Add support for grouping by artist

osu.Game.Tests/Resources/TestResources.cs

@@ -85,7 +85,8 @@ namespace osu.Game.Tests.Resources
         /// </summary>
         /// <param name="difficultyCount">Number of difficulties. If null, a random number between 1 and 20 will be used.</param>
         /// <param name="rulesets">Rulesets to cycle through when creating difficulties. If <c>null</c>, osu! ruleset will be used.</param>
-        public static BeatmapSetInfo CreateTestBeatmapSetInfo(int? difficultyCount = null, RulesetInfo[] rulesets = null)
+        /// <param name="randomiseMetadata">Whether to randomise metadata to create a better distribution.</param>
+        public static BeatmapSetInfo CreateTestBeatmapSetInfo(int? difficultyCount = null, RulesetInfo[] rulesets = null, bool randomiseMetadata = false)
         {
             int j = 0;
 
@@ -95,13 +96,27 @@ namespace osu.Game.Tests.Resources
 
             int setId = GetNextTestID();
 
-            var metadata = new BeatmapMetadata
+            char getRandomCharacter()
             {
-                // Create random metadata, then we can check if sorting works based on these
+                const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz*";
-                Artist = "Some Artist " + RNG.Next(0, 9),
+                return chars[RNG.Next(chars.Length)];
-                Title = $"Some Song (set id {setId:000}) {Guid.NewGuid()}",
+            }
-                Author = { Username = "Some Guy " + RNG.Next(0, 9) },
+
-            };
+            var metadata = randomiseMetadata
+                ? new BeatmapMetadata
+                {
+                    // Create random metadata, then we can check if sorting works based on these
+                    Artist = $"{getRandomCharacter()}ome Artist " + RNG.Next(0, 9),
+                    Title = $"{getRandomCharacter()}ome Song (set id {setId:000}) {Guid.NewGuid()}",
+                    Author = { Username = $"{getRandomCharacter()}ome Guy " + RNG.Next(0, 9) },
+                }
+                : new BeatmapMetadata
+                {
+                    // Create random metadata, then we can check if sorting works based on these
+                    Artist = "Some Artist " + RNG.Next(0, 9),
+                    Title = $"Some Song (set id {setId:000}) {Guid.NewGuid()}",
+                    Author = { Username = "Some Guy " + RNG.Next(0, 9) },
+                };
 
             Logger.Log($"🛠️ Generating beatmap set \"{metadata}\" for test consumption.");
 

osu.Game.Tests/Visual/SongSelect/BeatmapCarouselV2TestScene.cs

@@ -193,7 +193,7 @@ namespace osu.Game.Tests.Visual.SongSelect
         protected void AddBeatmaps(int count, int? fixedDifficultiesPerSet = null) => AddStep($"add {count} beatmaps", () =>
         {
             for (int i = 0; i < count; i++)
-                BeatmapSets.Add(TestResources.CreateTestBeatmapSetInfo(fixedDifficultiesPerSet ?? RNG.Next(1, 4)));
+                BeatmapSets.Add(TestResources.CreateTestBeatmapSetInfo(fixedDifficultiesPerSet ?? RNG.Next(1, 4), randomiseMetadata: true));
         });
 
         protected void RemoveAllBeatmaps() => AddStep("clear all beatmaps", () => BeatmapSets.Clear());

osu.Game.Tests/Visual/SongSelect/TestSceneBeatmapCarouselV2Basics.cs

@@ -51,6 +51,7 @@ namespace osu.Game.Tests.Visual.SongSelect
         {
             AddBeatmaps(10);
             SortBy(new FilterCriteria { Group = GroupMode.Difficulty, Sort = SortMode.Difficulty });
+            SortBy(new FilterCriteria { Group = GroupMode.Artist, Sort = SortMode.Artist });
             SortBy(new FilterCriteria { Sort = SortMode.Artist });
         }
 

osu.Game/Screens/SelectV2/BeatmapCarousel.cs

@@ -119,20 +119,12 @@ namespace osu.Game.Screens.SelectV2
                     return false;
 
                 case BeatmapInfo beatmapInfo:
+                    // Find any containing group. There should never be too many groups so iterating is efficient enough.
+                    GroupDefinition? containingGroup = grouping.GroupItems.SingleOrDefault(kvp => kvp.Value.Any(i => ReferenceEquals(i.Model, beatmapInfo))).Key;
 
-                    // If we have groups, we need to account for them.
+                    if (containingGroup != null)
-                    if (Criteria.SplitOutDifficulties)
+                        setExpandedGroup(containingGroup);
-                    {
+                    setExpandedSet(beatmapInfo);
-                        // Find the containing group. There should never be too many groups so iterating is efficient enough.
-                        GroupDefinition? group = grouping.GroupItems.SingleOrDefault(kvp => kvp.Value.Any(i => ReferenceEquals(i.Model, beatmapInfo))).Key;
-
-                        if (group != null)
-                            setExpandedGroup(group);
-                    }
-                    else
-                    {
-                        setExpandedSet(beatmapInfo);
-                    }
 
                     return true;
             }
@@ -170,6 +162,7 @@ namespace osu.Game.Screens.SelectV2
         {
             if (grouping.GroupItems.TryGetValue(group, out var items))
             {
+                // First pass ignoring set groupings.
                 foreach (var i in items)
                 {
                     if (i.Model is GroupDefinition)
@@ -177,6 +170,16 @@ namespace osu.Game.Screens.SelectV2
                     else
                         i.IsVisible = expanded;
                 }
+
+                // Second pass to hide set children when not meant to be displayed.
+                if (expanded)
+                {
+                    foreach (var i in items)
+                    {
+                        if (i.Model is BeatmapSetInfo set)
+                            setExpansionStateOfSetItems(set, i.IsExpanded);
+                    }
+                }
             }
         }
 

osu.Game/Screens/SelectV2/BeatmapCarouselFilterGrouping.cs

@@ -52,6 +52,33 @@ namespace osu.Game.Screens.SelectV2
                     newItems.AddRange(items);
                     break;
 
+                case GroupMode.Artist:
+                    groupSetsTogether = true;
+                    char groupChar = (char)0;
+
+                    foreach (var item in items)
+                    {
+                        cancellationToken.ThrowIfCancellationRequested();
+
+                        var b = (BeatmapInfo)item.Model;
+
+                        char beatmapFirstChar = char.ToUpperInvariant(b.Metadata.Artist[0]);
+
+                        if (beatmapFirstChar > groupChar)
+                        {
+                            groupChar = beatmapFirstChar;
+                            var groupDefinition = new GroupDefinition($"{groupChar}");
+                            var groupItem = new CarouselItem(groupDefinition) { DrawHeight = GroupPanel.HEIGHT };
+
+                            newItems.Add(groupItem);
+                            groupItems[groupDefinition] = new HashSet<CarouselItem> { groupItem };
+                        }
+
+                        newItems.Add(item);
+                    }
+
+                    break;
+
                 case GroupMode.Difficulty:
                     groupSetsTogether = false;
                     int starGroup = int.MinValue;
@@ -91,7 +118,7 @@ namespace osu.Game.Screens.SelectV2
 
                     if (item.Model is BeatmapInfo beatmap)
                     {
-                        bool newBeatmapSet = lastItem == null || (lastItem.Model is BeatmapInfo lastBeatmap && lastBeatmap.BeatmapSet!.ID != beatmap.BeatmapSet!.ID);
+                        bool newBeatmapSet = lastItem?.Model is not BeatmapInfo lastBeatmap || lastBeatmap.BeatmapSet!.ID != beatmap.BeatmapSet!.ID;
 
                         if (newBeatmapSet)
                         {