Merge pull request #33241 from bdach/participant-list-transform-spam

Implement list virtualisation in multiplayer participants list
2026-05-17 05:52:36 +08:00 · 2025-05-26 23:58:27 +09:00
parent dc09d170f3 ea8ad6b637
commit 7cc89dfd4e
4 changed files with 190 additions and 100 deletions
@@ -3,6 +3,7 @@

 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 using NUnit.Framework;
 using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
@@ -15,6 +16,7 @@ using osu.Game.Online;
 using osu.Game.Online.API;
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Online.Multiplayer;
+using osu.Game.Online.Multiplayer.MatchTypes.TeamVersus;
 using osu.Game.Online.Rooms;
 using osu.Game.Rulesets.Catch.Mods;
 using osu.Game.Rulesets.Mods;
@@ -24,6 +26,7 @@ using osu.Game.Screens.OnlinePlay.Multiplayer.Participants;
 using osu.Game.Tests.Resources;
 using osu.Game.Users;
 using osuTK;
+using osuTK.Input;

 namespace osu.Game.Tests.Visual.Multiplayer
 {
@@ -41,7 +44,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
        [Test]
        public void TestAddUser()
        {
-            AddAssert("one unique panel", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.User).Distinct().Count() == 1);
+            AddAssert("one unique panel", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.Current.Value).Distinct().Count() == 1);

            AddStep("add user", () => MultiplayerClient.AddUser(new APIUser
            {
@@ -50,20 +53,20 @@ namespace osu.Game.Tests.Visual.Multiplayer
                CoverUrl = TestResources.COVER_IMAGE_3,
            }));

-            AddAssert("two unique panels", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.User).Distinct().Count() == 2);
+            AddAssert("two unique panels", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.Current.Value).Distinct().Count() == 2);
        }

        [Test]
        public void TestAddUnresolvedUser()
        {
-            AddAssert("one unique panel", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.User).Distinct().Count() == 1);
+            AddAssert("one unique panel", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.Current.Value).Distinct().Count() == 1);

            AddStep("add non-resolvable user", () => MultiplayerClient.TestAddUnresolvedUser());
            AddUntilStep("null user added", () => MultiplayerClient.ClientRoom.AsNonNull().Users.Count(u => u.User == null) == 1);

-            AddUntilStep("two unique panels", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.User).Distinct().Count() == 2);
+            AddUntilStep("two unique panels", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.Current.Value).Distinct().Count() == 2);

-            AddStep("kick null user", () => this.ChildrenOfType<ParticipantPanel>().Single(p => p.User.User == null)
+            AddStep("kick null user", () => this.ChildrenOfType<ParticipantPanel>().Single(p => p.Current.Value.User == null)
                                                .ChildrenOfType<ParticipantPanel.KickButton>().Single().TriggerClick());

            AddUntilStep("null user kicked", () => MultiplayerClient.ClientRoom.AsNonNull().Users.Count == 1);
@@ -86,7 +89,7 @@ namespace osu.Game.Tests.Visual.Multiplayer

            AddStep("remove host", () => MultiplayerClient.RemoveUser(API.LocalUser.Value));

-            AddAssert("single panel is for second user", () => this.ChildrenOfType<ParticipantPanel>().Single().User.UserID == secondUser?.Id);
+            AddAssert("single panel is for second user", () => this.ChildrenOfType<ParticipantPanel>().Single().Current.Value.UserID == secondUser?.Id);
        }

        [Test]
@@ -122,7 +125,7 @@ namespace osu.Game.Tests.Visual.Multiplayer

            AddRepeatStep("increment progress", () =>
            {
-                float progress = this.ChildrenOfType<ParticipantPanel>().Single().User.BeatmapAvailability.DownloadProgress ?? 0;
+                float progress = this.ChildrenOfType<ParticipantPanel>().Single().Current.Value.BeatmapAvailability.DownloadProgress ?? 0;
                MultiplayerClient.ChangeBeatmapAvailability(BeatmapAvailability.Downloading(progress + RNG.NextSingle(0.1f)));
            }, 25);

@@ -163,13 +166,17 @@ namespace osu.Game.Tests.Visual.Multiplayer
                CoverUrl = TestResources.COVER_IMAGE_3,
            }));

-            AddUntilStep("first user crown visible", () => this.ChildrenOfType<ParticipantPanel>().ElementAt(0).ChildrenOfType<SpriteIcon>().First().Alpha == 1);
-            AddUntilStep("second user crown hidden", () => this.ChildrenOfType<ParticipantPanel>().ElementAt(1).ChildrenOfType<SpriteIcon>().First().Alpha == 0);
+            AddUntilStep("first user crown visible",
+                () => this.ChildrenOfType<ParticipantPanel>().Single(p => p.Current.Value.UserID == 1001).ChildrenOfType<SpriteIcon>().First().Alpha == 1);
+            AddUntilStep("second user crown hidden",
+                () => this.ChildrenOfType<ParticipantPanel>().Single(p => p.Current.Value.UserID == 3).ChildrenOfType<SpriteIcon>().First().Alpha == 0);

            AddStep("make second user host", () => MultiplayerClient.TransferHost(3));

-            AddUntilStep("first user crown hidden", () => this.ChildrenOfType<ParticipantPanel>().ElementAt(0).ChildrenOfType<SpriteIcon>().First().Alpha == 0);
-            AddUntilStep("second user crown visible", () => this.ChildrenOfType<ParticipantPanel>().ElementAt(1).ChildrenOfType<SpriteIcon>().First().Alpha == 1);
+            AddUntilStep("first user crown visible",
+                () => this.ChildrenOfType<ParticipantPanel>().Single(p => p.Current.Value.UserID == 1001).ChildrenOfType<SpriteIcon>().First().Alpha == 0);
+            AddUntilStep("second user crown hidden",
+                () => this.ChildrenOfType<ParticipantPanel>().Single(p => p.Current.Value.UserID == 3).ChildrenOfType<SpriteIcon>().First().Alpha == 1);
        }

        [Test]
@@ -185,9 +192,9 @@ namespace osu.Game.Tests.Visual.Multiplayer
            AddStep("make second user host", () => MultiplayerClient.TransferHost(3));
            AddAssert("second user above first", () =>
            {
-                var first = this.ChildrenOfType<ParticipantPanel>().ElementAt(0);
-                var second = this.ChildrenOfType<ParticipantPanel>().ElementAt(1);
-                return second.Y < first.Y;
+                var first = this.ChildrenOfType<ParticipantPanel>().Single(u => u.Current.Value.UserID == 1001);
+                var second = this.ChildrenOfType<ParticipantPanel>().Single(u => u.Current.Value.UserID == 3);
+                return second.ScreenSpaceDrawQuad.TopLeft.Y < first.ScreenSpaceDrawQuad.TopLeft.Y;
            });
        }

@@ -230,7 +237,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
        [Test]
        public void TestManyUsers()
        {
-            const int users_count = 20;
+            const int users_count = 200;

            AddStep("add many users", () =>
            {
@@ -276,6 +283,15 @@ namespace osu.Game.Tests.Visual.Multiplayer

            AddRepeatStep("switch hosts", () => MultiplayerClient.TransferHost(RNG.Next(0, users_count)), 10);
            AddStep("give host back", () => MultiplayerClient.TransferHost(API.LocalUser.Value.Id));
+
+            AddRepeatStep("perform many random state changes at once", () =>
+            {
+                for (int i = 0; i < users_count; ++i)
+                {
+                    MultiplayerClient.ChangeUserBeatmapAvailability(i, BeatmapAvailability.LocallyAvailable());
+                    MultiplayerClient.ChangeUserState(i, RNG.NextBool() ? MultiplayerUserState.Idle : MultiplayerUserState.Ready);
+                }
+            }, 100);
        }

        [Test]
@@ -434,6 +450,35 @@ namespace osu.Game.Tests.Visual.Multiplayer
            });
        }

+        [Test]
+        public void TestTeams()
+        {
+            AddStep("enable teams", () => MultiplayerClient.ChangeSettings(matchType: MatchType.TeamVersus));
+            AddAssert("one unique panel", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.Current.Value).Distinct().Count() == 1);
+
+            int id = 3;
+            AddRepeatStep("add users", () => MultiplayerClient.AddUser(new APIUser
+            {
+                Id = Interlocked.Increment(ref id),
+                Username = "Second",
+                CoverUrl = TestResources.COVER_IMAGE_3,
+            }), 5);
+
+            AddAssert("two unique panels", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.Current.Value).Distinct().Count() == 6);
+
+            AddAssert("user 1001 on red team",
+                () => (MultiplayerClient.ClientRoom!.Users.Single(u => u.UserID == 1001).MatchState as TeamVersusUserState)?.TeamID,
+                () => Is.EqualTo(0));
+            AddStep("click first team indicator", () =>
+            {
+                InputManager.MoveMouseTo(this.ChildrenOfType<TeamDisplay>().First());
+                InputManager.Click(MouseButton.Left);
+            });
+            AddAssert("user 1001 on blue team",
+                () => (MultiplayerClient.ClientRoom!.Users.Single(u => u.UserID == 1001).MatchState as TeamVersusUserState)?.TeamID,
+                () => Is.EqualTo(1));
+        }
+
        private void createNewParticipantsList()
        {
            ParticipantsList? participantsList = null;
@@ -7,12 +7,13 @@ using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Extensions.Color4Extensions;
-using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Colour;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Cursor;
+using osu.Framework.Graphics.Pooling;
 using osu.Framework.Graphics.Shapes;
 using osu.Framework.Graphics.Sprites;
 using osu.Framework.Graphics.UserInterface;
@@ -36,9 +37,17 @@ using osuTK.Graphics;

 namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
 {
-    public partial class ParticipantPanel : CompositeDrawable, IHasContextMenu
+    public partial class ParticipantPanel : PoolableDrawable, IHasContextMenu, IHasCurrentValue<MultiplayerRoomUser>
    {
-        public readonly MultiplayerRoomUser User;
+        public const int HEIGHT = 40;
+
+        public Bindable<MultiplayerRoomUser> Current
+        {
+            get => current.Current;
+            set => current.Current = value;
+        }
+
+        private readonly BindableWithCurrent<MultiplayerRoomUser> current = new BindableWithCurrent<MultiplayerRoomUser>(new MultiplayerRoomUser(-1));

        [Resolved]
        private IAPIProvider api { get; set; } = null!;
@@ -51,6 +60,10 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants

        private SpriteIcon crown = null!;

+        private UserCoverBackground userCover = null!;
+        private UpdateableAvatar userAvatar = null!;
+        private OsuSpriteText username = null!;
+        private Container teamFlagContainer = null!;
        private OsuSpriteText userRankText = null!;
        private StyleDisplayIcon userStyleDisplay = null!;
        private ModDisplay userModsDisplay = null!;
@@ -58,19 +71,15 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants

        private IconButton kickButton = null!;

-        public ParticipantPanel(MultiplayerRoomUser user)
+        public ParticipantPanel()
        {
-            User = user;
-
            RelativeSizeAxes = Axes.X;
-            Height = 40;
+            Height = HEIGHT;
        }

        [BackgroundDependencyLoader]
        private void load()
        {
-            var user = User.User;
-
            var backgroundColour = Color4Extensions.FromHex("#33413C");

            InternalChild = new GridContainer
@@ -96,7 +105,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
                            Colour = Color4Extensions.FromHex("#F7E65D"),
                            Alpha = 0
                        },
-                        new TeamDisplay(User),
+                        new TeamDisplay { Current = Current },
                        new Container
                        {
                            RelativeSizeAxes = Axes.Both,
@@ -109,13 +118,12 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
                                    RelativeSizeAxes = Axes.Both,
                                    Colour = backgroundColour
                                },
-                                new UserCoverBackground
+                                userCover = new UserCoverBackground
                                {
                                    Anchor = Anchor.CentreRight,
                                    Origin = Anchor.CentreRight,
                                    RelativeSizeAxes = Axes.Both,
                                    Width = 0.75f,
-                                    User = user,
                                    Colour = ColourInfo.GradientHorizontal(Color4.White.Opacity(0), Color4.White.Opacity(0.25f))
                                },
                                new FillFlowContainer
@@ -125,33 +133,30 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
                                    Direction = FillDirection.Horizontal,
                                    Children = new Drawable[]
                                    {
-                                        new UpdateableAvatar
+                                        userAvatar = new UpdateableAvatar
                                        {
                                            Anchor = Anchor.CentreLeft,
                                            Origin = Anchor.CentreLeft,
                                            RelativeSizeAxes = Axes.Both,
                                            FillMode = FillMode.Fit,
-                                            User = user
                                        },
                                        new UpdateableFlag
                                        {
                                            Anchor = Anchor.CentreLeft,
                                            Origin = Anchor.CentreLeft,
                                            Size = new Vector2(28, 20),
-                                            CountryCode = user?.CountryCode ?? default
                                        },
-                                        new UpdateableTeamFlag(user?.Team)
+                                        teamFlagContainer = new Container
                                        {
+                                            AutoSizeAxes = Axes.Both,
                                            Anchor = Anchor.CentreLeft,
                                            Origin = Anchor.CentreLeft,
-                                            Size = new Vector2(40, 20),
                                        },
-                                        new OsuSpriteText
+                                        username = new OsuSpriteText
                                        {
                                            Anchor = Anchor.CentreLeft,
                                            Origin = Anchor.CentreLeft,
                                            Font = OsuFont.GetFont(weight: FontWeight.Bold, size: 18),
-                                            Text = user?.Username ?? string.Empty
                                        },
                                        userRankText = new OsuSpriteText
                                        {
@@ -198,18 +203,50 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
                            Origin = Anchor.Centre,
                            Alpha = 0,
                            Margin = new MarginPadding(4),
-                            Action = () => client.KickUser(User.UserID).FireAndForget(),
+                            Action = () => client.KickUser(current.Value.UserID).FireAndForget(),
                        },
                    },
                }
            };
        }

-        protected override void LoadComplete()
+        protected override void PrepareForUse()
        {
-            base.LoadComplete();
+            base.PrepareForUse();

            client.RoomUpdated += onRoomUpdated;
+            updateUser();
+            FinishTransforms(true);
+        }
+
+        protected override void FreeAfterUse()
+        {
+            base.FreeAfterUse();
+
+            client.RoomUpdated -= onRoomUpdated;
+            // this is a safety measure.
+            // `MultiplayerRoomUser` has equality members overridden to compare by `UserID` only.
+            // `MultiplayerClient` only delivers updates of fields values to specific object references.
+            // if this operation is not done here, in a scenario wherein a user quits and rejoins a room,
+            // it is possible for a single poolable panel to be freed and then used for the same user with the same ID,
+            // which at bindable level will lead to `current` not changing (because of the overridden equality member),
+            // which will lead to this instance not showing any updates for the user in question
+            // because it's associated with an object reference that `MultiplayerClient` is no longer updating.
+            current.SetDefault();
+        }
+
+        private void updateUser()
+        {
+            var user = current.Value.User;
+
+            userCover.User = user;
+            userAvatar.User = user;
+            teamFlagContainer.Child = new UpdateableTeamFlag(user?.Team)
+            {
+                Size = new Vector2(40, 20)
+            };
+            username.Text = user?.Username ?? string.Empty;
+
            updateState();
        }

@@ -222,13 +259,15 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants

            const double fade_time = 50;

+            var user = current.Value;
+
            if (client.Room.GetCurrentItem() is MultiplayerPlaylistItem currentItem)
            {
-                int userBeatmapId = User.BeatmapId ?? currentItem.BeatmapID;
-                int userRulesetId = User.RulesetId ?? currentItem.RulesetID;
+                int userBeatmapId = user.BeatmapId ?? currentItem.BeatmapID;
+                int userRulesetId = user.RulesetId ?? currentItem.RulesetID;
                Ruleset? userRuleset = rulesets.GetRuleset(userRulesetId)?.CreateInstance();

-                int? currentModeRank = userRuleset == null ? null : User.User?.RulesetsStatistics?.GetValueOrDefault(userRuleset.ShortName)?.GlobalRank;
+                int? currentModeRank = userRuleset == null ? null : user.User?.RulesetsStatistics?.GetValueOrDefault(userRuleset.ShortName)?.GlobalRank;
                userRankText.Text = currentModeRank != null ? $"#{currentModeRank.Value:N0}" : string.Empty;

                if (userBeatmapId == currentItem.BeatmapID && userRulesetId == currentItem.RulesetID)
@@ -238,12 +277,12 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants

                // If the mods are updated at the end of the frame, the flow container will skip a reflow cycle: https://github.com/ppy/osu-framework/issues/4187
                // This looks particularly jarring here, so re-schedule the update to that start of our frame as a fix.
-                Schedule(() => userModsDisplay.Current.Value = userRuleset == null ? Array.Empty<Mod>() : User.Mods.Select(m => m.ToMod(userRuleset)).ToList());
+                Schedule(() => userModsDisplay.Current.Value = userRuleset == null ? Array.Empty<Mod>() : user.Mods.Select(m => m.ToMod(userRuleset)).ToList());
            }

-            userStateDisplay.UpdateStatus(User.State, User.BeatmapAvailability);
+            userStateDisplay.UpdateStatus(user.State, user.BeatmapAvailability);

-            if (User.BeatmapAvailability.State == DownloadState.LocallyAvailable && User.State != MultiplayerUserState.Spectating)
+            if (user.BeatmapAvailability.State == DownloadState.LocallyAvailable && user.State != MultiplayerUserState.Spectating)
            {
                userModsDisplay.FadeIn(fade_time);
                userStyleDisplay.FadeIn(fade_time);
@@ -254,8 +293,8 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
                userStyleDisplay.FadeOut(fade_time);
            }

-            kickButton.Alpha = client.IsHost && !User.Equals(client.LocalUser) ? 1 : 0;
-            crown.Alpha = client.Room.Host?.Equals(User) == true ? 1 : 0;
+            kickButton.Alpha = client.IsHost && !user.Equals(client.LocalUser) ? 1 : 0;
+            crown.Alpha = client.Room.Host?.Equals(user) == true ? 1 : 0;
        }

        public MenuItem[]? ContextMenuItems
@@ -265,15 +304,17 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
                if (client.Room == null)
                    return null;

+                var user = current.Value;
+
                // If the local user is targetted.
-                if (User.UserID == api.LocalUser.Value.Id)
+                if (user.UserID == api.LocalUser.Value.Id)
                    return null;

                // If the local user is not the host of the room.
                if (client.Room.Host?.UserID != api.LocalUser.Value.Id)
                    return null;

-                int targetUser = User.UserID;
+                int targetUser = user.UserID;

                return new MenuItem[]
                {
@@ -297,14 +338,6 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
            }
        }

-        protected override void Dispose(bool isDisposing)
-        {
-            base.Dispose(isDisposing);
-
-            if (client.IsNotNull())
-                client.RoomUpdated -= onRoomUpdated;
-        }
-
        public partial class KickButton : IconButton
        {
            public KickButton()
@@ -3,40 +3,34 @@

 using System.Linq;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Game.Graphics.Containers;
 using osu.Game.Online.Multiplayer;
-using osuTK;

 namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
 {
-    public partial class ParticipantsList : CompositeDrawable
+    public partial class ParticipantsList : VirtualisedListContainer<MultiplayerRoomUser, ParticipantPanel>
    {
-        private FillFlowContainer<ParticipantPanel> panels = null!;
-        private ParticipantPanel? currentHostPanel;
+        private BindableList<MultiplayerRoomUser> participants => RowData;
+
+        private MultiplayerRoomUser? currentHost;

        [Resolved]
        private MultiplayerClient client { get; set; } = null!;

-        [BackgroundDependencyLoader]
-        private void load()
+        public ParticipantsList()
+            : base(ParticipantPanel.HEIGHT, initialPoolSize: 20)
        {
-            InternalChild = new OsuScrollContainer
-            {
-                RelativeSizeAxes = Axes.Both,
-                ScrollbarVisible = false,
-                Child = panels = new FillFlowContainer<ParticipantPanel>
-                {
-                    RelativeSizeAxes = Axes.X,
-                    AutoSizeAxes = Axes.Y,
-                    Direction = FillDirection.Vertical,
-                    Spacing = new Vector2(0, 2)
-                }
-            };
        }

+        protected override ScrollContainer<Drawable> CreateScrollContainer() => new OsuScrollContainer
+        {
+            ScrollbarVisible = false,
+        };
+
        protected override void LoadComplete()
        {
            base.LoadComplete();
@@ -50,36 +44,38 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
        private void updateState()
        {
            if (client.Room == null)
-                panels.Clear();
+                participants.Clear();
            else
            {
                // Remove panels for users no longer in the room.
-                foreach (var p in panels)
+                for (int i = participants.Count - 1; i >= 0; i--)
                {
+                    var participant = participants[i];
+
                    // Note that we *must* use reference equality here, as this call is scheduled and a user may have left and joined since it was last run.
-                    if (client.Room.Users.All(u => !ReferenceEquals(p.User, u)))
-                        p.Expire();
+                    if (client.Room.Users.All(u => !ReferenceEquals(participant, u)))
+                        participants.RemoveAt(i);
                }

                // Add panels for all users new to the room.
-                foreach (var user in client.Room.Users.Except(panels.Select(p => p.User)))
-                    panels.Add(new ParticipantPanel(user));
+                foreach (var user in client.Room.Users.Except(participants))
+                    participants.Add(user);

-                if (currentHostPanel == null || !currentHostPanel.User.Equals(client.Room.Host))
+                if (currentHost == null || !currentHost.Equals(client.Room.Host))
                {
-                    // Reset position of previous host back to normal, if one existing.
-                    if (currentHostPanel != null && panels.Contains(currentHostPanel))
-                        panels.SetLayoutPosition(currentHostPanel, 0);
-
-                    currentHostPanel = null;
+                    currentHost = null;

                    // Change position of new host to display above all participants.
                    if (client.Room.Host != null)
                    {
-                        currentHostPanel = panels.SingleOrDefault(u => u.User.Equals(client.Room.Host));
+                        currentHost = participants.SingleOrDefault(u => u.Equals(client.Room.Host));
+                        int currentHostIndex = participants.IndexOf(client.Room.Host);

-                        if (currentHostPanel != null)
-                            panels.SetLayoutPosition(currentHostPanel, -1);
+                        if (currentHostIndex > 0)
+                        {
+                            participants.Move(currentHostIndex, 0);
+                            currentHost = participants[0];
+                        }
                    }
                }
            }
@@ -5,11 +5,13 @@ using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Audio;
 using osu.Framework.Audio.Sample;
+using osu.Framework.Bindables;
 using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Colour;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
+using osu.Framework.Graphics.UserInterface;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
 using osu.Game.Online.Multiplayer;
@@ -19,9 +21,15 @@ using osuTK.Graphics;

 namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
 {
-    internal partial class TeamDisplay : CompositeDrawable
+    internal partial class TeamDisplay : CompositeDrawable, IHasCurrentValue<MultiplayerRoomUser>
    {
-        private readonly MultiplayerRoomUser user;
+        public Bindable<MultiplayerRoomUser> Current
+        {
+            get => current.Current;
+            set => current.Current = value;
+        }
+
+        private readonly BindableWithCurrent<MultiplayerRoomUser> current = new BindableWithCurrent<MultiplayerRoomUser>(new MultiplayerRoomUser(-1));

        [Resolved]
        private OsuColour colours { get; set; } = null!;
@@ -33,10 +41,8 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
        private Drawable box = null!;
        private Sample? sampleTeamSwap;

-        public TeamDisplay(MultiplayerRoomUser user)
+        public TeamDisplay()
        {
-            this.user = user;
-
            RelativeSizeAxes = Axes.Y;
            AutoSizeAxes = Axes.X;
            Margin = new MarginPadding { Horizontal = 3 };
@@ -69,12 +75,6 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
                }
            };

-            if (client.LocalUser?.Equals(user) == true)
-            {
-                clickableContent.Action = changeTeam;
-                clickableContent.TooltipText = "Change team";
-            }
-
            sampleTeamSwap = audio.Samples.Get(@"Multiplayer/team-swap");
        }

@@ -83,7 +83,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
            base.LoadComplete();

            client.RoomUpdated += onRoomUpdated;
-            updateState();
+            current.BindValueChanged(_ => updateUser(), true);
        }

        private void changeTeam()
@@ -96,12 +96,28 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants

        public int? DisplayedTeam { get; private set; }

+        private void updateUser()
+        {
+            var user = current.Value;
+
+            if (client.LocalUser?.Equals(user) == true)
+            {
+                clickableContent.Action = changeTeam;
+                clickableContent.TooltipText = "Change team";
+            }
+
+            // reset to ensure samples don't play
+            DisplayedTeam = null;
+            updateState();
+        }
+
        private void onRoomUpdated() => Scheduler.AddOnce(updateState);

        private void updateState()
        {
            // we don't have a way of knowing when an individual user's state has updated, so just handle on RoomUpdated for now.

+            var user = current.Value;
            var userRoomState = client.Room?.Users.FirstOrDefault(u => u.Equals(user))?.MatchState;

            const double duration = 400;