Use proportion of difficult sliders to better estimate sliderbreaks on classic accuracy scores

osu.Game.Rulesets.Osu/Difficulty/OsuDifficultyAttributes.cs

@@ -53,6 +53,22 @@ public class OsuDifficultyAttributes : DifficultyAttributes
         [JsonProperty("slider_factor")]
         public double SliderFactor { get; set; }
 
+        /// <summary>
+        /// Describes how much of <see cref="AimDifficultStrainCount"/> is contributed to by hitcircles or sliders
+        /// A value closer to 0.0 indicates most of <see cref="AimDifficultStrainCount"/> is contributed by hitcircles
+        /// A value closer to Infinity indicates most of <see cref="AimDifficultStrainCount"/> is contributed by sliders
+        /// </summary>
+        [JsonProperty("aim_top_weighted_slider_factor")]
+        public double AimTopWeightedSliderFactor { get; set; }
+
+        /// <summary>
+        /// Describes how much of <see cref="SpeedDifficultStrainCount"/> is contributed to by hitcircles or sliders
+        /// A value closer to 0.0 indicates most of <see cref="SpeedDifficultStrainCount"/> is contributed by hitcircles
+        /// A value closer to Infinity indicates most of <see cref="SpeedDifficultStrainCount"/> is contributed by sliders
+        /// </summary>
+        [JsonProperty("speed_top_weighted_slider_factor")]
+        public double SpeedTopWeightedSliderFactor { get; set; }
+
         [JsonProperty("aim_difficult_strain_count")]
         public double AimDifficultStrainCount { get; set; }
 

osu.Game.Rulesets.Osu/Difficulty/OsuDifficultyCalculator.cs

@@ -51,6 +51,12 @@ protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beat
             double aimDifficultyStrainCount = ((OsuStrainSkill)skills[0]).CountTopWeightedStrains();
             double speedDifficultyStrainCount = ((OsuStrainSkill)skills[2]).CountTopWeightedStrains();
 
+            double aimNoSlidersTopWeightedSliderCount = ((OsuStrainSkill)skills[1]).CountTopWeightedSliders();
+            double aimNoSlidersDifficultyStrainCount = ((OsuStrainSkill)skills[1]).CountTopWeightedStrains();
+            double aimTopWeightedSliderFactor = aimNoSlidersTopWeightedSliderCount / (aimNoSlidersDifficultyStrainCount - aimNoSlidersTopWeightedSliderCount);
+            double speedTopWeightedSliderCount = ((OsuStrainSkill)skills[2]).CountTopWeightedSliders();
+            double speedTopWeightedSliderFactor = speedTopWeightedSliderCount / (speedDifficultyStrainCount - speedTopWeightedSliderCount);
+
             if (mods.Any(m => m is OsuModTouchDevice))
             {
                 aimRating = Math.Pow(aimRating, 0.8);
@@ -106,6 +112,8 @@ protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beat
                 SliderFactor = sliderFactor,
                 AimDifficultStrainCount = aimDifficultyStrainCount,
                 SpeedDifficultStrainCount = speedDifficultyStrainCount,
+                AimTopWeightedSliderFactor = aimTopWeightedSliderFactor,
+                SpeedTopWeightedSliderFactor = speedTopWeightedSliderFactor,
                 ApproachRate = preempt > 1200 ? (1800 - preempt) / 120 : (1200 - preempt) / 150 + 5,
                 OverallDifficulty = (80 - hitWindowGreat) / 6,
                 DrainRate = drainRate,

osu.Game.Rulesets.Osu/Difficulty/OsuPerformanceCalculator.cs

@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using osu.Game.Rulesets.Difficulty;
+using osu.Game.Rulesets.Difficulty.Utils;
 using osu.Game.Rulesets.Osu.Difficulty.Skills;
 using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Scoring;
@@ -165,7 +166,11 @@ private double computeAimValue(ScoreInfo score, OsuDifficultyAttributes attribut
             aimValue *= lengthBonus;
 
             if (effectiveMissCount > 0)
-                aimValue *= calculateMissPenalty(effectiveMissCount, attributes.AimDifficultStrainCount);
+            {
+                double missedComboPercent = 1.0 - (double)score.MaxCombo / attributes.MaxCombo;
+                double estimatedSliderbreaks = Math.Min(countMeh + countOk, countMiss * attributes.AimTopWeightedSliderFactor) * DifficultyCalculationUtils.Logistic(missedComboPercent, 0.33, 15);
+                aimValue *= calculateMissPenalty(effectiveMissCount + (usingClassicSliderAccuracy ? estimatedSliderbreaks : 0), attributes.AimDifficultStrainCount);
+            }
 
             double approachRateFactor = 0.0;
             if (attributes.ApproachRate > 10.33)
@@ -205,7 +210,11 @@ private double computeSpeedValue(ScoreInfo score, OsuDifficultyAttributes attrib
             speedValue *= lengthBonus;
 
             if (effectiveMissCount > 0)
-                speedValue *= calculateMissPenalty(effectiveMissCount, attributes.SpeedDifficultStrainCount);
+            {
+                double missedComboPercent = 1.0 - (double)score.MaxCombo / attributes.MaxCombo;
+                double estimatedSliderbreaks = Math.Min(countMeh + countOk, countMiss * attributes.SpeedTopWeightedSliderFactor) * DifficultyCalculationUtils.Logistic(missedComboPercent, 0.33, 15);
+                speedValue *= calculateMissPenalty(effectiveMissCount + (usingClassicSliderAccuracy ? estimatedSliderbreaks : 0), attributes.SpeedDifficultStrainCount);
+            }
 
             double approachRateFactor = 0.0;
             if (attributes.ApproachRate > 10.33)

osu.Game.Rulesets.Osu/Difficulty/Skills/Aim.cs

@@ -2,7 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
 using System.Collections.Generic;
 using System.Linq;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Mods;
@@ -29,8 +29,6 @@
         private double skillMultiplier => 25.18;
         private double strainDecayBase => 0.15;
 
-        private readonly List<double> sliderStrains = new List<double>();
-
         private double strainDecay(double ms) => Math.Pow(strainDecayBase, ms / 1000);
 
         protected override double CalculateInitialStrain(double time, DifficultyHitObject current) => currentStrain * strainDecay(time - current.Previous(0).StartTime);
@@ -41,9 +39,7 @@
             currentStrain += AimEvaluator.EvaluateDifficultyOf(current, withSliders) * skillMultiplier;
 
             if (current.BaseObject is Slider)
-            {
                 sliderStrains.Add(currentStrain);
-            }
 
             return currentStrain;
         }

osu.Game.Rulesets.Osu/Difficulty/Skills/OsuStrainSkill.cs

@@ -23,6 +23,8 @@
         /// </summary>
         protected virtual double ReducedStrainBaseline => 0.75;
 
+        protected readonly List<double> sliderStrains = new List<double>();
+
         protected OsuStrainSkill(Mod[] mods)
             : base(mods)
         {
@@ -57,6 +59,20 @@
             return difficulty;
         }
 
+        public double CountTopWeightedSliders()
+        {
+            if (sliderStrains.Count == 0)
+                return 0;
+
+            double consistentTopStrain = DifficultyValue() / 10; // What would the top strain be if all strain values were identical
+
+            if (consistentTopStrain == 0)
+                return 0;
+
+            // Use a weighted sum of all strains. Constants are arbitrary and give nice values
+            return sliderStrains.Sum(s => 1.1 / (1 + Math.Exp(-10 * (s / consistentTopStrain - 0.88))));
+        }
+
         public static double DifficultyToPerformance(double difficulty) => Math.Pow(5.0 * Math.Max(1.0, difficulty / 0.0675) - 4.0, 3.0) / 100000.0;
     }
 }

osu.Game.Rulesets.Osu/Difficulty/Skills/Speed.cs

@@ -6,6 +6,7 @@
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu.Difficulty.Evaluators;
 using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Osu.Objects;
 using System.Linq;
 
 namespace osu.Game.Rulesets.Osu.Difficulty.Skills
@@ -40,6 +41,8 @@ protected override double StrainValueAt(DifficultyHitObject current)
             currentRhythm = RhythmEvaluator.EvaluateDifficultyOf(current);
 
             double totalStrain = currentStrain * currentRhythm;
+            if (current.BaseObject is Slider)
+                sliderStrains.Add(totalStrain);
 
             return totalStrain;
         }