 1 of the matrix

m12 - The value at row 1, column 2 of the matrix

m13 - The value at row 1, column 3 of the matrix

m21 - The value at row 2, column 1 of the matrix

m22 - The value at row 2, column 2 of the matrix

m23 - The value at row 2, column 3 of the matrix

m31 - The value at row 3, column 1 of the matrix

m32 - The value at row 3, column 2 of the matrix

m33 - The value at row 3, column 3 of the matrix

Matrix3d

public Matrix3d(double[] matrix)

Creates a new Matrix3d object that gets initialized by a given 9 element double array representing a 3x3 matrix.

Parameters:

matrix - The nine components of the matrix

Matrix3d

public Matrix3d(Matrix3d matrix)

Constructor that initializes the components of the Matrix3d object with the elements taken from another Matrix3d object.

The following example demonstrates how to create a Matrix3d object that is an exact copy of another Matrix3d object:

 Matrix3d given_mat = ...;
 Matrix3d mat = new Matrix3d(given_mat);
 

Parameters:

matrix - The other matrix used to initialize the new matrix.

Method Detail

get

public final void get(double[] matrix)

Returns the matrix elements.

The following example extracts the translation vector from the matrix and prints it to the console:

 Matrix3d mat = ...;
 double[] m = new double[9];
 mat.get(m);
 double x = m[6];
 double y = m[7];
 System.out.println("Translation = " + x + " " + y);
 

Parameters:

matrix - A double array that gets filled with the elements of the matrix. This array must have at least nine elements.

get

public final double get(int index)

Returns one element of the matrix.

The following example extracts the translation vector from the matrix and prints it to the console:

 Matrix3d mat = ...;
 double x = mat.get(6);
 double y = mat.get(7);
 System.out.println("Translation = " + x + " " + y);
 

Parameters:

index - The index of the element. This must be between 0 and 8, inclusively.

Returns:

The value of the element.

equals

public final boolean equals(java.lang.Object obj)

Compares the matrix to another object. The result is true if the object is not null and is a Matrix3d object and the matrix elements of the other Matrix3d object are the same as the matrix elements of this matrix.

The following example compares two matrices and prints the result to the console:

 Matrix3d mat1 = ...;
 Matrix3d mat2 = ...;
 System.out.println("Matrices are the same: " + mat1.equals(mat2));
 

Overrides:

equals in class java.lang.Object

Parameters:

obj - the object to compare the matrix to

Returns:

true when the matrices are equal, false otherwise

toString

public final java.lang.String toString()

Converts the matrix to a string. The string representation consists of the nine matrix elements, separated by space characters.

The following example prints the string representation of a Matrix3d object to the console:

 Matrix3d mat = ...;
 System.out.println("Matrix = " + mat.toString());
 

Overrides:

toString in class java.lang.Object

Returns:

A string representation of the matrix

valueOf

public static final Matrix3d valueOf(java.lang.String str)

Converts a string to a Matrix3d object. The string must consist of the nine matrix elements, separated by space characters.

The following example creates a new Matrix3d object that represents a translation of 1 unit along the x axis and 2 units along the y axis:

 Matrix3d mat = Matrix3d.valueOf("1.0 0.0 0.0 0.0 1.0 0.0 1.0 2.0 1.0");
 

Parameters:

str - The string representation of the matrix.

Returns:

The new Matrix3d object, parsed from the string.