phaser/src/math/interpolation/LinearInterpolation.js
2018-04-02 10:54:46 -05:00

40 lines
963 B
JavaScript

/**
* @author Richard Davey <rich@photonstorm.com>
* @copyright 2018 Photon Storm Ltd.
* @license {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
*/
var Linear = require('../Linear');
/**
* A Linear Interpolation Method.
*
* @function Phaser.Math.Interpolation.Linear
* @since 3.0.0
* @see https://en.wikipedia.org/wiki/Linear_interpolation
*
* @param {number[]} v - The input array of values to interpolate between.
* @param {!number} k - The percentage of interploation, between 0 and 1.
*
* @return {!number} The interpolated value.
*/
var LinearInterpolation = function (v, k)
{
var m = v.length - 1;
var f = m * k;
var i = Math.floor(f);
if (k < 0)
{
return Linear(v[0], v[1], f);
}
if (k > 1)
{
return Linear(v[m], v[m - 1], m - f);
}
return Linear(v[i], v[(i + 1 > m) ? m : i + 1], f - i);
};
module.exports = LinearInterpolation;