From 84a1a86c6329ff60021190f4c070c28707e736c3 Mon Sep 17 00:00:00 2001
From: ekrctb <ekrctb@gmail.com>
Date: Tue, 18 May 2021 19:55:31 +0900
Subject: [PATCH] Revert "Use entry to calculate lifetime in ScrollingHOC"

This reverts commit 632bb70e
---
 .../Scrolling/ScrollingHitObjectContainer.cs  | 60 +++++++++++--------
 1 file changed, 36 insertions(+), 24 deletions(-)

diff --git a/osu.Game/Rulesets/UI/Scrolling/ScrollingHitObjectContainer.cs b/osu.Game/Rulesets/UI/Scrolling/ScrollingHitObjectContainer.cs
index 915bab9a51..a9eaf3da68 100644
--- a/osu.Game/Rulesets/UI/Scrolling/ScrollingHitObjectContainer.cs
+++ b/osu.Game/Rulesets/UI/Scrolling/ScrollingHitObjectContainer.cs
@@ -5,9 +5,7 @@ using System.Collections.Generic;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
-using osu.Framework.Graphics.Primitives;
 using osu.Framework.Layout;
-using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.Objects.Types;
 using osuTK;
@@ -19,18 +17,16 @@ namespace osu.Game.Rulesets.UI.Scrolling
         private readonly IBindable<double> timeRange = new BindableDouble();
         private readonly IBindable<ScrollingDirection> direction = new Bindable<ScrollingDirection>();
 
+        /// <summary>
+        /// Hit objects which require lifetime computation in the next update call.
+        /// </summary>
+        private readonly HashSet<DrawableHitObject> toComputeLifetime = new HashSet<DrawableHitObject>();
+
         /// <summary>
         /// A set containing all <see cref="HitObjectContainer.AliveObjects"/> which have an up-to-date layout.
         /// </summary>
         private readonly HashSet<DrawableHitObject> layoutComputed = new HashSet<DrawableHitObject>();
 
-        /// <summary>
-        /// A conservative estimate of maximum bounding box of a <see cref="DrawableHitObject"/>
-        /// with respect to the start time position of the hit object.
-        /// It is used to calculate when the object appears inbound.
-        /// </summary>
-        protected virtual RectangleF GetDrawRectangle(HitObjectLifetimeEntry entry) => new RectangleF().Inflate(100);
-
         [Resolved]
         private IScrollingInfo scrollingInfo { get; set; }
 
@@ -58,6 +54,7 @@ namespace osu.Game.Rulesets.UI.Scrolling
         {
             base.Clear();
 
+            toComputeLifetime.Clear();
             layoutComputed.Clear();
         }
 
@@ -169,6 +166,7 @@ namespace osu.Game.Rulesets.UI.Scrolling
 
         private void onRemoveRecursive(DrawableHitObject hitObject)
         {
+            toComputeLifetime.Remove(hitObject);
             layoutComputed.Remove(hitObject);
 
             hitObject.DefaultsApplied -= invalidateHitObject;
@@ -177,11 +175,14 @@ namespace osu.Game.Rulesets.UI.Scrolling
                 onRemoveRecursive(nested);
         }
 
+        /// <summary>
+        /// Make this <see cref="DrawableHitObject"/> lifetime and layout computed in next update.
+        /// </summary>
         private void invalidateHitObject(DrawableHitObject hitObject)
         {
-            if (hitObject.ParentHitObject == null)
-                updateLifetime(hitObject.Entry);
-
+            // Lifetime computation is delayed until next update because
+            // when the hit object is not pooled this container is not loaded here and `scrollLength` cannot be computed.
+            toComputeLifetime.Add(hitObject);
             layoutComputed.Remove(hitObject);
         }
 
@@ -193,8 +194,13 @@ namespace osu.Game.Rulesets.UI.Scrolling
 
             if (!layoutCache.IsValid)
             {
-                foreach (var entry in Entries)
-                    updateLifetime(entry);
+                toComputeLifetime.Clear();
+
+                foreach (var hitObject in Objects)
+                {
+                    if (hitObject.HitObject != null)
+                        toComputeLifetime.Add(hitObject);
+                }
 
                 layoutComputed.Clear();
 
@@ -214,6 +220,11 @@ namespace osu.Game.Rulesets.UI.Scrolling
 
                 layoutCache.Validate();
             }
+
+            foreach (var hitObject in toComputeLifetime)
+                hitObject.LifetimeStart = computeOriginAdjustedLifetimeStart(hitObject);
+
+            toComputeLifetime.Clear();
         }
 
         protected override void UpdateAfterChildrenLife()
@@ -236,31 +247,32 @@ namespace osu.Game.Rulesets.UI.Scrolling
             }
         }
 
-        private void updateLifetime(HitObjectLifetimeEntry entry)
+        private double computeOriginAdjustedLifetimeStart(DrawableHitObject hitObject)
         {
-            var rectangle = GetDrawRectangle(entry);
-            float startOffset = 0;
+            float originAdjustment = 0.0f;
 
+            // calculate the dimension of the part of the hitobject that should already be visible
+            // when the hitobject origin first appears inside the scrolling container
             switch (direction.Value)
             {
-                case ScrollingDirection.Right:
-                    startOffset = rectangle.Right;
+                case ScrollingDirection.Up:
+                    originAdjustment = hitObject.OriginPosition.Y;
                     break;
 
                 case ScrollingDirection.Down:
-                    startOffset = rectangle.Bottom;
+                    originAdjustment = hitObject.DrawHeight - hitObject.OriginPosition.Y;
                     break;
 
                 case ScrollingDirection.Left:
-                    startOffset = -rectangle.Left;
+                    originAdjustment = hitObject.OriginPosition.X;
                     break;
 
-                case ScrollingDirection.Up:
-                    startOffset = -rectangle.Top;
+                case ScrollingDirection.Right:
+                    originAdjustment = hitObject.DrawWidth - hitObject.OriginPosition.X;
                     break;
             }
 
-            entry.LifetimeStart = scrollingInfo.Algorithm.GetDisplayStartTime(entry.HitObject.StartTime, startOffset, timeRange.Value, scrollLength);
+            return scrollingInfo.Algorithm.GetDisplayStartTime(hitObject.HitObject.StartTime, originAdjustment, timeRange.Value, scrollLength);
         }
 
         private void updateLayoutRecursive(DrawableHitObject hitObject)