Add the ability for the game OSD to display user bindings

Adds binding display for mouse button toggle / HUD toggle keys.

- [ ] Depends on #10786 for ease-of-merge

osu.Game/Configuration/OsuConfigManager.cs

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using System.Diagnostics;
 using osu.Framework.Bindables;
 using osu.Framework.Configuration;
 using osu.Framework.Configuration.Tracking;
@@ -9,6 +10,7 @@ using osu.Framework.Extensions;
 using osu.Framework.Platform;
 using osu.Framework.Testing;
 using osu.Game.Input;
+using osu.Game.Input.Bindings;
 using osu.Game.Overlays;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Screens.Select;
@@ -173,19 +175,28 @@ namespace osu.Game.Configuration
             }
         }
 
-        public override TrackedSettings CreateTrackedSettings() => new TrackedSettings
+        public override TrackedSettings CreateTrackedSettings()
         {
-            new TrackedSetting<bool>(OsuSetting.MouseDisableButtons, v => new SettingDescription(!v, "gameplay mouse buttons", v ? "disabled" : "enabled")),
+            // these need to be assigned in normal game startup scenarios.
-            new TrackedSetting<HUDVisibilityMode>(OsuSetting.HUDVisibilityMode, m => new SettingDescription(m, "HUD Visibility", m.GetDescription())),
+            Debug.Assert(LookupKeyBindings != null);
-            new TrackedSetting<ScalingMode>(OsuSetting.Scaling, m => new SettingDescription(m, "scaling", m.GetDescription())),
+            Debug.Assert(LookupSkinName != null);
-            new TrackedSetting<int>(OsuSetting.Skin, m =>
-            {
-                string skinName = LookupSkinName?.Invoke(m) ?? string.Empty;
-                return new SettingDescription(skinName, "skin", skinName);
-            })
-        };
 
-        public Func<int, string> LookupSkinName { get; set; }
+            return new TrackedSettings
+            {
+                new TrackedSetting<bool>(OsuSetting.MouseDisableButtons, v => new SettingDescription(!v, "gameplay mouse buttons", v ? "disabled" : "enabled", LookupKeyBindings(GlobalAction.ToggleGameplayMouseButtons))),
+                new TrackedSetting<HUDVisibilityMode>(OsuSetting.HUDVisibilityMode, m => new SettingDescription(m, "HUD Visibility", m.GetDescription(), $"cycle: shift-tab quick view: {LookupKeyBindings(GlobalAction.HoldForHUD)}")),
+                new TrackedSetting<ScalingMode>(OsuSetting.Scaling, m => new SettingDescription(m, "scaling", m.GetDescription())),
+                new TrackedSetting<int>(OsuSetting.Skin, m =>
+                {
+                    string skinName = LookupSkinName(m) ?? string.Empty;
+                    return new SettingDescription(skinName, "skin", skinName);
+                })
+            };
+        }
+
+        public Func<int, string> LookupSkinName { private get; set; }
+
+        public Func<GlobalAction, string> LookupKeyBindings { private get; set; }
     }
 
     public enum OsuSetting

osu.Game/Input/KeyBindingStore.cs

@@ -32,6 +32,23 @@ namespace osu.Game.Input
 
         public void Register(KeyBindingContainer manager) => insertDefaults(manager.DefaultKeyBindings);
 
+        /// <summary>
+        /// Retrieve all user-defined key combinations (in a format that can be displayed) for a specific action.
+        /// </summary>
+        /// <param name="globalAction">The action to lookup.</param>
+        /// <returns>A set of display strings for all the user's key configuration for the action.</returns>
+        public IEnumerable<string> GetReadableKeyCombinationsFor(GlobalAction globalAction)
+        {
+            foreach (var action in Query().Where(b => (GlobalAction)b.Action == globalAction))
+            {
+                string str = action.KeyCombination.ReadableString();
+
+                // even if found, the readable string may be empty for an unbound action.
+                if (str.Length > 0)
+                    yield return str;
+            }
+        }
+
         private void insertDefaults(IEnumerable<KeyBinding> defaults, int? rulesetId = null, int? variant = null)
         {
             using (var usage = ContextFactory.GetForWrite())

osu.Game/OsuGame.cs

@@ -552,6 +552,16 @@ namespace osu.Game
             // if this becomes a more common thing, tracked settings should be reconsidered to allow local DI.
             LocalConfig.LookupSkinName = id => SkinManager.GetAllUsableSkins().FirstOrDefault(s => s.ID == id)?.ToString() ?? "Unknown";
 
+            LocalConfig.LookupKeyBindings = l =>
+            {
+                var combinations = KeyBindingStore.GetReadableKeyCombinationsFor(l).ToArray();
+
+                if (combinations.Length == 0)
+                    return "none";
+
+                return string.Join(" or ", combinations);
+            };
+
             Container logoContainer;
             BackButton.Receptor receptor;