From 7bb984eb8da4e0390ad9671330a0bb61d2a8920f Mon Sep 17 00:00:00 2001
From: mcendu <nathandu@outlook.com>
Date: Sat, 21 Dec 2019 20:47:34 +0800
Subject: [PATCH] Basic kiai flash implementation

---
 .../Objects/Drawables/Pieces/CirclePiece.cs   |  4 ++
 .../Objects/Drawables/Pieces/KiaiFlash.cs     | 40 +++++++++++++++++++
 .../Skinning/LegacyMainCirclePiece.cs         | 12 ++++++
 3 files changed, 56 insertions(+)
 create mode 100644 osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/KiaiFlash.cs

diff --git a/osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/CirclePiece.cs b/osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/CirclePiece.cs
index aab01f45d4..84470d7f30 100644
--- a/osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/CirclePiece.cs
+++ b/osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/CirclePiece.cs
@@ -35,6 +35,10 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
                     Origin = Anchor.Centre,
                     Texture = textures.Get(@"Gameplay/osu/disc"),
                 },
+                new KiaiFlash
+                {
+                    RelativeSizeAxes = Axes.Both,
+                },
                 new TrianglesPiece
                 {
                     RelativeSizeAxes = Axes.Both,
diff --git a/osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/KiaiFlash.cs b/osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/KiaiFlash.cs
new file mode 100644
index 0000000000..9f9ca42d69
--- /dev/null
+++ b/osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/KiaiFlash.cs
@@ -0,0 +1,40 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Shapes;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Containers;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class KiaiFlash : BeatSyncedContainer
+    {
+        public Drawable FlashComponent { get; set; }
+
+        public KiaiFlash()
+        {
+            Blending = BlendingParameters.Additive;
+
+            Child = FlashComponent = new Box
+            {
+                RelativeSizeAxes = Axes.Both,
+                Colour = OsuColour.Gray(1f),
+                Alpha = 0f,
+            };
+        }
+
+        protected new double EarlyActivationMilliseconds = 80;
+
+        protected override void OnNewBeat(int beatIndex, Game.Beatmaps.ControlPoints.TimingControlPoint timingPoint, Game.Beatmaps.ControlPoints.EffectControlPoint effectPoint, Framework.Audio.Track.TrackAmplitudes amplitudes)
+        {
+            if (effectPoint.KiaiMode)
+            {
+                FlashComponent
+                    .FadeTo(0.25f, EarlyActivationMilliseconds, Easing.OutQuint)
+                    .Then()
+                    .FadeOut(timingPoint.BeatLength - 80, Easing.OutSine);
+            }
+        }
+    }
+}
diff --git a/osu.Game.Rulesets.Osu/Skinning/LegacyMainCirclePiece.cs b/osu.Game.Rulesets.Osu/Skinning/LegacyMainCirclePiece.cs
index 93ae0371df..97541d171b 100644
--- a/osu.Game.Rulesets.Osu/Skinning/LegacyMainCirclePiece.cs
+++ b/osu.Game.Rulesets.Osu/Skinning/LegacyMainCirclePiece.cs
@@ -10,6 +10,7 @@ using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Rulesets.Osu.Objects.Drawables.Pieces;
 using osu.Game.Skinning;
 using osuTK;
 using osuTK.Graphics;
@@ -44,6 +45,17 @@ namespace osu.Game.Rulesets.Osu.Skinning
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
                 },
+                new KiaiFlash
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    Size = new Vector2(0.921875f),
+
+                    Masking = true,
+                    CornerRadius = Size.X / 2,
+                    CornerExponent = 2,
+                },
                 hitCircleText = new SkinnableSpriteText(new OsuSkinComponent(OsuSkinComponents.HitCircleText), _ => new OsuSpriteText
                 {
                     Font = OsuFont.Numeric.With(size: 40),