From 664a4ba540677fb6851d7a6c7277bc1eb788928c Mon Sep 17 00:00:00 2001
From: David Zhao <nyquill@ppy.sh>
Date: Fri, 12 Apr 2019 10:47:22 +0900
Subject: [PATCH] Implement flashlight dimming on slider slide

---
 .../Mods/OsuModFlashlight.cs                  | 30 +++++++++++++++++--
 .../Objects/Drawables/DrawableRepeatPoint.cs  |  2 +-
 .../Objects/Drawables/DrawableSlider.cs       |  4 +--
 osu.Game/Rulesets/Mods/ModFlashlight.cs       | 17 +++++++++++
 4 files changed, 48 insertions(+), 5 deletions(-)

diff --git a/osu.Game.Rulesets.Osu/Mods/OsuModFlashlight.cs b/osu.Game.Rulesets.Osu/Mods/OsuModFlashlight.cs
index 2c40d18f1b..26c0c26f0f 100644
--- a/osu.Game.Rulesets.Osu/Mods/OsuModFlashlight.cs
+++ b/osu.Game.Rulesets.Osu/Mods/OsuModFlashlight.cs
@@ -1,23 +1,49 @@
 // 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 System.Collections.Generic;
+using System.Linq;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Input;
 using osu.Framework.Input.Events;
 using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Rulesets.Osu.Objects.Drawables;
 using osuTK;
 
 namespace osu.Game.Rulesets.Osu.Mods
 {
-    public class OsuModFlashlight : ModFlashlight<OsuHitObject>
+    public class OsuModFlashlight : ModFlashlight<OsuHitObject>, IApplicableToDrawableHitObjects
     {
         public override double ScoreMultiplier => 1.12;
 
         private const float default_flashlight_size = 180;
 
-        public override Flashlight CreateFlashlight() => new OsuFlashlight();
+        private int trackingSliders;
+
+        private OsuFlashlight flashlight;
+
+        public override Flashlight CreateFlashlight() => flashlight = new OsuFlashlight();
+
+        public void ApplyToDrawableHitObjects(IEnumerable<DrawableHitObject> drawables)
+        {
+            foreach (DrawableSlider drawable in drawables.OfType<DrawableSlider>())
+            {
+                drawable.Tracking.ValueChanged += updateTrackingSliders;
+            }
+        }
+
+        private void updateTrackingSliders(ValueChangedEvent<bool> value)
+        {
+            if (value.NewValue)
+                trackingSliders++;
+            else
+                trackingSliders--;
+
+            flashlight.FlashlightLightness = trackingSliders > 0 ? 0.2f : 1.0f;
+        }
 
         private class OsuFlashlight : Flashlight, IRequireHighFrequencyMousePosition
         {
diff --git a/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableRepeatPoint.cs b/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableRepeatPoint.cs
index edf2d90c08..bece2a49cd 100644
--- a/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableRepeatPoint.cs
+++ b/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableRepeatPoint.cs
@@ -44,7 +44,7 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
         protected override void CheckForResult(bool userTriggered, double timeOffset)
         {
             if (repeatPoint.StartTime <= Time.Current)
-                ApplyResult(r => r.Type = drawableSlider.Tracking ? HitResult.Great : HitResult.Miss);
+                ApplyResult(r => r.Type = drawableSlider.Tracking.Value ? HitResult.Great : HitResult.Miss);
         }
 
         protected override void UpdatePreemptState()
diff --git a/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs b/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs
index 57ea0abdd8..c1a4c1981f 100644
--- a/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs
+++ b/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs
@@ -130,13 +130,13 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
             }
         }
 
-        public bool Tracking;
+        public readonly Bindable<bool> Tracking = new Bindable<bool>();
 
         protected override void Update()
         {
             base.Update();
 
-            Tracking = Ball.Tracking;
+            Tracking.Value = Ball.Tracking;
 
             double completionProgress = MathHelper.Clamp((Time.Current - slider.StartTime) / slider.Duration, 0, 1);
 
diff --git a/osu.Game/Rulesets/Mods/ModFlashlight.cs b/osu.Game/Rulesets/Mods/ModFlashlight.cs
index 0ad99d13ff..fa070dc9e8 100644
--- a/osu.Game/Rulesets/Mods/ModFlashlight.cs
+++ b/osu.Game/Rulesets/Mods/ModFlashlight.cs
@@ -80,6 +80,7 @@ namespace osu.Game.Rulesets.Mods
                 flashNode.ScreenSpaceDrawQuad = ScreenSpaceDrawQuad;
                 flashNode.FlashlightPosition = Vector2Extensions.Transform(FlashlightPosition, DrawInfo.Matrix);
                 flashNode.FlashlightSize = Vector2Extensions.Transform(FlashlightSize, DrawInfo.Matrix);
+                flashNode.FlashlightLightness = FlashlightLightness;
             }
 
             [BackgroundDependencyLoader]
@@ -136,6 +137,20 @@ namespace osu.Game.Rulesets.Mods
                     Invalidate(Invalidation.DrawNode);
                 }
             }
+
+            private float flashlightLightness = 1.0f;
+
+            public float FlashlightLightness
+            {
+                get => flashlightLightness;
+                set
+                {
+                    if (flashlightLightness == value) return;
+
+                    flashlightLightness = value;
+                    Invalidate(Invalidation.DrawNode);
+                }
+            }
         }
 
         private class FlashlightDrawNode : DrawNode
@@ -144,6 +159,7 @@ namespace osu.Game.Rulesets.Mods
             public Quad ScreenSpaceDrawQuad;
             public Vector2 FlashlightPosition;
             public Vector2 FlashlightSize;
+            public float FlashlightLightness;
 
             public override void Draw(Action<TexturedVertex2D> vertexAction)
             {
@@ -153,6 +169,7 @@ namespace osu.Game.Rulesets.Mods
 
                 Shader.GetUniform<Vector2>("flashlightPos").UpdateValue(ref FlashlightPosition);
                 Shader.GetUniform<Vector2>("flashlightSize").UpdateValue(ref FlashlightSize);
+                Shader.GetUniform<float>("flashlightLightness").UpdateValue(ref FlashlightLightness);
 
                 Texture.WhitePixel.DrawQuad(ScreenSpaceDrawQuad, DrawColourInfo.Colour, vertexAction: vertexAction);