Merge pull request #18321 from smoogipoo/legacy-catmull

Fix compatibility issues with legacy Catmull sliders

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

@@ -863,5 +863,40 @@ namespace osu.Game.Tests.Beatmaps.Formats
                 Assert.That(decoded.Difficulty.OverallDifficulty, Is.EqualTo(1));
             }
         }
+
+        [Test]
+        public void TestLegacyAdjacentImplicitCatmullSegmentsAreMerged()
+        {
+            var decoder = new LegacyBeatmapDecoder { ApplyOffsets = false };
+
+            using (var resStream = TestResources.OpenResource("adjacent-catmull-segments.osu"))
+            using (var stream = new LineBufferedReader(resStream))
+            {
+                var decoded = decoder.Decode(stream);
+                var controlPoints = ((IHasPath)decoded.HitObjects[0]).Path.ControlPoints;
+
+                Assert.That(controlPoints.Count, Is.EqualTo(6));
+                Assert.That(controlPoints.Single(c => c.Type != null).Type, Is.EqualTo(PathType.Catmull));
+            }
+        }
+
+        [Test]
+        public void TestNonLegacyAdjacentImplicitCatmullSegmentsAreNotMerged()
+        {
+            var decoder = new LegacyBeatmapDecoder(LegacyBeatmapEncoder.FIRST_LAZER_VERSION) { ApplyOffsets = false };
+
+            using (var resStream = TestResources.OpenResource("adjacent-catmull-segments.osu"))
+            using (var stream = new LineBufferedReader(resStream))
+            {
+                var decoded = decoder.Decode(stream);
+                var controlPoints = ((IHasPath)decoded.HitObjects[0]).Path.ControlPoints;
+
+                Assert.That(controlPoints.Count, Is.EqualTo(4));
+                Assert.That(controlPoints[0].Type, Is.EqualTo(PathType.Catmull));
+                Assert.That(controlPoints[1].Type, Is.EqualTo(PathType.Catmull));
+                Assert.That(controlPoints[2].Type, Is.EqualTo(PathType.Catmull));
+                Assert.That(controlPoints[3].Type, Is.Null);
+            }
+        }
     }
 }

osu.Game.Tests/Resources/adjacent-catmull-segments.osu

@@ -0,0 +1,2 @@
+[HitObjects]
+200,304,23875,6,0,C|288:304|288:304|288:208|288:208|352:208,1,260,8|0

osu.Game/Beatmaps/Formats/LegacyBeatmapEncoder.cs

@@ -22,7 +22,7 @@ namespace osu.Game.Beatmaps.Formats
 {
     public class LegacyBeatmapEncoder
     {
-        public const int LATEST_VERSION = 128;
+        public const int FIRST_LAZER_VERSION = 128;
 
         /// <summary>
         /// osu! is generally slower than taiko, so a factor is added to increase
@@ -55,7 +55,7 @@ namespace osu.Game.Beatmaps.Formats
 
         public void Encode(TextWriter writer)
         {
-            writer.WriteLine($"osu file format v{LATEST_VERSION}");
+            writer.WriteLine($"osu file format v{FIRST_LAZER_VERSION}");
 
             writer.WriteLine();
             handleGeneral(writer);

osu.Game/Rulesets/Objects/Legacy/ConvertHitObjectParser.cs

@@ -336,10 +336,14 @@ namespace osu.Game.Rulesets.Objects.Legacy
 
             while (++endIndex < vertices.Length - endPointLength)
             {
-                // Keep incrementing while an implicit segment doesn't need to be started
+                // Keep incrementing while an implicit segment doesn't need to be started.
                 if (vertices[endIndex].Position != vertices[endIndex - 1].Position)
                     continue;
 
+                // Adjacent legacy Catmull segments should be treated as a single segment.
+                if (FormatVersion < LegacyBeatmapEncoder.FIRST_LAZER_VERSION && type == PathType.Catmull)
+                    continue;
+
                 // The last control point of each segment is not allowed to start a new implicit segment.
                 if (endIndex == vertices.Length - endPointLength - 1)
                     continue;