From 35c72012e94df1691aa7ca295b5bf67b5d54e4f7 Mon Sep 17 00:00:00 2001
From: apollo-dw <83023433+apollo-dw@users.noreply.github.com>
Date: Sat, 27 Aug 2022 18:33:07 +0100
Subject: [PATCH] Various high AR tweaks

---
 .../Evaluators/CognitionEvaluator.cs          | 41 ++++++++++++++++---
 1 file changed, 35 insertions(+), 6 deletions(-)

diff --git a/osu.Game.Rulesets.Osu/Difficulty/Evaluators/CognitionEvaluator.cs b/osu.Game.Rulesets.Osu/Difficulty/Evaluators/CognitionEvaluator.cs
index 13c2e6f79d..98905391b0 100644
--- a/osu.Game.Rulesets.Osu/Difficulty/Evaluators/CognitionEvaluator.cs
+++ b/osu.Game.Rulesets.Osu/Difficulty/Evaluators/CognitionEvaluator.cs
@@ -46,10 +46,6 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
                 // Small distances means objects may be cheesed, so it doesn't matter whether they are arranged confusingly.
                 loopDifficulty *= logistic((loopObj.MinimumJumpDistance - 90) / 15);
 
-                // Objects that are arranged in a mostly-linear fashion should be easy to read (such as circles in a stream).
-                //if (loopObj.Angle.IsNotNull() && prevLoopObj.Angle.IsNotNull())
-                //   loopDifficulty *= 1 - Math.Pow(Math.Sin(0.5 * loopObj.Angle.Value), 5);
-
                 double timeBetweenCurrAndLoopObj = (currObj.BaseObject.StartTime - loopObj.BaseObject.StartTime) / clockRateEstimate;
                 loopDifficulty *= getTimeNerfFactor(timeBetweenCurrAndLoopObj);
 
@@ -76,14 +72,45 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
             }
 
             double preemptDifficulty = 0.0;
+
             if (currObj.preempt < 400)
+            {
                 preemptDifficulty += Math.Pow(400 - currObj.preempt, 1.5) / 14;
 
-            // Buff rhythm on high AR.
-            preemptDifficulty *= RhythmEvaluator.EvaluateDifficultyOf(current, 30);
+                // Buff spacing.
+                preemptDifficulty *= Math.Max(1, 0.3 * currVelocity);
+
+                // Buff rhythm.
+                preemptDifficulty *= RhythmEvaluator.EvaluateDifficultyOf(current, 30);
+
+                // Buff small circles.
+                // Very arbitrary, but lets assume CS5 is when AR11 becomes more uncomfortable.
+                // This is likely going to need adjustments in the future as player meta develops.
+                preemptDifficulty *= 1 + Math.Max((30 - ((OsuHitObject)currObj.BaseObject).Radius) / 20, 0);
+
+                // Nerf repeated angles on high AR.
+                if (current.Index > 1)
+                {
+                    var prevPrevObj = (OsuDifficultyHitObject)current.Previous(1);
+
+                    if (currObj.Angle != null && prevObj.Angle != null)
+                    {
+                        preemptDifficulty *= getAngleDifferenceNerfFactor(Math.Abs(currObj.Angle.Value - prevObj.Angle.Value));
+                    }
+
+                    if (currObj.Angle != null && prevPrevObj.Angle != null)
+                    {
+                        preemptDifficulty *= getAngleDifferenceNerfFactor(Math.Abs(currObj.Angle.Value - prevPrevObj.Angle.Value));
+                    }
+                }
+            }
 
             double difficulty = Math.Max(preemptDifficulty, hiddenDifficulty) + noteDensityDifficulty;
 
+            // While there is slider leniency...
+            if (currObj.BaseObject is Slider)
+                difficulty *= 0.2;
+
             return difficulty;
         }
 
@@ -140,6 +167,8 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
             return Math.Clamp(2 - (deltaTime / 1500), 0, 1);
         }
 
+        private static double getAngleDifferenceNerfFactor(double angleDifference) => 1 - 1 * Math.Cos(2 * Math.Min(Math.PI / 4, angleDifference));
+
         private static double logistic(double x) => 1 / (1 + Math.Pow(Math.E, -x));
     }
 }