Add sound when players change ready state

osu.Game.Tests/Visual/RealtimeMultiplayer/TestSceneRealtimeReadyButton.cs

@@ -7,6 +7,7 @@ using osu.Framework.Allocation;
 using osu.Framework.Audio;
 using osu.Framework.Graphics;
 using osu.Framework.Platform;
+using osu.Framework.Utils;
 using osu.Game.Beatmaps;
 using osu.Game.Online.Multiplayer;
 using osu.Game.Online.RealtimeMultiplayer;
@@ -124,6 +125,36 @@ namespace osu.Game.Tests.Visual.RealtimeMultiplayer
             AddAssert("match not started", () => Client.Room?.Users[0].State == MultiplayerUserState.Idle);
         }
 
+        [TestCase(true)]
+        [TestCase(false)]
+        public void TestManyUsersChangingState(bool isHost)
+        {
+            const int users = 10;
+            AddStep("setup", () =>
+            {
+                Client.TransferHost(Client.Room?.Users[0].UserID ?? 0);
+                for (int i = 0; i < users; i++)
+                    Client.AddUser(new User { Id = i, Username = "Another user" });
+            });
+
+            if (!isHost)
+                AddStep("transfer host", () => Client.TransferHost(2));
+
+            addClickButtonStep();
+
+            AddRepeatStep("change user ready state", () =>
+            {
+                Client.ChangeUserState(RNG.Next(0, users), RNG.NextBool() ? MultiplayerUserState.Ready : MultiplayerUserState.Idle);
+            }, 20);
+
+            AddRepeatStep("ready all users", () =>
+            {
+                var nextUnready = Client.Room?.Users.FirstOrDefault(c => c.State == MultiplayerUserState.Idle);
+                if (nextUnready != null)
+                    Client.ChangeUserState(nextUnready.UserID, MultiplayerUserState.Ready);
+            }, users);
+        }
+
         private void addClickButtonStep() => AddStep("click button", () =>
         {
             InputManager.MoveMouseTo(button);

osu.Game/Screens/Multi/RealtimeMultiplayer/Match/RealtimeReadyButton.cs

@@ -5,6 +5,8 @@ using System.Diagnostics;
 using System.Linq;
 using JetBrains.Annotations;
 using osu.Framework.Allocation;
+using osu.Framework.Audio;
+using osu.Framework.Audio.Sample;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Game.Extensions;
@@ -31,8 +33,12 @@ namespace osu.Game.Screens.Multi.RealtimeMultiplayer.Match
         [Resolved]
         private OsuColour colours { get; set; }
 
+        private SampleChannel sampleReadyCount;
+
         private readonly ButtonWithTrianglesExposed button;
 
+        private int countReady;
+
         public RealtimeReadyButton()
         {
             InternalChild = button = new ButtonWithTrianglesExposed
@@ -44,6 +50,12 @@ namespace osu.Game.Screens.Multi.RealtimeMultiplayer.Match
             };
         }
 
+        [BackgroundDependencyLoader]
+        private void load(AudioManager audio)
+        {
+            sampleReadyCount = audio.Samples.Get(@"SongSelect/select-difficulty");
+        }
+
         protected override void OnRoomChanged()
         {
             base.OnRoomChanged();
@@ -60,6 +72,10 @@ namespace osu.Game.Screens.Multi.RealtimeMultiplayer.Match
 
             Debug.Assert(Room != null);
 
+            int newCountReady = Room.Users.Count(u => u.State == MultiplayerUserState.Ready);
+
+            string countText = $"({newCountReady} / {Room.Users.Count} ready)";
+
             switch (localUser.State)
             {
                 case MultiplayerUserState.Idle:
@@ -70,18 +86,32 @@ namespace osu.Game.Screens.Multi.RealtimeMultiplayer.Match
                 case MultiplayerUserState.Ready:
                     if (Room?.Host?.Equals(localUser) == true)
                     {
-                        int countReady = Room.Users.Count(u => u.State == MultiplayerUserState.Ready);
+                        button.Text = $"Start match {countText}";
-                        button.Text = $"Start match ({countReady} / {Room.Users.Count} ready)";
                         updateButtonColour(true);
                     }
                     else
                     {
-                        button.Text = "Waiting for host...";
+                        button.Text = $"Waiting for host... {countText}";
                         updateButtonColour(false);
                     }
 
                     break;
             }
+
+            if (newCountReady != countReady)
+            {
+                countReady = newCountReady;
+                Scheduler.AddOnce(playSound);
+            }
+        }
+
+        private void playSound()
+        {
+            if (sampleReadyCount != null)
+            {
+                sampleReadyCount.Frequency.Value = 0.77f + countReady * 0.06f;
+                sampleReadyCount.Play();
+            }
         }
 
         private void updateButtonColour(bool green)