diff --git a/osu.Game/Beatmaps/BeatmapDifficultyManager.cs b/osu.Game/Beatmaps/BeatmapDifficultyManager.cs new file mode 100644 index 0000000000..f09118a24a --- /dev/null +++ b/osu.Game/Beatmaps/BeatmapDifficultyManager.cs @@ -0,0 +1,99 @@ +// Copyright (c) ppy Pty Ltd . Licensed under the MIT Licence. +// See the LICENCE file in the repository root for full licence text. + +using System; +using System.Collections.Generic; +using System.Diagnostics; +using System.Linq; +using System.Threading; +using System.Threading.Tasks; +using JetBrains.Annotations; +using osu.Framework.Allocation; +using osu.Framework.Graphics.Containers; +using osu.Framework.Threading; +using osu.Game.Rulesets; +using osu.Game.Rulesets.Mods; + +namespace osu.Game.Beatmaps +{ + public class BeatmapDifficultyManager : CompositeDrawable + { + // Too many simultaneous updates can lead to stutters. One thread seems to work fine for song select display purposes. + private readonly ThreadedTaskScheduler updateScheduler = new ThreadedTaskScheduler(1, nameof(BeatmapDifficultyManager)); + + private readonly TimedExpiryCache difficultyCache = new TimedExpiryCache { ExpiryTime = 60000 }; + private readonly BeatmapManager beatmapManager; + + public BeatmapDifficultyManager(BeatmapManager beatmapManager) + { + this.beatmapManager = beatmapManager; + } + + public Task GetDifficultyAsync([NotNull] BeatmapInfo beatmapInfo, [CanBeNull] RulesetInfo rulesetInfo = null, [CanBeNull] IReadOnlyList mods = null, + CancellationToken cancellationToken = default) + => Task.Factory.StartNew(() => GetDifficulty(beatmapInfo, rulesetInfo, mods), cancellationToken, + TaskCreationOptions.HideScheduler | TaskCreationOptions.RunContinuationsAsynchronously, + updateScheduler); + + public double GetDifficulty([NotNull] BeatmapInfo beatmapInfo, [CanBeNull] RulesetInfo rulesetInfo = null, [CanBeNull] IReadOnlyList mods = null) + { + // Difficulty can only be computed if the beatmap is locally available. + if (beatmapInfo.ID == 0) + return 0; + + // In the case that the user hasn't given us a ruleset, use the beatmap's default ruleset. + rulesetInfo ??= beatmapInfo.Ruleset; + + var key = new DifficultyCacheLookup(beatmapInfo, rulesetInfo, mods); + if (difficultyCache.TryGetValue(key, out var existing)) + return existing; + + try + { + var ruleset = rulesetInfo.CreateInstance(); + Debug.Assert(ruleset != null); + + var calculator = ruleset.CreateDifficultyCalculator(beatmapManager.GetWorkingBeatmap(beatmapInfo)); + var attributes = calculator.Calculate(mods?.ToArray() ?? Array.Empty()); + + difficultyCache.Add(key, attributes.StarRating); + return attributes.StarRating; + } + catch + { + difficultyCache.Add(key, 0); + return 0; + } + } + + private readonly struct DifficultyCacheLookup : IEquatable + { + private readonly BeatmapInfo beatmapInfo; + private readonly RulesetInfo rulesetInfo; + private readonly IReadOnlyList mods; + + public DifficultyCacheLookup(BeatmapInfo beatmapInfo, RulesetInfo rulesetInfo, IEnumerable mods) + { + this.beatmapInfo = beatmapInfo; + this.rulesetInfo = rulesetInfo; + this.mods = mods?.OrderBy(m => m.Acronym).ToArray() ?? Array.Empty(); + } + + public bool Equals(DifficultyCacheLookup other) + => beatmapInfo.Equals(other.beatmapInfo) + && mods.SequenceEqual(other.mods); + + public override int GetHashCode() + { + var hashCode = new HashCode(); + + hashCode.Add(beatmapInfo.Hash); + hashCode.Add(rulesetInfo.GetHashCode()); + foreach (var mod in mods) + hashCode.Add(mod.Acronym); + + return hashCode.ToHashCode(); + } + } + } +} diff --git a/osu.Game/OsuGameBase.cs b/osu.Game/OsuGameBase.cs index dd120937af..1e6631ffa0 100644 --- a/osu.Game/OsuGameBase.cs +++ b/osu.Game/OsuGameBase.cs @@ -199,6 +199,7 @@ namespace osu.Game ScoreManager.Undelete(getBeatmapScores(item), true); }); + dependencies.Cache(new BeatmapDifficultyManager(BeatmapManager)); dependencies.Cache(KeyBindingStore = new KeyBindingStore(contextFactory, RulesetStore)); dependencies.Cache(SettingsStore = new SettingsStore(contextFactory)); dependencies.Cache(RulesetConfigCache = new RulesetConfigCache(SettingsStore));