From 5d8c153c1e21949156a0dbf54b9cf8d71bca4c4d Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Tue, 5 Jan 2021 16:41:03 +0900
Subject: [PATCH] Move schedule logic to buttons rather than section

It turns out there's some quite convoluted scheduling / order of
execution requirements of ModSelectOverlay and ModSection. Applying
scheduling causes a runaway condition ending in zero frames after many
mod button changes.

I wanted to avoid rewriting the whole component, so have just moved the
schedule to guard against the part where drawables are actually changed.
---
 osu.Game/Overlays/Mods/ModButton.cs  | 62 +++++++++++++++-------------
 osu.Game/Overlays/Mods/ModSection.cs |  8 ++--
 2 files changed, 37 insertions(+), 33 deletions(-)

diff --git a/osu.Game/Overlays/Mods/ModButton.cs b/osu.Game/Overlays/Mods/ModButton.cs
index e574828cd2..51c8bcf9a9 100644
--- a/osu.Game/Overlays/Mods/ModButton.cs
+++ b/osu.Game/Overlays/Mods/ModButton.cs
@@ -64,41 +64,45 @@ namespace osu.Game.Overlays.Mods
             if (newIndex >= 0 && !Mods[newIndex].HasImplementation)
                 return false;
 
-            selectedIndex = newIndex;
-            Mod modAfter = SelectedMod ?? Mods[0];
-
-            if (beforeSelected != Selected)
+            Schedule(() =>
             {
-                iconsContainer.RotateTo(Selected ? 5f : 0f, 300, Easing.OutElastic);
-                iconsContainer.ScaleTo(Selected ? 1.1f : 1f, 300, Easing.OutElastic);
-            }
+                selectedIndex = newIndex;
+                Mod modAfter = SelectedMod ?? Mods[0];
 
-            if (modBefore != modAfter)
-            {
-                const float rotate_angle = 16;
-
-                foregroundIcon.RotateTo(rotate_angle * direction, mod_switch_duration, mod_switch_easing);
-                backgroundIcon.RotateTo(-rotate_angle * direction, mod_switch_duration, mod_switch_easing);
-
-                backgroundIcon.Mod = modAfter;
-
-                using (BeginDelayedSequence(mod_switch_duration, true))
+                if (beforeSelected != Selected)
                 {
-                    foregroundIcon
-                        .RotateTo(-rotate_angle * direction)
-                        .RotateTo(0f, mod_switch_duration, mod_switch_easing);
-
-                    backgroundIcon
-                        .RotateTo(rotate_angle * direction)
-                        .RotateTo(0f, mod_switch_duration, mod_switch_easing);
-
-                    Schedule(() => displayMod(modAfter));
+                    iconsContainer.RotateTo(Selected ? 5f : 0f, 300, Easing.OutElastic);
+                    iconsContainer.ScaleTo(Selected ? 1.1f : 1f, 300, Easing.OutElastic);
                 }
-            }
 
-            foregroundIcon.Selected.Value = Selected;
+                if (modBefore != modAfter)
+                {
+                    const float rotate_angle = 16;
+
+                    foregroundIcon.RotateTo(rotate_angle * direction, mod_switch_duration, mod_switch_easing);
+                    backgroundIcon.RotateTo(-rotate_angle * direction, mod_switch_duration, mod_switch_easing);
+
+                    backgroundIcon.Mod = modAfter;
+
+                    using (BeginDelayedSequence(mod_switch_duration, true))
+                    {
+                        foregroundIcon
+                            .RotateTo(-rotate_angle * direction)
+                            .RotateTo(0f, mod_switch_duration, mod_switch_easing);
+
+                        backgroundIcon
+                            .RotateTo(rotate_angle * direction)
+                            .RotateTo(0f, mod_switch_duration, mod_switch_easing);
+
+                        Schedule(() => displayMod(modAfter));
+                    }
+                }
+
+                foregroundIcon.Selected.Value = Selected;
+
+                SelectionChanged?.Invoke(SelectedMod);
+            });
 
-            SelectionChanged?.Invoke(SelectedMod);
             return true;
         }
 
diff --git a/osu.Game/Overlays/Mods/ModSection.cs b/osu.Game/Overlays/Mods/ModSection.cs
index 47b101c2b0..0107f94dcf 100644
--- a/osu.Game/Overlays/Mods/ModSection.cs
+++ b/osu.Game/Overlays/Mods/ModSection.cs
@@ -104,7 +104,7 @@ namespace osu.Game.Overlays.Mods
         /// </summary>
         /// <param name="modTypes">The types of <see cref="Mod"/>s which should be deselected.</param>
         /// <param name="immediate">Set to true to bypass animations and update selections immediately.</param>
-        public void DeselectTypes(IEnumerable<Type> modTypes, bool immediate = false) => Schedule(() =>
+        public void DeselectTypes(IEnumerable<Type> modTypes, bool immediate = false)
         {
             int delay = 0;
 
@@ -124,13 +124,13 @@ namespace osu.Game.Overlays.Mods
                     }
                 }
             }
-        });
+        }
 
         /// <summary>
         /// Select one or more mods in this section and deselects all other ones.
         /// </summary>
         /// <param name="modTypes">The types of <see cref="Mod"/>s which should be selected.</param>
-        public void SelectTypes(IEnumerable<Type> modTypes) => Schedule(() =>
+        public void SelectTypes(IEnumerable<Type> modTypes)
         {
             foreach (var button in buttons)
             {
@@ -141,7 +141,7 @@ namespace osu.Game.Overlays.Mods
                 else
                     button.Deselect();
             }
-        });
+        }
 
         protected ModSection()
         {