text: /**
  * @file    VInterpolate.h
  * @author  Tim Stoddard <tim@gamepopper.co.uk>
  *
  * @section LICENSE
  *
  * MIT License
  *
  * Copyright (c) 2020 Tim Stoddard
  *
  * 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.
  *
  * @section DESCRIPTION
  *
  * Functions for calculating interpolation and easings using Robert Penner's Easing Functions.
  * Implementation based on C++ port by Jesus Gollonet: https://github.com/jesusgollonet/ofpennereasing
  */
  
  #pragma once
  #include <SFML/Graphics/Color.hpp>
  #include <SFML/System/Vector2.hpp>
  #include <SFML/System/Vector3.hpp>
  
  ///A helper class for calculating interpolation using Robert Penner's Easing functions.
  class VInterpolate
  {
  private:
  	static float backIn(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float backOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float backInOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float bounceIn(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float bounceOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float bounceInOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float circIn(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float circOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float circInOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float cubicIn(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float cubicOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float cubicInOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float elasticIn(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float elasticOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float elasticInOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float expoIn(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float expoOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float expoInOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float linear(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float quadIn(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float quadOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float quadInOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float quartIn(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float quartOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float quartInOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float quintIn(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float quintOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float quintInOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float sineIn(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float sineOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  	static float sineInOut(float t = 0.0f, float b = 0.0f, float c = 1.0f, float d = 1.0f);
  
  public:
  
  	///The many types of easing functions, both intro, outtro and inouttros.
  	enum VInterpolateType
  	{
  		InBack,
  		OutBack,
  		InOutBack,
  		InBounce,
  		OutBounce,
  		InOutBounce,
  		InCirc,
  		OutCirc,
  		InOutCirc,
  		InCubic,
  		OutCubic,
  		InOutCubic,
  		InElastic,
  		OutElastic,
  		InOutElastic,
  		InExpo,
  		OutExpo,
  		InOutExpo,
  		Linear,
  		InQuad,
  		OutQuad,
  		InOutQuad,
  		InQuart,
  		OutQuart,
  		InOutQuart,
  		InQuint,
  		OutQuint,
  		InOutQuint,
  		InSine,
  		OutSine,
  		InOutSine,
  		NumInterpolationTypes,
  	};
  
  	/**
  	* Interpolates based on angle in degrees (0 - 360)
  	* @param a Start point.
  	* @param b Finish point.
  	* @param t Current point in time.
  	* @param d Total length of time.
  	* @param type Easing function.
  	*/
  	static float Angle(float a, float b, float t, float d = 1.0f, VInterpolateType type = Linear);
  
  	/**
  	* Interpolates standard float variables.
  	* @param a Start point.
  	* @param b Finish point.
  	* @param t Current point in time.
  	* @param d Total length of time.
  	* @param type Easing function.
  	*/
  	static float Float(float a, float b, float t, float d = 1.0f, VInterpolateType type = Linear);
  
  	/**
  	* Interpolates color values using the sf::Color variable.
  	* @param a Start point.
  	* @param b Finish point.
  	* @param t Current point in time.
  	* @param d Total length of time.
  	* @param type Easing function.
  	*/
  	static sf::Color Color(sf::Color a, sf::Color b, float t, float d = 1.0f, VInterpolateType type = Linear);
  
  	/**
  	* Interpolates two dimensional vector floats using sf::Vector2f.
  	* @param a Start point.
  	* @param b Finish point.
  	* @param t Current point in time.
  	* @param d Total length of time.
  	* @param type Easing function.
  	*/
  	static sf::Vector2f Vector2f(sf::Vector2f a, sf::Vector2f b, float t, float d = 1.0f, VInterpolateType type = Linear);
  
  	/**
  	* Interpolates three dimensional vector floats variables.
  	* @param a Start point.
  	* @param b Finish point.
  	* @param t Current point in time.
  	* @param d Total length of time.
  	* @param type Easing function.
  	*/
  	static sf::Vector3f Vector3f(sf::Vector3f a, sf::Vector3f b, float t, float d = 1.0f, VInterpolateType type = Linear);
  };
  