Merge pull request #13483 from emu1337/diffspike-balance

Spike difficulty / AR&FL adjustments

osu.Game.Rulesets.Osu.Tests/OsuDifficultyCalculatorTest.cs

@@ -15,13 +15,13 @@ namespace osu.Game.Rulesets.Osu.Tests
     {
         protected override string ResourceAssembly => "osu.Game.Rulesets.Osu";
 
-        [TestCase(6.9311451172574934d, "diffcalc-test")]
-        [TestCase(1.0736586907780401d, "zero-length-sliders")]
+        [TestCase(6.7568168283591499d, "diffcalc-test")]
+        [TestCase(1.0348244046058293d, "zero-length-sliders")]
         public void Test(double expected, string name)
             => base.Test(expected, name);
 
-        [TestCase(8.7212283220412345d, "diffcalc-test")]
-        [TestCase(1.3212137158641493d, "zero-length-sliders")]
+        [TestCase(8.4783236764532557d, "diffcalc-test")]
+        [TestCase(1.2708532136987165d, "zero-length-sliders")]
         public void TestClockRateAdjusted(double expected, string name)
             => Test(expected, name, new OsuModDoubleTime());
 

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

@@ -103,22 +103,26 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
             double approachRateTotalHitsFactor = 1.0 / (1.0 + Math.Exp(-(0.007 * (totalHits - 400))));
 
-            aimValue *= 1.0 + (0.03 + 0.37 * approachRateTotalHitsFactor) * approachRateFactor;
+            double approachRateBonus = 1.0 + (0.03 + 0.37 * approachRateTotalHitsFactor) * approachRateFactor;
 
             // We want to give more reward for lower AR when it comes to aim and HD. This nerfs high AR and buffs lower AR.
             if (mods.Any(h => h is OsuModHidden))
                 aimValue *= 1.0 + 0.04 * (12.0 - Attributes.ApproachRate);
 
+            double flashlightBonus = 1.0;
+
             if (mods.Any(h => h is OsuModFlashlight))
             {
                 // Apply object-based bonus for flashlight.
-                aimValue *= 1.0 + 0.35 * Math.Min(1.0, totalHits / 200.0) +
+                flashlightBonus = 1.0 + 0.35 * Math.Min(1.0, totalHits / 200.0) +
                                   (totalHits > 200
                                       ? 0.3 * Math.Min(1.0, (totalHits - 200) / 300.0) +
                                         (totalHits > 500 ? (totalHits - 500) / 1200.0 : 0.0)
                                       : 0.0);
             }
 
+            aimValue *= Math.Max(flashlightBonus, approachRateBonus);
+
             // Scale the aim value with accuracy _slightly_
             aimValue *= 0.5 + accuracy / 2.0;
             // It is important to also consider accuracy difficulty when doing that

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

@@ -3,7 +3,6 @@
 
 using System;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
-using osu.Game.Rulesets.Difficulty.Skills;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Osu.Objects;
@@ -13,7 +12,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
     /// <summary>
     /// Represents the skill required to correctly aim at every object in the map with a uniform CircleSize and normalized distances.
     /// </summary>
-    public class Aim : StrainSkill
+    public class Aim : OsuStrainSkill
     {
         private const double angle_bonus_begin = Math.PI / 3;
         private const double timing_threshold = 107;
@@ -47,7 +46,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
                         Math.Max(osuPrevious.JumpDistance - scale, 0)
                         * Math.Pow(Math.Sin(osuCurrent.Angle.Value - angle_bonus_begin), 2)
                         * Math.Max(osuCurrent.JumpDistance - scale, 0));
-                    result = 1.5 * applyDiminishingExp(Math.Max(0, angleBonus)) / Math.Max(timing_threshold, osuPrevious.StrainTime);
+                    result = 1.4 * applyDiminishingExp(Math.Max(0, angleBonus)) / Math.Max(timing_threshold, osuPrevious.StrainTime);
                 }
             }
 

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

@@ -0,0 +1,61 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Collections.Generic;
+using osu.Game.Rulesets.Difficulty.Skills;
+using osu.Game.Rulesets.Mods;
+using System.Linq;
+using osu.Framework.Utils;
+
+namespace osu.Game.Rulesets.Osu.Difficulty.Skills
+{
+    public abstract class OsuStrainSkill : StrainSkill
+    {
+        /// <summary>
+        /// The number of sections with the highest strains, which the peak strain reductions will apply to.
+        /// This is done in order to decrease their impact on the overall difficulty of the map for this skill.
+        /// </summary>
+        protected virtual int ReducedSectionCount => 10;
+
+        /// <summary>
+        /// The baseline multiplier applied to the section with the biggest strain.
+        /// </summary>
+        protected virtual double ReducedStrainBaseline => 0.75;
+
+        /// <summary>
+        /// The final multiplier to be applied to <see cref="DifficultyValue"/> after all other calculations.
+        /// </summary>
+        protected virtual double DifficultyMultiplier => 1.06;
+
+        protected OsuStrainSkill(Mod[] mods)
+            : base(mods)
+        {
+        }
+
+        public override double DifficultyValue()
+        {
+            double difficulty = 0;
+            double weight = 1;
+
+            List<double> strains = GetCurrentStrainPeaks().OrderByDescending(d => d).ToList();
+
+            // We are reducing the highest strains first to account for extreme difficulty spikes
+            for (int i = 0; i < Math.Min(strains.Count, ReducedSectionCount); i++)
+            {
+                double scale = Math.Log10(Interpolation.Lerp(1, 10, Math.Clamp((float)i / ReducedSectionCount, 0, 1)));
+                strains[i] *= Interpolation.Lerp(ReducedStrainBaseline, 1.0, scale);
+            }
+
+            // Difficulty is the weighted sum of the highest strains from every section.
+            // We're sorting from highest to lowest strain.
+            foreach (double strain in strains.OrderByDescending(d => d))
+            {
+                difficulty += strain * weight;
+                weight *= DecayWeight;
+            }
+
+            return difficulty * DifficultyMultiplier;
+        }
+    }
+}

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

@@ -3,7 +3,6 @@
 
 using System;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
-using osu.Game.Rulesets.Difficulty.Skills;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Osu.Objects;
@@ -13,7 +12,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
     /// <summary>
     /// Represents the skill required to press keys with regards to keeping up with the speed at which objects need to be hit.
     /// </summary>
-    public class Speed : StrainSkill
+    public class Speed : OsuStrainSkill
     {
         private const double single_spacing_threshold = 125;
 
@@ -23,6 +22,8 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
 
         protected override double SkillMultiplier => 1400;
         protected override double StrainDecayBase => 0.3;
+        protected override int ReducedSectionCount => 5;
+        protected override double DifficultyMultiplier => 1.04;
 
         private const double min_speed_bonus = 75; // ~200BPM
         private const double max_speed_bonus = 45; // ~330BPM

osu.Game/Rulesets/Difficulty/Skills/StrainSkill.cs

@@ -109,7 +109,7 @@ namespace osu.Game.Rulesets.Difficulty.Skills
         /// <summary>
         /// Returns the calculated difficulty value representing all <see cref="DifficultyHitObject"/>s that have been processed up to this point.
         /// </summary>
-        public sealed override double DifficultyValue()
+        public override double DifficultyValue()
         {
             double difficulty = 0;
             double weight = 1;