Quaternion

class Quaternion extends MathArray extends Array

A class to handle Quaternions. More information on quternions can be found here. The quaternion will be represented by an instance with x, y, z, w components that make a quaternion like: xi + yj + zk + w.

Usage

import {Quaternion} from '@math.gl/core';

Members

x, y, z, w

Gets or sets element 0, 1, 2 or 3 respectively

Methods

Many of the most commonly used methods are inherited from MathArray:

• quaternion.clone()
• quaternion.copy(array)
• quaternion.set(...args)
• quaternion.fromArray(array, offset = 0)
• quaternion.toString()
• quaternion.toArray(array = [], offset = 0)
• quaternion.equals(array)
• quaternion.exactEquals(array)
• quaternion.validate(array = this)
• quaternion.check(array = this)
• quaternion.normalize()

Note that Quaternion is a subclass of the built in JavaScript Array and can thus technically be supplied as a parameter to any function expecting an Array.

constructor

constructor(x = 0, y = 0, z = 0, w = 1)

fromMatrix3

Creates a quaternion from the given 3x3 rotation matrix. NOTE: The resultant quaternion is not normalized, so you should be sure to renormalize the quaternion yourself where necessary.

fromMatrix3(m)

fromValues

Creates a new quat initialized with the given values

fromValues(x, y, z, w)

identity

Set a quat to the identity quaternion

identity()

length

Calculates the length of a quaternion

length()

squaredLength

Calculates the squared length of a quaternion

squaredLength(a)

@returnNumber}

dot

Calculates the dot product of two quat's

quaternion.dot(a, b)

getAxisAngle

Gets the rotation axis and angle for a given quaternion.

quaternion.getAxisAngle()

If a quaternion is created with setAxisAngle, this method will return the same values as providied in the original parameter list OR functionally equivalent values.

Example: The quaternion formed by axis [0, 0, 1] and angle -90 is the same as the quaternion formed by [0, 0, 1] and 270. This method favors the latter.

rotationTo

Sets a quaternion to represent the shortest rotation from one vector to another. Both vectors are assumed to be unit length.

quaternion.rotationTo(vectorA, vectorB)

add

Adds two quaternions

quaternion.add(a, b)

calculateW

Calculates the W component of a quat from the X, Y, and Z components. Any existing W component will be ignored.

quaternion.calculateW()

conjugate

Calculates the conjugate of a quat If the quaternion is normalized, this function is faster than quat_inverse and produces the same result.

quaternion.conjugate()

invert

Calculates the inverse of a quat

quaternion.invert()

lerp

Performs a linear interpolation between two quat's

quaternion.lerp(a, b, t)

multiply

Multiplies two quat's

multiply(a, b)

normalize

Normalize a quat

rotateX

Rotates a quaternion by the given angle about the X axis

rotateX(rad)

rotateY

Rotates a quaternion by the given angle about the Y axis

rotateY(rad)

rotateZ

Rotates a quaternion by the given angle about the Z axis

rotateZ(rad)

scale

Scales a quat by a scalar number

scale(b)

set

Set the components of a quat to the given values

set(i, j, k, l)

setAxisAngle

Sets a quat from the given angle and rotation axis, then returns it.

setAxisAngle(axis, rad)

slerp

Performs a spherical linear interpolation between two quaternions

slerp({start = [0, 0, 0, 1], target, ratio})

s