easing.h

/*
 This file is part of the Tweeny library.

 Copyright (c) 2016-2018 Leonardo G. Lucena de Freitas
 Copyright (c) 2016 Guilherme R. Costa

 Permission is hereby granted, free of charge, to any person obtaining a copy of
 this software and associated documentation files (the "Software"), to deal in
 the Software without restriction, including without limitation the rights to
 use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 the Software, and to permit persons to whom the Software is furnished to do so,
 subject to the following conditions:

 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#ifndef TWEENY_EASING_H
#define TWEENY_EASING_H

#include <cmath>
#include <type_traits>

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

namespace tweeny {
    class easing {
        public:
            static constexpr struct linearEasing {
                template<typename T>
                static typename std::enable_if<std::is_integral<T>::value, T>::type run(float position, T start, T end) {
                    return static_cast<T>(roundf((end - start) * position + start));
                }

                template<typename T>
                static typename std::enable_if<!std::is_integral<T>::value, T>::type run(float position, T start, T end) {
                    return static_cast<T>((end - start) * position + start);
                }
            } linear = linearEasing{};

            static constexpr struct quadraticInEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    return static_cast<T>((end - start) * position * position + start);
                }
            } quadraticIn = quadraticInEasing{};

            static constexpr struct quadraticOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    return static_cast<T>((-(end - start)) * position * (position - 2) + start);
                }
            } quadraticOut = quadraticOutEasing{};

            static constexpr struct quadraticInOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    position *= 2;
                    if (position < 1) {
                        return static_cast<T>(((end - start) / 2) * position * position + start);
                    }

                    --position;
                    return static_cast<T>((-(end - start) / 2) * (position * (position - 2) - 1) + start);
                }
            } quadraticInOut = quadraticInOutEasing{};

            static constexpr struct cubicInEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    return static_cast<T>((end - start) * position * position * position + start);
                }
            } cubicIn = cubicInEasing{};

            static constexpr struct cubicOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    --position;
                    return static_cast<T>((end - start) * (position * position * position + 1) + start);
                }
            } cubicOut = cubicOutEasing{};

            static constexpr struct cubicInOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    position *= 2;
                    if (position < 1) {
                        return static_cast<T>(((end - start) / 2) * position * position * position + start);
                    }
                    position -= 2;
                    return static_cast<T>(((end - start) / 2) * (position * position * position + 2) + start);
                }
            } cubicInOut = cubicInOutEasing{};

            static constexpr struct quarticInEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    return static_cast<T>((end - start) * position * position * position * position + start);
                }
            } quarticIn = quarticInEasing{};

            static constexpr struct quarticOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    --position;
                    return static_cast<T>( -(end - start) * (position * position * position * position - 1) + start);
                }
            } quarticOut = quarticOutEasing{};

            static constexpr struct quarticInOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    position *= 2;
                    if (position < 1) {
                        return static_cast<T>(((end - start) / 2) * (position * position * position * position) +
                                              start);
                    }
                    position -= 2;
                    return static_cast<T>((-(end - start) / 2) * (position * position * position * position - 2) +
                                          start);
                }
            } quarticInOut = quarticInOutEasing{};

            static constexpr struct quinticInEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    return static_cast<T>((end - start) * position * position * position * position * position + start);
                }
            } quinticIn = quinticInEasing{};

            static constexpr struct quinticOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    position--;
                    return static_cast<T>((end - start) * (position * position * position * position * position + 1) +
                                          start);
                }
            } quinticOut = quinticOutEasing{};

            static constexpr struct quinticInOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    position *= 2;
                    if (position < 1) {
                        return static_cast<T>(
                            ((end - start) / 2) * (position * position * position * position * position) +
                            start);
                    }
                    position -= 2;
                    return static_cast<T>(
                        ((end - start) / 2) * (position * position * position * position * position + 2) +
                        start);
                }
            } quinticInOut = quinticInOutEasing{};

            static constexpr struct sinusoidalInEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    return static_cast<T>(-(end - start) * cosf(position * static_cast<float>(M_PI) / 2) + (end - start) + start);
                }
            } sinusoidalIn = sinusoidalInEasing{};

            static constexpr struct sinusoidalOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    return static_cast<T>((end - start) * sinf(position * static_cast<float>(M_PI) / 2) + start);
                }
            } sinusoidalOut = sinusoidalOutEasing{};

            static constexpr struct sinusoidalInOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    return static_cast<T>((-(end - start) / 2) * (cosf(position * static_cast<float>(M_PI)) - 1) + start);
                }
            } sinusoidalInOut = sinusoidalInOutEasing{};

            static constexpr struct exponentialInEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    return static_cast<T>((end - start) * powf(2, 10 * (position - 1)) + start);
                }
            } exponentialIn = exponentialInEasing{};

            static constexpr struct exponentialOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    return static_cast<T>((end - start) * (-powf(2, -10 * position) + 1) + start);
                }
            } exponentialOut = exponentialOutEasing{};

            static constexpr struct exponentialInOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    position *= 2;
                    if (position < 1) {
                        return static_cast<T>(((end - start) / 2) * powf(2, 10 * (position - 1)) + start);
                    }
                    --position;
                    return static_cast<T>(((end - start) / 2) * (-powf(2, -10 * position) + 2) + start);
                }
            } exponentialInOut = exponentialInOutEasing{};

            static constexpr struct circularInEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    return static_cast<T>( -(end - start) * (sqrtf(1 - position * position) - 1) + start );
                }
            } circularIn = circularInEasing{};

            static constexpr struct circularOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    --position;
                    return static_cast<T>((end - start) * (sqrtf(1 - position * position)) + start);
                }
            } circularOut = circularOutEasing{};

            static constexpr struct circularInOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    position *= 2;
                    if (position < 1) {
                        return static_cast<T>((-(end - start) / 2) * (sqrtf(1 - position * position) - 1) + start);
                    }

                    position -= 2;
                    return static_cast<T>(((end - start) / 2) * (sqrtf(1 - position * position) + 1) + start);
                }
            } circularInOut = circularInOutEasing{};

            static constexpr struct bounceInEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    return (end - start) - bounceOut.run((1 - position), T(), end) + start;
                }
            } bounceIn = bounceInEasing{};

            static constexpr struct bounceOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    T c = end - start;
                    if (position < (1 / 2.75f)) {
                        return static_cast<T>(c * (7.5625f * position * position) + start);
                    } else if (position < (2.0f / 2.75f)) {
                        float postFix = position -= (1.5f / 2.75f);
                        return static_cast<T>(c * (7.5625f * (postFix) * position + .75f) + start);
                    } else if (position < (2.5f / 2.75f)) {
                        float postFix = position -= (2.25f / 2.75f);
                        return static_cast<T>(c * (7.5625f * (postFix) * position + .9375f) + start);
                    } else {
                        float postFix = position -= (2.625f / 2.75f);
                        return static_cast<T>(c * (7.5625f * (postFix) * position + .984375f) + start);
                    }
                }
            } bounceOut = bounceOutEasing{};

            static constexpr struct bounceInOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    if (position < 0.5f) return static_cast<T>(bounceIn.run(position * 2, T(), end) * .5f + start);
                    else return static_cast<T>(bounceOut.run((position * 2 - 1), T(), end) * .5f + (end - start) * .5f + start);
                }
            } bounceInOut = bounceInOutEasing{};

            static constexpr struct elasticInEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    if (position <= 0.00001f) return start;
                    if (position >= 0.999f) return end;
                    float p = .3f;
                    float a = end - start;
                    float s = p / 4;
                    float postFix =
                        a * powf(2, 10 * (position -= 1)); // this is a fix, again, with post-increment operators
                    return static_cast<T>(-(postFix * sinf((position - s) * (2 * static_cast<float>(M_PI)) / p)) + start);
                }
            } elasticIn = elasticInEasing{};

            static constexpr struct elasticOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    if (position <= 0.00001f) return start;
                    if (position >= 0.999f) return end;
                    float p = .3f;
                    float a = end - start;
                    float s = p / 4;
                    return static_cast<T>(a * powf(2, -10 * position) * sinf((position - s) * (2 * static_cast<float>(M_PI)) / p) + end);
                }
            } elasticOut = elasticOutEasing{};

            static constexpr struct elasticInOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    if (position <= 0.00001f) return start;
                    if (position >= 0.999f) return end;
                    position *= 2;
                    float p = (.3f * 1.5f);
                    float a = end - start;
                    float s = p / 4;
                    float postFix;

                    if (position < 1) {
                        postFix = a * powf(2, 10 * (position -= 1)); // postIncrement is evil
                        return static_cast<T>(-0.5f * (postFix * sinf((position - s) * (2 * static_cast<float>(M_PI)) / p)) + start);
                    }
                    postFix = a * powf(2, -10 * (position -= 1)); // postIncrement is evil
                    return static_cast<T>(postFix * sinf((position - s) * (2 * static_cast<float>(M_PI)) / p) * .5f + end);
                }
            } elasticInOut = elasticInOutEasing{};

            static constexpr struct backInEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    float s = 1.70158f;
                    float postFix = position;
                    return static_cast<T>((end - start) * (postFix) * position * ((s + 1) * position - s) + start);
                }
            } backIn = backInEasing{};

            static constexpr struct backOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    float s = 1.70158f;
                    position -= 1;
                    return static_cast<T>((end - start) * ((position) * position * ((s + 1) * position + s) + 1) + start);
                }
            } backOut = backOutEasing{};

            static constexpr struct backInOutEasing {
                template<typename T>
                static T run(float position, T start, T end) {
                    float s = 1.70158f;
                    float t = position;
                    T b = start;
                    T c = end - start;
                    float d = 1;
                    s *= (1.525f);
                    if ((t /= d / 2) < 1) return static_cast<T>(c / 2 * (t * t * (((s) + 1) * t - s)) + b);
                    float postFix = t -= 2;
                    return static_cast<T>(c / 2 * ((postFix) * t * (((s) + 1) * t + s) + 2) + b);
                }
            } backInOut = backInOutEasing{};
    };
}
#endif //TWEENY_EASING_H