From 25af091409142d702041f5a5bd15bea093c78897 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Thu, 12 Nov 2020 17:03:42 +0900
Subject: [PATCH] Fix storyboard animations of very old beatmaps playing too
 slow

Closes https://github.com/ppy/osu/issues/10772.
---
 osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs    |  2 --
 osu.Game/Beatmaps/Formats/LegacyDecoder.cs           |  2 ++
 osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs | 12 +++++++++---
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs b/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs
index 442be6e837..37ab489da5 100644
--- a/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs
+++ b/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs
@@ -16,8 +16,6 @@ namespace osu.Game.Beatmaps.Formats
 {
     public class LegacyBeatmapDecoder : LegacyDecoder<Beatmap>
     {
-        public const int LATEST_VERSION = 14;
-
         private Beatmap beatmap;
 
         private ConvertHitObjectParser parser;
diff --git a/osu.Game/Beatmaps/Formats/LegacyDecoder.cs b/osu.Game/Beatmaps/Formats/LegacyDecoder.cs
index 7b377e481f..de4dc8cdc8 100644
--- a/osu.Game/Beatmaps/Formats/LegacyDecoder.cs
+++ b/osu.Game/Beatmaps/Formats/LegacyDecoder.cs
@@ -16,6 +16,8 @@ namespace osu.Game.Beatmaps.Formats
     public abstract class LegacyDecoder<T> : Decoder<T>
         where T : new()
     {
+        public const int LATEST_VERSION = 14;
+
         protected readonly int FormatVersion;
 
         protected LegacyDecoder(int version)
diff --git a/osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs b/osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs
index 8d8ca523d5..9a244c8bb2 100644
--- a/osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs
+++ b/osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs
@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using osu.Framework.Graphics;
 using osu.Framework.Utils;
 using osu.Game.Beatmaps.Legacy;
@@ -23,15 +24,15 @@ namespace osu.Game.Beatmaps.Formats
 
         private readonly Dictionary<string, string> variables = new Dictionary<string, string>();
 
-        public LegacyStoryboardDecoder()
-            : base(0)
+        public LegacyStoryboardDecoder(int version = LATEST_VERSION)
+            : base(version)
         {
         }
 
         public static void Register()
         {
             // note that this isn't completely correct
-            AddDecoder<Storyboard>(@"osu file format v", m => new LegacyStoryboardDecoder());
+            AddDecoder<Storyboard>(@"osu file format v", m => new LegacyStoryboardDecoder(Parsing.ParseInt(m.Split('v').Last())));
             AddDecoder<Storyboard>(@"[Events]", m => new LegacyStoryboardDecoder());
             SetFallbackDecoder<Storyboard>(() => new LegacyStoryboardDecoder());
         }
@@ -133,6 +134,11 @@ namespace osu.Game.Beatmaps.Formats
                         var y = Parsing.ParseFloat(split[5], Parsing.MAX_COORDINATE_VALUE);
                         var frameCount = Parsing.ParseInt(split[6]);
                         var frameDelay = Parsing.ParseDouble(split[7]);
+
+                        if (FormatVersion < 6)
+                            // this is random as hell but taken straight from osu-stable.
+                            frameDelay = Math.Round(0.015 * frameDelay) * 1.186 * (1000 / 60f);
+
                         var loopType = split.Length > 8 ? (AnimationLoopType)Enum.Parse(typeof(AnimationLoopType), split[8]) : AnimationLoopType.LoopForever;
                         storyboardSprite = new StoryboardAnimation(path, origin, new Vector2(x, y), frameCount, frameDelay, loopType);
                         storyboard.GetLayer(layer).Add(storyboardSprite);