From 420df124b5fba03eaf59196b5a2d70f2c973f4c8 Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Thu, 3 Jun 2021 17:27:21 +0900
Subject: [PATCH] Add framestable-bypassing seek for spectator

---
 .../Visual/Gameplay/TestSceneHitErrorMeter.cs |  1 +
 osu.Game/Rulesets/UI/DrawableRuleset.cs       |  4 ++-
 osu.Game/Screens/Play/Player.cs               | 18 ++++++++++++
 osu.Game/Screens/Play/SpectatorPlayer.cs      | 28 ++++++++++---------
 4 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/osu.Game.Tests/Visual/Gameplay/TestSceneHitErrorMeter.cs b/osu.Game.Tests/Visual/Gameplay/TestSceneHitErrorMeter.cs
index 2c5443fe08..ab13095af4 100644
--- a/osu.Game.Tests/Visual/Gameplay/TestSceneHitErrorMeter.cs
+++ b/osu.Game.Tests/Visual/Gameplay/TestSceneHitErrorMeter.cs
@@ -177,6 +177,7 @@ namespace osu.Game.Tests.Visual.Gameplay
             public override Container Overlays { get; }
             public override Container FrameStableComponents { get; }
             public override IFrameStableClock FrameStableClock { get; }
+            internal override bool FrameStablePlayback { get; set; }
             public override IReadOnlyList<Mod> Mods { get; }
 
             public override double GameplayStartTime { get; }
diff --git a/osu.Game/Rulesets/UI/DrawableRuleset.cs b/osu.Game/Rulesets/UI/DrawableRuleset.cs
index a2dade2627..0cd5804fd0 100644
--- a/osu.Game/Rulesets/UI/DrawableRuleset.cs
+++ b/osu.Game/Rulesets/UI/DrawableRuleset.cs
@@ -71,7 +71,7 @@ namespace osu.Game.Rulesets.UI
         /// <summary>
         /// Whether to enable frame-stable playback.
         /// </summary>
-        internal bool FrameStablePlayback
+        internal override bool FrameStablePlayback
         {
             get => frameStablePlayback;
             set
@@ -432,6 +432,8 @@ namespace osu.Game.Rulesets.UI
         /// </summary>
         public abstract IFrameStableClock FrameStableClock { get; }
 
+        internal abstract bool FrameStablePlayback { get; set; }
+
         /// <summary>
         /// The mods which are to be applied.
         /// </summary>
diff --git a/osu.Game/Screens/Play/Player.cs b/osu.Game/Screens/Play/Player.cs
index 2258d509b7..f8f9103c89 100644
--- a/osu.Game/Screens/Play/Player.cs
+++ b/osu.Game/Screens/Play/Player.cs
@@ -576,6 +576,24 @@ namespace osu.Game.Screens.Play
         /// <param name="time">The destination time to seek to.</param>
         public void Seek(double time) => GameplayClockContainer.Seek(time);
 
+        /// <summary>
+        /// Seeks to a specific time in gameplay, bypassing frame stability.
+        /// </summary>
+        /// <remarks>
+        /// Intermediate hitobject judgements may not be applied or reverted correctly during this seek.
+        /// </remarks>
+        /// <param name="time">The destination time to seek to.</param>
+        public void NonFrameStableSeek(double time)
+        {
+            bool wasFrameStable = DrawableRuleset.FrameStablePlayback;
+            DrawableRuleset.FrameStablePlayback = false;
+
+            Seek(time);
+
+            // Delay resetting frame-stable playback for one frame to give the FrameStabilityContainer a chance to seek.
+            ScheduleAfterChildren(() => DrawableRuleset.FrameStablePlayback = wasFrameStable);
+        }
+
         /// <summary>
         /// Restart gameplay via a parent <see cref="PlayerLoader"/>.
         /// <remarks>This can be called from a child screen in order to trigger the restart process.</remarks>
diff --git a/osu.Game/Screens/Play/SpectatorPlayer.cs b/osu.Game/Screens/Play/SpectatorPlayer.cs
index c5e26bdef6..605702c8e2 100644
--- a/osu.Game/Screens/Play/SpectatorPlayer.cs
+++ b/osu.Game/Screens/Play/SpectatorPlayer.cs
@@ -1,11 +1,9 @@
 // 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.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Screens;
-using osu.Game.Beatmaps;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Online.Spectator;
@@ -50,6 +48,7 @@ namespace osu.Game.Screens.Play
             base.LoadComplete();
 
             spectatorClient.OnNewFrames += userSentFrames;
+            seekToGameplay();
         }
 
         private void userSentFrames(int userId, FrameDataBundle bundle)
@@ -73,6 +72,20 @@ namespace osu.Game.Screens.Play
 
                 score.Replay.Frames.Add(convertedFrame);
             }
+
+            seekToGameplay();
+        }
+
+        private bool seekedToGameplay;
+
+        private void seekToGameplay()
+        {
+            if (seekedToGameplay || score.Replay.Frames.Count == 0)
+                return;
+
+            NonFrameStableSeek(score.Replay.Frames[0].Time);
+
+            seekedToGameplay = true;
         }
 
         protected override ResultsScreen CreateResults(ScoreInfo score)
@@ -85,17 +98,6 @@ namespace osu.Game.Screens.Play
             DrawableRuleset?.SetReplayScore(score);
         }
 
-        protected override GameplayClockContainer CreateGameplayClockContainer(WorkingBeatmap beatmap, double gameplayStart)
-        {
-            // if we already have frames, start gameplay at the point in time they exist, should they be too far into the beatmap.
-            double? firstFrameTime = score.Replay.Frames.FirstOrDefault()?.Time;
-
-            if (firstFrameTime == null || firstFrameTime <= gameplayStart + 5000)
-                return base.CreateGameplayClockContainer(beatmap, gameplayStart);
-
-            return new MasterGameplayClockContainer(beatmap, firstFrameTime.Value, true);
-        }
-
         public override bool OnExiting(IScreen next)
         {
             spectatorClient.OnUserBeganPlaying -= userBeganPlaying;