Add consistentRatioPenalty to the Colour skill.

osu.Game.Rulesets.Taiko/Difficulty/Evaluators/ColourEvaluator.cs

@@ -36,18 +36,64 @@ public static double EvaluateDifficultyOf(RepeatingHitPatterns repeatingHitPatte
             return 2 * (1 - DifficultyCalculationUtils.Logistic(exponent: Math.E * repeatingHitPattern.RepetitionInterval - 2 * Math.E));
         }
 
+        /// <summary>
+        /// Calculates a consistency penalty based on the number of consecutive consistent intervals,
+        /// considering the delta time between each colour sequence.
+        /// </summary>
+        /// <param name="hitObject">The current hitObject to consider.</param>
+        /// <param name="threshold"> The allowable margin of error for determining whether ratios are consistent.</param>
+        private static double consistentRatioPenalty(TaikoDifficultyHitObject hitObject, double threshold = 0.01)
+        {
+            int consistentRatioCount = 0;
+            double totalRatioCount = 0.0;
+
+            TaikoDifficultyHitObject current = hitObject;
+
+            while (current.Previous(1) is TaikoDifficultyHitObject previousHitObject)
+            {
+                double currentRatio = current.Rhythm.Ratio;
+                double previousRatio = previousHitObject.Rhythm.Ratio;
+
+                // If there's no valid hit object before the previous one, break the loop.
+                if (previousHitObject.Previous(1) is not TaikoDifficultyHitObject)
+                    break;
+
+                // A consistent interval is defined as the percentage difference between the two rhythmic ratios with the margin of error.
+                if (Math.Abs(1 - currentRatio / previousRatio) <= threshold)
+                {
+                    consistentRatioCount++;
+                    totalRatioCount += currentRatio;
+                }
+
+                current = previousHitObject;
+            }
+
+            double ratioPenalty = 1 - totalRatioCount / (consistentRatioCount + 1) * 0.15;
+
+            return 1.0 - (1 - ratioPenalty);
+        }
+
+        /// <summary>
+        /// Evaluate the difficulty of the first hitobject within a colour streak.
+        /// </summary>
         public static double EvaluateDifficultyOf(DifficultyHitObject hitObject)
         {
             TaikoDifficultyHitObjectColour colour = ((TaikoDifficultyHitObject)hitObject).Colour;
+            var taikoObject = (TaikoDifficultyHitObject)hitObject;
             double difficulty = 0.0d;
 
             if (colour.MonoStreak?.FirstHitObject == hitObject) // Difficulty for MonoStreak
                 difficulty += EvaluateDifficultyOf(colour.MonoStreak);
+
             if (colour.AlternatingMonoPattern?.FirstHitObject == hitObject) // Difficulty for AlternatingMonoPattern
                 difficulty += EvaluateDifficultyOf(colour.AlternatingMonoPattern);
+
             if (colour.RepeatingHitPattern?.FirstHitObject == hitObject) // Difficulty for RepeatingHitPattern
                 difficulty += EvaluateDifficultyOf(colour.RepeatingHitPattern);
 
+            double consistencyPenalty = consistentRatioPenalty(taikoObject);
+            difficulty *= consistencyPenalty;
+
             return difficulty;
         }
     }