phaser/src/math/SmootherStep.js
2023-01-02 17:36:27 +00:00

33 lines
1.2 KiB
JavaScript

/**
* @author Richard Davey <rich@photonstorm.com>
* @copyright 2013-2023 Photon Storm Ltd.
* @license {@link https://opensource.org/licenses/MIT|MIT License}
*/
/**
* Calculate a smoother interpolation percentage of `x` between `min` and `max`.
*
* The function receives the number `x` as an argument and returns 0 if `x` is less than or equal to the left edge,
* 1 if `x` is greater than or equal to the right edge, and smoothly interpolates, using a Hermite polynomial,
* between 0 and 1 otherwise.
*
* Produces an even smoother interpolation than {@link Phaser.Math.SmoothStep}.
*
* @function Phaser.Math.SmootherStep
* @since 3.0.0
* @see {@link https://en.wikipedia.org/wiki/Smoothstep#Variations}
*
* @param {number} x - The input value.
* @param {number} min - The minimum value, also known as the 'left edge', assumed smaller than the 'right edge'.
* @param {number} max - The maximum value, also known as the 'right edge', assumed greater than the 'left edge'.
*
* @return {number} The percentage of interpolation, between 0 and 1.
*/
var SmootherStep = function (x, min, max)
{
x = Math.max(0, Math.min(1, (x - min) / (max - min)));
return x * x * x * (x * (x * 6 - 15) + 10);
};
module.exports = SmootherStep;