/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview Defines a 3-element vector class that can be used for
* coordinate math, useful for animation systems and point manipulation.
*
* Based heavily on code originally by:
*/
goog.provide('goog.math.Vec3');
goog.require('goog.math');
goog.require('goog.math.Coordinate3');
/**
* Class for a three-dimensional vector object and assorted functions useful for
* manipulation.
*
* Inherits from goog.math.Coordinate3 so that a Vec3 may be passed in to any
* function that requires a Coordinate.
*
* @param {number} x The x value for the vector.
* @param {number} y The y value for the vector.
* @param {number} z The z value for the vector.
* @struct
* @constructor
* @extends {goog.math.Coordinate3}
*/
goog.math.Vec3 = function(x, y, z) {
'use strict';
/**
* X-value
* @type {number}
*/
this.x = x;
/**
* Y-value
* @type {number}
*/
this.y = y;
/**
* Z-value
* @type {number}
*/
this.z = z;
};
goog.inherits(goog.math.Vec3, goog.math.Coordinate3);
/**
* Generates a random unit vector.
*
* http://mathworld.wolfram.com/SpherePointPicking.html
* Using (6), (7), and (8) to generate coordinates.
* @return {!goog.math.Vec3} A random unit-length vector.
*/
goog.math.Vec3.randomUnit = function() {
'use strict';
var theta = Math.random() * Math.PI * 2;
var phi = Math.random() * Math.PI * 2;
var z = Math.cos(phi);
var x = Math.sqrt(1 - z * z) * Math.cos(theta);
var y = Math.sqrt(1 - z * z) * Math.sin(theta);
return new goog.math.Vec3(x, y, z);
};
/**
* Generates a random vector inside the unit sphere.
*
* @return {!goog.math.Vec3} A random vector.
*/
goog.math.Vec3.random = function() {
'use strict';
return goog.math.Vec3.randomUnit().scale(Math.random());
};
/**
* Returns a new Vec3 object from a given coordinate.
*
* @param {goog.math.Coordinate3} a The coordinate.
* @return {!goog.math.Vec3} A new vector object.
*/
goog.math.Vec3.fromCoordinate3 = function(a) {
'use strict';
return new goog.math.Vec3(a.x, a.y, a.z);
};
/**
* Creates a new copy of this Vec3.
*
* @return {!goog.math.Vec3} A new vector with the same coordinates as this one.
* @override
*/
goog.math.Vec3.prototype.clone = function() {
'use strict';
return new goog.math.Vec3(this.x, this.y, this.z);
};
/**
* Returns the magnitude of the vector measured from the origin.
*
* @return {number} The length of the vector.
*/
goog.math.Vec3.prototype.magnitude = function() {
'use strict';
return Math.sqrt(this.x * this.x + this.y * this.y + this.z * this.z);
};
/**
* Returns the squared magnitude of the vector measured from the origin.
* NOTE(brenneman): Leaving out the square root is not a significant
* optimization in JavaScript.
*
* @return {number} The length of the vector, squared.
*/
goog.math.Vec3.prototype.squaredMagnitude = function() {
'use strict';
return this.x * this.x + this.y * this.y + this.z * this.z;
};
/**
* Scales the current vector by a constant.
*
* @param {number} s The scale factor.
* @return {!goog.math.Vec3} This vector, scaled.
*/
goog.math.Vec3.prototype.scale = function(s) {
'use strict';
this.x *= s;
this.y *= s;
this.z *= s;
return this;
};
/**
* Reverses the sign of the vector. Equivalent to scaling the vector by -1.
*
* @return {!goog.math.Vec3} This vector, inverted.
*/
goog.math.Vec3.prototype.invert = function() {
'use strict';
this.x = -this.x;
this.y = -this.y;
this.z = -this.z;
return this;
};
/**
* Normalizes the current vector to have a magnitude of 1.
*
* @return {!goog.math.Vec3} This vector, normalized.
*/
goog.math.Vec3.prototype.normalize = function() {
'use strict';
return this.scale(1 / this.magnitude());
};
/**
* Adds another vector to this vector in-place.
*
* @param {goog.math.Vec3} b The vector to add.
* @return {!goog.math.Vec3} This vector with `b` added.
*/
goog.math.Vec3.prototype.add = function(b) {
'use strict';
this.x += b.x;
this.y += b.y;
this.z += b.z;
return this;
};
/**
* Subtracts another vector from this vector in-place.
*
* @param {goog.math.Vec3} b The vector to subtract.
* @return {!goog.math.Vec3} This vector with `b` subtracted.
*/
goog.math.Vec3.prototype.subtract = function(b) {
'use strict';
this.x -= b.x;
this.y -= b.y;
this.z -= b.z;
return this;
};
/**
* Compares this vector with another for equality.
*
* @param {goog.math.Vec3} b The other vector.
* @return {boolean} True if this vector's x, y and z equal the given vector's
* x, y, and z, respectively.
*/
goog.math.Vec3.prototype.equals = function(b) {
'use strict';
return this == b || !!b && this.x == b.x && this.y == b.y && this.z == b.z;
};
/**
* Returns the distance between two vectors.
*
* @param {goog.math.Vec3} a The first vector.
* @param {goog.math.Vec3} b The second vector.
* @return {number} The distance.
*/
goog.math.Vec3.distance = goog.math.Coordinate3.distance;
/**
* Returns the squared distance between two vectors.
*
* @param {goog.math.Vec3} a The first vector.
* @param {goog.math.Vec3} b The second vector.
* @return {number} The squared distance.
*/
goog.math.Vec3.squaredDistance = goog.math.Coordinate3.squaredDistance;
/**
* Compares vectors for equality.
*
* @param {goog.math.Vec3} a The first vector.
* @param {goog.math.Vec3} b The second vector.
* @return {boolean} True if the vectors have equal x, y, and z coordinates.
*/
goog.math.Vec3.equals = goog.math.Coordinate3.equals;
/**
* Returns the sum of two vectors as a new Vec3.
*
* @param {goog.math.Vec3} a The first vector.
* @param {goog.math.Vec3} b The second vector.
* @return {!goog.math.Vec3} The sum vector.
*/
goog.math.Vec3.sum = function(a, b) {
'use strict';
return new goog.math.Vec3(a.x + b.x, a.y + b.y, a.z + b.z);
};
/**
* Returns the difference of two vectors as a new Vec3.
*
* @param {goog.math.Vec3} a The first vector.
* @param {goog.math.Vec3} b The second vector.
* @return {!goog.math.Vec3} The difference vector.
*/
goog.math.Vec3.difference = function(a, b) {
'use strict';
return new goog.math.Vec3(a.x - b.x, a.y - b.y, a.z - b.z);
};
/**
* Returns the dot-product of two vectors.
*
* @param {goog.math.Vec3} a The first vector.
* @param {goog.math.Vec3} b The second vector.
* @return {number} The dot-product of the two vectors.
*/
goog.math.Vec3.dot = function(a, b) {
'use strict';
return a.x * b.x + a.y * b.y + a.z * b.z;
};
/**
* Returns the cross-product of two vectors.
*
* @param {goog.math.Vec3} a The first vector.
* @param {goog.math.Vec3} b The second vector.
* @return {!goog.math.Vec3} The cross-product of the two vectors.
*/
goog.math.Vec3.cross = function(a, b) {
'use strict';
return new goog.math.Vec3(
a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z, a.x * b.y - a.y * b.x);
};
/**
* Returns a new Vec3 that is the linear interpolant between vectors a and b at
* scale-value x.
*
* @param {goog.math.Vec3} a Vector a.
* @param {goog.math.Vec3} b Vector b.
* @param {number} x The proportion between a and b.
* @return {!goog.math.Vec3} The interpolated vector.
*/
goog.math.Vec3.lerp = function(a, b, x) {
'use strict';
return new goog.math.Vec3(
goog.math.lerp(a.x, b.x, x), goog.math.lerp(a.y, b.y, x),
goog.math.lerp(a.z, b.z, x));
};
/**
* Returns a new Vec3 that is a copy of the vector a, but rescaled by a factor s
* in all dimensions.
* @param {!goog.math.Vec3} a Vector a.
* @param {number} s Scale factor.
* @return {!goog.math.Vec3} A new rescaled vector.
*/
goog.math.Vec3.rescaled = function(a, s) {
'use strict';
return new goog.math.Vec3(a.x * s, a.y * s, a.z * s);
};
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