Mat4 - GL Math

PHP-GLFW comes with a built-in math library this is a quick reference for the Mat4 class. The Mat4 represents a matrix 4x4 Matrix with 16 values.

The values hold by the Mat4 object are stored internally as real float values, and can be accessed in an array like fashion:

$mat = new Mat4();
$mat[0] = 42.0;
$mat[15] = 42.0;

echo $mat[0];
echo $mat[15];

Methods

__construct

Constructucts a new Mat4 matrix Does not take any arguments and always returns an identity matrix.

function __construct()

aka:

1 0 0 0
0 1 0 0
0 0 1 0
0 0 0 1

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fromArray

Constructs and returns a new matrix based on the given array of values

static function fromArray(array $values) : \GL\Math\Mat4

$matrix = Mat4::fromArray([
    1, 0, 0, 0,
    0, 1, 0, 0,
    0, 0, 1, 0,
    0, 0, 0, 1
]);

arguments

1. array $values The values to use for the matrix. (flat)

returns

\Mat4 The new matrix.

---

inverted

Constructs and returns an inverse of the given matrix

static function inverted(\GL\Math\Mat4 $matrix) : \GL\Math\Mat4

$inverse = Mat4::inverse($matrix);

arguments

1. \Mat4 $matrix The matrix to invert.

returns

\Mat4 The inverted matrix.

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multiplyQuat

Mat4 * Quat

static function multiplyQuat(\GL\Math\Mat4 $left, \GL\Math\Quat $right) : \GL\Math\Mat4

Multiplies the left matrix by the right quaternion

Note: This method only exists because there is a bug with the order of operation in PHP.

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copy

Copys the current matrix

function copy() : \GL\Math\Mat4

Returns a new instance of the current matrix with the same values. This means that any modifications made to the returned matrix will not affect the current matrix.

$copy = $matrix->copy();

returns

\Mat4 The copy of the current matrix.

---

row

Returns the row at the given index.

function row(int $index) : \GL\Math\Vec4

Example usage:

$matrix = Mat4::fromArray([
    [1.0, 2.0, 3.0, 4.0],
    [5.0, 6.0, 7.0, 8.0],
    [9.0, 10.0, 11.0, 12.0],
    [13.0, 14.0, 15.0, 16.0]
]);

// Get the first row
$row = $matrix->row(0);
// Expected result: Vec4(1.0, 2.0, 3.0, 4.0)

arguments

1. int $index The index of the row to return.

returns

\Vec4 The row at the given index.

---

setRow

Sets the row at the given index to the given row

function setRow(int $index, \GL\Math\Vec4 $row) : void

Example usage:

$matrix = new Mat4();
$row = new Vec4(1, 2, 3, 4);
$matrix->setRow(0, $row);

arguments

1. int $index The index of the row to set.
2. \Vec4 $row The row to set.

returns

void

---

col

Returns the column at the given index.

function col(int $index) : \GL\Math\Vec4

This method retrieves a column from the matrix at the specified index and returns it as a Vec4 object.

Example:

$matrix = Mat4::fromArray([
    [1.0, 2.0, 3.0, 4.0],
    [5.0, 6.0, 7.0, 8.0],
    [9.0, 10.0, 11.0, 12.0],
    [13.0, 14.0, 15.0, 16.0]
]);

$col = $matrix->col(0);

// Returns Vec4(1.0, 5.0, 9.0, 13.0)

arguments

1. int $index The index of the column to return.

returns

\Vec4 The column at the given index.

---

setCol

Sets the column at the given index to the given column

function setCol(int $index, \GL\Math\Vec4 $col) : void

// Create a new matrix and set the second column
$matrix = new Mat4();
$col = new Vec4(1, 2, 3, 4);
$matrix->setCol(1, $col);

arguments

1. int $index The index of the column to set.
2. \Vec4 $col The column to set.

returns

void

---

lookAt

Sets the matrix to a lookAt matrix

function lookAt(\GL\Math\Vec3 $eye, \GL\Math\Vec3 $center, \GL\Math\Vec3 $up) : void

The lookAt() method sets the matrix to a lookAt matrix based on the camera's position and orientation. It takes three parameters: $eye, $center, and $up, which are all instances of the Vec3 class.

The $eye parameter indicates the position of the camera, while $center indicates the point in space to look at. The $up parameter specifies the up vector, which determines the orientation of the camera.

Example usage:

// Create a new matrix
$matrix = new Mat4();

// Set the matrix to a lookAt matrix
$matrix->lookAt(
   new Vec3(0, 0, 5), // eye
   new Vec3(0, 0, 0), // center
   new Vec3(0, 1, 0)  // up
);

This will create a new matrix and set it to a lookAt matrix with the camera positioned at (0, 0, 5), looking at the origin (0, 0, 0), with the up vector pointing in the positive y direction.

arguments

1. \Vec3 $eye The position of the camera.
2. \Vec3 $center The position to look at.
3. \Vec3 $up The up vector.

returns

void

---

perspective

Sets the matrix to a perspective matrix

function perspective(float $fov, float $aspect, float $near, float $far) : void

$matrix->perspective($fov, $aspect, $near, $far);

arguments

1. float $fov The field of view.
2. float $aspect The aspect ratio.
3. float $near The near plane.
4. float $far The far plane.

returns

void

---

ortho

Sets the matrix to an orthographic matrix

function ortho(float $left, float $right, float $bottom, float $top, float $near, float $far) : void

$matrix->ortho($left, $right, $bottom, $top, $near, $far);

arguments

1. float $left The left plane.
2. float $right The right plane.
3. float $bottom The bottom plane.
4. float $top The top plane.
5. float $near The near plane.
6. float $far The far plane.

returns

void

---

transpose

Tranposes the matrix

function transpose() : void

$matrix->transpose();

returns

void

---

inverse

Inverts the current matrix

function inverse() : void

$matrix->inverse();

returns

void

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scale

Scale the matrix by the given vector

function scale(\GL\Math\Vec3 $scale) : void

$matrix->scale(new Vec3(2, 2, 2));

---

translate

Translates the matrix by the given vector

function translate(\GL\Math\Vec3 $vector) : void

$matrix->translate(new Vec3(1, 1, 1));

arguments

1. \Vec3 $vector The vector to translate by.

returns

void

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rotate

Rotates the matrix by the given angle around the given axis

function rotate(float $angle, \GL\Math\Vec3 $axis) : void

$matrix->rotate(GLM::radians(90), new Vec3(0, 1, 0));

arguments

1. float $angle The angle to rotate by.
2. \Vec3 $axis The axis to rotate around.

returns

void

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determinant

Retruns the determinant of the matrix

function determinant() : float

$det = $matrix->determinant();

returns

float The determinant of the matrix.

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