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added an extension method to auto-reverse an easing function

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Ell 2020-10-24 22:10:34 +02:00
parent cdc08c5cf2
commit 3005b3edcb
2 changed files with 26 additions and 3 deletions
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19
Demos/EasingsDemo.cs
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@ -17,6 +17,7 @@ namespace Demos {
.Select(f => (Easings.Easing) f.GetValue(null)).ToArray();
private Group group;
private int current;
private float progress;
public EasingsDemo(MlemGame game) : base(game) {
}
@ -26,7 +27,10 @@ namespace Demos {
this.group = new Group(Anchor.TopCenter, Vector2.One) {SetWidthBasedOnChildren = true};
this.group.AddChild(new Button(Anchor.AutoCenter, new Vector2(30, 10), "Next") {
OnPressed = e => this.current = (this.current + 1) % Easings.Length
OnPressed = e => {
this.current = (this.current + 1) % Easings.Length;
this.progress = 0;
}
});
this.group.AddChild(new Paragraph(Anchor.AutoCenter, 1, p => EasingFields[this.current].Name, true));
this.UiRoot.AddChild(this.group);
@ -42,11 +46,20 @@ namespace Demos {
this.SpriteBatch.Begin(SpriteSortMode.Deferred, null, SamplerState.PointClamp);
var view = this.GraphicsDevice.Viewport;
var easing = Easings[this.current].ScaleInput(0, view.Width).ScaleOutput(-view.Height / 3, view.Height / 3);
// graph the easing function
var graphEase = Easings[this.current].ScaleInput(0, view.Width).ScaleOutput(-view.Height / 3, view.Height / 3);
for (var x = 0; x < view.Width; x++) {
var area = new RectangleF(x - 2, view.Height / 2 - easing(x) - 2, 4, 4);
var area = new RectangleF(x - 2, view.Height / 2 - graphEase(x) - 2, 4, 4);
this.SpriteBatch.Draw(this.SpriteBatch.GetBlankTexture(), area, Color.Green);
}
// draw a little dot to show what it would look like
this.progress = (this.progress + (float) time.ElapsedGameTime.TotalSeconds / 2) % 1;
var dotEase = Easings[this.current].AndReverse().ScaleOutput(0, view.Height / 4);
var pos = new RectangleF(view.Width / 2 - 4, view.Height - 20 - dotEase(this.progress), 8, 8);
this.SpriteBatch.Draw(this.SpriteBatch.GetBlankTexture(), pos, Color.Red);
this.SpriteBatch.End();
}

10
MLEM/Misc/Easings.cs
View file

@ -100,6 +100,16 @@ namespace MLEM.Misc {
return p => easing(p) * (max - min) + min;
}
/// <summary>
/// Causes the easing functino to play fully, and then play fully in reverse, in the span between an input of 0 and 1.
/// In some places, this behavior is also called "auto-reversing".
/// </summary>
/// <param name="easing">The easing function to play in reverse as well</param>
/// <returns>An auto-reversing version of the easing function</returns>
public static Easing AndReverse(this Easing easing) {
return p => p <= 0.5F ? easing(p * 2) : easing(1 - (p - 0.5F) * 2);
}
/// <summary>
/// A delegate method used by <see cref="Easings"/>.
/// </summary>