From a10cd2288dc4433196a931ee5a85dd4a6a8e909a Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Tue, 12 Mar 2019 18:15:18 +0900
Subject: [PATCH] Improve ModRamp's handling of external rate changes

---
 osu.Game/Rulesets/Mods/ModTimeRamp.cs | 30 ++++++++++++++++++++-------
 osu.Game/Rulesets/Mods/ModWindDown.cs |  5 +++++
 osu.Game/Rulesets/Mods/ModWindUp.cs   |  7 ++++++-
 3 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/osu.Game/Rulesets/Mods/ModTimeRamp.cs b/osu.Game/Rulesets/Mods/ModTimeRamp.cs
index 4a0ed0f9bb..1573418d95 100644
--- a/osu.Game/Rulesets/Mods/ModTimeRamp.cs
+++ b/osu.Game/Rulesets/Mods/ModTimeRamp.cs
@@ -15,7 +15,7 @@ namespace osu.Game.Rulesets.Mods
 {
     public abstract class ModTimeRamp : Mod
     {
-        public override Type[] IncompatibleMods => new[] { typeof(ModDoubleTime), typeof(ModHalfTime) };
+        public override Type[] IncompatibleMods => new[] { typeof(ModTimeAdjust) };
 
         protected abstract double FinalRateAdjustment { get; }
     }
@@ -29,20 +29,26 @@ namespace osu.Game.Rulesets.Mods
 
         private IAdjustableClock clock;
 
-        private IHasPitchAdjust pitchAdjust;
-
         /// <summary>
         /// The point in the beatmap at which the final ramping rate should be reached.
         /// </summary>
         private const double final_rate_progress = 0.75f;
 
+        /// <summary>
+        /// The adjustment applied on entering this mod's application method.
+        /// </summary>
+        private double baseAdjust;
+
         public virtual void ApplyToClock(IAdjustableClock clock)
         {
             this.clock = clock;
-            pitchAdjust = (IHasPitchAdjust)clock;
 
-            // for preview purposes
-            pitchAdjust.PitchAdjust = 1.0 + FinalRateAdjustment;
+            // we capture the adjustment applied before entering our application method.
+            // this will cover external changes, which should re-fire this method.
+            baseAdjust = (clock as IHasPitchAdjust)?.PitchAdjust ?? clock.Rate;
+
+            // for preview purposes. during gameplay, Update will overwrite this setting.
+            applyAdjustment(1);
         }
 
         public virtual void ApplyToBeatmap(Beatmap<T> beatmap)
@@ -56,9 +62,17 @@ namespace osu.Game.Rulesets.Mods
         public virtual void Update(Playfield playfield)
         {
             var absRate = Math.Abs(FinalRateAdjustment);
-            var adjustment = MathHelper.Clamp(absRate * ((clock.CurrentTime - beginRampTime) / finalRateTime), 0, absRate);
+            applyAdjustment(MathHelper.Clamp(absRate * ((clock.CurrentTime - beginRampTime) / finalRateTime), 0, absRate));
+        }
 
-            pitchAdjust.PitchAdjust = 1 + Math.Sign(FinalRateAdjustment) * adjustment;
+        private void applyAdjustment(double adjustment)
+        {
+            var localAdjust = 1 + Math.Sign(FinalRateAdjustment) * adjustment;
+
+            if (clock is IHasPitchAdjust tempo)
+                tempo.PitchAdjust = baseAdjust * localAdjust;
+            else
+                clock.Rate *= baseAdjust * localAdjust;
         }
     }
 }
diff --git a/osu.Game/Rulesets/Mods/ModWindDown.cs b/osu.Game/Rulesets/Mods/ModWindDown.cs
index 646c5c64e4..174070eb85 100644
--- a/osu.Game/Rulesets/Mods/ModWindDown.cs
+++ b/osu.Game/Rulesets/Mods/ModWindDown.cs
@@ -1,6 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. 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.Graphics;
 using osu.Game.Rulesets.Objects;
 
@@ -14,6 +16,9 @@ namespace osu.Game.Rulesets.Mods
         public override string Description => "Sloooow doooown...";
         public override FontAwesome Icon => FontAwesome.fa_chevron_circle_down;
         public override double ScoreMultiplier => 1.0;
+
         protected override double FinalRateAdjustment => -0.25;
+
+        public override Type[] IncompatibleMods => base.IncompatibleMods.Append(typeof(ModWindUp<T>)).ToArray();
     }
 }
diff --git a/osu.Game/Rulesets/Mods/ModWindUp.cs b/osu.Game/Rulesets/Mods/ModWindUp.cs
index 9050b5591a..bf9af8a51d 100644
--- a/osu.Game/Rulesets/Mods/ModWindUp.cs
+++ b/osu.Game/Rulesets/Mods/ModWindUp.cs
@@ -1,6 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. 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.Graphics;
 using osu.Game.Rulesets.Objects;
 
@@ -14,6 +16,9 @@ namespace osu.Game.Rulesets.Mods
         public override string Description => "Can you keep up?";
         public override FontAwesome Icon => FontAwesome.fa_chevron_circle_up;
         public override double ScoreMultiplier => 1.0;
+
         protected override double FinalRateAdjustment => 0.5;
+
+        public override Type[] IncompatibleMods => base.IncompatibleMods.Append(typeof(ModWindDown<T>)).ToArray();
     }
-}
\ No newline at end of file
+}