149 lines
4.5 KiB
C++
149 lines
4.5 KiB
C++
/* Copyright (C) 2012 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef INCLUDED_EASE
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#define INCLUDED_EASE
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/*
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* Straightforward C++ port of Robert Penner's easing equations
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* http://www.robertpenner.com/easing/
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*
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* Copyright (c) 2001 Robert Penner
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification, are permitted
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* provided that the following conditions are met:
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* - Redistributions of source code must retain the above copyright notice, this list of
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* conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright notice, this list of
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* conditions and the following disclaimer in the documentation and/or other materials provided
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* with the distribution.
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* - Neither the name of the author nor the names of contributors may be used to endorse or
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* promote products derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
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* IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <math.h>
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/**
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* Generic easing functions. In each function, the parameters are:
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*
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* @param t Current time in seconds, as a float between 0 and d (inclusive).
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* @param d Total duration of the ease, in seconds. Must be strictly positive.
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* @param b Baseline value (at t = 0).
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* @param c Delta from baseline value to reach the target value (at t = d). I.e., target = b + c.
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*
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* Each function outputs the eased value between 'b' and 'b+c' at time 't'.
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*/
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class Ease
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{
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public:
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static float QuadIn(float t, const float b, const float c, const float d)
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{
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t /= d;
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return c*t*t + b;
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}
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static float QuadOut(float t, const float b, const float c, const float d)
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{
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t /= d;
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return -c * t*(t-2) + b;
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}
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static float QuadInOut(float t, const float b, const float c, const float d)
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{
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t /= d/2;
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if (t < 1)
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return c/2*t*t + b;
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--t;
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return -c/2 * (t*(t-2) - 1) + b;
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}
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static float CubicIn(float t, const float b, const float c, const float d)
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{
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t /= d;
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return c*t*t*t + b;
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}
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static float CubicOut(float t, const float b, const float c, const float d)
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{
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t = t/d - 1;
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return c*(t*t*t + 1) + b;
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}
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static float CubicInOut(float t, const float b, const float c, const float d)
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{
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t /= d/2;
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if (t < 1)
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return c/2*t*t*t + b;
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t -= 2;
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return c/2*(t*t*t + 2) + b;
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}
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static float QuartIn(float t, const float b, const float c, const float d)
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{
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t /= d;
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return c*t*t*t*t + b;
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}
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static float QuartOut(float t, const float b, const float c, const float d)
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{
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t = t/d - 1;
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return -c*(t*t*t*t - 1) + b;
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}
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static float QuartInOut(float t, const float b, const float c, const float d)
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{
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t /= d/2;
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if (t < 1)
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return c/2*t*t*t*t + b;
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t -= 2;
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return -c/2 * (t*t*t*t - 2) + b;
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}
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static float QuintIn(float t, const float b, const float c, const float d)
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{
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t /= d;
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return c*t*t*t*t*t + b;
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}
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static float QuintOut(float t, const float b, const float c, const float d)
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{
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t = t/d - 1;
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return c*(t*t*t*t*t + 1) + b;
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}
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static float QuintInOut(float t, const float b, const float c, const float d)
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{
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t /= d/2;
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if (t < 1)
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return c/2*t*t*t*t*t + b;
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t -= 2;
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return c/2*(t*t*t*t*t + 2) + b;
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}
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};
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#endif // INCLUDED_EASE
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