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<h1 class="page-title">Source: math/mathf.js</h1>
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<pre class="prettyprint source"><code>if (typeof(define) !== "function") {
var define = require("amdefine")(module);
}
define(
function() {
"use strict";
var random = Math.random,
abs = Math.abs,
cos = Math.cos,
pow = Math.pow,
floor = Math.floor,
ceil = Math.ceil,
atan2 = Math.atan2,
EPSILON = 0.000001,
PI = 3.1415926535897932384626433832795028841968,
TWO_PI = PI * 2,
HALF_PI = PI * 0.5,
TO_RADS = PI / 180,
TO_DEGS = 180 / PI,
keys = Object.keys,
modulo, clamp01, standardRadian, standardAngle, radsToDegs;
/**
* @class Mathf
* collection of common math functions
*/
function Mathf() {
/**
* @property Number PI
* The infamous 3.1415926535897932384626433832795028841968
* @memberof Odin.Mathf
*/
this.PI = PI;
/**
* @property Number TWO_PI
* 2 * PI
* @memberof Odin.Mathf
*/
this.TWO_PI = TWO_PI;
/**
* @property Number HALF_PI
* PI / 2
* @memberof Odin.Mathf
*/
this.HALF_PI = HALF_PI;
/**
* @property Number EPSILON
* A small number value
* @memberof Odin.Mathf
*/
this.EPSILON = EPSILON;
/**
* @property Number TO_RADS
* Degrees to radians conversion constant
* @memberof Odin.Mathf
*/
this.TO_RADS = TO_RADS;
/**
* @property Number TO_DEGS
* Radians to degrees conversion constant
* @memberof Odin.Mathf
*/
this.TO_DEGS = TO_DEGS;
this._classes = {};
}
Mathf.prototype.acos = Math.acos;
Mathf.prototype.asin = Math.asin;
Mathf.prototype.atan = Math.atan;
Mathf.prototype.atan2 = Math.atan2;
Mathf.prototype.cos = Math.cos;
Mathf.prototype.sin = Math.sin;
Mathf.prototype.tan = Math.tan;
Mathf.prototype.abs = Math.abs;
Mathf.prototype.ceil = Math.ceil;
Mathf.prototype.exp = Math.exp;
Mathf.prototype.floor = Math.floor;
Mathf.prototype.log = Math.log;
Mathf.prototype.max = Math.max;
Mathf.prototype.min = Math.min;
Mathf.prototype.pow = Math.pow;
Mathf.prototype.random = Math.random;
Mathf.prototype.round = Math.round;
Mathf.prototype.sqrt = Math.sqrt;
/**
* @method equals
* @memberof Odin.Mathf
* returns if a = b within some value, defaults to Mathf.EPSILON
* @param Number a
* @param Number b
* @param Number e
* @return Boolean
*/
Mathf.prototype.equals = function(a, b, e) {
return abs(a - b) < (e || EPSILON);
};
/**
* @method modulo
* @memberof Odin.Mathf
* returns remainder of a / b
* @param Number a
* @param Number b
* @return Number
*/
Mathf.prototype.modulo = modulo = function(a, b) {
var r = a % b;
return (r * b < 0) ? r + b : r;
};
/**
* @method standardRadian
* @memberof Odin.Mathf
* convertes x to radian where 0 <= x < 2PI
* @param Number x
* @return Number
*/
Mathf.prototype.standardRadian = standardRadian = function(x) {
return modulo(x, TWO_PI);
};
/**
* @method standardAngle
* @memberof Odin.Mathf
* convertes x to angle where 0 <= x < 360
* @param Number x
* @return Number
*/
Mathf.prototype.standardAngle = standardAngle = function(x) {
return modulo(x, 360);
};
/**
* @method sign
* @memberof Odin.Mathf
* gets sign of x
* @param Number x
* @return Number
*/
Mathf.prototype.sign = function(x) {
return x < 0 ? -1 : 1;
};
/**
* @method clamp
* @memberof Odin.Mathf
* clamp x between min and max
* @param Number x
* @param Number min
* @param Number max
* @return Number
*/
Mathf.prototype.clamp = function(x, min, max) {
return x < min ? min : x > max ? max : x;
};
/**
* @method clampBottom
* @memberof Odin.Mathf
* clamp x between min and Infinity
* @param Number x
* @param Number min
* @return Number
*/
Mathf.prototype.clampBottom = function(x, min) {
return x < min ? min : x;
};
/**
* @method clampTop
* @memberof Odin.Mathf
* clamp x between -Infinity and max
* @param Number x
* @param Number max
* @return Number
*/
Mathf.prototype.clampTop = function(x, max) {
return x > max ? max : x;
};
/**
* @method clamp01
* @memberof Odin.Mathf
* clamp x between 0 and 1
* @param Number x
* @return Number
*/
Mathf.prototype.clamp01 = clamp01 = function(x) {
return x < 0 ? 0 : x > 1 ? 1 : x;
};
/**
* @method truncate
* @memberof Odin.Mathf
* truncate x to have n number of decial places
* @param Number x
* @param Number n
* @return Number
*/
Mathf.prototype.truncate = function(x, n) {
var p = pow(10, n),
num = x * p;
return (num < 0 ? ceil(num) : floor(num)) / p;
};
/**
* @method lerp
* @memberof Odin.Mathf
* linear interpolation between a and b by x
* @param Number a
* @param Number b
* @param Number x
* @return Number
*/
Mathf.prototype.lerp = function(a, b, x) {
return a + (b - a) * x;
};
/**
* @method lerpAngle
* @memberof Odin.Mathf
* linear interpolation between a and b by x insures 0 <= x < 2PI
* @param Number a
* @param Number b
* @param Number x
* @return Number
*/
Mathf.prototype.lerpAngle = function(a, b, x) {
return standardRadian(a + (b - a) * x);
};
/**
* @method cosLerp
* @memberof Odin.Mathf
* cosine interpolation between a and b by x
* @param Number a
* @param Number b
* @param Number x
* @return Number
*/
Mathf.prototype.lerpCos = function(a, b, x) {
var ft = x * PI,
f = (1 - cos(ft)) * 0.5;
return a * (1 - f) + b * f;
};
/**
* @method lerpCubic
* @memberof Odin.Mathf
* cubic interpolation between v1 and v2 by x
* @param Number v0
* @param Number v1
* @param Number v2
* @param Number v3
* @param Number x
* @return Number
*/
Mathf.prototype.lerpCubic = function(v0, v1, v2, v3, x) {
v0 || (v0 = v1);
v3 || (v3 = v2);
var P = (v3 - v2) - (v0 - v1),
Q = (v0 - v1) - P,
R = v2 - v0,
S = v1,
Px = P * x,
Qx = Q * x,
Rx = R * x;
return (Px * Px * Px) + (Qx * Qx) + Rx + S;
};
/**
* smooth step, if input is between min and max this returns a value proportionately between 0 and 1
* @method smoothStep
* @memberof Odin.Mathf
* @param Number x
* @param Number min
* @param Number max
* @return Number
*/
Mathf.prototype.smoothStep = function(x, min, max) {
if (x <= min) return 0;
if (x >= max) return 1;
x = (x - min) / (max - min);
return x * x * (3 - 2 * x);
};
/**
* @method smootherStep
* @memberof Odin.Mathf
* smoother step, if input is between min and max this returns a value proportionately between 0 and 1
* @param Number x
* @param Number min
* @param Number max
* @return Number
*/
Mathf.prototype.smootherStep = function(x, min, max) {
if (x <= min) return 0;
if (x >= max) return 1;
x = (x - min) / (max - min);
return x * x * x * (x * (x * 6 - 15) + 10);
};
/**
* @method pingPong
* @memberof Odin.Mathf
* PingPongs the value x, so that it is never larger than length and never smaller than 0.
* @param Number x
* @param Number length
* @return Number
*/
Mathf.prototype.pingPong = function(x, length) {
length || (length = 1);
return length - abs(x % (2 * length) - length);
};
/**
* @method degsToRads
* @memberof Odin.Mathf
* convertes degrees to radians
* @param Number x
* @return Number
*/
Mathf.prototype.degsToRads = function(x) {
return standardRadian(x * TO_RADS);
};
/**
* @method radsToDegs
* @memberof Odin.Mathf
* convertes radians to degrees
* @param Number x
* @return Number
*/
Mathf.prototype.radsToDegs = radsToDegs = function(x) {
return standardAngle(x * TO_DEGS);
};
/**
* @method randInt
* @memberof Odin.Mathf
* returns random number between min and max
* @param Number min
* @param Number max
* @return Number
*/
Mathf.prototype.randInt = function(min, max) {
return floor(min + (random() * (max + 1 - min)));
};
/**
* @method randFloat
* @memberof Odin.Mathf
* returns random number between min and max
* @param Number min
* @param Number max
* @return Number
*/
Mathf.prototype.randFloat = function(min, max) {
return min + (random() * (max - min));
};
/**
* @method randSign
* @memberof Odin.Mathf
* returns either -1 or 1
* @param Number min
* @param Number max
* @return Number
*/
Mathf.prototype.randSign = function() {
return random() < 0.5 ? 1 : -1;
};
/**
* @method randChoice
* @memberof Odin.Mathf
* returns random item from array
* @param Array array
* @return Number
*/
Mathf.prototype.randChoice = function(array) {
return array[(random() * array.length) | 0];
};
/**
* @method shuffle
* @memberof Odin.Mathf
* shuffles array
* @param Array array
* @return Array
*/
Mathf.prototype.shuffle = function(array) {
for (var j, x, i = array.length; i; j = (random() * i) | 0, x = array[--i], array[i] = array[j], array[j] = x);
return array;
};
/**
* @method randArg
* @memberof Odin.Mathf
* returns random argument from arguments
* @return Number
*/
Mathf.prototype.randArg = function() {
return arguments[(random() * arguments.length) | 0];
};
/**
* @method randChoiceObject
* @memberof Odin.Mathf
* returns random key from object
* @param Object obj
* @return Number
*/
Mathf.prototype.randChoiceObject = function(obj) {
var array = keys(obj);
return array[(random() * array.length) | 0];
};
/**
* @method isPowerOfTwo
* @memberof Odin.Mathf
* checks if x is a power of 2
* @param Number x
* @return Number
*/
Mathf.prototype.isPowerOfTwo = function(x) {
return (x & -x) === x;
};
/**
* @method toPowerOfTwo
* @memberof Odin.Mathf
* returns number's next power of 2
* @param Number x
* @return Number
*/
Mathf.prototype.toPowerOfTwo = function(x) {
var i = 2;
while (i < x) {
i *= 2;
}
return i;
};
/**
* @method fromJSON
* @memberof Odin.Mathf
* returns Math class based on json _className
* @param Object json
* @return MATH_CLASS
*/
Mathf.prototype.fromJSON = function(json) {
return new this._classes[json._className]().fromJSON(json);
};
var RIGHT = "right",
UP_RIGHT = "up_right",
UP = "up",
UP_LEFT = "up_left",
LEFT = "left",
DOWN_LEFT = "down_left",
DOWN = "down",
DOWN_RIGHT = "down_right";
/**
* @method directionAngle
* @memberof Odin.Mathf
* returns direction string of an angle in radians
* @param Number x
* @param Number y
* @return String
*/
var n225 = 0.39269908169872414,
n675 = 1.1780972450961724,
n1125 = 1.9634954084936207,
n1575 = 2.748893571891069,
n2025 = 3.5342917352885173,
n2475 = 4.319689898685966,
n2925 = 5.105088062083414,
n3375 = 5.8904862254808625;
Mathf.prototype.directionAngle = function(a) {
a = standardRadian(a);
if (a >= n3375 && a < n225) return RIGHT;
if (a >= n225 && a < n675) return UP_RIGHT;
if (a >= n675 && a < n1125) return UP;
if (a >= n1125 && a < n1575) return UP_LEFT;
if (a >= n1575 && a < n2025) return LEFT;
if (a >= n2025 && a < n2475) return DOWN_LEFT;
if (a >= n2475 && a < n2925) return DOWN;
if (a >= n2925 && a < n3375) return DOWN_RIGHT;
return RIGHT;
};
/**
* @method direction
* @memberof Odin.Mathf
* returns direction string from an x and a y coordinate
* @param Number x
* @param Number y
* @return String
*/
Mathf.prototype.direction = function(x, y) {
var a = standardRadian(atan2(y, x));
if (a >= n3375 && a < n225) return RIGHT;
if (a >= n225 && a < n675) return UP_RIGHT;
if (a >= n675 && a < n1125) return UP;
if (a >= n1125 && a < n1575) return UP_LEFT;
if (a >= n1575 && a < n2025) return LEFT;
if (a >= n2025 && a < n2475) return DOWN_LEFT;
if (a >= n2475 && a < n2925) return DOWN;
if (a >= n2925 && a < n3375) return DOWN_RIGHT;
return RIGHT;
};
return new Mathf;
}
);
</code></pre>
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