From 243e913e4a9129a2f1043d2ca8ba414828b9cedb Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Thu, 12 Nov 2020 18:32:20 +0900
Subject: [PATCH] Add hitobject usage events

---
 osu.Game/Rulesets/UI/HitObjectContainer.cs | 20 ++++++++++++++++++++
 osu.Game/Rulesets/UI/Playfield.cs          | 20 ++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/osu.Game/Rulesets/UI/HitObjectContainer.cs b/osu.Game/Rulesets/UI/HitObjectContainer.cs
index 4164681ffc..1797f0acb8 100644
--- a/osu.Game/Rulesets/UI/HitObjectContainer.cs
+++ b/osu.Game/Rulesets/UI/HitObjectContainer.cs
@@ -42,6 +42,22 @@ namespace osu.Game.Rulesets.UI
         /// </summary>
         public event Action<DrawableHitObject, JudgementResult> RevertResult;
 
+        /// <summary>
+        /// Invoked when a <see cref="HitObject"/> becomes used by a <see cref="DrawableHitObject"/>.
+        /// </summary>
+        /// <remarks>
+        /// If this <see cref="HitObjectContainer"/> uses pooled objects, this represents the time when the <see cref="HitObject"/>s become alive.
+        /// </remarks>
+        public event Action<HitObject> HitObjectUsageBegan;
+
+        /// <summary>
+        /// Invoked when a <see cref="HitObject"/> becomes unused by a <see cref="DrawableHitObject"/>.
+        /// </summary>
+        /// <remarks>
+        /// If this <see cref="HitObjectContainer"/> uses pooled objects, this represents the time when the <see cref="HitObject"/>s become dead.
+        /// </remarks>
+        public event Action<HitObject> HitObjectUsageFinished;
+
         private readonly Dictionary<DrawableHitObject, IBindable> startTimeMap = new Dictionary<DrawableHitObject, IBindable>();
         private readonly Dictionary<HitObjectLifetimeEntry, DrawableHitObject> drawableMap = new Dictionary<HitObjectLifetimeEntry, DrawableHitObject>();
         private readonly LifetimeEntryManager lifetimeManager = new LifetimeEntryManager();
@@ -88,6 +104,8 @@ namespace osu.Game.Rulesets.UI
 
             bindStartTime(drawable);
             AddInternal(drawableMap[entry] = drawable, false);
+
+            HitObjectUsageBegan?.Invoke(entry.HitObject);
         }
 
         private void removeDrawable(HitObjectLifetimeEntry entry)
@@ -103,6 +121,8 @@ namespace osu.Game.Rulesets.UI
 
             unbindStartTime(drawable);
             RemoveInternal(drawable);
+
+            HitObjectUsageFinished?.Invoke(entry.HitObject);
         }
 
         #endregion
diff --git a/osu.Game/Rulesets/UI/Playfield.cs b/osu.Game/Rulesets/UI/Playfield.cs
index 454880c885..8f2be81c36 100644
--- a/osu.Game/Rulesets/UI/Playfield.cs
+++ b/osu.Game/Rulesets/UI/Playfield.cs
@@ -29,6 +29,22 @@ namespace osu.Game.Rulesets.UI
         /// </summary>
         public event Action<DrawableHitObject, JudgementResult> RevertResult;
 
+        /// <summary>
+        /// Invoked when a <see cref="HitObject"/> becomes used by a <see cref="DrawableHitObject"/>.
+        /// </summary>
+        /// <remarks>
+        /// If this <see cref="HitObjectContainer"/> uses pooled objects, this represents the time when the <see cref="HitObject"/>s become alive.
+        /// </remarks>
+        public event Action<HitObject> HitObjectUsageBegan;
+
+        /// <summary>
+        /// Invoked when a <see cref="HitObject"/> becomes unused by a <see cref="DrawableHitObject"/>.
+        /// </summary>
+        /// <remarks>
+        /// If this <see cref="HitObjectContainer"/> uses pooled objects, this represents the time when the <see cref="HitObject"/>s become dead.
+        /// </remarks>
+        public event Action<HitObject> HitObjectUsageFinished;
+
         /// <summary>
         /// The <see cref="DrawableHitObject"/> contained in this Playfield.
         /// </summary>
@@ -88,6 +104,8 @@ namespace osu.Game.Rulesets.UI
             {
                 h.NewResult += (d, r) => NewResult?.Invoke(d, r);
                 h.RevertResult += (d, r) => RevertResult?.Invoke(d, r);
+                h.HitObjectUsageBegan += o => HitObjectUsageBegan?.Invoke(o);
+                h.HitObjectUsageFinished += o => HitObjectUsageFinished?.Invoke(o);
             }));
         }
 
@@ -247,6 +265,8 @@ namespace osu.Game.Rulesets.UI
 
             otherPlayfield.NewResult += (d, r) => NewResult?.Invoke(d, r);
             otherPlayfield.RevertResult += (d, r) => RevertResult?.Invoke(d, r);
+            otherPlayfield.HitObjectUsageBegan += h => HitObjectUsageBegan?.Invoke(h);
+            otherPlayfield.HitObjectUsageFinished += h => HitObjectUsageFinished?.Invoke(h);
 
             nestedPlayfields.Value.Add(otherPlayfield);
         }