/****************************************************************************
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Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.
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https://www.cocos.com/
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated engine source code (the "Software"), a limited,
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worldwide, royalty-free, non-assignable, revocable and non-exclusive license
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to use Cocos Creator solely to develop games on your target platforms. You shall
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not use Cocos Creator software for developing other software or tools that's
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used for developing games. You are not granted to publish, distribute,
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sublicense, and/or sell copies of Cocos Creator.
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The software or tools in this License Agreement are licensed, not sold.
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Xiamen Yaji Software Co., Ltd. reserves all rights not expressly granted to you.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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****************************************************************************/
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var easing = {
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constant: function () { return 0; },
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linear: function (k) { return k; },
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// quad
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// easing equation function for a quadratic (t^2)
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// @param t: Current time (in frames or seconds).
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// @return: The correct value.
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quadIn: function (k) { return k * k; },
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quadOut: function (k) { return k * ( 2 - k ); },
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quadInOut: function (k) {
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if (( k *= 2 ) < 1) {
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return 0.5 * k * k;
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}
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return -0.5 * ( --k * ( k - 2 ) - 1 );
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},
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// cubic
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// easing equation function for a cubic (t^3)
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// @param t: Current time (in frames or seconds).
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// @return: The correct value.
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cubicIn: function (k) { return k * k * k; },
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cubicOut: function (k) { return --k * k * k + 1; },
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cubicInOut: function (k) {
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if (( k *= 2 ) < 1) {
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return 0.5 * k * k * k;
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}
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return 0.5 * ( ( k -= 2 ) * k * k + 2 );
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},
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// quart
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// easing equation function for a quartic (t^4)
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// @param t: Current time (in frames or seconds).
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// @return: The correct value.
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quartIn: function (k) { return k * k * k * k; },
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quartOut: function (k) { return 1 - ( --k * k * k * k ); },
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quartInOut: function (k) {
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if (( k *= 2 ) < 1) {
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return 0.5 * k * k * k * k;
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}
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return -0.5 * ( ( k -= 2 ) * k * k * k - 2 );
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},
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// quint
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// easing equation function for a quintic (t^5)
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// @param t: Current time (in frames or seconds).
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// @return: The correct value.
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quintIn: function (k) { return k * k * k * k * k; },
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quintOut: function (k) { return --k * k * k * k * k + 1; },
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quintInOut: function (k) {
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if (( k *= 2 ) < 1) {
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return 0.5 * k * k * k * k * k;
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}
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return 0.5 * ( ( k -= 2 ) * k * k * k * k + 2 );
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},
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// sine
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// easing equation function for a sinusoidal (sin(t))
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// @param t: Current time (in frames or seconds).
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// @return: The correct value.
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sineIn: function (k) { return 1 - Math.cos(k * Math.PI / 2); },
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sineOut: function (k) { return Math.sin(k * Math.PI / 2); },
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sineInOut: function (k) { return 0.5 * ( 1 - Math.cos(Math.PI * k) ); },
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// expo
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// easing equation function for an exponential (2^t)
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// param t: Current time (in frames or seconds).
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// return: The correct value.
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expoIn: function (k) { return k === 0 ? 0 : Math.pow(1024, k - 1); },
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expoOut: function (k) { return k === 1 ? 1 : 1 - Math.pow(2, -10 * k); },
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expoInOut: function (k) {
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if (k === 0) {
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return 0;
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}
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if (k === 1) {
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return 1;
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}
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if (( k *= 2 ) < 1) {
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return 0.5 * Math.pow(1024, k - 1);
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}
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return 0.5 * ( -Math.pow(2, -10 * ( k - 1 )) + 2 );
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},
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// circ
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// easing equation function for a circular (sqrt(1-t^2))
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// @param t: Current time (in frames or seconds).
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// @return: The correct value.
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circIn: function (k) { return 1 - Math.sqrt(1 - k * k); },
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circOut: function (k) { return Math.sqrt(1 - ( --k * k )); },
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circInOut: function (k) {
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if (( k *= 2 ) < 1) {
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return -0.5 * ( Math.sqrt(1 - k * k) - 1);
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}
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return 0.5 * ( Math.sqrt(1 - ( k -= 2) * k) + 1);
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},
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// elastic
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// easing equation function for an elastic (exponentially decaying sine wave)
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// @param t: Current time (in frames or seconds).
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// @return: The correct value.
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// recommand value: elastic (t)
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elasticIn: function (k) {
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var s, a = 0.1, p = 0.4;
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if (k === 0) {
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return 0;
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}
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if (k === 1) {
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return 1;
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}
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if (!a || a < 1) {
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a = 1;
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s = p / 4;
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}
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else {
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s = p * Math.asin(1 / a) / ( 2 * Math.PI );
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}
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return -( a * Math.pow(2, 10 * ( k -= 1 )) * Math.sin(( k - s ) * ( 2 * Math.PI ) / p) );
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},
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elasticOut: function (k) {
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var s, a = 0.1, p = 0.4;
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if (k === 0) {
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return 0;
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}
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if (k === 1) {
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return 1;
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}
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if (!a || a < 1) {
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a = 1;
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s = p / 4;
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}
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else {
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s = p * Math.asin(1 / a) / ( 2 * Math.PI );
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}
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return ( a * Math.pow(2, -10 * k) * Math.sin(( k - s ) * ( 2 * Math.PI ) / p) + 1 );
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},
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elasticInOut: function (k) {
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var s, a = 0.1, p = 0.4;
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if (k === 0) {
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return 0;
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}
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if (k === 1) {
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return 1;
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}
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if (!a || a < 1) {
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a = 1;
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s = p / 4;
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}
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else {
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s = p * Math.asin(1 / a) / ( 2 * Math.PI );
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}
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if (( k *= 2 ) < 1) {
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return -0.5 *
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( a * Math.pow(2, 10 * ( k -= 1 )) * Math.sin(( k - s ) * ( 2 * Math.PI ) / p) );
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}
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return a * Math.pow(2, -10 * ( k -= 1 )) * Math.sin(( k - s ) * ( 2 * Math.PI ) / p) * 0.5 + 1;
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},
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// back
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// easing equation function for a back (overshooting cubic easing: (s+1)*t^3 - s*t^2)
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// @param t: Current time (in frames or seconds).
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// @return: The correct value.
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backIn: function (k) {
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var s = 1.70158;
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return k * k * ( ( s + 1 ) * k - s );
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},
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backOut: function (k) {
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var s = 1.70158;
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return --k * k * ( ( s + 1 ) * k + s ) + 1;
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},
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backInOut: function (k) {
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var s = 1.70158 * 1.525;
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if (( k *= 2 ) < 1) {
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return 0.5 * ( k * k * ( ( s + 1 ) * k - s ) );
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}
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return 0.5 * ( ( k -= 2 ) * k * ( ( s + 1 ) * k + s ) + 2 );
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},
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// bounce
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// easing equation function for a bounce (exponentially decaying parabolic bounce)
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// @param t: Current time (in frames or seconds).
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// @return: The correct value.
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bounceOut: function (k) {
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if (k < ( 1 / 2.75 )) {
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return 7.5625 * k * k;
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}
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else if (k < ( 2 / 2.75 )) {
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return 7.5625 * ( k -= ( 1.5 / 2.75 ) ) * k + 0.75;
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}
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else if (k < ( 2.5 / 2.75 )) {
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return 7.5625 * ( k -= ( 2.25 / 2.75 ) ) * k + 0.9375;
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}
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else {
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return 7.5625 * ( k -= ( 2.625 / 2.75 ) ) * k + 0.984375;
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}
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},
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// smooth
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// t<=0: 0 | 0<t<1: 3*t^2 - 2*t^3 | t>=1: 1
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smooth: function (t) {
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if (t <= 0) {
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return 0;
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}
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if (t >= 1) {
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return 1;
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}
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return t * t * (3 - 2 * t);
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},
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// fade
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// t<=0: 0 | 0<t<1: 6*t^5 - 15*t^4 + 10*t^3 | t>=1: 1
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fade: function (t) {
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if (t <= 0) {
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return 0;
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}
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if (t >= 1) {
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return 1;
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}
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return t * t * t * (t * (t * 6 - 15) + 10);
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},
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};
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function _makeOutIn (fnIn, fnOut) {
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return function (k) {
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if (k < 0.5) {
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return fnOut(k * 2) / 2;
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}
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return fnIn(2 * k - 1) / 2 + 0.5;
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};
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}
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easing.quadOutIn = _makeOutIn(easing.quadIn, easing.quadOut);
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easing.cubicOutIn = _makeOutIn(easing.cubicIn, easing.cubicOut);
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easing.quartOutIn = _makeOutIn(easing.quartIn, easing.quartOut);
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easing.quintOutIn = _makeOutIn(easing.quintIn, easing.quintOut);
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easing.sineOutIn = _makeOutIn(easing.sineIn, easing.sineOut);
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easing.expoOutIn = _makeOutIn(easing.expoIn, easing.expoOut);
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easing.circOutIn = _makeOutIn(easing.circIn, easing.circOut);
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easing.backOutIn = _makeOutIn(easing.backIn, easing.backOut);
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easing.backOutIn = _makeOutIn(easing.backIn, easing.backOut);
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easing.bounceIn = function (k) { return 1 - easing.bounceOut(1 - k); };
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easing.bounceInOut = function (k) {
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if (k < 0.5) {
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return easing.bounceIn(k * 2) * 0.5;
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}
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return easing.bounceOut(k * 2 - 1) * 0.5 + 0.5;
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};
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easing.bounceOutIn = _makeOutIn(easing.bounceIn, easing.bounceOut);
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cc.easing = module.exports = easing;
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