Remove combo scaling from Aim and Speed from osu! performance calculation

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

@@ -46,6 +46,12 @@ public class OsuDifficultyAttributes : DifficultyAttributes
  [JsonProperty("slider_factor")]
  public double SliderFactor { get; set; }
 
+ [JsonProperty("aim_difficult_strain_count")]
+ public double AimDifficultStrainCount { get; set; }
+
+ [JsonProperty("speed_difficult_strain_count")]
+ public double SpeedDifficultStrainCount { get; set; }
+
  /// <summary>
  /// The perceived approach rate inclusive of rate-adjusting mods (DT/HT/etc).
  /// </summary>
@@ -99,6 +105,9 @@ public class OsuDifficultyAttributes : DifficultyAttributes
  yield return (ATTRIB_ID_FLASHLIGHT, FlashlightDifficulty);
 
  yield return (ATTRIB_ID_SLIDER_FACTOR, SliderFactor);
+
+ yield return (ATTRIB_ID_AIM_DIFFICULT_STRAIN_COUNT, AimDifficultStrainCount);
+ yield return (ATTRIB_ID_SPEED_DIFFICULT_STRAIN_COUNT, SpeedDifficultStrainCount);
  yield return (ATTRIB_ID_SPEED_NOTE_COUNT, SpeedNoteCount);
  }
 
@@ -113,8 +122,9 @@ public override void FromDatabaseAttributes(IReadOnlyDictionary<int, double> val
  StarRating = values[ATTRIB_ID_DIFFICULTY];
  FlashlightDifficulty = values.GetValueOrDefault(ATTRIB_ID_FLASHLIGHT);
  SliderFactor = values[ATTRIB_ID_SLIDER_FACTOR];
+ AimDifficultStrainCount = values[ATTRIB_ID_AIM_DIFFICULT_STRAIN_COUNT];
+ SpeedDifficultStrainCount = values[ATTRIB_ID_SPEED_DIFFICULT_STRAIN_COUNT];
  SpeedNoteCount = values[ATTRIB_ID_SPEED_NOTE_COUNT];
-
  DrainRate = onlineInfo.DrainRate;
  HitCircleCount = onlineInfo.CircleCount;
  SliderCount = onlineInfo.SliderCount;

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

@@ -48,6 +48,9 @@ protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beat
 
  double sliderFactor = aimRating > 0 ? aimRatingNoSliders / aimRating : 1;
 
+ double aimDifficultyStrainCount = ((OsuStrainSkill)skills[0]).CountDifficultStrains();
+ double speedDifficultyStrainCount = ((OsuStrainSkill)skills[2]).CountDifficultStrains();
+
  if (mods.Any(m => m is OsuModTouchDevice))
  {
  aimRating = Math.Pow(aimRating, 0.8);
@@ -101,6 +104,8 @@ protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beat
  SpeedNoteCount = speedNotes,
  FlashlightDifficulty = flashlightRating,
  SliderFactor = sliderFactor,
+ AimDifficultStrainCount = aimDifficultyStrainCount,
+ SpeedDifficultStrainCount = speedDifficultyStrainCount,
  ApproachRate = preempt > 1200 ? (1800 - preempt) / 120 : (1200 - preempt) / 150 + 5,
  OverallDifficulty = (80 - hitWindowGreat) / 6,
  DrainRate = drainRate,

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

@@ -92,11 +92,8 @@ private double computeAimValue(ScoreInfo score, OsuDifficultyAttributes attribut
  (totalHits > 2000 ? Math.Log10(totalHits / 2000.0) * 0.5 : 0.0);
  aimValue *= lengthBonus;
 
- // Penalize misses by assessing # of misses relative to the total # of objects. Default a 3% reduction for any # of misses.
  if (effectiveMissCount > 0)
- aimValue *= 0.97 * Math.Pow(1 - Math.Pow(effectiveMissCount / totalHits, 0.775), effectiveMissCount);
-
- aimValue *= getComboScalingFactor(attributes);
+ aimValue *= calculateMissPenalty(effectiveMissCount, attributes.AimDifficultStrainCount);
 
  double approachRateFactor = 0.0;
  if (attributes.ApproachRate > 10.33)
@@ -145,11 +142,8 @@ private double computeSpeedValue(ScoreInfo score, OsuDifficultyAttributes attrib
  (totalHits > 2000 ? Math.Log10(totalHits / 2000.0) * 0.5 : 0.0);
  speedValue *= lengthBonus;
 
- // Penalize misses by assessing # of misses relative to the total # of objects. Default a 3% reduction for any # of misses.
  if (effectiveMissCount > 0)
- speedValue *= 0.97 * Math.Pow(1 - Math.Pow(effectiveMissCount / totalHits, 0.775), Math.Pow(effectiveMissCount, .875));
-
- speedValue *= getComboScalingFactor(attributes);
+ speedValue *= calculateMissPenalty(effectiveMissCount, attributes.SpeedDifficultStrainCount);
 
  double approachRateFactor = 0.0;
  if (attributes.ApproachRate > 10.33)
@@ -264,6 +258,10 @@ private double calculateEffectiveMissCount(OsuDifficultyAttributes attributes)
  return Math.Max(countMiss, comboBasedMissCount);
  }
 
+ // Miss penalty assumes that a player will miss on the hardest parts of a map,
+ // so we use the amount of relatively difficult sections to adjust miss penalty
+ // to make it more punishing on maps with lower amount of hard sections.
+ private double calculateMissPenalty(double missCount, double difficultStrainCount) => 0.96 / ((missCount / (4 * Math.Pow(Math.Log(difficultStrainCount), 0.94))) + 1);
  private double getComboScalingFactor(OsuDifficultyAttributes attributes) => attributes.MaxCombo <= 0 ? 1.0 : Math.Min(Math.Pow(scoreMaxCombo, 0.8) / Math.Pow(attributes.MaxCombo, 0.8), 1.0);
  private int totalHits => countGreat + countOk + countMeh + countMiss;
  }

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

@@ -34,6 +34,7 @@ protected override double StrainValueAt(DifficultyHitObject current)
  {
  currentStrain *= strainDecay(current.DeltaTime);
  currentStrain += AimEvaluator.EvaluateDifficultyOf(current, withSliders) * skillMultiplier;
+ ObjectStrains.Add(currentStrain);
 
  return currentStrain;
  }

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

@@ -34,14 +34,17 @@ public abstract class OsuStrainSkill : StrainSkill
  /// </summary>
  protected virtual double DifficultyMultiplier => DEFAULT_DIFFICULTY_MULTIPLIER;
 
+ protected List<double> ObjectStrains = new List<double>();
+ protected double Difficulty;
+
  protected OsuStrainSkill(Mod[] mods)
  : base(mods)
  {
  }
 
  public override double DifficultyValue()
  {
- double difficulty = 0;
+ Difficulty = 0;
  double weight = 1;
 
  // Sections with 0 strain are excluded to avoid worst-case time complexity of the following sort (e.g. /b/2351871).
@@ -61,11 +64,25 @@ public override double DifficultyValue()
  // We're sorting from highest to lowest strain.
  foreach (double strain in strains.OrderDescending())
  {
- difficulty += strain * weight;
+ Difficulty += strain * weight;
  weight *= DecayWeight;
  }
 
- return difficulty * DifficultyMultiplier;
+ return Difficulty * DifficultyMultiplier;
+ }
+
+ /// <summary>
+ /// Returns the number of strains weighted against the top strain.
+ /// The result is scaled by clock rate as it affects the total number of strains.
+ /// </summary>
+ public double CountDifficultStrains()
+ {
+ if (Difficulty == 0)
+ return 0.0;
+
+ double consistentTopStrain = Difficulty / 10; // What would the top strain be if all strain values were identical
+ // Use a weighted sum of all strains. Constants are arbitrary and give nice values
+ return ObjectStrains.Sum(s => 1.1 / (1 + Math.Exp(-10 * (s / consistentTopStrain - 0.88))));
  }
  }
 }

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

@@ -6,7 +6,6 @@
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu.Difficulty.Evaluators;
 using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
-using System.Collections.Generic;
 using System.Linq;
 
 namespace osu.Game.Rulesets.Osu.Difficulty.Skills
@@ -25,8 +24,6 @@ public class Speed : OsuStrainSkill
  protected override int ReducedSectionCount => 5;
  protected override double DifficultyMultiplier => 1.04;
 
- private readonly List<double> objectStrains = new List<double>();
-
  public Speed(Mod[] mods)
  : base(mods)
  {
@@ -44,23 +41,21 @@ protected override double StrainValueAt(DifficultyHitObject current)
  currentRhythm = RhythmEvaluator.EvaluateDifficultyOf(current);
 
  double totalStrain = currentStrain * currentRhythm;
-
- objectStrains.Add(totalStrain);
+ ObjectStrains.Add(totalStrain);
 
  return totalStrain;
  }
 
  public double RelevantNoteCount()
  {
- if (objectStrains.Count == 0)
+ if (ObjectStrains.Count == 0)
  return 0;
 
- double maxStrain = objectStrains.Max();
-
+ double maxStrain = ObjectStrains.Max();
  if (maxStrain == 0)
  return 0;
 
- return objectStrains.Sum(strain => 1.0 / (1.0 + Math.Exp(-(strain / maxStrain * 12.0 - 6.0))));
+ return ObjectStrains.Sum(strain => 1.0 / (1.0 + Math.Exp(-(strain / maxStrain * 12.0 - 6.0))));
  }
  }
 }

osu.Game/Rulesets/Difficulty/DifficultyAttributes.cs

@@ -25,6 +25,8 @@ public class DifficultyAttributes
  protected const int ATTRIB_ID_SCORE_MULTIPLIER = 15;
  protected const int ATTRIB_ID_FLASHLIGHT = 17;
  protected const int ATTRIB_ID_SLIDER_FACTOR = 19;
+ protected const int ATTRIB_ID_AIM_DIFFICULT_STRAIN_COUNT = 21;
+ protected const int ATTRIB_ID_SPEED_DIFFICULT_STRAIN_COUNT = 23;
  protected const int ATTRIB_ID_SPEED_NOTE_COUNT = 21;
 
  /// <summary>