Quat([x], [y], [z], [w]) 

Create a new Quat instance.

Parameters

x	number, number[]	The quaternion's x component. Defaults to 0. If x is an array of length 4, the array will be used to populate all components.
y	number	The quaternion's y component. Defaults to 0.
z	number	The quaternion's z component. Defaults to 0.
w	number	The quaternion's w component. Defaults to 1.

numberw 

The w component of the quaternion.

numberx 

The x component of the quaternion.

numbery 

The y component of the quaternion.

numberz 

The z component of the quaternion.

clone() 

Returns an identical copy of the specified quaternion.

const q = new pc.Quat(-0.11, -0.15, -0.46, 0.87);
const qclone = q.clone();

console.log("The result of the cloning is: " + q.toString());

Returns

this

A quaternion containing the result of the cloning.

copy(rhs) 

Copies the contents of a source quaternion to a destination quaternion.

const src = new pc.Quat();
const dst = new pc.Quat();
dst.copy(src, src);
console.log("The two quaternions are " + (src.equals(dst) ? "equal" : "different"));

Parameters

rhs

Quat

The quaternion to be copied.

Returns

Quat

Self for chaining.

equals(rhs) 

Reports whether two quaternions are equal.

const a = new pc.Quat();
const b = new pc.Quat();
console.log("The two quaternions are " + (a.equals(b) ? "equal" : "different"));

Parameters

rhs

Quat

The quaternion to be compared against.

Returns

boolean

True if the quaternions are equal and false otherwise.

equalsApprox(rhs, [epsilon]) 

Reports whether two quaternions are equal using an absolute error tolerance.

const a = new pc.Quat();
const b = new pc.Quat();
console.log("The two quaternions are approximately " + (a.equalsApprox(b, 1e-9) ? "equal" : "different"));

Parameters

rhs	Quat	The quaternion to be compared against.
epsilon	number	The maximum difference between each component of the two quaternions. Defaults to 1e-6.

Returns

boolean

True if the quaternions are equal and false otherwise.

getAxisAngle(axis) 

Gets the rotation axis and angle for a given quaternion. If a quaternion is created with setFromAxisAngle, this method will return the same values as provided in the original parameter list OR functionally equivalent values.

const q = new pc.Quat();
q.setFromAxisAngle(new pc.Vec3(0, 1, 0), 90);
const v = new pc.Vec3();
const angle = q.getAxisAngle(v);
// Outputs 90
console.log(angle);
// Outputs [0, 1, 0]
console.log(v.toString());

Parameters

axis

Vec3

The 3-dimensional vector to receive the axis of rotation.

Returns

number

Angle, in degrees, of the rotation.

getEulerAngles([eulers]) 

Converts the supplied quaternion to Euler angles.

Parameters

eulers

Vec3

The 3-dimensional vector to receive the Euler angles.

Returns

Vec3

The 3-dimensional vector holding the Euler angles that correspond to the supplied quaternion.

invert([src]) 

Generates the inverse of the specified quaternion.

// Create a quaternion rotated 180 degrees around the y-axis
const rot = new pc.Quat().setFromEulerAngles(0, 180, 0);

// Invert in place
rot.invert();

Parameters

src

Quat

The quaternion to invert. If not set, the operation is done in place.

Returns

Quat

Self for chaining.

length() 

Returns the magnitude of the specified quaternion.

const q = new pc.Quat(0, 0, 0, 5);
const len = q.length();
// Outputs 5
console.log("The length of the quaternion is: " + len);

Returns

number

The magnitude of the specified quaternion.

lengthSq() 

Returns the magnitude squared of the specified quaternion.

const q = new pc.Quat(3, 4, 0);
const lenSq = q.lengthSq();
// Outputs 25
console.log("The length squared of the quaternion is: " + lenSq);

Returns

number

The magnitude of the specified quaternion.

mul(rhs) 

Returns the result of multiplying the specified quaternions together.

const a = new pc.Quat().setFromEulerAngles(0, 30, 0);
const b = new pc.Quat().setFromEulerAngles(0, 60, 0);

// a becomes a 90 degree rotation around the Y axis
// In other words, a = a * b
a.mul(b);

console.log("The result of the multiplication is: " + a.toString());

Parameters

rhs

Quat

The quaternion used as the second multiplicand of the operation.

Returns

Quat

Self for chaining.

mul2(lhs, rhs) 

Returns the result of multiplying the specified quaternions together.

const a = new pc.Quat().setFromEulerAngles(0, 30, 0);
const b = new pc.Quat().setFromEulerAngles(0, 60, 0);
const r = new pc.Quat();

// r is set to a 90 degree rotation around the Y axis
// In other words, r = a * b
r.mul2(a, b);

console.log("The result of the multiplication is: " + r.toString());

Parameters

lhs	Quat	The quaternion used as the first multiplicand of the operation.
rhs	Quat	The quaternion used as the second multiplicand of the operation.

Returns

Quat

Self for chaining.

normalize([src]) 

Returns the specified quaternion converted in place to a unit quaternion.

const v = new pc.Quat(0, 0, 0, 5);

v.normalize();

// Outputs 0, 0, 0, 1
console.log("The result of the vector normalization is: " + v.toString());

Parameters

src

Quat

The quaternion to normalize. If not set, the operation is done in place.

Returns

Quat

The result of the normalization.

set(x, y, z, w) 

Sets the specified quaternion to the supplied numerical values.

const q = new pc.Quat();
q.set(1, 0, 0, 0);

// Outputs 1, 0, 0, 0
console.log("The result of the vector set is: " + q.toString());

Parameters

x	number	The x component of the quaternion.
y	number	The y component of the quaternion.
z	number	The z component of the quaternion.
w	number	The w component of the quaternion.

Returns

Quat

Self for chaining.

setFromAxisAngle(axis, angle) 

Sets a quaternion from an angular rotation around an axis.

const q = new pc.Quat();
q.setFromAxisAngle(pc.Vec3.UP, 90);

Parameters

axis	Vec3	World space axis around which to rotate.
angle	number	Angle to rotate around the given axis in degrees.

Returns

Quat

Self for chaining.

setFromDirections(from, to) 

Set the quaternion that represents the shortest rotation from one direction to another.

Parameters

from	Vec3	The direction to rotate from. It should be normalized.
to	Vec3	The direction to rotate to. It should be normalized.

Returns

Quat

Self for chaining.

Proof of correctness

setFromEulerAngles(ex, [ey], [ez]) 

Sets a quaternion from Euler angles specified in XYZ order.

// Create a quaternion from 3 euler angles
const q = new pc.Quat();
q.setFromEulerAngles(45, 90, 180);

// Create the same quaternion from a vector containing the same 3 euler angles
const v = new pc.Vec3(45, 90, 180);
const r = new pc.Quat();
r.setFromEulerAngles(v);

Parameters

ex	number, Vec3	Angle to rotate around X axis in degrees. If ex is a Vec3, the three angles will be read from it instead.
ey	number	Angle to rotate around Y axis in degrees.
ez	number	Angle to rotate around Z axis in degrees.

Returns

Quat

Self for chaining.

setFromMat4(m) 

Converts the specified 4x4 matrix to a quaternion. Note that since a quaternion is purely a representation for orientation, only the translational part of the matrix is lost.

// Create a 4x4 rotation matrix of 180 degrees around the y-axis
const rot = new pc.Mat4().setFromAxisAngle(pc.Vec3.UP, 180);

// Convert to a quaternion
const q = new pc.Quat().setFromMat4(rot);

Parameters

m

Mat4

The 4x4 matrix to convert.

Returns

Quat

Self for chaining.

slerp(lhs, rhs, alpha) 

Performs a spherical interpolation between two quaternions. The result of the interpolation is written to the quaternion calling the function.

const q1 = new pc.Quat(-0.11, -0.15, -0.46, 0.87);
const q2 = new pc.Quat(-0.21, -0.21, -0.67, 0.68);

const result;
result = new pc.Quat().slerp(q1, q2, 0);   // Return q1
result = new pc.Quat().slerp(q1, q2, 0.5); // Return the midpoint interpolant
result = new pc.Quat().slerp(q1, q2, 1);   // Return q2

Parameters

lhs	Quat	The quaternion to interpolate from.
rhs	Quat	The quaternion to interpolate to.
alpha	number	The value controlling the interpolation in relation to the two input quaternions. The value is in the range 0 to 1, 0 generating q1, 1 generating q2 and anything in between generating a spherical interpolation between the two.

Returns

Quat

Self for chaining.

toString() 

Converts the quaternion to string form.

const v = new pc.Quat(0, 0, 0, 1);
// Outputs [0, 0, 0, 1]
console.log(v.toString());

Returns

string

The quaternion in string form.

transformVector(vec, [res]) 

Transforms a 3-dimensional vector by the specified quaternion.

// Create a 3-dimensional vector
const v = new pc.Vec3(1, 2, 3);

// Create a 4x4 rotation matrix
const q = new pc.Quat().setFromEulerAngles(10, 20, 30);

const tv = q.transformVector(v);

Parameters

vec	Vec3	The 3-dimensional vector to be transformed.
res	Vec3	An optional 3-dimensional vector to receive the result of the transformation.

Returns

Vec3

The input vector v transformed by the current instance.