Mode -> Ruleset.

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/ApproachCircle.cs

@@ -0,0 +1,35 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Graphics.Textures;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class ApproachCircle : Container
+    {
+        private readonly Sprite approachCircle;
+
+        public ApproachCircle()
+        {
+            Anchor = Anchor.Centre;
+            Origin = Anchor.Centre;
+
+            AutoSizeAxes = Axes.Both;
+
+            Children = new Drawable[]
+            {
+                approachCircle = new Sprite()
+            };
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(TextureStore textures)
+        {
+            approachCircle.Texture = textures.Get(@"Play/osu/approachcircle");
+        }
+    }
+}

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/CirclePiece.cs

@@ -0,0 +1,58 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Graphics.Textures;
+using osu.Framework.Input;
+using OpenTK;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class CirclePiece : Container
+    {
+        private readonly Sprite disc;
+
+
+        public Func<bool> Hit;
+
+        public CirclePiece()
+        {
+            Size = new Vector2((float)OsuHitObject.OBJECT_RADIUS * 2);
+            Masking = true;
+            CornerRadius = Size.X / 2;
+
+            Anchor = Anchor.Centre;
+            Origin = Anchor.Centre;
+
+            Children = new Drawable[]
+            {
+                disc = new Sprite
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre
+                },
+                new TrianglesPiece
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    BlendingMode = BlendingMode.Additive,
+                    Alpha = 0.5f,
+                }
+            };
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(TextureStore textures)
+        {
+            disc.Texture = textures.Get(@"Play/osu/disc");
+        }
+
+        protected override bool OnMouseDown(InputState state, MouseDownEventArgs args)
+        {
+            return Hit?.Invoke() ?? false;
+        }
+    }
+}

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/ExplodePiece.cs

@@ -0,0 +1,33 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using OpenTK;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class ExplodePiece : Container
+    {
+        public ExplodePiece()
+        {
+            Size = new Vector2(128);
+
+            Anchor = Anchor.Centre;
+            Origin = Anchor.Centre;
+
+            BlendingMode = BlendingMode.Additive;
+            Alpha = 0;
+
+            Children = new Drawable[]
+            {
+                new TrianglesPiece
+                {
+                    BlendingMode = BlendingMode.Additive,
+                    RelativeSizeAxes = Axes.Both,
+                    Alpha = 0.2f,
+                }
+            };
+        }
+    }
+}

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/FlashPiece.cs

@@ -0,0 +1,35 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
+using OpenTK;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class FlashPiece : Container
+    {
+        public FlashPiece()
+        {
+            Size = new Vector2(128);
+
+            Masking = true;
+            CornerRadius = Size.X / 2;
+
+            Anchor = Anchor.Centre;
+            Origin = Anchor.Centre;
+
+            BlendingMode = BlendingMode.Additive;
+            Alpha = 0;
+
+            Children = new Drawable[]
+            {
+                new Box
+                {
+                    RelativeSizeAxes = Axes.Both
+                }
+            };
+        }
+    }
+}

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/GlowPiece.cs

@@ -0,0 +1,39 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Graphics.Textures;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class GlowPiece : Container
+    {
+        private readonly Sprite layer;
+
+        public GlowPiece()
+        {
+            Anchor = Anchor.Centre;
+            Origin = Anchor.Centre;
+
+            Children = new[]
+            {
+                layer = new Sprite
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    BlendingMode = BlendingMode.Additive,
+                    Alpha = 0.5f
+                }
+            };
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(TextureStore textures)
+        {
+            layer.Texture = textures.Get(@"Play/osu/ring-glow");
+        }
+    }
+}

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/NumberPiece.cs

@@ -0,0 +1,58 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Extensions.Color4Extensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Graphics.Sprites;
+using OpenTK.Graphics;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class NumberPiece : Container
+    {
+        private readonly SpriteText number;
+
+        public string Text
+        {
+            get { return number.Text; }
+            set { number.Text = value; }
+        }
+
+        public NumberPiece()
+        {
+            Anchor = Anchor.Centre;
+            Origin = Anchor.Centre;
+
+            Children = new Drawable[]
+            {
+                new CircularContainer
+                {
+                    Masking = true,
+                    Origin = Anchor.Centre,
+                    EdgeEffect = new EdgeEffect
+                    {
+                        Type = EdgeEffectType.Glow,
+                        Radius = 60,
+                        Colour = Color4.White.Opacity(0.5f),
+                    },
+                    Children = new[]
+                    {
+                        new Box()
+                    }
+                },
+                number = new OsuSpriteText
+                {
+                    Text = @"1",
+                    Font = @"Venera",
+                    UseFullGlyphHeight = false,
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    TextSize = 40,
+                    Alpha = 1
+                }
+            };
+        }
+    }
+}

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/RingPiece.cs

@@ -0,0 +1,38 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
+using OpenTK;
+using OpenTK.Graphics;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class RingPiece : Container
+    {
+        public RingPiece()
+        {
+            Size = new Vector2(128);
+
+            Masking = true;
+            CornerRadius = Size.X / 2;
+
+            Anchor = Anchor.Centre;
+            Origin = Anchor.Centre;
+
+            BorderThickness = 10;
+            BorderColour = Color4.White;
+
+            Children = new Drawable[]
+            {
+                new Box
+                {
+                    AlwaysPresent = true,
+                    Alpha = 0,
+                    RelativeSizeAxes = Axes.Both
+                }
+            };
+        }
+    }
+}

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/SliderBall.cs

@@ -0,0 +1,129 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Input;
+using OpenTK.Graphics;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class SliderBall : CircularContainer, ISliderProgress
+    {
+        private const float width = 128;
+
+        private Color4 accentColour = Color4.Black;
+        /// <summary>
+        /// The colour that is used for the slider ball.
+        /// </summary>
+        public Color4 AccentColour
+        {
+            get { return accentColour; }
+            set
+            {
+                accentColour = value;
+                if (ball != null)
+                    ball.Colour = value;
+            }
+        }
+
+        private readonly Slider slider;
+        private readonly Box follow;
+        private readonly Box ball;
+
+        public SliderBall(Slider slider)
+        {
+            this.slider = slider;
+            Masking = true;
+            AutoSizeAxes = Axes.Both;
+            BlendingMode = BlendingMode.Additive;
+            Origin = Anchor.Centre;
+            BorderThickness = 10;
+            BorderColour = Color4.Orange;
+
+            Children = new Drawable[]
+            {
+                follow = new Box
+                {
+                    Origin = Anchor.Centre,
+                    Anchor = Anchor.Centre,
+                    Colour = Color4.Orange,
+                    Width = width,
+                    Height = width,
+                    Alpha = 0,
+                },
+                new CircularContainer
+                {
+                    Masking = true,
+                    AutoSizeAxes = Axes.Both,
+                    Origin = Anchor.Centre,
+                    Anchor = Anchor.Centre,
+                    BorderThickness = 10,
+                    BorderColour = Color4.White,
+                    Alpha = 1,
+                    Children = new[]
+                    {
+                        ball = new Box
+                        {
+                            Colour = AccentColour,
+                            Alpha = 0.4f,
+                            Width = width,
+                            Height = width,
+                        },
+                    }
+                }
+            };
+        }
+
+        private InputState lastState;
+
+        protected override bool OnMouseDown(InputState state, MouseDownEventArgs args)
+        {
+            lastState = state;
+            return base.OnMouseDown(state, args);
+        }
+
+        protected override bool OnMouseUp(InputState state, MouseUpEventArgs args)
+        {
+            lastState = state;
+            return base.OnMouseUp(state, args);
+        }
+
+        protected override bool OnMouseMove(InputState state)
+        {
+            lastState = state;
+            return base.OnMouseMove(state);
+        }
+
+        private bool tracking;
+        public bool Tracking
+        {
+            get { return tracking; }
+            set
+            {
+                if (value == tracking) return;
+
+                tracking = value;
+
+                follow.ScaleTo(tracking ? 2.8f : 1, 300, EasingTypes.OutQuint);
+                follow.FadeTo(tracking ? 0.2f : 0, 300, EasingTypes.OutQuint);
+            }
+        }
+
+        private bool canCurrentlyTrack => Time.Current >= slider.StartTime && Time.Current < slider.EndTime;
+
+        protected override void Update()
+        {
+            base.Update();
+
+            if (Time.Current < slider.EndTime)
+                Tracking = canCurrentlyTrack && lastState != null && Contains(lastState.Mouse.NativeState.Position) && lastState.Mouse.HasMainButtonPressed;
+        }
+
+        public void UpdateProgress(double progress, int repeat)
+        {
+            Position = slider.Curve.PositionAt(progress);
+        }
+    }
+}

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/SliderBody.cs

@@ -0,0 +1,185 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using System.Collections.Generic;
+using osu.Framework.Allocation;
+using osu.Framework.Configuration;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.OpenGL.Textures;
+using osu.Framework.Graphics.Lines;
+using osu.Framework.Graphics.Textures;
+using osu.Game.Configuration;
+using OpenTK;
+using OpenTK.Graphics.ES30;
+using OpenTK.Graphics;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class SliderBody : Container, ISliderProgress
+    {
+        private readonly Path path;
+        private readonly BufferedContainer container;
+
+        public float PathWidth
+        {
+            get { return path.PathWidth; }
+            set { path.PathWidth = value; }
+        }
+
+        public double? SnakedStart { get; private set; }
+        public double? SnakedEnd { get; private set; }
+
+        private Color4 accentColour;
+        /// <summary>
+        /// Used to colour the path.
+        /// </summary>
+        public Color4 AccentColour
+        {
+            get { return accentColour; }
+            set
+            {
+                if (accentColour == value)
+                    return;
+                accentColour = value;
+
+                if (LoadState == LoadState.Loaded)
+                    Schedule(reloadTexture);
+            }
+        }
+
+        private int textureWidth => (int)PathWidth * 2;
+
+        private readonly Slider slider;
+        public SliderBody(Slider s)
+        {
+            slider = s;
+
+            Children = new Drawable[]
+            {
+                container = new BufferedContainer
+                {
+                    CacheDrawnFrameBuffer = true,
+                    Children = new Drawable[]
+                    {
+                        path = new Path
+                        {
+                            BlendingMode = BlendingMode.None,
+                        },
+                    }
+                },
+            };
+
+            container.Attach(RenderbufferInternalFormat.DepthComponent16);
+        }
+
+        public void SetRange(double p0, double p1)
+        {
+            if (p0 > p1)
+                MathHelper.Swap(ref p0, ref p1);
+
+            if (updateSnaking(p0, p1))
+            {
+                // Autosizing does not give us the desired behaviour here.
+                // We want the container to have the same size as the slider,
+                // and to be positioned such that the slider head is at (0,0).
+                container.Size = path.Size;
+                container.Position = -path.PositionInBoundingBox(slider.Curve.PositionAt(0) - currentCurve[0]);
+
+                container.ForceRedraw();
+            }
+        }
+
+        private Bindable<bool> snakingIn;
+        private Bindable<bool> snakingOut;
+
+        [BackgroundDependencyLoader]
+        private void load(OsuConfigManager config)
+        {
+            snakingIn = config.GetBindable<bool>(OsuConfig.SnakingInSliders);
+            snakingOut = config.GetBindable<bool>(OsuConfig.SnakingOutSliders);
+
+            reloadTexture();
+        }
+
+        private void reloadTexture()
+        {
+            var texture = new Texture(textureWidth, 1);
+
+            //initialise background
+            var upload = new TextureUpload(textureWidth * 4);
+            var bytes = upload.Data;
+
+            const float aa_portion = 0.02f;
+            const float border_portion = 0.128f;
+            const float gradient_portion = 1 - border_portion;
+
+            const float opacity_at_centre = 0.3f;
+            const float opacity_at_edge = 0.8f;
+
+            for (int i = 0; i < textureWidth; i++)
+            {
+                float progress = (float)i / (textureWidth - 1);
+
+                if (progress <= border_portion)
+                {
+                    bytes[i * 4] = 255;
+                    bytes[i * 4 + 1] = 255;
+                    bytes[i * 4 + 2] = 255;
+                    bytes[i * 4 + 3] = (byte)(Math.Min(progress / aa_portion, 1) * 255);
+                }
+                else
+                {
+                    progress -= border_portion;
+
+                    bytes[i * 4] = (byte)(AccentColour.R * 255);
+                    bytes[i * 4 + 1] = (byte)(AccentColour.G * 255);
+                    bytes[i * 4 + 2] = (byte)(AccentColour.B * 255);
+                    bytes[i * 4 + 3] = (byte)((opacity_at_edge - (opacity_at_edge - opacity_at_centre) * progress / gradient_portion) * (AccentColour.A * 255));
+                }
+            }
+
+            texture.SetData(upload);
+            path.Texture = texture;
+        }
+
+        private readonly List<Vector2> currentCurve = new List<Vector2>();
+        private bool updateSnaking(double p0, double p1)
+        {
+            if (SnakedStart == p0 && SnakedEnd == p1) return false;
+
+            SnakedStart = p0;
+            SnakedEnd = p1;
+
+            slider.Curve.GetPathToProgress(currentCurve, p0, p1);
+
+            path.ClearVertices();
+            foreach (Vector2 p in currentCurve)
+                path.AddVertex(p - currentCurve[0]);
+
+            return true;
+        }
+
+        public void UpdateProgress(double progress, int repeat)
+        {
+            double start = 0;
+            double end = snakingIn ? MathHelper.Clamp((Time.Current - (slider.StartTime - DrawableOsuHitObject.TIME_PREEMPT)) / DrawableOsuHitObject.TIME_FADEIN, 0, 1) : 1;
+
+            if (repeat >= slider.RepeatCount - 1)
+            {
+                if (Math.Min(repeat, slider.RepeatCount - 1) % 2 == 1)
+                {
+                    start = 0;
+                    end = snakingOut ? progress : 1;
+                }
+                else
+                {
+                    start = snakingOut ? progress : 0;
+                }
+            }
+
+            SetRange(start, end);
+        }
+    }
+}

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/SliderBouncer.cs

@@ -0,0 +1,52 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Game.Graphics;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class SliderBouncer : Container, ISliderProgress
+    {
+        private readonly Slider slider;
+        private readonly bool isEnd;
+        private readonly TextAwesome icon;
+
+        public SliderBouncer(Slider slider, bool isEnd)
+        {
+            this.slider = slider;
+            this.isEnd = isEnd;
+
+            AutoSizeAxes = Axes.Both;
+            BlendingMode = BlendingMode.Additive;
+            Origin = Anchor.Centre;
+
+            Children = new Drawable[]
+            {
+                icon = new TextAwesome
+                {
+                    Icon = FontAwesome.fa_eercast,
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    TextSize = 48,
+                }
+            };
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+            icon.RotateTo(360, 1000);
+            icon.Loop();
+        }
+
+        public void UpdateProgress(double progress, int repeat)
+        {
+            if (Time.Current < slider.StartTime)
+                Alpha = 0;
+
+            Alpha = repeat + 1 < slider.RepeatCount && repeat % 2 == (isEnd ? 0 : 1) ? 1 : 0;
+        }
+    }
+}

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/SpinnerBackground.cs

@@ -0,0 +1,10 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class SpinnerBackground : SpinnerDisc
+    {
+        public override bool HandleInput => false;
+    }
+}

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/SpinnerDisc.cs

@@ -0,0 +1,208 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using System.Linq;
+using osu.Framework.Allocation;
+using osu.Framework.Extensions.Color4Extensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Colour;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Graphics.Transforms;
+using osu.Framework.Input;
+using osu.Game.Graphics;
+using OpenTK;
+using OpenTK.Graphics;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class SpinnerDisc : CircularContainer
+    {
+        protected Sprite Disc;
+
+        public SRGBColour DiscColour
+        {
+            get { return Disc.Colour; }
+            set { Disc.Colour = value; }
+        }
+
+        private Color4 completeColour;
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            completeColour = colours.YellowLight.Opacity(0.8f);
+            Masking = true;
+        }
+
+        private class SpinnerBorder : Container
+        {
+            public SpinnerBorder()
+            {
+                Origin = Anchor.Centre;
+                Anchor = Anchor.Centre;
+                RelativeSizeAxes = Axes.Both;
+
+                layout();
+            }
+
+            private int lastLayoutDotCount;
+            private void layout()
+            {
+                int count = (int)(MathHelper.Pi * ScreenSpaceDrawQuad.Width / 9);
+
+                if (count == lastLayoutDotCount) return;
+
+                lastLayoutDotCount = count;
+
+                while (Children.Count() < count)
+                {
+                    Add(new CircularContainer
+                    {
+                        Colour = Color4.White,
+                        RelativePositionAxes = Axes.Both,
+                        Masking = true,
+                        Origin = Anchor.Centre,
+                        Size = new Vector2(1 / ScreenSpaceDrawQuad.Width * 2000),
+                        Children = new[]
+                        {
+                            new Box
+                            {
+                                Origin = Anchor.Centre,
+                                Anchor = Anchor.Centre,
+                                RelativeSizeAxes = Axes.Both,
+                            }
+                        }
+                    });
+                }
+
+                var size = new Vector2(1 / ScreenSpaceDrawQuad.Width * 2000);
+
+                int i = 0;
+                foreach (var d in Children)
+                {
+                    d.Size = size;
+                    d.Position = new Vector2(
+                        0.5f + (float)Math.Sin((float)i / count * 2 * MathHelper.Pi) / 2,
+                        0.5f + (float)Math.Cos((float)i / count * 2 * MathHelper.Pi) / 2
+                    );
+
+                    i++;
+                }
+            }
+
+            protected override void Update()
+            {
+                base.Update();
+                layout();
+            }
+        }
+
+        public SpinnerDisc()
+        {
+            AlwaysReceiveInput = true;
+
+            RelativeSizeAxes = Axes.Both;
+
+            Children = new Drawable[]
+            {
+                Disc = new Box
+                {
+                    Origin = Anchor.Centre,
+                    Anchor = Anchor.Centre,
+                    RelativeSizeAxes = Axes.Both,
+                    Alpha = 0.2f,
+                },
+                new SpinnerBorder()
+            };
+        }
+
+        private bool tracking;
+        public bool Tracking
+        {
+            get { return tracking; }
+            set
+            {
+                if (value == tracking) return;
+
+                tracking = value;
+
+                Disc.FadeTo(tracking ? 0.5f : 0.2f, 100);
+            }
+        }
+
+        private bool complete;
+        public bool Complete
+        {
+            get { return complete; }
+            set
+            {
+                if (value == complete) return;
+
+                complete = value;
+
+                Disc.FadeColour(completeColour, 200);
+
+                updateCompleteTick();
+            }
+        }
+
+        protected override bool OnMouseDown(InputState state, MouseDownEventArgs args)
+        {
+            Tracking = true;
+            return base.OnMouseDown(state, args);
+        }
+
+        protected override bool OnMouseUp(InputState state, MouseUpEventArgs args)
+        {
+            Tracking = false;
+            return base.OnMouseUp(state, args);
+        }
+
+        protected override bool OnMouseMove(InputState state)
+        {
+            Tracking |= state.Mouse.HasMainButtonPressed;
+            mousePosition = state.Mouse.Position;
+            return base.OnMouseMove(state);
+        }
+
+        private Vector2 mousePosition;
+
+        private float lastAngle;
+        private float currentRotation;
+        public float RotationAbsolute;
+
+        private int completeTick;
+
+        private bool updateCompleteTick() => completeTick != (completeTick = (int)(RotationAbsolute / 360));
+
+        protected override void Update()
+        {
+            base.Update();
+
+            var thisAngle = -(float)MathHelper.RadiansToDegrees(Math.Atan2(mousePosition.X - DrawSize.X / 2, mousePosition.Y - DrawSize.Y / 2));
+            if (tracking)
+            {
+                if (thisAngle - lastAngle > 180)
+                    lastAngle += 360;
+                else if (lastAngle - thisAngle > 180)
+                    lastAngle -= 360;
+
+                currentRotation += thisAngle - lastAngle;
+                RotationAbsolute += Math.Abs(thisAngle - lastAngle);
+            }
+            lastAngle = thisAngle;
+
+            if (Complete && updateCompleteTick())
+            {
+                Disc.Flush(flushType: typeof(TransformAlpha));
+                Disc.FadeTo(0.75f, 30, EasingTypes.OutExpo);
+                Disc.Delay(30);
+                Disc.FadeTo(0.5f, 250, EasingTypes.OutQuint);
+            }
+
+            RotateTo(currentRotation, 100, EasingTypes.OutExpo);
+        }
+    }
+}

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/TrianglesPiece.cs

@@ -0,0 +1,26 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Game.Graphics.Backgrounds;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
+{
+    public class TrianglesPiece : Triangles
+    {
+        protected override bool ExpireOffScreenTriangles => false;
+        protected override bool CreateNewTriangles => false;
+        protected override float SpawnRatio => 0.5f;
+
+        public TrianglesPiece()
+        {
+            TriangleScale = 1.2f;
+            HideAlphaDiscrepancies = false;
+        }
+
+        protected override void Update()
+        {
+            if (IsPresent)
+                base.Update();
+        }
+    }
+}