From 80269689393f5be2f72d03ed85a829a4448140e1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Dach?= <dach.bartlomiej@gmail.com>
Date: Sat, 18 Sep 2021 14:24:50 +0200
Subject: [PATCH] Move difficulty -> effect point conversion back to decoder

---
 .../Beatmaps/ManiaBeatmapConverter.cs         | 33 -------------------
 .../Beatmaps/Formats/LegacyBeatmapDecoder.cs  | 27 ++++++++++-----
 .../Beatmaps/Formats/LegacyBeatmapEncoder.cs  |  2 +-
 3 files changed, 20 insertions(+), 42 deletions(-)

diff --git a/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs b/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs
index 65dc65b28a..5903e161d0 100644
--- a/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs
+++ b/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs
@@ -8,8 +8,6 @@ using System.Collections.Generic;
 using System.Threading;
 using osu.Game.Audio;
 using osu.Game.Beatmaps;
-using osu.Game.Beatmaps.ControlPoints;
-using osu.Game.Beatmaps.Legacy;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Types;
 using osu.Game.Rulesets.Mania.Beatmaps.Patterns;
@@ -84,37 +82,6 @@ namespace osu.Game.Rulesets.Mania.Beatmaps
         protected override Beatmap<ManiaHitObject> ConvertBeatmap(IBeatmap original, CancellationToken cancellationToken)
         {
             BeatmapDifficulty difficulty = original.BeatmapInfo.BaseDifficulty;
-
-            if (IsForCurrentRuleset && original.ControlPointInfo is LegacyControlPointInfo originalLegacyControlPoints)
-            {
-                // original is cloned so we're safe to replace control point storage at this point.
-                original.ControlPointInfo = new LegacyControlPointInfo();
-
-                // convert all slider velocity adjustments to scroll speed adjustments.
-                foreach (var controlPoint in originalLegacyControlPoints.AllControlPoints)
-                {
-                    double time = controlPoint.Time;
-
-                    switch (controlPoint)
-                    {
-                        default:
-                            original.ControlPointInfo.Add(time, controlPoint);
-                            break;
-
-                        case DifficultyControlPoint difficultyPoint:
-                            var reference = originalLegacyControlPoints.EffectPointAt(time);
-
-                            var scrollControlPoint = new EffectControlPoint();
-
-                            scrollControlPoint.CopyFrom(reference);
-                            scrollControlPoint.ScrollSpeed = difficultyPoint.SliderVelocity;
-
-                            original.ControlPointInfo.Add(time, scrollControlPoint);
-                            break;
-                    }
-                }
-            }
-
             int seed = (int)MathF.Round(difficulty.DrainRate + difficulty.CircleSize) * 20 + (int)(difficulty.OverallDifficulty * 41.2) + (int)MathF.Round(difficulty.ApproachRate);
             Random = new FastRandom(seed);
 
diff --git a/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs b/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs
index a9b5793565..68e6a8ac00 100644
--- a/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs
+++ b/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs
@@ -376,18 +376,29 @@ namespace osu.Game.Beatmaps.Formats
                 addControlPoint(time, controlPoint, true);
             }
 
-#pragma warning disable 618
-            addControlPoint(time, new LegacyDifficultyControlPoint(beatLength)
-#pragma warning restore 618
-            {
-                SliderVelocity = speedMultiplier,
-            }, timingChange);
+            bool isOsuRuleset = beatmap.BeatmapInfo.RulesetID == 0;
 
-            addControlPoint(time, new EffectControlPoint
+            if (isOsuRuleset)
+            {
+#pragma warning disable 618
+                addControlPoint(time, new LegacyDifficultyControlPoint(beatLength)
+#pragma warning restore 618
+                {
+                    SliderVelocity = speedMultiplier,
+                }, timingChange);
+            }
+
+            var effectPoint = new EffectControlPoint
             {
                 KiaiMode = kiaiMode,
                 OmitFirstBarLine = omitFirstBarSignature,
-            }, timingChange);
+            };
+
+            // scrolling rulesets use effect points rather than difficulty points for scroll speed adjustments.
+            if (!isOsuRuleset)
+                effectPoint.ScrollSpeed = speedMultiplier;
+
+            addControlPoint(time, effectPoint, timingChange);
 
             addControlPoint(time, new LegacySampleControlPoint
             {
diff --git a/osu.Game/Beatmaps/Formats/LegacyBeatmapEncoder.cs b/osu.Game/Beatmaps/Formats/LegacyBeatmapEncoder.cs
index ebb326ccc8..d903ab3a6d 100644
--- a/osu.Game/Beatmaps/Formats/LegacyBeatmapEncoder.cs
+++ b/osu.Game/Beatmaps/Formats/LegacyBeatmapEncoder.cs
@@ -189,7 +189,7 @@ namespace osu.Game.Beatmaps.Formats
             }
 
             // handle scroll speed, which is stored as "slider velocity" in legacy formats.
-            // note that this is only relevant for mania beatmaps.
+            // this is relevant for scrolling ruleset beatmaps.
             if (!isOsuRuleset)
             {
                 foreach (var point in legacyControlPoints.EffectPoints)