// 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.Linq; using osu.Game.Beatmaps; using osu.Game.Rulesets.Difficulty; using osu.Game.Rulesets.Difficulty.Preprocessing; using osu.Game.Rulesets.Difficulty.Skills; using osu.Game.Rulesets.Mods; using osu.Game.Rulesets.Objects; using osu.Game.Rulesets.Osu.Difficulty.Preprocessing; using osu.Game.Rulesets.Osu.Difficulty.Skills; using osu.Game.Rulesets.Osu.Mods; using osu.Game.Rulesets.Osu.Objects; namespace osu.Game.Rulesets.Osu.Difficulty { public class OsuDifficultyCalculator : DifficultyCalculator { private const double difficulty_multiplier = 0.0675; public OsuDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap) : base(ruleset, beatmap) { } protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate) { if (beatmap.HitObjects.Count == 0) return new OsuDifficultyAttributes { Mods = mods, Skills = skills }; double aimRating = Math.Sqrt(skills[0].DifficultyValue()) * difficulty_multiplier; double speedRating = Math.Sqrt(skills[1].DifficultyValue()) * difficulty_multiplier; double starRating = aimRating + speedRating + Math.Abs(aimRating - speedRating) / 2; HitWindows hitWindows = new OsuHitWindows(); hitWindows.SetDifficulty(beatmap.BeatmapInfo.BaseDifficulty.OverallDifficulty); // Todo: These int casts are temporary to achieve 1:1 results with osu!stable, and should be removed in the future double hitWindowGreat = (int)(hitWindows.Great / 2) / clockRate; double preempt = (int)BeatmapDifficulty.DifficultyRange(beatmap.BeatmapInfo.BaseDifficulty.ApproachRate, 1800, 1200, 450) / clockRate; int maxCombo = beatmap.HitObjects.Count; // Add the ticks + tail of the slider. 1 is subtracted because the head circle would be counted twice (once for the slider itself in the line above) maxCombo += beatmap.HitObjects.OfType().Sum(s => s.NestedHitObjects.Count - 1); return new OsuDifficultyAttributes { StarRating = starRating, Mods = mods, AimStrain = aimRating, SpeedStrain = speedRating, ApproachRate = preempt > 1200 ? (1800 - preempt) / 120 : (1200 - preempt) / 150 + 5, OverallDifficulty = (80 - hitWindowGreat) / 6, MaxCombo = maxCombo, Skills = skills }; } protected override IEnumerable CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate) { // The first jump is formed by the first two hitobjects of the map. // If the map has less than two OsuHitObjects, the enumerator will not return anything. for (int i = 1; i < beatmap.HitObjects.Count; i++) { var lastLast = i > 1 ? beatmap.HitObjects[i - 2] : null; var last = beatmap.HitObjects[i - 1]; var current = beatmap.HitObjects[i]; yield return new OsuDifficultyHitObject(current, lastLast, last, clockRate); } } protected override Skill[] CreateSkills(IBeatmap beatmap) => new Skill[] { new Aim(), new Speed() }; protected override Mod[] DifficultyAdjustmentMods => new Mod[] { new OsuModDoubleTime(), new OsuModHalfTime(), new OsuModEasy(), new OsuModHardRock(), }; } }