phaser/src/tweens/builders/GetEaseFunction.js
2022-08-23 15:20:14 +01:00

101 lines
2.7 KiB
JavaScript

/**
* @author Richard Davey <rich@photonstorm.com>
* @copyright 2022 Photon Storm Ltd.
* @license {@link https://opensource.org/licenses/MIT|MIT License}
*/
var EaseMap = require('../../math/easing/EaseMap');
var UppercaseFirst = require('../../utils/string/UppercaseFirst');
/**
* This internal function is used to return the correct ease function for a Tween.
*
* It can take a variety of input, including an EaseMap based string, or a custom function.
*
* @function Phaser.Tweens.Builders.GetEaseFunction
* @since 3.0.0
*
* @param {(string|function)} ease - The ease to find. This can be either a string from the EaseMap, or a custom function.
* @param {number[]} [easeParams] - An optional array of ease parameters to go with the ease.
*
* @return {function} The ease function.
*/
var GetEaseFunction = function (ease, easeParams)
{
// Default ease function
var easeFunction = EaseMap.Power0;
// Prepare ease function
if (typeof ease === 'string')
{
// String based look-up
// 1) They specified it correctly
if (EaseMap.hasOwnProperty(ease))
{
easeFunction = EaseMap[ease];
}
else
{
// Do some string manipulation to try and find it
var direction = '';
if (ease.indexOf('.'))
{
// quad.in = Quad.easeIn
// quad.out = Quad.easeOut
// quad.inout = Quad.easeInOut
direction = ease.substring(ease.indexOf('.') + 1);
var directionLower = direction.toLowerCase();
if (directionLower === 'in')
{
direction = 'easeIn';
}
else if (directionLower === 'out')
{
direction = 'easeOut';
}
else if (directionLower === 'inout')
{
direction = 'easeInOut';
}
}
ease = UppercaseFirst(ease.substring(0, ease.indexOf('.') + 1) + direction);
if (EaseMap.hasOwnProperty(ease))
{
easeFunction = EaseMap[ease];
}
}
}
else if (typeof ease === 'function')
{
// Custom function
easeFunction = ease;
}
// No custom ease parameters?
if (!easeParams)
{
// Return ease function
return easeFunction;
}
var cloneParams = easeParams.slice(0);
cloneParams.unshift(0);
// Return ease function with custom ease parameters
return function (v)
{
cloneParams[0] = v;
return easeFunction.apply(this, cloneParams);
};
};
module.exports = GetEaseFunction;