Class Matrix3

A class representing a 3x3 matrix.

Example

const m = new Matrix3();

Remark

A Note on Row-Major and Column-Major Ordering The set() method takes arguments in row-major order, while internally they are stored in the elements array in column-major order.

This means that calling

m.set( 11, 12, 13,
     21, 22, 23,
     31, 32, 33 );

will result in the elements array containing:

m.elements = [ 11, 21, 31,
               12, 22, 32,
               13, 23, 33 ];

and internally all calculations are performed using column-major ordering. However, as the actual ordering makes no difference mathematically and most people are used to thinking about matrices in row-major order, the three.js documentation shows matrices in row-major order. Just bear in mind that if you are reading the source code, you'll have to take the transpose of any matrices outlined here to make sense of the calculations.

Hierarchy

  • Base
    • Matrix3

Implements

Constructors

constructor

Properties

elements

Accessors

isBox2 isBox3 isColor isCylindrical isEuler isLine3 isMatrix isMatrix3 isMatrix4 isPlane isQuaternion isRay isSphere isSpherical isTriangle isVector2 isVector3 isVector4

Methods

clone copy determinant equals extractBasis fromArray getNormalMatrix identity invert makeRotation makeScale makeTranslation multiply multiplyMatrices multiplyScalar premultiply rotate scale set setFromMatrix4 setUvTransform toArray translate transpose transposeIntoArray

Constructors

constructor

  • Creates and initializes the Matrix3 to the 3x3 identity matrix.

    Returns Matrix3

Properties

elements

elements: number[]

A column-major list of matrix values.

Default

[1, 0, 0, 0, 1, 0, 0, 0, 1]

Accessors

isBox2

  • get isBox2(): boolean

  • Returns boolean

isBox3

  • get isBox3(): boolean

  • Returns boolean

isColor

  • get isColor(): boolean

  • Returns boolean

isCylindrical

  • get isCylindrical(): boolean

  • Returns boolean

isEuler

  • get isEuler(): boolean

  • Returns boolean

isLine3

  • get isLine3(): boolean

  • Returns boolean

isMatrix

  • get isMatrix(): boolean

  • Read-only flag to check if a given object is of type Matrix.

    Returns boolean

isMatrix3

  • get isMatrix3(): boolean

  • Read-only flag to check if a given object is of type Matrix3.

    Returns boolean

isMatrix4

  • get isMatrix4(): boolean

  • Returns boolean

isPlane

  • get isPlane(): boolean

  • Returns boolean

isQuaternion

  • get isQuaternion(): boolean

  • Returns boolean

isRay

  • get isRay(): boolean

  • Returns boolean

isSphere

  • get isSphere(): boolean

  • Returns boolean

isSpherical

  • get isSpherical(): boolean

  • Returns boolean

isTriangle

  • get isTriangle(): boolean

  • Returns boolean

isVector2

  • get isVector2(): boolean

  • Returns boolean

isVector3

  • get isVector3(): boolean

  • Returns boolean

isVector4

  • get isVector4(): boolean

  • Returns boolean

Methods

clone

copy

determinant

  • Computes the determinant of this matrix.

    Returns

    A float.

    Returns number

equals

  • Test if this instance is equivalent to another matrix.

    Returns

    True if this matrix and m are equal.

    Parameters

    Returns boolean

extractBasis

  • Extracts the basis of this matrix into the three axis vectors provided. If this matrix is:

    a, b, c,
    d, e, f,
    g, h, i

    then the xAxis, yAxis, zAxis will be set to:

    xAxis = (a, d, g)
    yAxis = (b, e, h)
    zAxis = (c, f, i)

    Returns

    This instance.

    Parameters

    Returns Matrix3

fromArray

  • Sets the elements of this matrix based on an array in column-major format.

    Returns

    This instance.

    Parameters

    • array: number[]

      the array to read the elements from.

    • Optional offset: number

      index of first element in the array. Default is 0.

    Returns Matrix3

getNormalMatrix

  • Sets this matrix as the upper left 3x3 of the normal matrix of the passed matrix4. The normal matrix is the inverse transpose of the matrix m.

    Returns

    This instance.

    Parameters

    Returns Matrix3

identity

  • Resets this matrix to the 3x3 identity matrix:

    1, 0, 0
    0, 1, 0
    0, 0, 1

    Returns

    This instance.

    Returns Matrix3

invert

  • Inverts this matrix, using the analytic method. You can not invert with a determinant of zero. If you attempt this, the method produces a zero matrix instead.

    Returns

    This instance

    Returns Matrix3

makeRotation

  • Sets this matrix as a 2D rotational transformation by theta radians. The resulting matrix will be: cos(θ) -sin(θ) 0 sin(θ) cos(θ) 0 0 0 1

    Returns

    This instance.

    Parameters

    • theta: number

      — Rotation angle in radians. Positive values rotate counterclockwise

    Returns Matrix3

makeScale

  • Sets this matrix as a 2D scale transform x, 0, 0, 0, y, 0, 0, 0, 1

    Returns

    This instance.

    Parameters

    • x: number

      the amount to scale in the X axis

    • y: number

      the amount to scale in the Y axis

    Returns Matrix3

makeTranslation

  • Sets this matrix as a 2D translation transform: 1, 0, x, 0, 1, y, 0, 0, 1

    Returns

    This instance.

    Parameters

    • x: number
    • y: number

    Returns Matrix3

multiply

multiplyMatrices

multiplyScalar

  • Multiplies every component of the matrix by the scalar value s.

    Returns

    This instance.

    Parameters

    • s: number

    Returns Matrix3

premultiply

rotate

  • Rotates this matrix by the given angle (in radians).

    Returns

    This instance.

    Parameters

    • theta: number

      The angle in radians to rotate

    Returns Matrix3

scale

  • Scales this matrix with the given scalar values.

    Returns

    This instance.

    Parameters

    • sx: number

      x scale factor

    • sy: number

      y scale factor

    Returns Matrix3

set

  • Sets the 3x3 matrix values to the given row-major sequence of values.

    Returns

    This instance.

    Parameters

    • n11: number
    • n12: number
    • n13: number
    • n21: number
    • n22: number
    • n23: number
    • n31: number
    • n32: number
    • n33: number

    Returns Matrix3

setFromMatrix4

setUvTransform

  • Set this matrix to the upper 3x3 matrix of the Matrix4 m.

    Returns

    This instance.

    Parameters

    • tx: number

      offset x

    • ty: number

      offset y

    • sx: number

      repeat x

    • sy: number

      repeat y

    • rotation: number

      rotation, in radians. Positive values rotate counterclockwise

    • cx: number

      center x of rotation

    • cy: number

      center y of rotation

    Returns Matrix3

toArray

  • Writes the elements of this matrix to an array in column-major format.

    Returns

    The array param or a new instance

    Parameters

    • Optional array: number[]

      array to store the resulting vector in. If not given a new array will be created.

    • Optional offset: number

      offset in the array at which to put the result.

    Returns number[]

translate

  • Translates this matrix by the given scalar values.

    Returns

    This instance.

    Parameters

    • tx: number

      The x direction translation

    • ty: number

      The y direction translation

    Returns Matrix3

transpose

  • Transposes this matrix in place.

    Returns

    This instance.

    Returns Matrix3

transposeIntoArray

  • Transposes this matrix into the supplied array, and returns itself unchanged.

    Returns

    This instance.

    Parameters

    • r: number[]

      array to store the resulting vector in.

    Returns Matrix3

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