/// <summary>
/// Creates a new Interpolator.
/// </summary>
/// <param name="start">The starting value.</param>
/// <param name="end">The ending value.</param>
/// <param name="length">The length of time, in seconds, to perform the interpolation.</param>
/// <param name="scale">A method to perform</param>
/// <param name="step">An optional callback to invoke when the Interpolator is updated.</param>
/// <param name="completed">An optional callback to invoke when the Interpolator completes.</param>
/// <returns>The Interpolator instance.</returns>
public static Interpolator Create(
float start,
float end,
float length,
InterpolatorScaleDelegate scale,
InterpolatorEaseDirection direction,
Action <Interpolator> step,
Action <Interpolator> completed)
{
if (length <= 0f)
{
throw new ArgumentException("length must be greater than zero");
}
if (scale == null)
{
throw new ArgumentNullException("scale");
}
var i = Interpolators.New();
i.Start = start;
i.End = end;
i._range = end - start;
i._step = step;
i._completed = completed;
i._scale = scale;
i._speed = 1f / length;
i._direction = direction;
return(i);
}
private static float ExponentialInterpolation(float progress, InterpolatorEaseDirection direction)
{
switch (direction)
{
case InterpolatorEaseDirection.In:
return((progress == 0f) ? 0f : (float)Math.Pow(2f, 10f * (progress - 1f)));
case InterpolatorEaseDirection.Out:
return((progress == 1f) ? 0f : -(float)Math.Pow(2f, (-10f * progress) + 1f));
case InterpolatorEaseDirection.InOut:
progress *= 2f;
if (progress < 1f)
{
return(0.5f * (float)Math.Pow(2f, 10f * (progress - 1)));
}
return(0.5f * -(float)Math.Pow(2f, -10f * (progress - 1)) + 2f);
default:
return((progress == 0f) ? 0f : (float)Math.Pow(2f, 10f * (progress - 1f)));
}
}
private static float QuadraticInterpolation(float progress, InterpolatorEaseDirection direction)
{
switch (direction)
{
case InterpolatorEaseDirection.In:
return(progress * progress);
case InterpolatorEaseDirection.Out:
return(-progress * (progress - 2f));
case InterpolatorEaseDirection.InOut:
progress *= 2f;
if (progress < 1f)
{
return(0.5f * progress * progress);
}
progress--;
return(-0.5f * (progress * (progress - 2f) - 1f));
default:
return(progress * progress);
}
}
private static float BackInterpolation(float progress, InterpolatorEaseDirection direction)
{
switch (direction)
{
case InterpolatorEaseDirection.In:
return(progress * progress * (2.70158f * progress - 1.70158f));
case InterpolatorEaseDirection.Out:
progress--;
return(progress * progress * (2.70158f * progress + 1.70158f) + 1f);
case InterpolatorEaseDirection.InOut:
progress *= 2f;
if (progress < 1f)
{
return(0.5f * progress * progress * (3.59491f * progress - 2.59491f));
}
progress -= 2;
return(0.5f * progress * progress * (3.59491f * progress - 2.59491f) + 2f);
default:
return(progress * progress * (2.70158f * progress - 1.70158f));
}
}
private static float CircularInterpolation(float progress, InterpolatorEaseDirection direction)
{
switch (direction)
{
case InterpolatorEaseDirection.In:
return(-(float)(Math.Sqrt(1f - progress * progress) - 1f));
case InterpolatorEaseDirection.Out:
progress--;
return((float)Math.Sqrt(1f - progress * progress));
case InterpolatorEaseDirection.InOut:
progress *= 2f;
if (progress < 1)
{
return(-0.5f * (float)Math.Sqrt(1f - progress * progress) - 1f);
}
progress -= 2;
return(0.5f * (float)Math.Sqrt(1f - progress * progress) + 1f);
default:
return(-(float)(Math.Sqrt(1f - progress * progress) - 1f));
}
}
private static float LinearInterpolation(float progress, InterpolatorEaseDirection direction)
{
return(progress);
}
private static float BackInterpolation(float progress, InterpolatorEaseDirection direction)
{
switch (direction)
{
case InterpolatorEaseDirection.In:
return progress * progress * (2.70158f * progress - 1.70158f);
case InterpolatorEaseDirection.Out:
progress--;
return progress * progress * (2.70158f * progress + 1.70158f) + 1f;
case InterpolatorEaseDirection.InOut:
progress *= 2f;
if (progress < 1f)
return 0.5f * progress * progress * (3.59491f * progress - 2.59491f);
progress -= 2;
return 0.5f * progress * progress * (3.59491f * progress - 2.59491f) + 2f;
default:
return progress * progress * (2.70158f * progress - 1.70158f);
}
}
private static float CircularInterpolation(float progress, InterpolatorEaseDirection direction)
{
switch (direction)
{
case InterpolatorEaseDirection.In:
return -(float)(Math.Sqrt(1f - progress * progress) - 1f);
case InterpolatorEaseDirection.Out:
progress--;
return (float)Math.Sqrt(1f - progress * progress);
case InterpolatorEaseDirection.InOut:
progress *= 2f;
if (progress < 1)
return -0.5f * (float)Math.Sqrt(1f - progress * progress) - 1f;
progress -= 2;
return 0.5f * (float)Math.Sqrt(1f - progress * progress) + 1f;
default:
return -(float)(Math.Sqrt(1f - progress * progress) - 1f);
}
}
private static float ExponentialInterpolation(float progress, InterpolatorEaseDirection direction)
{
switch (direction)
{
case InterpolatorEaseDirection.In:
return (progress == 0f) ? 0f : (float)Math.Pow(2f, 10f * (progress - 1f));
case InterpolatorEaseDirection.Out:
return (progress == 1f) ? 0f : -(float)Math.Pow(2f, (-10f * progress) + 1f);
case InterpolatorEaseDirection.InOut:
progress *= 2f;
if (progress < 1f)
return 0.5f * (float)Math.Pow(2f, 10f * (progress - 1));
return 0.5f * -(float)Math.Pow(2f, -10f * (progress - 1)) + 2f;
default:
return (progress == 0f) ? 0f : (float)Math.Pow(2f, 10f * (progress - 1f));
}
}
private static float QuinticInterpolation(float progress, InterpolatorEaseDirection direction)
{
switch (direction)
{
case InterpolatorEaseDirection.In:
return progress * progress * progress * progress * progress;
case InterpolatorEaseDirection.Out:
progress--;
return (progress * progress * progress * progress * progress - 1f);
case InterpolatorEaseDirection.InOut:
progress *= 2f;
if (progress < 1)
return 0.5f * progress * progress * progress * progress * progress;
progress -= 2;
return -0.5f * (progress * progress * progress * progress * progress - 2f);
default:
return progress * progress * progress * progress * progress;
}
}
private static float LinearInterpolation(float progress, InterpolatorEaseDirection direction)
{
return progress;
}
/// <summary>
/// Creates a new Interpolator.
/// </summary>
/// <param name="start">The starting value.</param>
/// <param name="end">The ending value.</param>
/// <param name="length">The length of time, in seconds, to perform the interpolation.</param>
/// <param name="scale">A method to perform</param>
/// <param name="step">An optional callback to invoke when the Interpolator is updated.</param>
/// <param name="completed">An optional callback to invoke when the Interpolator completes.</param>
/// <returns>The Interpolator instance.</returns>
public static Interpolator Create(
float start,
float end,
float length,
InterpolatorScaleDelegate scale,
InterpolatorEaseDirection direction,
Action<Interpolator> step,
Action<Interpolator> completed)
{
if (length <= 0f)
throw new ArgumentException("length must be greater than zero");
if (scale == null)
throw new ArgumentNullException("scale");
var i = Interpolators.New();
i.Start = start;
i.End = end;
i._range = end - start;
i._step = step;
i._completed = completed;
i._scale = scale;
i._speed = 1f / length;
i._direction = direction;
return i;
}