just misc

LightlessSync/Services/ModelDecimation/MdlDecimator.cs

@@ -1,6 +1,7 @@
 using Lumina.Data.Parsing;
 using Lumina.Extensions;
 using MeshDecimator;
+using MeshDecimator.Algorithms;
 using MeshDecimator.Math;
 using Microsoft.Extensions.Logging;
 using Penumbra.GameData.Files.ModelStructs;
@@ -94,6 +95,8 @@ internal static class MdlDecimator
             var newVertexBuffer = new List<byte>(mdl.VertexBufferSize[lodIndex] > 0 ? (int)mdl.VertexBufferSize[lodIndex] : 0);
             var newIndexBuffer = new List<ushort>(mdl.IndexBufferSize[lodIndex] > 0 ? (int)(mdl.IndexBufferSize[lodIndex] / sizeof(ushort)) : 0);
             var subMeshCursor = 0;
+            DecimationAlgorithm? decimationAlgorithm = null;
+            int? decimationUvChannelCount = null;
 
             for (var meshIndex = 0; meshIndex < meshes.Length; meshIndex++)
             {
@@ -119,6 +122,8 @@ internal static class MdlDecimator
                         out vertexStreams,
                         out indices,
                         out decimated,
+                        ref decimationAlgorithm,
+                        ref decimationUvChannelCount,
                         logger))
                 {
                     updatedSubMeshes = OffsetSubMeshes(updatedSubMeshes, meshIndexBase);
@@ -309,6 +314,8 @@ internal static class MdlDecimator
         out byte[][] vertexStreams,
         out int[] indices,
         out bool decimated,
+        ref DecimationAlgorithm? decimationAlgorithm,
+        ref int? decimationUvChannelCount,
         MsLogger logger)
     {
         updatedMesh = mesh;
@@ -352,8 +359,7 @@ internal static class MdlDecimator
         }
 
         var meshDecimatorMesh = BuildMesh(decoded, subMeshIndices);
-        var algorithm = MeshDecimation.CreateAlgorithm(Algorithm.Default);
-        algorithm.Logger = logger;
+        var algorithm = GetOrCreateAlgorithm(format, ref decimationAlgorithm, ref decimationUvChannelCount, logger);
         algorithm.Initialize(meshDecimatorMesh);
         algorithm.DecimateMesh(targetTriangles);
         var decimatedMesh = algorithm.ToMesh();
@@ -374,6 +380,23 @@ internal static class MdlDecimator
         return true;
     }
 
+    private static DecimationAlgorithm GetOrCreateAlgorithm(
+        VertexFormat format,
+        ref DecimationAlgorithm? decimationAlgorithm,
+        ref int? decimationUvChannelCount,
+        MsLogger logger)
+    {
+        var uvChannelCount = format.UvChannelCount;
+        if (decimationAlgorithm == null || decimationUvChannelCount != uvChannelCount)
+        {
+            decimationAlgorithm = MeshDecimation.CreateAlgorithm(Algorithm.Default);
+            decimationAlgorithm.Logger = logger;
+            decimationUvChannelCount = uvChannelCount;
+        }
+
+        return decimationAlgorithm;
+    }
+
     private static Mesh BuildMesh(DecodedMeshData decoded, int[][] subMeshIndices)
     {
         var mesh = new Mesh(decoded.Positions, subMeshIndices);