Merge pull request #14885 from Wieku/storyboard-fixes

Force storyboard's loop commands to be run at least once

osu.Game.Tests/Beatmaps/Formats/LegacyStoryboardDecoderTest.cs

@@ -149,5 +149,32 @@ namespace osu.Game.Tests.Beatmaps.Formats
                 Assert.AreEqual(AnimationLoopType.LoopForever, ((StoryboardAnimation)foreground.Elements[5]).LoopType);
             }
         }
+
+        [Test]
+        public void TestDecodeLoopCount()
+        {
+            // all loop sequences in loop-count.osb have a total duration of 2000ms (fade in 0->1000ms, fade out 1000->2000ms).
+            const double loop_duration = 2000;
+
+            var decoder = new LegacyStoryboardDecoder();
+
+            using (var resStream = TestResources.OpenResource("loop-count.osb"))
+            using (var stream = new LineBufferedReader(resStream))
+            {
+                var storyboard = decoder.Decode(stream);
+
+                StoryboardLayer background = storyboard.Layers.Single(l => l.Depth == 3);
+
+                // stable ensures that any loop command executes at least once, even if the loop count specified in the .osb is zero or negative.
+                StoryboardSprite zeroTimes = background.Elements.OfType<StoryboardSprite>().Single(s => s.Path == "zero-times.png");
+                Assert.That(zeroTimes.EndTime, Is.EqualTo(1000 + loop_duration));
+
+                StoryboardSprite oneTime = background.Elements.OfType<StoryboardSprite>().Single(s => s.Path == "one-time.png");
+                Assert.That(oneTime.EndTime, Is.EqualTo(4000 + loop_duration));
+
+                StoryboardSprite manyTimes = background.Elements.OfType<StoryboardSprite>().Single(s => s.Path == "many-times.png");
+                Assert.That(manyTimes.EndTime, Is.EqualTo(9000 + 40 * loop_duration));
+            }
+        }
     }
 }

osu.Game.Tests/Resources/loop-count.osb

@@ -0,0 +1,15 @@
+osu file format v14
+
+[Events]
+Sprite,Background,TopCentre,"zero-times.png",320,240
+ L,1000,0
+  F,0,0,1000,0,1
+  F,0,1000,2000,1,0
+Sprite,Background,TopCentre,"one-time.png",320,240
+ L,4000,1
+  F,0,0,1000,0,1
+  F,0,1000,2000,1,0
+Sprite,Background,TopCentre,"many-times.png",320,240
+ L,9000,40
+  F,0,0,1000,0,1
+  F,0,1000,2000,1,0

osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs

@@ -176,8 +176,8 @@ namespace osu.Game.Beatmaps.Formats
                     case "L":
                     {
                         var startTime = Parsing.ParseDouble(split[1]);
-                        var loopCount = Parsing.ParseInt(split[2]);
+                        var repeatCount = Parsing.ParseInt(split[2]);
-                        timelineGroup = storyboardSprite?.AddLoop(startTime, loopCount);
+                        timelineGroup = storyboardSprite?.AddLoop(startTime, Math.Max(0, repeatCount - 1));
                         break;
                     }
 

osu.Game/Storyboards/CommandLoop.cs

@@ -1,6 +1,7 @@
 // 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.Collections.Generic;
 
 namespace osu.Game.Storyboards
@@ -8,20 +9,31 @@ namespace osu.Game.Storyboards
     public class CommandLoop : CommandTimelineGroup
     {
         public double LoopStartTime;
-        public int LoopCount;
+
+        /// <summary>
+        /// The total number of times this loop is played back. Always greater than zero.
+        /// </summary>
+        public readonly int TotalIterations;
 
         public override double StartTime => LoopStartTime + CommandsStartTime;
-        public override double EndTime => StartTime + CommandsDuration * LoopCount;
+        public override double EndTime => StartTime + CommandsDuration * TotalIterations;
 
-        public CommandLoop(double startTime, int loopCount)
+        /// <summary>
+        /// Construct a new command loop.
+        /// </summary>
+        /// <param name="startTime">The start time of the loop.</param>
+        /// <param name="repeatCount">The number of times the loop should repeat. Should be greater than zero. Zero means a single playback.</param>
+        public CommandLoop(double startTime, int repeatCount)
         {
+            if (repeatCount < 0) throw new ArgumentException("Repeat count must be zero or above.", nameof(repeatCount));
+
             LoopStartTime = startTime;
-            LoopCount = loopCount;
+            TotalIterations = repeatCount + 1;
         }
 
         public override IEnumerable<CommandTimeline<T>.TypedCommand> GetCommands<T>(CommandTimelineSelector<T> timelineSelector, double offset = 0)
         {
-            for (var loop = 0; loop < LoopCount; loop++)
+            for (var loop = 0; loop < TotalIterations; loop++)
             {
                 var loopOffset = LoopStartTime + loop * CommandsDuration;
                 foreach (var command in base.GetCommands(timelineSelector, offset + loopOffset))
@@ -30,6 +42,6 @@ namespace osu.Game.Storyboards
         }
 
         public override string ToString()
-            => $"{LoopStartTime} x{LoopCount}";
+            => $"{LoopStartTime} x{TotalIterations}";
     }
 }

osu.Game/Storyboards/StoryboardSprite.cs

@@ -1,13 +1,13 @@
 // 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 osuTK;
-using osu.Framework.Graphics;
-using osu.Game.Storyboards.Drawables;
 using System;
 using System.Collections.Generic;
 using System.Linq;
 using JetBrains.Annotations;
+using osu.Framework.Graphics;
+using osu.Game.Storyboards.Drawables;
+using osuTK;
 
 namespace osu.Game.Storyboards
 {
@@ -78,9 +78,9 @@ namespace osu.Game.Storyboards
             InitialPosition = initialPosition;
         }
 
-        public CommandLoop AddLoop(double startTime, int loopCount)
+        public CommandLoop AddLoop(double startTime, int repeatCount)
         {
-            var loop = new CommandLoop(startTime, loopCount);
+            var loop = new CommandLoop(startTime, repeatCount);
             loops.Add(loop);
             return loop;
         }