Move osu!catch movement diffcalc to an evaluator

osu.Game.Rulesets.Catch/Difficulty/Evaluators/MovementEvaluator.cs

@@ -0,0 +1,65 @@
+// Copyright (c) ppy Pty Ltd <[email protected]>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using osu.Game.Rulesets.Catch.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Difficulty.Preprocessing;
+
+namespace osu.Game.Rulesets.Catch.Difficulty.Evaluators
+{
+    public static class MovementEvaluator
+    {
+        private const double direction_change_bonus = 21.0;
+
+        public static double EvaluateDifficultyOf(DifficultyHitObject current, double catcherSpeedMultiplier)
+        {
+            var catchCurrent = (CatchDifficultyHitObject)current;
+            var catchLast = (CatchDifficultyHitObject)current.Previous(0);
+            var catchLastLast = (CatchDifficultyHitObject)current.Previous(1);
+
+            double weightedStrainTime = catchCurrent.StrainTime + 13 + (3 / catcherSpeedMultiplier);
+
+            double distanceAddition = (Math.Pow(Math.Abs(catchCurrent.DistanceMoved), 1.3) / 510);
+            double sqrtStrain = Math.Sqrt(weightedStrainTime);
+
+            double edgeDashBonus = 0;
+
+            // Direction change bonus.
+            if (Math.Abs(catchCurrent.DistanceMoved) > 0.1)
+            {
+                if (current.Index >= 1 && Math.Abs(catchLast.DistanceMoved) > 0.1 && Math.Sign(catchCurrent.DistanceMoved) != Math.Sign(catchLast.DistanceMoved))
+                {
+                    double bonusFactor = Math.Min(50, Math.Abs(catchCurrent.DistanceMoved)) / 50;
+                    double antiflowFactor = Math.Max(Math.Min(70, Math.Abs(catchLast.DistanceMoved)) / 70, 0.38);
+
+                    distanceAddition += direction_change_bonus / Math.Sqrt(catchLast.StrainTime + 16) * bonusFactor * antiflowFactor * Math.Max(1 - Math.Pow(weightedStrainTime / 1000, 3), 0);
+                }
+
+                // Base bonus for every movement, giving some weight to streams.
+                distanceAddition += 12.5 * Math.Min(Math.Abs(catchCurrent.DistanceMoved), CatchDifficultyHitObject.NORMALIZED_HALF_CATCHER_WIDTH * 2)
+                                    / (CatchDifficultyHitObject.NORMALIZED_HALF_CATCHER_WIDTH * 6) / sqrtStrain;
+            }
+
+            // Bonus for edge dashes.
+            if (catchCurrent.LastObject.DistanceToHyperDash <= 20.0f)
+            {
+                if (!catchCurrent.LastObject.HyperDash)
+                    edgeDashBonus += 5.7;
+
+                distanceAddition *= 1.0 + edgeDashBonus * ((20 - catchCurrent.LastObject.DistanceToHyperDash) / 20)
+                                                        * Math.Pow((Math.Min(catchCurrent.StrainTime * catcherSpeedMultiplier, 265) / 265), 1.5); // Edge Dashes are easier at lower ms values
+            }
+
+            // There is an edge case where horizontal back and forth sliders create "buzz" patterns which are repeated "movements" with a distance lower than
+            // the platter's width but high enough to be considered a movement due to the absolute_player_positioning_error and NORMALIZED_HALF_CATCHER_WIDTH offsets
+            // We are detecting this exact scenario. The first back and forth is counted but all subsequent ones are nullified.
+            // To achieve that, we need to store the exact distances (distance ignoring absolute_player_positioning_error and NORMALIZED_HALF_CATCHER_WIDTH)
+            if (current.Index >= 2 && Math.Abs(catchCurrent.ExactDistanceMoved) <= CatchDifficultyHitObject.NORMALIZED_HALF_CATCHER_WIDTH * 2
+                                   && catchCurrent.ExactDistanceMoved == -catchLast.ExactDistanceMoved && catchLast.ExactDistanceMoved == -catchLastLast.ExactDistanceMoved
+                                   && catchCurrent.StrainTime == catchLast.StrainTime && catchLast.StrainTime == catchLastLast.StrainTime)
+                distanceAddition = 0;
+
+            return distanceAddition / weightedStrainTime;
+        }
+    }
+}

osu.Game.Rulesets.Catch/Difficulty/Preprocessing/CatchDifficultyHitObject.cs

@@ -12,14 +12,48 @@ namespace osu.Game.Rulesets.Catch.Difficulty.Preprocessing
     public class CatchDifficultyHitObject : DifficultyHitObject
     {
         public const float NORMALIZED_HALF_CATCHER_WIDTH = 41.0f;
+        private const float absolute_player_positioning_error = 16.0f;
 
         public new PalpableCatchHitObject BaseObject => (PalpableCatchHitObject)base.BaseObject;
 
         public new PalpableCatchHitObject LastObject => (PalpableCatchHitObject)base.LastObject;
 
+        /// <summary>
+        /// Normalized position of <see cref="BaseObject"/>.
+        /// </summary>
         public readonly float NormalizedPosition;
+
+        /// <summary>
+        /// Normalized position of <see cref="LastObject"/>.
+        /// </summary>
         public readonly float LastNormalizedPosition;
 
+        /// <summary>
+        /// Normalized position of the player required to catch <see cref="BaseObject"/>, assuming the player moves as little as possible.
+        /// </summary>
+        public float PlayerPosition { get; private set; }
+
+        /// <summary>
+        /// Normalized position of the player after catching <see cref="LastObject"/>.
+        /// </summary>
+        public float LastPlayerPosition { get; private set; }
+
+        /// <summary>
+        /// Normalized distance between <see cref="LastPlayerPosition"/> and <see cref="PlayerPosition"/>.
+        /// </summary>
+        /// <remarks>
+        /// The sign of the value indicates the direction of the movement: negative is left and positive is right.
+        /// </remarks>
+        public float DistanceMoved { get; private set; }
+
+        /// <summary>
+        /// Normalized distance the player has to move from <see cref="LastPlayerPosition"/> in order to catch <see cref="BaseObject"/> at its <see cref="NormalizedPosition"/>.
+        /// </summary>
+        /// <remarks>
+        /// The sign of the value indicates the direction of the movement: negative is left and positive is right.
+        /// </remarks>
+        public float ExactDistanceMoved { get; private set; }
+
         /// <summary>
         /// Milliseconds elapsed since the start time of the previous <see cref="CatchDifficultyHitObject"/>, with a minimum of 40ms.
         /// </summary>
@@ -36,6 +70,28 @@ public CatchDifficultyHitObject(HitObject hitObject, HitObject lastObject, doubl
 
             // Every strain interval is hard capped at the equivalent of 375 BPM streaming speed as a safety measure
             StrainTime = Math.Max(40, DeltaTime);
+
+            setMovementState();
+        }
+
+        private void setMovementState()
+        {
+            LastPlayerPosition = Index == 0 ? LastNormalizedPosition : ((CatchDifficultyHitObject)Previous(0)).PlayerPosition;
+
+            PlayerPosition = Math.Clamp(
+                LastPlayerPosition,
+                NormalizedPosition - (NORMALIZED_HALF_CATCHER_WIDTH - absolute_player_positioning_error),
+                NormalizedPosition + (NORMALIZED_HALF_CATCHER_WIDTH - absolute_player_positioning_error)
+            );
+
+            DistanceMoved = PlayerPosition - LastPlayerPosition;
+
+            // For the exact position we consider that the catcher is in the correct position for both objects
+            ExactDistanceMoved = NormalizedPosition - LastPlayerPosition;
+
+            // After a hyperdash we ARE in the correct position. Always!
+            if (LastObject.HyperDash)
+                PlayerPosition = NormalizedPosition;
         }
     }
 }

osu.Game.Rulesets.Catch/Difficulty/Skills/Movement.cs

@@ -1,8 +1,7 @@
 // Copyright (c) ppy Pty Ltd <[email protected]>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System;
-using osu.Game.Rulesets.Catch.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Catch.Difficulty.Evaluators;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Difficulty.Skills;
 using osu.Game.Rulesets.Mods;
@@ -11,9 +10,6 @@ namespace osu.Game.Rulesets.Catch.Difficulty.Skills
 {
     public class Movement : StrainDecaySkill
     {
-        private const float absolute_player_positioning_error = 16f;
-        private const double direction_change_bonus = 21.0;
-
         protected override double SkillMultiplier => 1;
         protected override double StrainDecayBase => 0.2;
 
@@ -23,12 +19,6 @@ public class Movement : StrainDecaySkill
 
         protected readonly float HalfCatcherWidth;
 
-        private float? lastPlayerPosition;
-        private float lastDistanceMoved;
-        private float lastExactDistanceMoved;
-        private double lastStrainTime;
-        private bool isInBuzzSection;
-
         /// <summary>
         /// The speed multiplier applied to the player's catcher.
         /// </summary>
@@ -48,82 +38,7 @@ public Movement(Mod[] mods, float halfCatcherWidth, double clockRate)
 
         protected override double StrainValueOf(DifficultyHitObject current)
         {
-            var catchCurrent = (CatchDifficultyHitObject)current;
-
-            lastPlayerPosition ??= catchCurrent.LastNormalizedPosition;
-
-            float playerPosition = Math.Clamp(
-                lastPlayerPosition.Value,
-                catchCurrent.NormalizedPosition - (CatchDifficultyHitObject.NORMALIZED_HALF_CATCHER_WIDTH - absolute_player_positioning_error),
-                catchCurrent.NormalizedPosition + (CatchDifficultyHitObject.NORMALIZED_HALF_CATCHER_WIDTH - absolute_player_positioning_error)
-            );
-
-            float distanceMoved = playerPosition - lastPlayerPosition.Value;
-
-            // For the exact position we consider that the catcher is in the correct position for both objects
-            float exactDistanceMoved = catchCurrent.NormalizedPosition - lastPlayerPosition.Value;
-
-            double weightedStrainTime = catchCurrent.StrainTime + 13 + (3 / catcherSpeedMultiplier);
-
-            double distanceAddition = (Math.Pow(Math.Abs(distanceMoved), 1.3) / 510);
-            double sqrtStrain = Math.Sqrt(weightedStrainTime);
-
-            double edgeDashBonus = 0;
-
-            // Direction change bonus.
-            if (Math.Abs(distanceMoved) > 0.1)
-            {
-                if (Math.Abs(lastDistanceMoved) > 0.1 && Math.Sign(distanceMoved) != Math.Sign(lastDistanceMoved))
-                {
-                    double bonusFactor = Math.Min(50, Math.Abs(distanceMoved)) / 50;
-                    double antiflowFactor = Math.Max(Math.Min(70, Math.Abs(lastDistanceMoved)) / 70, 0.38);
-
-                    distanceAddition += direction_change_bonus / Math.Sqrt(lastStrainTime + 16) * bonusFactor * antiflowFactor * Math.Max(1 - Math.Pow(weightedStrainTime / 1000, 3), 0);
-                }
-
-                // Base bonus for every movement, giving some weight to streams.
-                distanceAddition += 12.5 * Math.Min(Math.Abs(distanceMoved), CatchDifficultyHitObject.NORMALIZED_HALF_CATCHER_WIDTH * 2) / (CatchDifficultyHitObject.NORMALIZED_HALF_CATCHER_WIDTH * 6)
-                    / sqrtStrain;
-            }
-
-            // Bonus for edge dashes.
-            if (catchCurrent.LastObject.DistanceToHyperDash <= 20.0f)
-            {
-                if (!catchCurrent.LastObject.HyperDash)
-                    edgeDashBonus += 5.7;
-                else
-                {
-                    // After a hyperdash we ARE in the correct position. Always!
-                    playerPosition = catchCurrent.NormalizedPosition;
-                }
-
-                distanceAddition *= 1.0 + edgeDashBonus * ((20 - catchCurrent.LastObject.DistanceToHyperDash) / 20)
-                                                        * Math.Pow((Math.Min(catchCurrent.StrainTime * catcherSpeedMultiplier, 265) / 265), 1.5); // Edge Dashes are easier at lower ms values
-            }
-
-            // There is an edge case where horizontal back and forth sliders create "buzz" patterns which are repeated "movements" with a distance lower than
-            // the platter's width but high enough to be considered a movement due to the absolute_player_positioning_error and NORMALIZED_HALF_CATCHER_WIDTH offsets
-            // We are detecting this exact scenario. The first back and forth is counted but all subsequent ones are nullified.
-            // To achieve that, we need to store the exact distances (distance ignoring absolute_player_positioning_error and NORMALIZED_HALF_CATCHER_WIDTH)
-            if (Math.Abs(exactDistanceMoved) <= CatchDifficultyHitObject.NORMALIZED_HALF_CATCHER_WIDTH * 2 && exactDistanceMoved == -lastExactDistanceMoved
-                                                                                                           && catchCurrent.StrainTime == lastStrainTime)
-            {
-                if (isInBuzzSection)
-                    distanceAddition = 0;
-                else
-                    isInBuzzSection = true;
-            }
-            else
-            {
-                isInBuzzSection = false;
-            }
-
-            lastPlayerPosition = playerPosition;
-            lastDistanceMoved = distanceMoved;
-            lastStrainTime = catchCurrent.StrainTime;
-            lastExactDistanceMoved = exactDistanceMoved;
-
-            return distanceAddition / weightedStrainTime;
+            return MovementEvaluator.EvaluateDifficultyOf(current, catcherSpeedMultiplier);
         }
     }
 }