syBR::Core::Matrix Class Reference

4x4 matrix class More...

#include <Matrix.hpp>

List of all members.

Public Types
enum	Mode { MODE_DEGREES = 0, MODE_RADIANS }
	Angle specification mode enumeration. More...
Public Member Functions
	Matrix ()
	Constructor #1.
	Matrix (const Mode mode)
	Constructor #2.
	Matrix (const Matrix &matrix)
	Copy constructor.
void	rotate (float x, float y, float z)
	Rotate the current matrix.
void	rotate (float angle, const Vector3D &axis)
	Rotate the matrix around an arbitray axis.
void	translate (const float x, const float y, const float z)
	Translate the current matrix.
void	scale (const float x, const float y, const float z)
	Scale the current matrix.
void	transpose ()
	Transpose the current matrix.
void	identity ()
	Set the current matrix to the identity matrix.
void	zero ()
	Set the current matrix to the zero matrix.
void	from3x3Array (const float array[3][3])
	Build the current matrix from a 3x3 array.
void	from4x4Array (const float array[4][4])
	Build the current matrix from a 4x4 array.
void	from16Array (const float array[16])
	Build the current matrix from a 16 elements array.
float &	operator() (const unsigned int line, const unsigned int column)
	Get/set an element.
const float &	operator() (const unsigned int line, const unsigned int column) const
	Get an element (constant).
Matrix &	operator= (const Matrix &arg)
	Set the content of the current matrix.
Matrix	operator+ (const Matrix &arg) const
	Add a matrix to the current matrix.
Matrix	operator- (const Matrix &arg) const
	Substract a matrix from the current matrix.
Matrix	operator * (const float arg) const
	Multiply the current matrix by a scalar.
Matrix	operator/ (const float arg) const
	Divide the current matrix by a scalar.
Vector3D	operator * (const Vector3D &arg) const
	Multiply the current matrix by a vector.
void	operator+= (const Matrix &arg)
	Add the content of a matrix to this.
void	operator-= (const Matrix &arg)
	Substract the content of a matrix from this.
void	operator *= (const float arg)
	Multiply the content of this by a scalar.
void	operator/= (const float arg)
	Divide the content of this by a scalar.
Matrix	operator * (const Matrix &arg) const
	Multiply the current matrix by another matrix.
void	operator *= (const Matrix &arg)
	Multiply this by another matrix.
	operator const float * () const
	Convert the matrix to a float array.
bool	operator== (const Matrix &arg) const
	Compare the current matrix to another matrix.
bool	operator!= (const Matrix &arg) const
	Compare the current matrix to another matrix.
bool	fastCompare (const Matrix &arg) const
	Check if two matrices are equal (fast version, binary compare).
Private Member Functions
void	multiply (float matrix[16])
	Multiply m_content[] by matrix[].
void	swap (float &arg1, float &arg2)
	Swap the content of two variables.
Private Attributes
float	m_content [16]
	Internal content of the matrix.
bool	m_mode
	Indicates if we use degrees or radians when rotating.
Friends
Matrix	operator * (const float scalar, const Matrix &matrix)
	Multiply a matrix by a scalar.
Matrix	operator/ (const float scalar, const Matrix &matrix)
	Divide a matrix by a scalar.
Vector3D	operator * (const Vector3D &vector, const Matrix &matrix)
	Multiply a matrix by a vector.

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Detailed Description

4x4 matrix class

A 4x4 matrix is the same as a 3x3 matrix (3D transformations) except that it contains a fourth column (not used here) and a fourth line used for adding translation informations. The internal memory representation of the matrix is a 16-element column-major array :
| array[0] array[4] array[8]   array[12] |
| array[1] array[5] array[9]   array[13] |
| array[2] array[6] array[10] array[14] |
| array[3] array[7] array[11] array[15] |

---

Member Enumeration Documentation

enum syBR::Core::Matrix::Mode

Angle specification mode enumeration.

Enumerator:

MODE_DEGREES	All angles are specified using degrees.
MODE_RADIANS	All angles are specified using radians.

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Constructor & Destructor Documentation

syBR::Core::Matrix::Matrix

(

)

Constructor #1.

It specifies by default that degrees are used when rotating (angles) and the matrix is initialized as the identity matrix.

syBR::Core::Matrix::Matrix

(

const Mode

mode

)

Constructor #2.

It receives a parametre which specify if the matrix is using radians or degrees when rotating (angles) and the matrix is initialized as the identity matrix.

Parameters:

mode

One of these: MODE_RADIANS if angles are specified using radians MODE_DEGREES if angles are specified using degrees

syBR::Core::Matrix::Matrix

(

const Matrix &

matrix

)

Copy constructor.

Parameters:

matrix

Matrix from which content must be copied

---

Member Function Documentation

void syBR::Core::Matrix::rotate	(	float	x,
		float	y,
		float	z
	)

Rotate the current matrix.

Create a rotation matrix using the parametres values and then, multiply the current matrix by this rotation matrix.

Parameters:

	x	X-axis rotation angle
	y	Y-axis rotation angle
	z	Z-axis rotation angle

void syBR::Core::Matrix::rotate	(	float	angle,
		const Vector3D &	axis
	)

Rotate the matrix around an arbitray axis.

Parameters:

	angle	Rotation angle
	axis	Axis to rotate around

void syBR::Core::Matrix::translate	(	const float	x,
		const float	y,
		const float	z
	)

Translate the current matrix.

As we are using 4x4 matrices, we simply put the translation informations in the fourth line.

Parameters:

	x	X-axis translation
	y	Y-axis translation
	z	Z-axis translation

void syBR::Core::Matrix::scale	(	const float	x,
		const float	y,
		const float	z
	)

Scale the current matrix.

Parameters:

	x	X-axis scaling
	y	Y-axis scaling
	z	Z-axis scaling

void syBR::Core::Matrix::transpose

(

)

Transpose the current matrix.

Revert colums and lines of the current matrix.

void syBR::Core::Matrix::identity

(

)

Set the current matrix to the identity matrix.

void syBR::Core::Matrix::zero

(

)

Set the current matrix to the zero matrix.

void syBR::Core::Matrix::from3x3Array

(

const float

array[3][3]

)

Build the current matrix from a 3x3 array.

Fill the 3x3 part of the matrix using the content of the array and set the other parts to default value (no translation). The array must be defined column-major.

Parameters:

array

Array to be used to fill the content of the matrix

void syBR::Core::Matrix::from4x4Array

(

const float

array[4][4]

)

Build the current matrix from a 4x4 array.

Fill the matrix using the content of the array. The array must be defined row-major : first index is the line index and the second is the column index.

Parameters:

array

Array to be used to fill the content of the matrix

void syBR::Core::Matrix::from16Array

(

const float

array[16]

)

Build the current matrix from a 16 elements array.

Fill the matrix using the content of the array. The array must be defined column-major.

Parameters:

array

Array to be used to fill the content of the matrix

float & syBR::Core::Matrix::operator()	(	const unsigned int	line,
		const unsigned int	column
	)

Get/set an element.

Parameters:

	line	line index of the item (0-based)
	column	Column index of the item (0-based)

Returns:

Requested element value or the value of the element located at (0,0) if the indexes are out of range

const float & syBR::Core::Matrix::operator()	(	const unsigned int	line,
		const unsigned int	column
	)			const

Get an element (constant).

Parameters:

	line	line index of the item (0-based)
	column	Column index of the item (0-based)

Returns:

Requested element value or the value of the element located at (0,0) if the indexes are out of range

Matrix & syBR::Core::Matrix::operator=

(

const Matrix &

arg

)

Set the content of the current matrix.

Parameters:

arg

New content for the matrix

Returns:

Matrix containing the new content (a reference to this)

Matrix syBR::Core::Matrix::operator+

(

const Matrix &

arg

)

const

Add a matrix to the current matrix.

Parameters:

arg

Matrix to be added to the current matrix

Returns:

Matrix containing the sum of the two matrices

Matrix syBR::Core::Matrix::operator-

(

const Matrix &

arg

)

const

Substract a matrix from the current matrix.

Parameters:

arg

Matrix to be substracted from the current matrix

Returns:

Matrix containing the difference of the two matrices

Matrix syBR::Core::Matrix::operator *

(

const float

arg

)

const

Multiply the current matrix by a scalar.

The multiplication of a matrix by a scalar is simple: every element of the matrix will be multiplied by this scalar.

Parameters:

arg

Scalar to multiply the matrix by

Returns:

Matrix containing the result of the multiplication of the matrix by the scalar

Matrix syBR::Core::Matrix::operator/

(

const float

arg

)

const

Divide the current matrix by a scalar.

The division of a matrix by a scalar is simple: every element of the matrix will be divided by this scalar.

Parameters:

arg

Scalar to divide the matrix by

Returns:

One of these:

• Matrix containing the result of the division of the matrix by the scalar
• Unmodified matrix if arg is zero

Vector3D syBR::Core::Matrix::operator *

(

const Vector3D &

arg

)

const

Multiply the current matrix by a vector.

Parameters:

arg

Vector to multiply the matrix to

Returns:

Vector containing the result of the multiplication of the matrix by the vector

void syBR::Core::Matrix::operator+=

(

const Matrix &

arg

)

Add the content of a matrix to this.

Parameters:

arg

Matrix to add

void syBR::Core::Matrix::operator-=

(

const Matrix &

arg

)

Substract the content of a matrix from this.

Parameters:

arg

Matrix to substract

void syBR::Core::Matrix::operator *=

(

const float

arg

)

Multiply the content of this by a scalar.

Parameters:

arg

Scalar to multiply

void syBR::Core::Matrix::operator/=

(

const float

arg

)

Divide the content of this by a scalar.

Parameters:

arg

Scalar to divide

Matrix syBR::Core::Matrix::operator *

(

const Matrix &

arg

)

const

Multiply the current matrix by another matrix.

Parameters:

arg

Matrix to multiply to

Returns:

Matrix containing the result of the multiplication of the current matrix by the other matrix

void syBR::Core::Matrix::operator *=

(

const Matrix &

arg

)

Multiply this by another matrix.

Parameters:

arg

Matrix to multiply to

syBR::Core::Matrix::operator const float *

(

)

const

Convert the matrix to a float array.

Returns:

Pointer to the first element of the array

bool syBR::Core::Matrix::operator==

(

const Matrix &

arg

)

const

Compare the current matrix to another matrix.

Parameters:

arg

Matrix to be compared

Returns:

One of these:

• true if the matrices are identical
• false otherwise

Note:

The comparison takes rounding errors in account by using the Math::EPSILON() constant.

bool syBR::Core::Matrix::operator!=

(

const Matrix &

arg

)

const

Compare the current matrix to another matrix.

Parameters:

arg

Matrix to be compared

Returns:

One of these:

• true if the matrices are different
• false otherwise

Note:

The comparison takes rounding errors in account by using the Math::EPSILON() constant.

bool syBR::Core::Matrix::fastCompare

(

const Matrix &

arg

)

const

Check if two matrices are equal (fast version, binary compare).

Parameters:

arg

Matrix to be compared

Returns:

One of these:

• true if the matrices are identical
• false otherwise

Note:

This function compares the matrices using a binary compare which should be faster but don't take any EPSILON into account (doesn't handle rounding errors).

void syBR::Core::Matrix::multiply

(

float

matrix[16]

)

[inline, private]

Multiply m_content[] by matrix[].

Private function used only when rotating the matrix. It computes the result of the multiplication of m_content (current matrix content) and matrix and then fills m_content with it.

Parameters:

matrix

Matrix to be used as second member of the multiplication

void syBR::Core::Matrix::swap	(	float &	arg1,
		float &	arg2
	)			[inline, private]

Swap the content of two variables.

Parameters:

	arg1	First variable
	arg2	Second variable

---

Friends And Related Function Documentation

Matrix operator *	(	const float	scalar,
		const Matrix &	matrix
	)			[friend]

Multiply a matrix by a scalar.

The multiplication of a matrix by a scalar is simple: every element of the matrix will be multiplied by this scalar.

Parameters:

	scalar	Scalar to multiply the matrix by
	matrix	Matrix to be multiplied

Returns:

Matrix containing the result of the multiplication of the matrix by the scalar

Matrix operator/	(	const float	scalar,
		const Matrix &	matrix
	)			[friend]

Divide a matrix by a scalar.

The division of a matrix by a scalar is simple: every element of the matrix will be divided by this scalar.

Parameters:

	scalar	Scalar to divide the matrix by
	matrix	Matrix to be divided

Returns:

One of these:

• Matrix containing the result of the division of the matrix by the scalar
• Unmodified matrix if scalar is zero

Vector3D operator *	(	const Vector3D &	vector,
		const Matrix &	matrix
	)			[friend]

Multiply a matrix by a vector.

Parameters:

	vector	Vector to multiply the matrix to
	matrix	Matrix to be multiplied by

Returns:

Vector containing the result of the multiplication of the matrix by the vector

Note:

This is a convenience operator used to allow two syntaxes for the multiplication of a matrix by a vector even if it isn't strictly correct mathematically speaking :

• matrix * vector
• vector * matrix

---

Member Data Documentation

float syBR::Core::Matrix::m_content[16] [private]

Internal content of the matrix.

bool syBR::Core::Matrix::m_mode [private]

Indicates if we use degrees or radians when rotating.

---

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

• /home/seb/syBR/core/src/math/Matrix.hpp
• /home/seb/syBR/core/src/math/Matrix.cpp

---

Copyright © 2008 by Sebastien Frippiat

This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 License.
Last modified Tue Dec 30 17:57:33 2008