Split RulesetInputManager out to FrameStabilityContainer

osu.Game/Rulesets/UI/FrameStabilityContainer.cs

@@ -0,0 +1,161 @@
+// 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;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Timing;
+using osu.Game.Input.Handlers;
+using osu.Game.Screens.Play;
+
+namespace osu.Game.Rulesets.UI
+{
+    /// <summary>
+    /// A container which consumes a parent gameplay clock and standardises frame counts for children.
+    /// Will ensure a minimum of 40 frames per clock second is maintained, regardless of any system lag or seeks.
+    /// </summary>
+    public class FrameStabilityContainer : Container, IHasReplayHandler
+    {
+        public FrameStabilityContainer()
+        {
+            RelativeSizeAxes = Axes.Both;
+            gameplayClock = new GameplayClock(framedClock = new FramedClock(manualClock = new ManualClock()));
+        }
+
+        #region Clock control
+
+        private readonly ManualClock manualClock;
+
+        private readonly FramedClock framedClock;
+
+        [Cached]
+        private GameplayClock gameplayClock;
+
+        private IFrameBasedClock parentGameplayClock;
+
+        [BackgroundDependencyLoader(true)]
+        private void load(GameplayClock clock)
+        {
+            if (clock != null)
+                parentGameplayClock = clock;
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+            setClock();
+        }
+
+        /// <summary>
+        /// Whether we are running up-to-date with our parent clock.
+        /// If not, we will need to keep processing children until we catch up.
+        /// </summary>
+        private bool requireMoreUpdateLoops;
+
+        /// <summary>
+        /// Whether we are in a valid state (ie. should we keep processing children frames).
+        /// This should be set to false when the replay is, for instance, waiting for future frames to arrive.
+        /// </summary>
+        private bool validState;
+
+        protected override bool RequiresChildrenUpdate => base.RequiresChildrenUpdate && validState;
+
+        private bool isAttached => ReplayInputHandler != null;
+
+        private const int max_catch_up_updates_per_frame = 50;
+
+        private const double sixty_frame_time = 1000.0 / 60;
+
+        public override bool UpdateSubTree()
+        {
+            requireMoreUpdateLoops = true;
+            validState = true;
+
+            int loops = 0;
+
+            while (validState && requireMoreUpdateLoops && loops++ < max_catch_up_updates_per_frame)
+            {
+                updateClock();
+
+                if (validState)
+                {
+                    base.UpdateSubTree();
+                    UpdateSubTreeMasking(this, ScreenSpaceDrawQuad.AABBFloat);
+                }
+            }
+
+            return true;
+        }
+
+        private void updateClock()
+        {
+            if (parentGameplayClock == null)
+                setClock(); // LoadComplete may not be run yet, but we still want the clock.
+
+            validState = true;
+
+            manualClock.Rate = parentGameplayClock.Rate;
+            manualClock.IsRunning = parentGameplayClock.IsRunning;
+
+            var newProposedTime = parentGameplayClock.CurrentTime;
+
+            try
+            {
+                if (Math.Abs(manualClock.CurrentTime - newProposedTime) > sixty_frame_time * 1.2f)
+                {
+                    newProposedTime = manualClock.Rate > 0
+                        ? Math.Min(newProposedTime, manualClock.CurrentTime + sixty_frame_time)
+                        : Math.Max(newProposedTime, manualClock.CurrentTime - sixty_frame_time);
+                }
+
+                if (!isAttached)
+                {
+                    manualClock.CurrentTime = newProposedTime;
+                }
+                else
+                {
+                    double? newTime = ReplayInputHandler.SetFrameFromTime(newProposedTime);
+
+                    if (newTime == null)
+                    {
+                        // we shouldn't execute for this time value. probably waiting on more replay data.
+                        validState = false;
+
+                        requireMoreUpdateLoops = true;
+                        manualClock.CurrentTime = newProposedTime;
+                        return;
+                    }
+
+                    manualClock.CurrentTime = newTime.Value;
+                }
+
+                requireMoreUpdateLoops = manualClock.CurrentTime != parentGameplayClock.CurrentTime;
+            }
+            finally
+            {
+                // 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();
+            }
+        }
+
+        private void setClock()
+        {
+            // in case a parent gameplay clock isn't available, just use the parent clock.
+            if (parentGameplayClock == null)
+                parentGameplayClock = Clock;
+
+            Clock = gameplayClock;
+            ProcessCustomClock = false;
+        }
+
+        #endregion
+
+        #region IHasReplayHandler
+
+        public ReplayInputHandler ReplayInputHandler { get; set; }
+
+        #endregion
+    }
+}