From 676df55a0e40df9a48e3661cf4f6ed89a90828d1 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Tue, 5 Oct 2021 15:39:29 +0900
Subject: [PATCH] Fade display out during rewind (as the value displayed is no
 longer valid)

---
 .../Graphics/UserInterface/RollingCounter.cs  | 12 +++++----
 .../Rulesets/Scoring/JudgementProcessor.cs    |  7 +++++
 .../Play/HUD/PerformancePointsCounter.cs      | 26 +++++++++++++++++++
 3 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/osu.Game/Graphics/UserInterface/RollingCounter.cs b/osu.Game/Graphics/UserInterface/RollingCounter.cs
index 67b0b6a06b..16555075d1 100644
--- a/osu.Game/Graphics/UserInterface/RollingCounter.cs
+++ b/osu.Game/Graphics/UserInterface/RollingCounter.cs
@@ -25,7 +25,9 @@ namespace osu.Game.Graphics.UserInterface
             set => current.Current = value;
         }
 
-        private IHasText displayedCountSpriteText;
+        private IHasText displayedCountText;
+
+        public Drawable DrawableCount { get; private set; }
 
         /// <summary>
         /// If true, the roll-up duration will be proportional to change in value.
@@ -72,16 +74,16 @@ namespace osu.Game.Graphics.UserInterface
         [BackgroundDependencyLoader]
         private void load()
         {
-            displayedCountSpriteText = CreateText();
+            displayedCountText = CreateText();
 
             UpdateDisplay();
-            Child = (Drawable)displayedCountSpriteText;
+            Child = DrawableCount = (Drawable)displayedCountText;
         }
 
         protected void UpdateDisplay()
         {
-            if (displayedCountSpriteText != null)
-                displayedCountSpriteText.Text = FormatCount(DisplayedCount);
+            if (displayedCountText != null)
+                displayedCountText.Text = FormatCount(DisplayedCount);
         }
 
         protected override void LoadComplete()
diff --git a/osu.Game/Rulesets/Scoring/JudgementProcessor.cs b/osu.Game/Rulesets/Scoring/JudgementProcessor.cs
index 201a05e569..ed4a16f0e8 100644
--- a/osu.Game/Rulesets/Scoring/JudgementProcessor.cs
+++ b/osu.Game/Rulesets/Scoring/JudgementProcessor.cs
@@ -18,6 +18,11 @@ namespace osu.Game.Rulesets.Scoring
         /// </summary>
         public event Action<JudgementResult> NewJudgement;
 
+        /// <summary>
+        /// Invoked when a judgement is reverted, usually due to rewinding gameplay.
+        /// </summary>
+        public event Action<JudgementResult> JudgementReverted;
+
         /// <summary>
         /// The maximum number of hits that can be judged.
         /// </summary>
@@ -71,6 +76,8 @@ namespace osu.Game.Rulesets.Scoring
             JudgedHits--;
 
             RevertResultInternal(result);
+
+            JudgementReverted?.Invoke(result);
         }
 
         /// <summary>
diff --git a/osu.Game/Screens/Play/HUD/PerformancePointsCounter.cs b/osu.Game/Screens/Play/HUD/PerformancePointsCounter.cs
index 2fc3f23190..b82a85691a 100644
--- a/osu.Game/Screens/Play/HUD/PerformancePointsCounter.cs
+++ b/osu.Game/Screens/Play/HUD/PerformancePointsCounter.cs
@@ -42,6 +42,9 @@ namespace osu.Game.Screens.Play.HUD
         [CanBeNull]
         private GameplayState gameplayState { get; set; }
 
+        [Resolved]
+        private GameplayClock gameplayClock { get; set; }
+
         [CanBeNull]
         private TimedDifficultyAttributes[] timedAttributes;
 
@@ -70,7 +73,24 @@ namespace osu.Game.Screens.Play.HUD
             base.LoadComplete();
 
             if (scoreProcessor != null)
+            {
                 scoreProcessor.NewJudgement += onNewJudgement;
+                scoreProcessor.JudgementReverted += onJudgementReverted;
+            }
+        }
+
+        private bool isValid;
+
+        protected bool IsValid
+        {
+            set
+            {
+                if (value == isValid)
+                    return;
+
+                isValid = value;
+                DrawableCount.FadeTo(isValid ? 1 : 0.3f, 1000, Easing.OutQuint);
+            }
         }
 
         private void onNewJudgement(JudgementResult judgement)
@@ -86,6 +106,12 @@ namespace osu.Game.Screens.Play.HUD
             var calculator = gameplayState.Ruleset.CreatePerformanceCalculator(timedAttributes[attribIndex].Attributes, gameplayState.Score.ScoreInfo);
 
             Current.Value = (int)Math.Round(calculator?.Calculate() ?? 0, MidpointRounding.AwayFromZero);
+            IsValid = true;
+        }
+
+        private void onJudgementReverted(JudgementResult obj)
+        {
+            IsValid = false;
         }
 
         protected override LocalisableString FormatCount(int count) => count.ToString(@"D");