raylib/src/easings.h
2017-03-19 12:52:58 +01:00

253 lines
9.2 KiB
C

/*******************************************************************************************
*
* raylib easings (header only file)
*
* Useful easing functions for values animation
*
* This header uses:
* #define EASINGS_STATIC_INLINE // Inlines all functions code, so it runs faster.
* // This requires lots of memory on system.
* How to use:
* The four inputs t,b,c,d are defined as follows:
* t = current time (in any unit measure, but same unit as duration)
* b = starting value to interpolate
* c = the total change in value of b that needs to occur
* d = total time it should take to complete (duration)
*
* Example:
*
* int currentTime = 0;
* int duration = 100;
* float startPositionX = 0.0f;
* float finalPositionX = 30.0f;
* float currentPositionX = startPositionX;
*
* while (currentPositionX < finalPositionX)
* {
* currentPositionX = EaseSineIn(currentTime, startPositionX, finalPositionX - startPositionX, duration);
* currentTime++;
* }
*
* A port of Robert Penner's easing equations to C (http://robertpenner.com/easing/)
*
* Robert Penner License
* ---------------------------------------------------------------------------------
* Open source under the BSD License.
*
* Copyright (c) 2001 Robert Penner. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of the author nor the names of contributors may be used
* to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ---------------------------------------------------------------------------------
*
* Copyright (c) 2015 Ramon Santamaria
*
* This software is provided "as-is", without any express or implied warranty. In no event
* will the authors be held liable for any damages arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose, including commercial
* applications, and to alter it and redistribute it freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not claim that you
* wrote the original software. If you use this software in a product, an acknowledgment
* in the product documentation would be appreciated but is not required.
*
* 2. Altered source versions must be plainly marked as such, and must not be misrepresented
* as being the original software.
*
* 3. This notice may not be removed or altered from any source distribution.
*
**********************************************************************************************/
#ifndef EASINGS_H
#define EASINGS_H
#define EASINGS_STATIC_INLINE // NOTE: By default, compile functions as static inline
#if defined(EASINGS_STATIC_INLINE)
#define EASEDEF static inline
#else
#define EASEDEF extern
#endif
#include <math.h> // Required for: sin(), cos(), sqrt(), pow()
#ifdef __cplusplus
extern "C" { // Prevents name mangling of functions
#endif
// Linear Easing functions
EASEDEF float EaseLinearNone(float t, float b, float c, float d) { return (c*t/d + b); }
EASEDEF float EaseLinearIn(float t, float b, float c, float d) { return (c*t/d + b); }
EASEDEF float EaseLinearOut(float t, float b, float c, float d) { return (c*t/d + b); }
EASEDEF float EaseLinearInOut(float t,float b, float c, float d) { return (c*t/d + b); }
// Sine Easing functions
EASEDEF float EaseSineIn(float t, float b, float c, float d) { return (-c*cos(t/d*(PI/2)) + c + b); }
EASEDEF float EaseSineOut(float t, float b, float c, float d) { return (c*sin(t/d*(PI/2)) + b); }
EASEDEF float EaseSineInOut(float t, float b, float c, float d) { return (-c/2*(cos(PI*t/d) - 1) + b); }
// Circular Easing functions
EASEDEF float EaseCircIn(float t, float b, float c, float d) { return (-c*(sqrt(1 - (t/=d)*t) - 1) + b); }
EASEDEF float EaseCircOut(float t, float b, float c, float d) { return (c*sqrt(1 - (t=t/d-1)*t) + b); }
EASEDEF float EaseCircInOut(float t, float b, float c, float d)
{
if ((t/=d/2) < 1) return (-c/2*(sqrt(1 - t*t) - 1) + b);
return (c/2*(sqrt(1 - t*(t-=2)) + 1) + b);
}
// Cubic Easing functions
EASEDEF float EaseCubicIn(float t, float b, float c, float d) { return (c*(t/=d)*t*t + b); }
EASEDEF float EaseCubicOut(float t, float b, float c, float d) { return (c*((t=t/d-1)*t*t + 1) + b); }
EASEDEF float EaseCubicInOut(float t, float b, float c, float d)
{
if ((t/=d/2) < 1) return (c/2*t*t*t + b);
return (c/2*((t-=2)*t*t + 2) + b);
}
// Quadratic Easing functions
EASEDEF float EaseQuadIn(float t, float b, float c, float d) { return (c*(t/=d)*t + b); }
EASEDEF float EaseQuadOut(float t, float b, float c, float d) { return (-c*(t/=d)*(t-2) + b); }
EASEDEF float EaseQuadInOut(float t, float b, float c, float d)
{
if ((t/=d/2) < 1) return (((c/2)*(t*t)) + b);
return (-c/2*(((t-2)*(--t)) - 1) + b);
}
// Exponential Easing functions
EASEDEF float EaseExpoIn(float t, float b, float c, float d) { return (t == 0) ? b : (c*pow(2, 10*(t/d - 1)) + b); }
EASEDEF float EaseExpoOut(float t, float b, float c, float d) { return (t == d) ? (b + c) : (c*(-pow(2, -10*t/d) + 1) + b); }
EASEDEF float EaseExpoInOut(float t, float b, float c, float d)
{
if (t == 0) return b;
if (t == d) return (b + c);
if ((t/=d/2) < 1) return (c/2*pow(2, 10*(t - 1)) + b);
return (c/2*(-pow(2, -10*--t) + 2) + b);
}
// Back Easing functions
EASEDEF float EaseBackIn(float t, float b, float c, float d)
{
float s = 1.70158f;
float postFix = t/=d;
return (c*(postFix)*t*((s + 1)*t - s) + b);
}
EASEDEF float EaseBackOut(float t, float b, float c, float d)
{
float s = 1.70158f;
return (c*((t=t/d-1)*t*((s + 1)*t + s) + 1) + b);
}
EASEDEF float EaseBackInOut(float t, float b, float c, float d)
{
float s = 1.70158f;
if ((t/=d/2) < 1) return (c/2*(t*t*(((s*=(1.525f)) + 1)*t - s)) + b);
float postFix = t-=2;
return (c/2*((postFix)*t*(((s*=(1.525f)) + 1)*t + s) + 2) + b);
}
// Bounce Easing functions
EASEDEF float EaseBounceOut(float t, float b, float c, float d)
{
if ((t/=d) < (1/2.75f))
{
return (c*(7.5625f*t*t) + b);
}
else if (t < (2/2.75f))
{
float postFix = t-=(1.5f/2.75f);
return (c*(7.5625f*(postFix)*t + 0.75f) + b);
}
else if (t < (2.5/2.75))
{
float postFix = t-=(2.25f/2.75f);
return (c*(7.5625f*(postFix)*t + 0.9375f) + b);
}
else
{
float postFix = t-=(2.625f/2.75f);
return (c*(7.5625f*(postFix)*t + 0.984375f) + b);
}
}
EASEDEF float EaseBounceIn(float t, float b, float c, float d) { return (c - EaseBounceOut(d-t, 0, c, d) + b); }
EASEDEF float EaseBounceInOut(float t, float b, float c, float d)
{
if (t < d/2) return (EaseBounceIn(t*2, 0, c, d)*0.5f + b);
else return (EaseBounceOut(t*2-d, 0, c, d)*0.5f + c*0.5f + b);
}
// Elastic Easing functions
EASEDEF float EaseElasticIn(float t, float b, float c, float d)
{
if (t == 0) return b;
if ((t/=d) == 1) return (b + c);
float p = d*0.3f;
float a = c;
float s = p/4;
float postFix = a*pow(2, 10*(t-=1));
return (-(postFix*sin((t*d-s)*(2*PI)/p )) + b);
}
EASEDEF float EaseElasticOut(float t, float b, float c, float d)
{
if (t == 0) return b;
if ((t/=d) == 1) return (b + c);
float p = d*0.3f;
float a = c;
float s = p/4;
return (a*pow(2,-10*t)*sin((t*d-s)*(2*PI)/p) + c + b);
}
EASEDEF float EaseElasticInOut(float t, float b, float c, float d)
{
if (t == 0) return b;
if ((t/=d/2) == 2) return (b + c);
float p = d*(0.3f*1.5f);
float a = c;
float s = p/4;
if (t < 1)
{
float postFix = a*pow(2, 10*(t-=1));
return -0.5f*(postFix*sin((t*d-s)*(2*PI)/p)) + b;
}
float postFix = a*pow(2, -10*(t-=1));
return (postFix*sin((t*d-s)*(2*PI)/p)*0.5f + c + b);
}
#ifdef __cplusplus
}
#endif
#endif // EASINGS_H