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A single file tween library in C# with support built in for XNA and Unity data types. MIT License.
// TinyTween.cs
//
// Copyright (c) 2013 Nick Gravelyn
//
// 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.
//
// For Unity, we can check all the individual platform defines to infer the environment.
#if UNITY_EDITOR || UNITY_STANDALONE_OSX || UNITY_DASHBOARD_WIDGET || UNITY_STANDALONE_WIN || UNITY_STANDALONE_LINUX || UNITY_WEBPLAYER || UNITY_WII || UNITY_IPHONE || UNITY_ANDROID || UNITY_PS3 || UNITY_XBOX360 || UNITY_NACL || UNITY_FLASH
#define UNITY
#else
// For XNA, you can either go into the project and add 'XNA' to the Build defines list or you can uncomment the following line.
//#define XNA
#endif
using System;
// XNA and Unity have such similar APIs we can use the same code by just swapping the namespaces.
#if XNA
using Microsoft.Xna.Framework;
#elif UNITY
using UnityEngine;
#endif
namespace TinyTween
{
/// <summary>
/// Takes in progress which is the percentage of the tween complete and returns
/// the interpolation value that is fed into the lerp function for the tween.
/// </summary>
/// <remarks>
/// Scale functions are used to define how the tween should occur. Examples would be linear,
/// easing in quadratic, or easing out circular. You can implement your own scale function
/// or use one of the many defined in the ScaleFuncs static class.
/// </remarks>
/// <param name="progress">The percentage of the tween complete in the range [0, 1].</param>
/// <returns>The scale value used to lerp between the tween's start and end values</returns>
public delegate float ScaleFunc(float progress);
/// <summary>
/// Standard linear interpolation function: "start + (end - start) * progress"
/// </summary>
/// <remarks>
/// In a language like C++ we wouldn't need this delegate at all. Templates in C++ would allow us
/// to simply write "start + (end - start) * progress" in the tween class and the compiler would
/// take care of enforcing that the type supported those operators. Unfortunately C#'s generics
/// are not so powerful so instead we must have the user provide the interpolation function.
///
/// Thankfully frameworks like XNA and Unity provide lerp functions on their primitive math types
/// which means that for most users there is nothing specific to do here. Additionally this file
/// provides concrete implementations of tweens for vectors, colors, and more for XNA and Unity
/// users, lessening the burden even more.
/// </remarks>
/// <typeparam name="T">The type to interpolate.</typeparam>
/// <param name="start">The starting value.</param>
/// <param name="end">The ending value.</param>
/// <param name="progress">The interpolation progress.</param>
/// <returns>The interpolated value, generally using "start + (end - start) * progress"</returns>
public delegate T LerpFunc<T>(T start, T end, float progress);
/// <summary>
/// State of an ITween object
/// </summary>
public enum TweenState
{
/// <summary>
/// The tween is running.
/// </summary>
Running,
/// <summary>
/// The tween is paused.
/// </summary>
Paused,
/// <summary>
/// The tween is stopped.
/// </summary>
Stopped
}
/// <summary>
/// The behavior to use when manually stopping a tween.
/// </summary>
public enum StopBehavior
{
/// <summary>
/// Does not change the current value.
/// </summary>
AsIs,
/// <summary>
/// Forces the tween progress to the end value.
/// </summary>
ForceComplete
}
/// <summary>
/// Interface for a tween object.
/// </summary>
public interface ITween
{
/// <summary>
/// Gets the current state of the tween.
/// </summary>
TweenState State { get; }
/// <summary>
/// Pauses the tween.
/// </summary>
void Pause();
/// <summary>
/// Resumes the paused tween.
/// </summary>
void Resume();
/// <summary>
/// Stops the tween.
/// </summary>
/// <param name="stopBehavior">The behavior to use to handle the stop.</param>
void Stop(StopBehavior stopBehavior);
/// <summary>
/// Updates the tween.
/// </summary>
/// <param name="elapsedTime">The elapsed time to add to the tween.</param>
void Update(float elapsedTime);
}
/// <summary>
/// Interface for a tween object that handles a specific type.
/// </summary>
/// <typeparam name="T">The type to tween.</typeparam>
public interface ITween<T> : ITween
where T : struct
{
/// <summary>
/// Gets the current value of the tween.
/// </summary>
T CurrentValue { get; }
/// <summary>
/// Starts a tween.
/// </summary>
/// <param name="start">The start value.</param>
/// <param name="end">The end value.</param>
/// <param name="duration">The duration of the tween.</param>
/// <param name="scaleFunc">A function used to scale progress over time.</param>
void Start(T start, T end, float duration, ScaleFunc scaleFunc);
}
/// <summary>
/// A concrete implementation of a tween object.
/// </summary>
/// <typeparam name="T">The type to tween.</typeparam>
public class Tween<T> : ITween<T>
where T : struct
{
private readonly LerpFunc<T> lerpFunc;
private float currentTime;
private float duration;
private ScaleFunc scaleFunc;
private TweenState state;
private T start;
private T end;
private T value;
/// <summary>
/// Gets the current time of the tween.
/// </summary>
public float CurrentTime { get { return currentTime; } }
/// <summary>
/// Gets the duration of the tween.
/// </summary>
public float Duration { get { return duration; } }
/// <summary>
/// Gets the current state of the tween.
/// </summary>
public TweenState State { get { return state; } }
/// <summary>
/// Gets the starting value of the tween.
/// </summary>
public T StartValue { get { return start; } }
/// <summary>
/// Gets the ending value of the tween.
/// </summary>
public T EndValue { get { return end; } }
/// <summary>
/// Gets the current value of the tween.
/// </summary>
public T CurrentValue { get { return value; } }
/// <summary>
/// Initializes a new Tween with a given lerp function.
/// </summary>
/// <remarks>
/// C# generics are good but not good enough. We need a delegate to know how to
/// interpolate between the start and end values for the given type.
/// </remarks>
/// <param name="lerpFunc">The interpolation function for the tween type.</param>
public Tween(LerpFunc<T> lerpFunc)
{
this.lerpFunc = lerpFunc;
state = TweenState.Stopped;
}
/// <summary>
/// Starts a tween.
/// </summary>
/// <param name="start">The start value.</param>
/// <param name="end">The end value.</param>
/// <param name="duration">The duration of the tween.</param>
/// <param name="scaleFunc">A function used to scale progress over time.</param>
public void Start(T start, T end, float duration, ScaleFunc scaleFunc)
{
if (duration <= 0)
{
throw new ArgumentException("duration must be greater than 0");
}
if (scaleFunc == null)
{
throw new ArgumentNullException("scaleFunc");
}
currentTime = 0;
this.duration = duration;
this.scaleFunc = scaleFunc;
state = TweenState.Running;
this.start = start;
this.end = end;
UpdateValue();
}
/// <summary>
/// Pauses the tween.
/// </summary>
public void Pause()
{
if (state == TweenState.Running)
{
state = TweenState.Paused;
}
}
/// <summary>
/// Resumes the paused tween.
/// </summary>
public void Resume()
{
if (state == TweenState.Paused)
{
state = TweenState.Running;
}
}
/// <summary>
/// Stops the tween.
/// </summary>
/// <param name="stopBehavior">The behavior to use to handle the stop.</param>
public void Stop(StopBehavior stopBehavior)
{
state = TweenState.Stopped;
if (stopBehavior == StopBehavior.ForceComplete)
{
currentTime = duration;
UpdateValue();
}
}
/// <summary>
/// Updates the tween.
/// </summary>
/// <param name="elapsedTime">The elapsed time to add to the tween.</param>
public void Update(float elapsedTime)
{
if (state != TweenState.Running)
{
return;
}
currentTime += elapsedTime;
if (currentTime >= duration)
{
currentTime = duration;
state = TweenState.Stopped;
}
UpdateValue();
}
/// <summary>
/// Helper that uses the current time, duration, and delegates to update the current value.
/// </summary>
private void UpdateValue()
{
value = lerpFunc(start, end, scaleFunc(currentTime / duration));
}
}
/// <summary>
/// Object used to tween float values.
/// </summary>
public class FloatTween : Tween<float>
{
private static float LerpFloat(float start, float end, float progress) { return start + (end - start) * progress; }
// Static readonly delegate to avoid multiple delegate allocations
private static readonly LerpFunc<float> LerpFunc = LerpFloat;
/// <summary>
/// Initializes a new FloatTween instance.
/// </summary>
public FloatTween() : base(LerpFunc) { }
}
// If XNA or Unity we can leverage their types to create more tween types to simplify usage.
#if XNA || UNITY
/// <summary>
/// Object used to tween Vector2 values.
/// </summary>
public class Vector2Tween : Tween<Vector2>
{
// Static readonly delegate to avoid multiple delegate allocations
private static readonly LerpFunc<Vector2> LerpFunc = Vector2.Lerp;
/// <summary>
/// Initializes a new Vector2Tween instance.
/// </summary>
public Vector2Tween() : base(LerpFunc) { }
}
/// <summary>
/// Object used to tween Vector3 values.
/// </summary>
public class Vector3Tween : Tween<Vector3>
{
// Static readonly delegate to avoid multiple delegate allocations
private static readonly LerpFunc<Vector3> LerpFunc = Vector3.Lerp;
/// <summary>
/// Initializes a new Vector3Tween instance.
/// </summary>
public Vector3Tween() : base(LerpFunc) { }
}
/// <summary>
/// Object used to tween Vector4 values.
/// </summary>
public class Vector4Tween : Tween<Vector4>
{
// Static readonly delegate to avoid multiple delegate allocations
private static readonly LerpFunc<Vector4> LerpFunc = Vector4.Lerp;
/// <summary>
/// Initializes a new Vector4Tween instance.
/// </summary>
public Vector4Tween() : base(LerpFunc) { }
}
/// <summary>
/// Object used to tween Color values.
/// </summary>
public class ColorTween : Tween<Color>
{
// Static readonly delegate to avoid multiple delegate allocations
private static readonly LerpFunc<Color> LerpFunc = Color.Lerp;
/// <summary>
/// Initializes a new ColorTween instance.
/// </summary>
public ColorTween() : base(LerpFunc) { }
}
/// <summary>
/// Object used to tween Quaternion values.
/// </summary>
public class QuaternionTween : Tween<Quaternion>
{
// Static readonly delegate to avoid multiple delegate allocations
private static readonly LerpFunc<Quaternion> LerpFunc = Quaternion.Lerp;
/// <summary>
/// Initializes a new QuaternionTween instance.
/// </summary>
public QuaternionTween() : base(LerpFunc) { }
}
#endif
/// <summary>
/// Defines a set of premade scale functions for use with tweens.
/// </summary>
/// <remarks>
/// To avoid excess allocations of delegates, the public members of ScaleFuncs are already
/// delegates that reference private methods.
///
/// Implementations based on http://theinstructionlimit.com/flash-style-tweeneasing-functions-in-c
/// which are based on http://www.robertpenner.com/easing/
/// </remarks>
public static class ScaleFuncs
{
/// <summary>
/// A linear progress scale function.
/// </summary>
public static readonly ScaleFunc Linear = LinearImpl;
/// <summary>
/// A quadratic (x^2) progress scale function that eases in.
/// </summary>
public static readonly ScaleFunc QuadraticEaseIn = QuadraticEaseInImpl;
/// <summary>
/// A quadratic (x^2) progress scale function that eases out.
/// </summary>
public static readonly ScaleFunc QuadraticEaseOut = QuadraticEaseOutImpl;
/// <summary>
/// A quadratic (x^2) progress scale function that eases in and out.
/// </summary>
public static readonly ScaleFunc QuadraticEaseInOut = QuadraticEaseInOutImpl;
/// <summary>
/// A cubic (x^3) progress scale function that eases in.
/// </summary>
public static readonly ScaleFunc CubicEaseIn = CubicEaseInImpl;
/// <summary>
/// A cubic (x^3) progress scale function that eases out.
/// </summary>
public static readonly ScaleFunc CubicEaseOut = CubicEaseOutImpl;
/// <summary>
/// A cubic (x^3) progress scale function that eases in and out.
/// </summary>
public static readonly ScaleFunc CubicEaseInOut = CubicEaseInOutImpl;
/// <summary>
/// A quartic (x^4) progress scale function that eases in.
/// </summary>
public static readonly ScaleFunc QuarticEaseIn = QuarticEaseInImpl;
/// <summary>
/// A quartic (x^4) progress scale function that eases out.
/// </summary>
public static readonly ScaleFunc QuarticEaseOut = QuarticEaseOutImpl;
/// <summary>
/// A quartic (x^4) progress scale function that eases in and out.
/// </summary>
public static readonly ScaleFunc QuarticEaseInOut = QuarticEaseInOutImpl;
/// <summary>
/// A quintic (x^5) progress scale function that eases in.
/// </summary>
public static readonly ScaleFunc QuinticEaseIn = QuinticEaseInImpl;
/// <summary>
/// A quintic (x^5) progress scale function that eases out.
/// </summary>
public static readonly ScaleFunc QuinticEaseOut = QuinticEaseOutImpl;
/// <summary>
/// A quintic (x^5) progress scale function that eases in and out.
/// </summary>
public static readonly ScaleFunc QuinticEaseInOut = QuinticEaseInOutImpl;
/// <summary>
/// A sinusoidal progress scale function that eases in.
/// </summary>
public static readonly ScaleFunc SineEaseIn = SineEaseInImpl;
/// <summary>
/// A sinusoidal progress scale function that eases out.
/// </summary>
public static readonly ScaleFunc SineEaseOut = SineEaseOutImpl;
/// <summary>
/// A sinusoidal progress scale function that eases in and out.
/// </summary>
public static readonly ScaleFunc SineEaseInOut = SineEaseInOutImpl;
private const float Pi = (float)Math.PI;
private const float HalfPi = Pi / 2f;
private static float LinearImpl(float progress) { return progress; }
private static float QuadraticEaseInImpl(float progress) { return EaseInPower(progress, 2); }
private static float QuadraticEaseOutImpl(float progress) { return EaseOutPower(progress, 2); }
private static float QuadraticEaseInOutImpl(float progress) { return EaseInOutPower(progress, 2); }
private static float CubicEaseInImpl(float progress) { return EaseInPower(progress, 3); }
private static float CubicEaseOutImpl(float progress) { return EaseOutPower(progress, 3); }
private static float CubicEaseInOutImpl(float progress) { return EaseInOutPower(progress, 3); }
private static float QuarticEaseInImpl(float progress) { return EaseInPower(progress, 4); }
private static float QuarticEaseOutImpl(float progress) { return EaseOutPower(progress, 4); }
private static float QuarticEaseInOutImpl(float progress) { return EaseInOutPower(progress, 4); }
private static float QuinticEaseInImpl(float progress) { return EaseInPower(progress, 5); }
private static float QuinticEaseOutImpl(float progress) { return EaseOutPower(progress, 5); }
private static float QuinticEaseInOutImpl(float progress) { return EaseInOutPower(progress, 5); }
private static float EaseInPower(float progress, int power)
{
return (float)Math.Pow(progress, power);
}
private static float EaseOutPower(float progress, int power)
{
int sign = power % 2 == 0 ? -1 : 1;
return (float)(sign * (Math.Pow(progress - 1, power) + sign));
}
private static float EaseInOutPower(float progress, int power)
{
progress *= 2;
if (progress < 1)
{
return (float)Math.Pow(progress, power) / 2f;
}
else
{
int sign = power % 2 == 0 ? -1 : 1;
return (float)(sign / 2.0 * (Math.Pow(progress - 2, power) + sign * 2));
}
}
private static float SineEaseInImpl(float progress)
{
return (float)Math.Sin(progress * HalfPi - HalfPi) + 1;
}
private static float SineEaseOutImpl(float progress)
{
return (float)Math.Sin(progress * HalfPi);
}
private static float SineEaseInOutImpl(float progress)
{
return (float)(Math.Sin(progress * Pi - HalfPi) + 1) / 2;
}
}
}

great to see other people combining Unity and XNA scripts. hope to see more from ya as id@xbox evolves for Xbox one indie stuff. cheers for the script...using it to animate my XNA camera and now I can carry over to Unity. SWEEEEET! ;-)

I know it's been a while but thanks a lot for this class. I'm planning to use it as a starting point for my own Tweening engine. Very helpful to have some of the structure premade

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