diff --git a/osu.Game.Rulesets.Taiko/Difficulty/Skills/CombinedStrain.cs b/osu.Game.Rulesets.Taiko/Difficulty/Skills/CombinedStrain.cs new file mode 100644 index 0000000000..e5052c3359 --- /dev/null +++ b/osu.Game.Rulesets.Taiko/Difficulty/Skills/CombinedStrain.cs @@ -0,0 +1,86 @@ +using System; +using System.Collections.Generic; +using System.Linq; +using osu.Game.Rulesets.Difficulty.Preprocessing; +using osu.Game.Rulesets.Difficulty.Skills; +using osu.Game.Rulesets.Mods; + +namespace osu.Game.Rulesets.Taiko.Difficulty.Skills +{ + public class CombinedStrain : Skill + { + private const double rhythm_skill_multiplier = 0.017; + private const double colour_skill_multiplier = 0.026; + private const double stamina_skill_multiplier = 0.018; + + private Rhythm rhythm; + private Colour colour; + private Stamina stamina; + + public double ColourDifficultyValue => colour.DifficultyValue() * colour_skill_multiplier; + public double RhythmDifficultyValue => rhythm.DifficultyValue() * rhythm_skill_multiplier; + public double StaminaDifficultyValue => stamina.DifficultyValue() * stamina_skill_multiplier; + + public CombinedStrain(Mod[] mods) : base(mods) + { + rhythm = new Rhythm(mods); + colour = new Colour(mods); + stamina = new Stamina(mods); + } + + /// + /// Returns the p-norm of an n-dimensional vector. + /// + /// The value of p to calculate the norm for. + /// The coefficients of the vector. + private double norm(double p, params double[] values) => Math.Pow(values.Sum(x => Math.Pow(x, p)), 1 / p); + + public override void Process(DifficultyHitObject current) + { + rhythm.Process(current); + colour.Process(current); + stamina.Process(current); + } + + /// + /// Returns the combined star rating of the beatmap, calculated using peak strains from all sections of the map. + /// + /// + /// For each section, the peak strains of all separate skills are combined into a single peak strain for the section. + /// The resulting partial rating of the beatmap is a weighted sum of the combined peaks (higher peaks are weighted more). + /// + public override double DifficultyValue() + { + List peaks = new List(); + + var colourPeaks = colour.GetCurrentStrainPeaks().ToList(); + var rhythmPeaks = rhythm.GetCurrentStrainPeaks().ToList(); + var staminaPeaks = stamina.GetCurrentStrainPeaks().ToList(); + + for (int i = 0; i < colourPeaks.Count; i++) + { + double colourPeak = colourPeaks[i] * colour_skill_multiplier; + double rhythmPeak = rhythmPeaks[i] * rhythm_skill_multiplier; + double staminaPeak = staminaPeaks[i] * stamina_skill_multiplier; + + double peak = norm(2, colourPeak, rhythmPeak, staminaPeak); + + // Sections with 0 strain are excluded to avoid worst-case time complexity of the following sort (e.g. /b/2351871). + // These sections will not contribute to the difficulty. + if (peak > 0) + peaks.Add(peak); + } + + double difficulty = 0; + double weight = 1; + + foreach (double strain in peaks.OrderByDescending(d => d)) + { + difficulty += strain * weight; + weight *= 0.9; + } + + return difficulty; + } + } +} \ No newline at end of file diff --git a/osu.Game.Rulesets.Taiko/Difficulty/TaikoDifficultyCalculator.cs b/osu.Game.Rulesets.Taiko/Difficulty/TaikoDifficultyCalculator.cs index 706fde77d2..f4a23930b3 100644 --- a/osu.Game.Rulesets.Taiko/Difficulty/TaikoDifficultyCalculator.cs +++ b/osu.Game.Rulesets.Taiko/Difficulty/TaikoDifficultyCalculator.cs @@ -20,21 +20,18 @@ namespace osu.Game.Rulesets.Taiko.Difficulty { public class TaikoDifficultyCalculator : DifficultyCalculator { - private const double rhythm_skill_multiplier = 0.017; - private const double colour_skill_multiplier = 0.026; - private const double stamina_skill_multiplier = 0.018; - public TaikoDifficultyCalculator(IRulesetInfo ruleset, IWorkingBeatmap beatmap) : base(ruleset, beatmap) { } - protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate) => new Skill[] + protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate) { - new Colour(mods), - new Rhythm(mods), - new Stamina(mods) - }; + return new Skill[] + { + new CombinedStrain(mods) + }; + } protected override Mod[] DifficultyAdjustmentMods => new Mod[] { @@ -71,27 +68,13 @@ namespace osu.Game.Rulesets.Taiko.Difficulty if (beatmap.HitObjects.Count == 0) return new TaikoDifficultyAttributes { Mods = mods }; - var colour = (Colour)skills[0]; - var rhythm = (Rhythm)skills[1]; - var stamina = (Stamina)skills[2]; + var combined = (CombinedStrain)skills[0]; - double colourRating = colour.DifficultyValue() * colour_skill_multiplier; - double rhythmRating = rhythm.DifficultyValue() * rhythm_skill_multiplier; - double staminaRating = stamina.DifficultyValue() * stamina_skill_multiplier; + double colourRating = combined.ColourDifficultyValue; + double rhythmRating = combined.RhythmDifficultyValue; + double staminaRating = combined.StaminaDifficultyValue; - // double staminaPenalty = simpleColourPenalty(staminaRating, colourRating); - // staminaRating *= staminaPenalty; - - //TODO : This is a temporary fix for the stamina rating of converts, due to their low colour variance. - // if (beatmap.BeatmapInfo.Ruleset.OnlineID == 0 && colourRating < 0.05) - // { - // staminaPenalty *= 0.25; - // } - - double combinedRating = locallyCombinedDifficulty(colour, rhythm, stamina); - // double separatedRating = norm(2, colourRating, rhythmRating, staminaRating); - double starRating = 1.9 * combinedRating; - starRating = rescale(starRating); + double starRating = rescale(1.9 * combined.DifficultyValue()); HitWindows hitWindows = new TaikoHitWindows(); hitWindows.SetDifficulty(beatmap.Difficulty.OverallDifficulty); @@ -108,68 +91,6 @@ namespace osu.Game.Rulesets.Taiko.Difficulty }; } - /// - /// Calculates the penalty for the stamina skill for maps with low colour difficulty. - /// - /// - /// Some maps (especially converts) can be easy to read despite a high note density. - /// This penalty aims to reduce the star rating of such maps by factoring in colour difficulty to the stamina skill. - /// - private double simpleColourPenalty(double staminaDifficulty, double colorDifficulty) - { - if (colorDifficulty <= 0) return 0.79 - 0.25; - - return 0.79 - Math.Atan(staminaDifficulty / colorDifficulty - 12) / Math.PI / 2; - } - - /// - /// Returns the p-norm of an n-dimensional vector. - /// - /// The value of p to calculate the norm for. - /// The coefficients of the vector. - private double norm(double p, params double[] values) => Math.Pow(values.Sum(x => Math.Pow(x, p)), 1 / p); - - /// - /// Returns the partial star rating of the beatmap, calculated using peak strains from all sections of the map. - /// - /// - /// For each section, the peak strains of all separate skills are combined into a single peak strain for the section. - /// The resulting partial rating of the beatmap is a weighted sum of the combined peaks (higher peaks are weighted more). - /// - private double locallyCombinedDifficulty(Colour colour, Rhythm rhythm, Stamina stamina) - { - List peaks = new List(); - - var colourPeaks = colour.GetCurrentStrainPeaks().ToList(); - var rhythmPeaks = rhythm.GetCurrentStrainPeaks().ToList(); - var staminaPeaks = stamina.GetCurrentStrainPeaks().ToList(); - - for (int i = 0; i < colourPeaks.Count; i++) - { - double colourPeak = colourPeaks[i] * colour_skill_multiplier; - double rhythmPeak = rhythmPeaks[i] * rhythm_skill_multiplier; - double staminaPeak = staminaPeaks[i] * stamina_skill_multiplier; - - double peak = norm(2, colourPeak, rhythmPeak, staminaPeak); - - // Sections with 0 strain are excluded to avoid worst-case time complexity of the following sort (e.g. /b/2351871). - // These sections will not contribute to the difficulty. - if (peak > 0) - peaks.Add(peak); - } - - double difficulty = 0; - double weight = 1; - - foreach (double strain in peaks.OrderByDescending(d => d)) - { - difficulty += strain * weight; - weight *= 0.9; - } - - return difficulty; - } - /// /// Applies a final re-scaling of the star rating to bring maps with recorded full combos below 9.5 stars. ///