easing.h

//
//  easing.h
//
//  Copyright (c) 2011, Auerhaus Development, LLC
//
//  This program is free software. It comes without any warranty, to
//  the extent permitted by applicable law. You can redistribute it
//  and/or modify it under the terms of the Do What The Fuck You Want
//  To Public License, Version 2, as published by Sam Hocevar. See
//  http://sam.zoy.org/wtfpl/COPYING for more details.
//

#ifndef AH_EASING_H
#define AH_EASING_H

#if defined(__LP64__) && !defined(AH_EASING_USE_DBL_PRECIS)
#define AH_EASING_USE_DBL_PRECIS
#endif

#ifdef AH_EASING_USE_DBL_PRECIS
#define AH_FLOAT_TYPE float
#else
#define AH_FLOAT_TYPE float
#endif
typedef AH_FLOAT_TYPE AHFloat;

#if defined __cplusplus
extern "C" {
#endif

#ifndef M_PI
#define M_PI 3.14159265358979323846 /* pi */
#endif
#ifndef M_PI_2
#define M_PI_2 1.57079632679489661923 /* pi/2 */
#endif

typedef AHFloat (*AHEasingFunction)(AHFloat);

// Linear interpolation (no easing)
AHFloat LinearInterpolation(AHFloat p);

// Quadratic easing; p^2
AHFloat QuadraticEaseIn(AHFloat p);
AHFloat QuadraticEaseOut(AHFloat p);
AHFloat QuadraticEaseInOut(AHFloat p);

// Cubic easing; p^3
AHFloat CubicEaseIn(AHFloat p);
AHFloat CubicEaseOut(AHFloat p);
AHFloat CubicEaseInOut(AHFloat p);

// Quartic easing; p^4
AHFloat QuarticEaseIn(AHFloat p);
AHFloat QuarticEaseOut(AHFloat p);
AHFloat QuarticEaseInOut(AHFloat p);

// Quintic easing; p^5
AHFloat QuinticEaseIn(AHFloat p);
AHFloat QuinticEaseOut(AHFloat p);
AHFloat QuinticEaseInOut(AHFloat p);

// Sine wave easing; sin(p * PI/2)
AHFloat SineEaseIn(AHFloat p);
AHFloat SineEaseOut(AHFloat p);
AHFloat SineEaseInOut(AHFloat p);

// Circular easing; sqrt(1 - p^2)
AHFloat CircularEaseIn(AHFloat p);
AHFloat CircularEaseOut(AHFloat p);
AHFloat CircularEaseInOut(AHFloat p);

// Exponential easing, base 2
AHFloat ExponentialEaseIn(AHFloat p);
AHFloat ExponentialEaseOut(AHFloat p);
AHFloat ExponentialEaseInOut(AHFloat p);

// Exponentially-damped sine wave easing
AHFloat ElasticEaseIn(AHFloat p);
AHFloat ElasticEaseOut(AHFloat p);
AHFloat ElasticEaseInOut(AHFloat p);

// Overshooting cubic easing;
AHFloat BackEaseIn(AHFloat p);
AHFloat BackEaseOut(AHFloat p);
AHFloat BackEaseInOut(AHFloat p);

// Exponentially-decaying bounce easing
AHFloat BounceEaseIn(AHFloat p);
AHFloat BounceEaseOut(AHFloat p);
AHFloat BounceEaseInOut(AHFloat p);

#ifdef __cplusplus
}
#endif

#endif