Revert "Replace vibro nerf with a faster (and still accurate) alterna…

…tive"

This reverts commit 8826443.

src/com/rian/osu/difficulty/attributes/DroidDifficultyAttributes.kt

@@ -61,6 +61,12 @@ class DroidDifficultyAttributes : DifficultyAttributes() {
     @JvmField
     var visualDifficultStrainCount = 0.0
 
+    /**
+     * The average delta time of speed objects.
+     */
+    @JvmField
+    var averageSpeedDeltaTime = 0.0
+
     /**
      * Possible sections at which the player can use three fingers on.
      */
@@ -92,4 +98,14 @@ class DroidDifficultyAttributes : DifficultyAttributes() {
      */
     @JvmField
     var visualSliderFactor = 1.0
+
+    /**
+     * Describes how much of tap difficulty is contributed by notes that are "vibroable".
+     *
+     * A value closer to 1 indicates most tap difficulty is contributed by notes that are not "vibroable".
+     *
+     * A value closer to 0 indicates most tap difficulty is contributed by notes that are "vibroable".
+     */
+    @JvmField
+    var vibroFactor = 1.0
 }

src/com/rian/osu/difficulty/calculator/DroidDifficultyCalculator.kt

@@ -72,6 +72,15 @@ class DroidDifficultyCalculator : DifficultyCalculator<DroidPlayableBeatmap, Dro
             tapDifficulty = calculateRating(it)
             tapDifficultStrainCount = it.countDifficultStrains()
             speedNoteCount = it.relevantNoteCount()
+            averageSpeedDeltaTime = it.relevantDeltaTime()
+
+            if (tapDifficulty > 0) {
+                val tapSkillVibro = DroidTap(mods, true, averageSpeedDeltaTime)
+
+                objects.forEach { o -> tapSkillVibro.process(o) }
+
+                vibroFactor = calculateRating(tapSkillVibro) / tapDifficulty
+            }
         }
 
         var firstObjectIndex = 0
@@ -253,7 +262,7 @@ class DroidDifficultyCalculator : DifficultyCalculator<DroidPlayableBeatmap, Dro
     ) = beatmap.createDroidPlayableBeatmap(
             parameters?.mods,
             parameters?.customSpeedMultiplier ?: 1f,
-            parameters?.oldStatistics == true,
+            parameters?.oldStatistics ?: false,
             scope
         )
 

src/com/rian/osu/difficulty/calculator/DroidPerformanceCalculator.kt

@@ -6,7 +6,6 @@ import com.rian.osu.beatmap.PreciseDroidHitWindow
 import com.rian.osu.difficulty.attributes.DroidDifficultyAttributes
 import com.rian.osu.difficulty.attributes.DroidPerformanceAttributes
 import com.rian.osu.math.ErrorFunction
-import com.rian.osu.math.Interpolation
 import com.rian.osu.mods.*
 import com.rian.osu.replay.SliderCheesePenalty
 import kotlin.math.*
@@ -142,11 +141,25 @@ class DroidPerformanceCalculator(
         // also cap the note count to prevent buffing filler patterns.
         tapValue *= calculateDeviationBasedLengthScaling(min(speedNoteCount, totalHits / 1.45))
 
+        // Normalize the deviation to 300 BPM.
+        val normalizedDeviation = tapDeviation * max(1.0, 50 / averageSpeedDeltaTime)
+
+        // We expect the player to get 7500/x deviation when doubletapping x BPM.
+        // Using this expectation, we penalize score with deviation above 25.
+        val averageBPM = 60000 / 4 / averageSpeedDeltaTime
+
+        val adjustedDeviation = normalizedDeviation *
+            (1 + 1 / (1 + exp(-(normalizedDeviation - 7500 / averageBPM) / (2 * 300 / averageBPM))))
+
         // Scale the tap value with tap deviation.
-        tapValue *= 1.05 * ErrorFunction.erf(20 / (sqrt(2.0) * tapDeviation)).pow(0.6)
+        tapValue *= 1.05 * ErrorFunction.erf(20 / (sqrt(2.0) * adjustedDeviation)).pow(0.6)
 
-        // Scale the tap value with high deviation nerf.
-        tapValue *= calculateTapHighDeviationNerf()
+        // Additional scaling for tap value based on average BPM and how "vibroable" the beatmap is.
+        // Higher BPMs require more precise tapping. When the deviation is too high,
+        // it can be assumed that the player taps invariant to rhythm.
+        // We make the punishment harsher punishment for such scenario.
+        tapValue *= vibroFactor.pow(6) +
+            (1 - vibroFactor.pow(6)) / (1 + exp((tapDeviation - 7500 / averageBPM) / (2 * 300 / averageBPM)))
 
         // Scale the tap value with three-fingered penalty.
         tapValue /= tapPenalty
@@ -428,37 +441,6 @@ class DroidPerformanceCalculator(
         Double.POSITIVE_INFINITY
     }
 
-    /**
-     * Calculates multiplier for tap to account for improper tapping based on the deviation and tap difficulty.
-     *
-     * https://www.desmos.com/calculator/dmogdhzofn
-     */
-    private fun calculateTapHighDeviationNerf(): Double {
-        if (tapDeviation == Double.POSITIVE_INFINITY) {
-            return 0.0
-        }
-
-        val tapValue = (5 * max(1.0, difficultyAttributes.tapDifficulty / 0.0675) - 4).pow(3) / 100000
-
-        // Decide a point where the PP value achieved compared to the tap deviation is assumed to be
-        // tapped improperly. Any PP above this point is considered "excess" tap difficulty.
-        // This is used to cause PP above the cutoff to scale logarithmically towards the original
-        // tap value, thus nerfing the value.
-        val excessTapDifficultyCutoff = 100 + 220 * (22 / tapDeviation).pow(6.5)
-
-        if (tapValue <= excessTapDifficultyCutoff) {
-            return 1.0
-        }
-
-        val scale = 50
-        val adjustedTapValue = scale * ln((tapValue - excessTapDifficultyCutoff) / scale + 1) + excessTapDifficultyCutoff / scale
-
-        // 200 UR and less are considered tapped correctly to ensure that normal scores will be punished as little as possible
-        val lerp = 1 - ((tapDeviation - 20) / (24 - 20)).coerceIn(0.0, 1.0)
-
-        return Interpolation.linear(adjustedTapValue, tapValue, lerp) / tapValue
-    }
-
     private fun getConvertedHitWindow(): HitWindow {
         var od = difficultyAttributes.overallDifficulty.toFloat()
         var hitWindow = if (isPrecise) PreciseDroidHitWindow(od) else DroidHitWindow(od)

src/com/rian/osu/difficulty/evaluators/DroidTapEvaluator.kt

@@ -3,6 +3,7 @@ package com.rian.osu.difficulty.evaluators
 import com.rian.osu.beatmap.hitobject.Spinner
 import com.rian.osu.difficulty.DroidDifficultyHitObject
 import com.rian.osu.math.ErrorFunction
+import kotlin.math.max
 import kotlin.math.pow
 
 /**
@@ -16,15 +17,19 @@ object DroidTapEvaluator {
      * Evaluates the difficulty of tapping the current object, based on:
      *
      * * time between pressing the previous and current object,
+     * * distance between those objects,
      * * and how easily they can be cheesed.
      *
      * @param current The current object.
      * @param considerCheesability Whether to consider cheesability.
+     * @param strainTimeCap The strain time to cap to.
      */
     @JvmStatic
+    @JvmOverloads
     fun evaluateDifficultyOf(
         current: DroidDifficultyHitObject,
-        considerCheesability: Boolean
+        considerCheesability: Boolean,
+        strainTimeCap: Double? = null
     ): Double {
         if (
             current.obj is Spinner ||
@@ -35,12 +40,17 @@ object DroidTapEvaluator {
         }
 
         val doubletapness = if (considerCheesability) 1 - current.doubletapness else 1.0
+
+        val strainTime =
+            if (strainTimeCap != null) max(50.0, max(strainTimeCap, current.strainTime))
+            else current.strainTime
+
         var speedBonus = 1.0
 
         if (current.strainTime < MIN_SPEED_BONUS) {
-            speedBonus += 0.75 * ErrorFunction.erf((MIN_SPEED_BONUS - current.strainTime) / 40).pow(2)
+            speedBonus += 0.75 * ErrorFunction.erf((MIN_SPEED_BONUS - strainTime) / 40).pow(2)
         }
 
-        return speedBonus * doubletapness.pow(1.5) * 1000 / current.strainTime
+        return speedBonus * doubletapness.pow(1.5) * 1000 / strainTime
     }
 }

src/com/rian/osu/difficulty/skills/DroidTap.kt

@@ -18,7 +18,12 @@ class DroidTap(
     /**
      * Whether to consider cheesability.
      */
-    private val considerCheesability: Boolean
+    private val considerCheesability: Boolean,
+
+    /**
+     * The strain time to cap to.
+     */
+    private val strainTimeCap: Double? = null
 ) : DroidStrainSkill(mods) {
     override val starsPerDouble = 1.1
 
@@ -28,6 +33,8 @@ class DroidTap(
     private val skillMultiplier = 1.375
     private val strainDecayBase = 0.3
 
+    private val objectDeltaTimes = mutableListOf<Double>()
+
     /**
      * Gets the amount of notes that are relevant to the difficulty.
      */
@@ -44,15 +51,38 @@ class DroidTap(
         fold(0.0) { acc, d -> acc + 1 / (1 + exp(-(d / maxStrain * 12 - 6))) }
     }
 
+    /**
+     * Gets the delta time relevant to the difficulty.
+     */
+    fun relevantDeltaTime() = objectStrains.run {
+        if (isEmpty()) {
+            return 0.0
+        }
+
+        val maxStrain = max()
+        if (maxStrain == 0.0) {
+            return 0.0
+        }
+
+        objectDeltaTimes.foldIndexed(0.0) { i, acc, d ->
+            acc + d / (1 + exp(-(this[i] / maxStrain * 25 - 20)))
+        } / fold(0.0) { acc, d ->
+            acc + 1 / (1 + exp(-(d / maxStrain * 25 - 20)))
+        }
+    }
+
     override fun strainValueAt(current: DroidDifficultyHitObject): Double {
         currentStrain *= strainDecay(current.strainTime)
-        currentStrain += DroidTapEvaluator.evaluateDifficultyOf(current, considerCheesability) * skillMultiplier
+        currentStrain += DroidTapEvaluator.evaluateDifficultyOf(
+            current, considerCheesability, strainTimeCap
+        ) * skillMultiplier
 
         currentRhythm = current.rhythmMultiplier
 
         val totalStrain = currentStrain * currentRhythm
 
         objectStrains.add(totalStrain)
+        objectDeltaTimes.add(current.deltaTime)
 
         return totalStrain
     }