Merge pull request ppy#15665 from MBmasher/fl-opacity

Consider opacity of hit objects in Flashlight skill

osu.Game.Rulesets.Osu/Difficulty/OsuDifficultyCalculator.cs

@@ -122,6 +122,7 @@ protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clo
             new OsuModEasy(),
             new OsuModHardRock(),
             new OsuModFlashlight(),
+            new MultiMod(new OsuModFlashlight(), new OsuModHidden())
         };
     }
 }

osu.Game.Rulesets.Osu/Difficulty/OsuPerformanceCalculator.cs

@@ -219,9 +219,6 @@ private double computeFlashlightValue(ScoreInfo score, OsuDifficultyAttributes a
 
             double flashlightValue = Math.Pow(rawFlashlight, 2.0) * 25.0;
 
-            if (score.Mods.Any(h => h is OsuModHidden))
-                flashlightValue *= 1.3;
-
             // Penalize misses by assessing # of misses relative to the total # of objects. Default a 3% reduction for any # of misses.
             if (effectiveMissCount > 0)
                 flashlightValue *= 0.97 * Math.Pow(1 - Math.Pow(effectiveMissCount / totalHits, 0.775), Math.Pow(effectiveMissCount, .875));

osu.Game.Rulesets.Osu/Difficulty/Preprocessing/OsuDifficultyHitObject.cs

@@ -4,6 +4,7 @@
 using System;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Osu.Objects;
 using osuTK;
 
@@ -85,6 +86,35 @@ public OsuDifficultyHitObject(HitObject hitObject, HitObject lastLastObject, Hit
             setDistances(clockRate);
         }
 
+        public double OpacityAt(double time, bool hidden)
+        {
+            if (time > BaseObject.StartTime)
+            {
+                // Consider a hitobject as being invisible when its start time is passed.
+                // In reality the hitobject will be visible beyond its start time up until its hittable window has passed,
+                // but this is an approximation and such a case is unlikely to be hit where this function is used.
+                return 0.0;
+            }
+
+            double fadeInStartTime = BaseObject.StartTime - BaseObject.TimePreempt;
+            double fadeInDuration = BaseObject.TimeFadeIn;
+
+            if (hidden)
+            {
+                // Taken from OsuModHidden.
+                double fadeOutStartTime = BaseObject.StartTime - BaseObject.TimePreempt + BaseObject.TimeFadeIn;
+                double fadeOutDuration = BaseObject.TimePreempt * OsuModHidden.FADE_OUT_DURATION_MULTIPLIER;
+
+                return Math.Min
+                (
+                    Math.Clamp((time - fadeInStartTime) / fadeInDuration, 0.0, 1.0),
+                    1.0 - Math.Clamp((time - fadeOutStartTime) / fadeOutDuration, 0.0, 1.0)
+                );
+            }
+
+            return Math.Clamp((time - fadeInStartTime) / fadeInDuration, 0.0, 1.0);
+        }
+
         private void setDistances(double clockRate)
         {
             if (BaseObject is Slider currentSlider)

osu.Game.Rulesets.Osu/Difficulty/Skills/Flashlight.cs

@@ -2,8 +2,10 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using System.Linq;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Osu.Objects;
 
@@ -17,13 +19,19 @@ public class Flashlight : OsuStrainSkill
         public Flashlight(Mod[] mods)
             : base(mods)
         {
+            hidden = mods.Any(m => m is OsuModHidden);
         }
 
-        private double skillMultiplier => 0.07;
+        private double skillMultiplier => 0.05;
         private double strainDecayBase => 0.15;
         protected override double DecayWeight => 1.0;
         protected override int HistoryLength => 10; // Look back for 10 notes is added for the sake of flashlight calculations.
 
+        private readonly bool hidden;
+
+        private const double max_opacity_bonus = 0.4;
+        private const double hidden_bonus = 0.2;
+
         private double currentStrain;
 
         private double strainValueOf(DifficultyHitObject current)
@@ -61,13 +69,22 @@ private double strainValueOf(DifficultyHitObject current)
                     // We also want to nerf stacks so that only the first object of the stack is accounted for.
                     double stackNerf = Math.Min(1.0, (currentObj.LazyJumpDistance / scalingFactor) / 25.0);
 
-                    result += stackNerf * scalingFactor * jumpDistance / cumulativeStrainTime;
+                    // Bonus based on how visible the object is.
+                    double opacityBonus = 1.0 + max_opacity_bonus * (1.0 - osuCurrent.OpacityAt(currentHitObject.StartTime, hidden));
+
+                    result += stackNerf * opacityBonus * scalingFactor * jumpDistance / cumulativeStrainTime;
                 }
 
                 lastObj = currentObj;
             }
 
-            return Math.Pow(smallDistNerf * result, 2.0);
+            result = Math.Pow(smallDistNerf * result, 2.0);
+
+            // Additional bonus for Hidden due to there being no approach circles.
+            if (hidden)
+                result *= 1.0 + hidden_bonus;
+
+            return result;
         }
 
         private double strainDecay(double ms) => Math.Pow(strainDecayBase, ms / 1000);

osu.Game.Rulesets.Osu/Mods/OsuModHidden.cs

@@ -27,8 +27,8 @@ public class OsuModHidden : ModHidden, IHidesApproachCircles
 
         public override Type[] IncompatibleMods => new[] { typeof(IRequiresApproachCircles), typeof(OsuModSpinIn) };
 
-        private const double fade_in_duration_multiplier = 0.4;
-        private const double fade_out_duration_multiplier = 0.3;
+        public const double FADE_IN_DURATION_MULTIPLIER = 0.4;
+        public const double FADE_OUT_DURATION_MULTIPLIER = 0.3;
 
         protected override bool IsFirstAdjustableObject(HitObject hitObject) => !(hitObject is Spinner || hitObject is SpinnerTick);
 
@@ -41,7 +41,7 @@ public override void ApplyToBeatmap(IBeatmap beatmap)
 
             static void applyFadeInAdjustment(OsuHitObject osuObject)
             {
-                osuObject.TimeFadeIn = osuObject.TimePreempt * fade_in_duration_multiplier;
+                osuObject.TimeFadeIn = osuObject.TimePreempt * FADE_IN_DURATION_MULTIPLIER;
                 foreach (var nested in osuObject.NestedHitObjects.OfType<OsuHitObject>())
                     applyFadeInAdjustment(nested);
             }
@@ -156,7 +156,7 @@ private void applyHiddenState(DrawableHitObject drawableObject, bool increaseVis
             static (double fadeStartTime, double fadeDuration) getParameters(OsuHitObject hitObject)
             {
                 double fadeOutStartTime = hitObject.StartTime - hitObject.TimePreempt + hitObject.TimeFadeIn;
-                double fadeOutDuration = hitObject.TimePreempt * fade_out_duration_multiplier;
+                double fadeOutDuration = hitObject.TimePreempt * FADE_OUT_DURATION_MULTIPLIER;
 
                 // new duration from completed fade in to end (before fading out)
                 double longFadeDuration = hitObject.GetEndTime() - fadeOutStartTime;