Merge pull request #1828 from UnderminersTeam/version-check-fix

Restore 2.3.1 version check (part 2)
UnderminersTeam · Jul 13, 2024 · 9b2eca6 · 9b2eca6
2 parents f7f2e7a + 3e0230b
commit 9b2eca6
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Showing 2 changed files with 34 additions and 7 deletions.
diff --git a/UndertaleModLib/Models/UndertaleAnimationCurve.cs b/UndertaleModLib/Models/UndertaleAnimationCurve.cs
@@ -170,6 +170,7 @@ public void Unserialize(UndertaleReader reader)
             Name = reader.ReadUndertaleString();
             Curve = (CurveType)reader.ReadUInt32();
             Iterations = reader.ReadUInt32();
+
             Points = reader.ReadUndertaleObject<UndertaleSimpleList<Point>>();
         }
 
@@ -178,14 +179,38 @@ public static uint UnserializeChildObjectCount(UndertaleReader reader)
         {
             reader.Position += 12;
 
+            // Read the number of points in the curve
+            uint pointCount = reader.ReadUInt32();
+
+            // This check is partly duplicated from UndertaleChunks.cs, but it's necessary to handle embedded curves
+            // (For example, those in SEQN in the TS!Underswap v1.0 demo; see issue #1414)
+            if (!reader.undertaleData.IsVersionAtLeast(2, 3, 1))
+            {
+                long returnPosition = reader.AbsPosition;
+                if (pointCount > 0)
+                {
+                    reader.AbsPosition += 8;
+                    if (reader.ReadUInt32() != 0) // In 2.3 an int with the value of 0 would be set here,
+                    {                             // It cannot be version 2.3 if this value isn't 0
+                        reader.undertaleData.SetGMS2Version(2, 3, 1);
+                    }
+                    else
+                    {
+                        if (reader.ReadUInt32() == 0)                      // At all points (besides the first one)
+                            reader.undertaleData.SetGMS2Version(2, 3, 1);  // If BezierX0 equals to 0 (the above check)
+                                                                           // Then BezierY0 equals to 0 as well (the current check)
+                    }
+                }
+                reader.AbsPosition = returnPosition;
+            }
+
             // "Points"
-            uint count = reader.ReadUInt32();
             if (reader.undertaleData.IsVersionAtLeast(2, 3, 1))
-                reader.Position += 24 * count;
+                reader.Position += 24 * pointCount;
             else
-                reader.Position += 12 * count;
+                reader.Position += 12 * pointCount;
 
-            return 1 + count;
+            return 1 + pointCount;
         }
 
         /// <inheritdoc/>

diff --git a/UndertaleModLib/UndertaleChunks.cs b/UndertaleModLib/UndertaleChunks.cs
@@ -1618,6 +1618,8 @@ public class UndertaleChunkACRV : UndertaleListChunk<UndertaleAnimationCurve>
         public override string Name => "ACRV";
 
         private static bool checkedForGMS2_3_1;
+
+        // See also a similar check in UndertaleAnimationCurve.cs, necessary for embedded animation curves.
         private void CheckForGMS2_3_1(UndertaleReader reader)
         {
             if (reader.undertaleData.IsVersionAtLeast(2, 3, 1))
@@ -1636,11 +1638,11 @@ private void CheckForGMS2_3_1(UndertaleReader reader)
                 return;
             }
 
-            reader.AbsPosition = reader.ReadUInt32(); // go to the first "Point"
+            reader.AbsPosition = reader.ReadUInt32(); // Go to the first "Point"
             reader.Position += 8;
 
-            if (reader.ReadUInt32() != 0) // in 2.3 a int with the value of 0 would be set here,
-            {                             // it cannot be version 2.3 if this value isn't 0
+            if (reader.ReadUInt32() != 0) // In 2.3 an int with the value of 0 would be set here,
+            {                             // It cannot be version 2.3 if this value isn't 0
                 reader.undertaleData.SetGMS2Version(2, 3, 1);
             }
             else