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Updated docs and added native clamping

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Richard Davey 2018-05-24 17:03:42 +01:00
parent 9a76f40f55
commit 2684e7d988
1 changed files with 20 additions and 8 deletions
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28
src/math/SmoothStep.js
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@ -5,24 +5,36 @@
*/
/**
* Smoothly interpolate between two values.
* 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.
*
* Computes a smooth step interpolation between `min` and `max` by `x`.
* https://en.wikipedia.org/wiki/Smoothstep
*
* @function Phaser.Math.SmoothStep
* @since 3.0.0
*
* @param {number} x - The percentage of interpolation, between 0 and 1.
* @param {number} min - The minimum value.
* @param {number} max - The maximum value.
* @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 smoothly interpolated value.
* @return {number} A number between 0 and 1.
*/
var SmoothStep = function (x, min, max)
{
x = Math.max(0, Math.min(1, (x - min) / (max - min)));
if (x <= min)
{
return 0;
}
return x * x * (3 - 2 * x);
if (x >= max)
{
return 1;
}
x = (x - min) / (max - min);
return x * x * ( 3 - 2 * x );
};
module.exports = SmoothStep;