Expose rewinding state of IGameplayClocks

The implementation of this requires a bit of a special case
for 0, so makes sense to implement in a central place.

osu.Game.Tests/Visual/Gameplay/TestSceneClicksPerSecondCalculator.cs

@@ -125,6 +125,7 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             public IEnumerable<double> NonGameplayAdjustments => throw new NotImplementedException();
             public IBindable<bool> IsPaused => throw new NotImplementedException();
+            public bool IsRewinding => false;
         }
     }
 }

osu.Game/Beatmaps/FramedBeatmapClock.cs

@@ -64,6 +64,8 @@ namespace osu.Game.Beatmaps
         [Resolved]
         private IBindable<WorkingBeatmap> beatmap { get; set; } = null!;
 
+        public bool IsRewinding { get; private set; }
+
         public bool IsCoupled
         {
             get => decoupledClock.IsCoupled;
@@ -133,6 +135,9 @@ namespace osu.Game.Beatmaps
             }
             else
                 finalClockSource.ProcessFrame();
+
+            if (Clock.ElapsedFrameTime != 0)
+                IsRewinding = Clock.ElapsedFrameTime < 0;
         }
 
         public double TotalAppliedOffset

osu.Game/Rulesets/UI/FrameStabilityContainer.cs

@@ -171,6 +171,9 @@ namespace osu.Game.Rulesets.UI
             // The manual clock time has changed in the above code. The framed clock now needs to be updated
             // to ensure that the its time is valid for our children before input is processed
             framedClock.ProcessFrame();
+
+            if (framedClock.ElapsedFrameTime != 0)
+                IsRewinding = framedClock.ElapsedFrameTime < 0;
         }
 
         /// <summary>
@@ -247,6 +250,8 @@ namespace osu.Game.Rulesets.UI
 
         public IBindable<bool> IsPaused { get; } = new BindableBool();
 
+        public bool IsRewinding { get; private set; }
+
         public double CurrentTime => framedClock.CurrentTime;
 
         public double Rate => framedClock.Rate;

osu.Game/Screens/Play/GameplayClockContainer.cs

@@ -19,11 +19,10 @@ namespace osu.Game.Screens.Play
     [Cached(typeof(IGameplayClock))]
     public partial class GameplayClockContainer : Container, IAdjustableClock, IGameplayClock
     {
-        /// <summary>
-        /// Whether gameplay is paused.
-        /// </summary>
         public IBindable<bool> IsPaused => isPaused;
 
+        public bool IsRewinding => GameplayClock.IsRewinding;
+
         /// <summary>
         /// The source clock. Should generally not be used for any timekeeping purposes.
         /// </summary>

osu.Game/Screens/Play/IGameplayClock.cs

@@ -23,6 +23,14 @@ namespace osu.Game.Screens.Play
         /// </summary>
         IAdjustableAudioComponent AdjustmentsFromMods { get; }
 
+        /// <summary>
+        /// Whether gameplay is paused.
+        /// </summary>
         IBindable<bool> IsPaused { get; }
+
+        /// <summary>
+        /// Whether the clock is currently rewinding.
+        /// </summary>
+        bool IsRewinding { get; }
     }
 }