Import attributes

Penumbra/Import/Models/Import/MeshImporter.cs

@@ -19,6 +19,8 @@ public class MeshImporter(IEnumerable<Node> nodes)
 
         public List<string>? Bones;
 
+        public List<string> MetaAttributes;
+
         public List<MeshShapeKey> ShapeKeys;
     }
 
@@ -48,6 +50,8 @@ public class MeshImporter(IEnumerable<Node> nodes)
 
     private List<string>? _bones;
 
+    private readonly List<string> _metaAttributes = [];
+
     private readonly Dictionary<string, List<MdlStructs.ShapeValueStruct>> _shapeValues = [];
 
     private Mesh Create()
@@ -83,6 +87,7 @@ public class MeshImporter(IEnumerable<Node> nodes)
             VertexBuffer      = _streams[0].Concat(_streams[1]).Concat(_streams[2]),
             Indices           = _indices,
             Bones             = _bones,
+            MetaAttributes    = _metaAttributes,
             ShapeKeys = _shapeValues
                 .Select(pair => new MeshShapeKey()
                 {
@@ -153,6 +158,8 @@ public class MeshImporter(IEnumerable<Node> nodes)
         _subMeshes.Add(subMesh.SubMeshStruct with
         {
             IndexOffset = (ushort)(subMesh.SubMeshStruct.IndexOffset + indexOffset),
+            AttributeIndexMask = Utility.GetMergedAttributeMask(
+                subMesh.SubMeshStruct.AttributeIndexMask, subMesh.MetaAttributes, _metaAttributes),
         });
     }
 

Penumbra/Import/Models/Import/ModelImporter.cs

@@ -29,6 +29,8 @@ public partial class ModelImporter(ModelRoot _model)
     private readonly List<string>                     _bones      = [];
     private readonly List<MdlStructs.BoneTableStruct> _boneTables = [];
 
+    private readonly List<string> _metaAttributes = [];
+
     private readonly Dictionary<string, List<MdlStructs.ShapeMeshStruct>> _shapeMeshes = [];
     private readonly List<MdlStructs.ShapeValueStruct>                    _shapeValues = [];
 
@@ -71,6 +73,7 @@ public partial class ModelImporter(ModelRoot _model)
             Bones              = [.. _bones],
             // TODO: Game doesn't seem to rely on this, but would be good to populate.
             SubMeshBoneMap = [],
+            Attributes     = [.. _metaAttributes],
             Shapes         = [.. shapes],
             ShapeMeshes    = [.. shapeMeshes],
             ShapeValues    = [.. _shapeValues],
@@ -155,6 +158,8 @@ public partial class ModelImporter(ModelRoot _model)
 
         _subMeshes.AddRange(mesh.SubMeshStructs.Select(m => m with
         {
+            AttributeIndexMask = Utility.GetMergedAttributeMask(
+                m.AttributeIndexMask, mesh.MetaAttributes, _metaAttributes),
             IndexOffset = (uint)(m.IndexOffset + indexOffset),
         }));
 

Penumbra/Import/Models/Import/SubMeshImporter.cs

@@ -1,3 +1,4 @@
+using System.Text.Json;
 using Lumina.Data.Parsing;
 using OtterGui;
 using SharpGLTF.Schema2;
@@ -20,6 +21,8 @@ public class SubMeshImporter
 
         public ushort[] Indices;
 
+        public string[] MetaAttributes;
+
         public Dictionary<string, List<MdlStructs.ShapeValueStruct>> ShapeValues;
     }
 
@@ -29,10 +32,11 @@ public class SubMeshImporter
         return importer.Create();
     }
 
-    private readonly MeshPrimitive                _primitive;
+    private readonly MeshPrimitive                     _primitive;
-    private readonly IDictionary<ushort, ushort>? _nodeBoneMap;
+    private readonly IDictionary<ushort, ushort>?      _nodeBoneMap;
+    private readonly IDictionary<string, JsonElement>? _nodeExtras;
 
-    private List<VertexAttribute>? _attributes;
+    private List<VertexAttribute>? _vertexAttributes;
 
     private          ushort       _vertexCount;
     private          byte[]       _strides = [0, 0, 0];
@@ -40,6 +44,8 @@ public class SubMeshImporter
 
     private ushort[]? _indices;
 
+    private string[]? _metaAttributes;
+
     private readonly List<string>?                                          _morphNames;
     private          Dictionary<string, List<MdlStructs.ShapeValueStruct>>? _shapeValues;
 
@@ -57,6 +63,15 @@ public class SubMeshImporter
         _primitive   = mesh.Primitives[0];
         _nodeBoneMap = nodeBoneMap;
 
+        try
+        {
+            _nodeExtras = node.Extras.Deserialize<Dictionary<string, JsonElement>>();
+        }
+        catch
+        {
+            _nodeExtras = null;    
+        }
+
         try
         {
             _morphNames = mesh.Extras.GetNode("targetNames").Deserialize<List<string>>();
@@ -76,24 +91,34 @@ public class SubMeshImporter
     {
         // Build all the data we'll need.
         BuildIndices();
-        BuildAttributes();
+        BuildVertexAttributes();
         BuildVertices();
+        BuildMetaAttributes();
 
         ArgumentNullException.ThrowIfNull(_indices);
-        ArgumentNullException.ThrowIfNull(_attributes);
+        ArgumentNullException.ThrowIfNull(_vertexAttributes);
         ArgumentNullException.ThrowIfNull(_shapeValues);
+        ArgumentNullException.ThrowIfNull(_metaAttributes);
 
         var material = _primitive.Material.Name;
         if (material == "")
             material = null;
 
+        // At this level, we assume that attributes are wholly controlled by this sub-mesh.
+        var attributeMask = _metaAttributes.Length switch
+        {
+            < 32 => (1u << _metaAttributes.Length) - 1,
+              32 => uint.MaxValue,
+            > 32 => throw new Exception("Models may utilise a maximum of 32 attributes."),
+        };
+
         return new SubMesh()
         {
             SubMeshStruct = new MdlStructs.SubmeshStruct()
             {
                 IndexOffset        = 0,
                 IndexCount         = (uint)_indices.Length,
-                AttributeIndexMask = 0,
+                AttributeIndexMask = attributeMask,
 
                 // TODO: Flesh these out. Game doesn't seem to rely on them existing, though.
                 BoneStartIndex = 0,
@@ -102,12 +127,13 @@ public class SubMeshImporter
             Material = material,
             VertexDeclaration = new MdlStructs.VertexDeclarationStruct()
             {
-                VertexElements = _attributes.Select(attribute => attribute.Element).ToArray(),
+                VertexElements = _vertexAttributes.Select(attribute => attribute.Element).ToArray(),
             },
             VertexCount = _vertexCount,
             Strides     = _strides,
             Streams     = _streams,
             Indices     = _indices,
+            MetaAttributes  = _metaAttributes, 
             ShapeValues = _shapeValues,
         };
     }
@@ -117,7 +143,7 @@ public class SubMeshImporter
         _indices = _primitive.GetIndices().Select(idx => (ushort)idx).ToArray();
     }
 
-    private void BuildAttributes()
+    private void BuildVertexAttributes()
     {
         var accessors = _primitive.VertexAccessors;
 
@@ -153,14 +179,14 @@ public class SubMeshImporter
             offsets[attribute.Stream] += attribute.Size;
         }
 
-        _attributes = attributes;
+        _vertexAttributes = attributes;
         // After building the attributes, the resulting next offsets are our stream strides.
         _strides = offsets;
     }
 
     private void BuildVertices()
     {
-        ArgumentNullException.ThrowIfNull(_attributes);
+        ArgumentNullException.ThrowIfNull(_vertexAttributes);
 
         // Lists of vertex indices that are effected by each morph target for this primitive.
         var morphModifiedVertices = Enumerable.Range(0, _primitive.MorphTargetsCount)
@@ -173,13 +199,13 @@ public class SubMeshImporter
         for (var vertexIndex = 0; vertexIndex < _vertexCount; vertexIndex++)
         {
             // Write out vertex data to streams for each attribute.
-            foreach (var attribute in _attributes)
+            foreach (var attribute in _vertexAttributes)
                 _streams[attribute.Stream].AddRange(attribute.Build(vertexIndex));
 
             // Record which morph targets have values for this vertex, if any.
             var changedMorphs = morphModifiedVertices
                 .WithIndex()
-                .Where(pair => _attributes.Any(attribute => attribute.HasMorph(pair.Index, vertexIndex)))
+                .Where(pair => _vertexAttributes.Any(attribute => attribute.HasMorph(pair.Index, vertexIndex)))
                 .Select(pair => pair.Value);
             foreach (var modifiedVertices in changedMorphs)
                 modifiedVertices.Add(vertexIndex);
@@ -191,7 +217,7 @@ public class SubMeshImporter
     private void BuildShapeValues(IEnumerable<List<int>> morphModifiedVertices)
     {
         ArgumentNullException.ThrowIfNull(_indices);
-        ArgumentNullException.ThrowIfNull(_attributes);
+        ArgumentNullException.ThrowIfNull(_vertexAttributes);
 
         var morphShapeValues = new Dictionary<string, List<MdlStructs.ShapeValueStruct>>();
 
@@ -203,7 +229,7 @@ public class SubMeshImporter
             foreach (var vertexIndex in modifiedVertices)
             {
                 // Write out the morphed vertex to the vertex streams.
-                foreach (var attribute in _attributes)
+                foreach (var attribute in _vertexAttributes)
                     _streams[attribute.Stream].AddRange(attribute.BuildMorph(morphIndex, vertexIndex));
 
                 // Find any indices that target this vertex index and create a mapping.
@@ -224,4 +250,13 @@ public class SubMeshImporter
 
         _shapeValues = morphShapeValues;
     }
+
+    private void BuildMetaAttributes()
+    {
+        // We consider any "extras" key with a boolean value set to `true` to be an attribute.
+        _metaAttributes = _nodeExtras?
+            .Where(pair => pair.Value.ValueKind == JsonValueKind.True)
+            .Select(pair => pair.Key)
+            .ToArray() ?? [];
+    }
 }

Penumbra/Import/Models/Import/Utility.cs

@@ -0,0 +1,34 @@
+namespace Penumbra.Import.Models.Import;
+
+public static class Utility
+{
+    /// <summary> Merge attributes into an existing attribute array, providing an updated submesh mask. </summary>
+    /// <param name="oldMask"> Old submesh attribute mask. </param>
+    /// <param name="oldAttributes"> Old attribute array that should be merged. </param>
+    /// <param name="newAttributes"> New attribute array. Will be mutated. </param>
+    /// <returns> New submesh attribute mask, updated to match the merged attribute array. </returns>
+    public static uint GetMergedAttributeMask(uint oldMask, IList<string> oldAttributes, List<string> newAttributes)
+    {
+        var metaAttributes = Enumerable.Range(0, 32)
+            .Where(index => ((oldMask >> index) & 1) == 1)
+            .Select(index => oldAttributes[index]);
+
+        var newMask = 0u;
+
+        foreach (var metaAttribute in metaAttributes)
+        {
+            var attributeIndex = newAttributes.IndexOf(metaAttribute);
+            if (attributeIndex == -1)
+            {
+                if (newAttributes.Count >= 32)
+                    throw new Exception("Models may utilise a maximum of 32 attributes.");
+
+                newAttributes.Add(metaAttribute);
+                attributeIndex = newAttributes.Count - 1;
+            }
+            newMask |= 1u << attributeIndex;
+        }
+
+        return newMask;
+    }
+}