Source: math/Quaternion.js

  1. /**
  2.  * @fileOverview
  3.  * @author David Gossow - dgossow@willowgarage.com
  4.  */
  6. /**
  7.  * A Quaternion.
  8.  *
  9.  * @constructor
  10.  * @param {Object} options
  11.  * @param {number} [options.x=0] - The x value.
  12.  * @param {number} [options.y=0] - The y value.
  13.  * @param {number} [options.z=0] - The z value.
  14.  * @param {number} [options.w=1] - The w value.
  15.  */
  16. function Quaternion(options) {
  17.   options = options || {};
  18.   this.x = options.x || 0;
  19.   this.y = options.y || 0;
  20.   this.z = options.z || 0;
  21.   this.w = (typeof options.w === 'number') ? options.w : 1;
  22. }
  24. /**
  25.  * Perform a conjugation on this quaternion.
  26.  */
  27. Quaternion.prototype.conjugate = function() {
  28.   this.x *= -1;
  29.   this.y *= -1;
  30.   this.z *= -1;
  31. };
  33. /**
  34.  * Return the norm of this quaternion.
  35.  */
  36. Quaternion.prototype.norm = function() {
  37.   return Math.sqrt(this.x * this.x + this.y * this.y + this.z * this.z + this.w * this.w);
  38. };
  40. /**
  41.  * Perform a normalization on this quaternion.
  42.  */
  43. Quaternion.prototype.normalize = function() {
  44.   var l = Math.sqrt(this.x * this.x + this.y * this.y + this.z * this.z + this.w * this.w);
  45.   if (l === 0) {
  46.     this.x = 0;
  47.     this.y = 0;
  48.     this.z = 0;
  49.     this.w = 1;
  50.   } else {
  51.     l = 1 / l;
  52.     this.x = this.x * l;
  53.     this.y = this.y * l;
  54.     this.z = this.z * l;
  55.     this.w = this.w * l;
  56.   }
  57. };
  59. /**
  60.  * Convert this quaternion into its inverse.
  61.  */
  62. Quaternion.prototype.invert = function() {
  63.   this.conjugate();
  64.   this.normalize();
  65. };
  67. /**
  68.  * Set the values of this quaternion to the product of itself and the given quaternion.
  69.  *
  70.  * @param {Quaternion} q - The quaternion to multiply with.
  71.  */
  72. Quaternion.prototype.multiply = function(q) {
  73.   var newX = this.x * q.w + this.y * q.z - this.z * q.y + this.w * q.x;
  74.   var newY = -this.x * q.z + this.y * q.w + this.z * q.x + this.w * q.y;
  75.   var newZ = this.x * q.y - this.y * q.x + this.z * q.w + this.w * q.z;
  76.   var newW = -this.x * q.x - this.y * q.y - this.z * q.z + this.w * q.w;
  77.   this.x = newX;
  78.   this.y = newY;
  79.   this.z = newZ;
  80.   this.w = newW;
  81. };
  83. /**
  84.  * Clone a copy of this quaternion.
  85.  *
  86.  * @returns {Quaternion} The cloned quaternion.
  87.  */
  88. Quaternion.prototype.clone = function() {
  89.   return new Quaternion(this);
  90. };
  92. module.exports = Quaternion;