Merge pull request #25418 from smoogipoo/hp-drain-v1-2

Add `OsuHealthProcessor` that uses the legacy drain rate algorithm

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -48,6 +48,8 @@ public class OsuRuleset : Ruleset, ILegacyRuleset
 
         public override ScoreProcessor CreateScoreProcessor() => new OsuScoreProcessor();
 
+        public override HealthProcessor CreateHealthProcessor(double drainStartTime) => new OsuHealthProcessor(drainStartTime);
+
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new OsuBeatmapConverter(beatmap, this);
 
         public override IBeatmapProcessor CreateBeatmapProcessor(IBeatmap beatmap) => new OsuBeatmapProcessor(beatmap);

osu.Game.Rulesets.Osu/Scoring/LegacyOsuHealthProcessor.cs

@@ -0,0 +1,215 @@
+// 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 System.Linq;
+using osu.Game.Beatmaps;
+using osu.Game.Beatmaps.Timing;
+using osu.Game.Rulesets.Judgements;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Rulesets.Scoring;
+
+namespace osu.Game.Rulesets.Osu.Scoring
+{
+    /// <summary>
+    /// Reference implementation for osu!stable's HP drain.
+    /// Cannot be used for gameplay.
+    /// </summary>
+    public partial class LegacyOsuHealthProcessor : DrainingHealthProcessor
+    {
+        private const double hp_bar_maximum = 200;
+        private const double hp_combo_geki = 14;
+        private const double hp_hit_300 = 6;
+        private const double hp_slider_repeat = 4;
+        private const double hp_slider_tick = 3;
+
+        public Action<string>? OnIterationFail;
+        public Action<string>? OnIterationSuccess;
+        public bool ApplyComboEndBonus { get; set; } = true;
+
+        private double lowestHpEver;
+        private double lowestHpEnd;
+        private double lowestHpComboEnd;
+        private double hpRecoveryAvailable;
+        private double hpMultiplierNormal;
+        private double hpMultiplierComboEnd;
+
+        public LegacyOsuHealthProcessor(double drainStartTime)
+            : base(drainStartTime)
+        {
+        }
+
+        public override void ApplyBeatmap(IBeatmap beatmap)
+        {
+            lowestHpEver = IBeatmapDifficultyInfo.DifficultyRange(beatmap.Difficulty.DrainRate, 195, 160, 60);
+            lowestHpComboEnd = IBeatmapDifficultyInfo.DifficultyRange(beatmap.Difficulty.DrainRate, 198, 170, 80);
+            lowestHpEnd = IBeatmapDifficultyInfo.DifficultyRange(beatmap.Difficulty.DrainRate, 198, 180, 80);
+            hpRecoveryAvailable = IBeatmapDifficultyInfo.DifficultyRange(beatmap.Difficulty.DrainRate, 8, 4, 0);
+
+            base.ApplyBeatmap(beatmap);
+        }
+
+        protected override void ApplyResultInternal(JudgementResult result)
+        {
+            if (!IsSimulating)
+                throw new NotSupportedException("The legacy osu! health processor is not supported for gameplay.");
+        }
+
+        protected override void RevertResultInternal(JudgementResult result)
+        {
+            if (!IsSimulating)
+                throw new NotSupportedException("The legacy osu! health processor is not supported for gameplay.");
+        }
+
+        protected override void Reset(bool storeResults)
+        {
+            hpMultiplierNormal = 1;
+            hpMultiplierComboEnd = 1;
+
+            base.Reset(storeResults);
+        }
+
+        protected override double ComputeDrainRate()
+        {
+            double testDrop = 0.05;
+            double currentHp;
+            double currentHpUncapped;
+
+            do
+            {
+                currentHp = hp_bar_maximum;
+                currentHpUncapped = hp_bar_maximum;
+
+                double lowestHp = currentHp;
+                double lastTime = DrainStartTime;
+                int currentBreak = 0;
+                bool fail = false;
+                int comboTooLowCount = 0;
+                string failReason = string.Empty;
+
+                for (int i = 0; i < Beatmap.HitObjects.Count; i++)
+                {
+                    HitObject h = Beatmap.HitObjects[i];
+
+                    // Find active break (between current and lastTime)
+                    double localLastTime = lastTime;
+                    double breakTime = 0;
+
+                    // Subtract any break time from the duration since the last object
+                    if (Beatmap.Breaks.Count > 0 && currentBreak < Beatmap.Breaks.Count)
+                    {
+                        BreakPeriod e = Beatmap.Breaks[currentBreak];
+
+                        if (e.StartTime >= localLastTime && e.EndTime <= h.StartTime)
+                        {
+                            // consider break start equal to object end time for version 8+ since drain stops during this time
+                            breakTime = (Beatmap.BeatmapInfo.BeatmapVersion < 8) ? (e.EndTime - e.StartTime) : e.EndTime - localLastTime;
+                            currentBreak++;
+                        }
+                    }
+
+                    reduceHp(testDrop * (h.StartTime - lastTime - breakTime));
+
+                    lastTime = h.GetEndTime();
+
+                    if (currentHp < lowestHp)
+                        lowestHp = currentHp;
+
+                    if (currentHp <= lowestHpEver)
+                    {
+                        fail = true;
+                        testDrop *= 0.96;
+                        failReason = $"hp too low ({currentHp / hp_bar_maximum} < {lowestHpEver / hp_bar_maximum})";
+                        break;
+                    }
+
+                    double hpReduction = testDrop * (h.GetEndTime() - h.StartTime);
+                    double hpOverkill = Math.Max(0, hpReduction - currentHp);
+                    reduceHp(hpReduction);
+
+                    if (h is Slider slider)
+                    {
+                        for (int j = 0; j < slider.RepeatCount + 2; j++)
+                            increaseHp(hpMultiplierNormal * hp_slider_repeat);
+                        foreach (var _ in slider.NestedHitObjects.OfType<SliderTick>())
+                            increaseHp(hpMultiplierNormal * hp_slider_tick);
+                    }
+                    else if (h is Spinner spinner)
+                    {
+                        foreach (var _ in spinner.NestedHitObjects.Where(t => t is not SpinnerBonusTick))
+                            increaseHp(hpMultiplierNormal * 1.7);
+                    }
+
+                    if (hpOverkill > 0 && currentHp - hpOverkill <= lowestHpEver)
+                    {
+                        fail = true;
+                        testDrop *= 0.96;
+                        failReason = $"overkill ({currentHp / hp_bar_maximum} - {hpOverkill / hp_bar_maximum} <= {lowestHpEver / hp_bar_maximum})";
+                        break;
+                    }
+
+                    if (ApplyComboEndBonus && (i == Beatmap.HitObjects.Count - 1 || ((OsuHitObject)Beatmap.HitObjects[i + 1]).NewCombo))
+                    {
+                        increaseHp(hpMultiplierComboEnd * hp_combo_geki + hpMultiplierNormal * hp_hit_300);
+
+                        if (currentHp < lowestHpComboEnd)
+                        {
+                            if (++comboTooLowCount > 2)
+                            {
+                                hpMultiplierComboEnd *= 1.07;
+                                hpMultiplierNormal *= 1.03;
+                                fail = true;
+                                failReason = $"combo end hp too low ({currentHp / hp_bar_maximum} < {lowestHpComboEnd / hp_bar_maximum})";
+                                break;
+                            }
+                        }
+                    }
+                    else
+                        increaseHp(hpMultiplierNormal * hp_hit_300);
+                }
+
+                if (!fail && currentHp < lowestHpEnd)
+                {
+                    fail = true;
+                    testDrop *= 0.94;
+                    hpMultiplierComboEnd *= 1.01;
+                    hpMultiplierNormal *= 1.01;
+                    failReason = $"end hp too low ({currentHp / hp_bar_maximum} < {lowestHpEnd / hp_bar_maximum})";
+                }
+
+                double recovery = (currentHpUncapped - hp_bar_maximum) / Beatmap.HitObjects.Count;
+
+                if (!fail && recovery < hpRecoveryAvailable)
+                {
+                    fail = true;
+                    testDrop *= 0.96;
+                    hpMultiplierComboEnd *= 1.02;
+                    hpMultiplierNormal *= 1.01;
+                    failReason = $"recovery too low ({recovery / hp_bar_maximum} < {hpRecoveryAvailable / hp_bar_maximum})";
+                }
+
+                if (fail)
+                {
+                    OnIterationFail?.Invoke($"FAILED drop {testDrop / hp_bar_maximum}: {failReason}");
+                    continue;
+                }
+
+                OnIterationSuccess?.Invoke($"PASSED drop {testDrop / hp_bar_maximum}");
+                return testDrop / hp_bar_maximum;
+            } while (true);
+
+            void reduceHp(double amount)
+            {
+                currentHpUncapped = Math.Max(0, currentHpUncapped - amount);
+                currentHp = Math.Max(0, currentHp - amount);
+            }
+
+            void increaseHp(double amount)
+            {
+                currentHpUncapped += amount;
+                currentHp = Math.Max(0, Math.Min(hp_bar_maximum, currentHp + amount));
+            }
+        }
+    }
+}