Change doubletap doubles nerf in Speed Evaluator to address for galloping

osu.Game.Rulesets.Osu/Difficulty/Evaluators/SpeedEvaluator.cs

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using osu.Framework.Extensions.ObjectExtensions;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Osu.Objects;
@@ -33,18 +34,28 @@ public static double EvaluateDifficultyOf(DifficultyHitObject current)
  var osuNextObj = (OsuDifficultyHitObject?)current.Next(0);
 
  double strainTime = osuCurrObj.StrainTime;
- double doubletapness = 1;
 
  // Nerf doubletappable doubles.
- if (osuNextObj != null)
- {
- double currDeltaTime = Math.Max(1, osuCurrObj.DeltaTime);
- double nextDeltaTime = Math.Max(1, osuNextObj.DeltaTime);
- double deltaDifference = Math.Abs(nextDeltaTime - currDeltaTime);
- double speedRatio = currDeltaTime / Math.Max(currDeltaTime, deltaDifference);
- double windowRatio = Math.Pow(Math.Min(1, currDeltaTime / osuCurrObj.HitWindowGreat), 2);
- doubletapness = Math.Pow(speedRatio, 1 - windowRatio);
- }
+ double currDeltaTime = Math.Max(1, osuCurrObj.DeltaTime);
+
+ // It's easier to gallop if you have more time between doubles
+ // Get max between next and prev ratio to avoid nerfing triples
+ double speedRatio = Math.Max(getSpeedRatio(osuCurrObj, osuPrevObj), getSpeedRatio(osuCurrObj, osuNextObj));
+
+ // Can't doubletap if circles don't intersect
+ double normalizedDistance = Math.Min(1, osuCurrObj.LazyJumpDistance / (OsuDifficultyHitObject.NORMALISED_RADIUS * 2));
+ double distanceFactor = normalizedDistance < 0.5 ? 1.0 : 1 - Math.Pow((normalizedDistance - 0.5) / 0.5, 0.5);
+
+ // Use HitWindowGreat * 2, because even if you can't get 300 with doubletapping - you still can gallop
+ const double power = 2;
+ double windowRatio = Math.Pow(Math.Min(1, currDeltaTime / (osuCurrObj.HitWindowGreat * 2)), power);
+
+ // Nerf even more if you don't need to gallop anymore
+ double halfPoint = Math.Pow(0.5, power);
+ if (windowRatio < halfPoint)
+ windowRatio *= windowRatio / halfPoint;
+
+ double doubletapness = Math.Pow(speedRatio, distanceFactor * (1 - windowRatio));
 
  // Cap deltatime to the OD 300 hitwindow.
  // 0.93 is derived from making sure 260bpm OD8 streams aren't nerfed harshly, whilst 0.92 limits the effect of the cap.
@@ -61,5 +72,18 @@ public static double EvaluateDifficultyOf(DifficultyHitObject current)
 
  return (speedBonus + speedBonus * Math.Pow(distance / single_spacing_threshold, 3.5)) * doubletapness / strainTime;
  }
+
+ private static double getSpeedRatio(OsuDifficultyHitObject current, OsuDifficultyHitObject? other)
+ {
+ if (other.IsNull())
+ return 0;
+
+ double currDeltaTime = Math.Max(1, current.DeltaTime);
+ double otherDeltaTime = Math.Max(1, other.DeltaTime);
+
+ double deltaDifference = Math.Abs(currDeltaTime - otherDeltaTime);
+
+ return currDeltaTime / Math.Max(currDeltaTime, deltaDifference);
+ }
  }
 }