Import material names

Penumbra/Import/Models/Import/MeshImporter.cs

@@ -10,6 +10,8 @@ public class MeshImporter(IEnumerable<Node> nodes)
         public MdlStructs.MeshStruct          MeshStruct;
         public List<MdlStructs.SubmeshStruct> SubMeshStructs;
 
+        public string? Material;
+
         public MdlStructs.VertexDeclarationStruct VertexDeclaration;
         public IEnumerable<byte>                  VertexBuffer;
 
@@ -35,6 +37,8 @@ public class MeshImporter(IEnumerable<Node> nodes)
 
     private readonly List<MdlStructs.SubmeshStruct> _subMeshes = [];
 
+    private string? _material;
+
     private          MdlStructs.VertexDeclarationStruct? _vertexDeclaration;
     private          byte[]?                             _strides;
     private          ushort                              _vertexCount;
@@ -74,6 +78,7 @@ public class MeshImporter(IEnumerable<Node> nodes)
                 BoneTableIndex = 0,
             },
             SubMeshStructs    = _subMeshes,
+            Material          = _material,
             VertexDeclaration = _vertexDeclaration.Value,
             VertexBuffer      = _streams[0].Concat(_streams[1]).Concat(_streams[2]),
             Indices           = _indices,
@@ -105,6 +110,9 @@ public class MeshImporter(IEnumerable<Node> nodes)
 
         var subMeshName = node.Name ?? node.Mesh.Name;
 
+        // TODO: Record a warning if there's a mismatch between current and incoming, as we can't support multiple materials per mesh.
+        _material ??= subMesh.Material;
+
         // Check that vertex declarations match - we need to combine the buffers, so a mismatch would take a whole load of resolution.
         if (_vertexDeclaration == null)
             _vertexDeclaration = subMesh.VertexDeclaration;

Penumbra/Import/Models/Import/ModelImporter.cs

@@ -19,6 +19,8 @@ public partial class ModelImporter(ModelRoot _model)
     private readonly List<MdlStructs.MeshStruct>    _meshes    = [];
     private readonly List<MdlStructs.SubmeshStruct> _subMeshes = [];
 
+    private readonly List<string> _materials = [];
+
     private readonly List<MdlStructs.VertexDeclarationStruct> _vertexDeclarations = [];
     private readonly List<byte>                               _vertexBuffer       = [];
 
@@ -37,6 +39,8 @@ public partial class ModelImporter(ModelRoot _model)
             BuildMeshForGroup(subMeshNodes);
 
         // Now that all the meshes have been built, we can build some of the model-wide metadata.
+        var materials = _materials.Count > 0 ? _materials : ["/NO_MATERIAL"];
+
         var shapes      = new List<MdlFile.Shape>();
         var shapeMeshes = new List<MdlStructs.ShapeMeshStruct>();
         foreach (var (keyName, keyMeshes) in _shapeMeshes)
@@ -86,8 +90,7 @@ public partial class ModelImporter(ModelRoot _model)
                 },
             ],
 
-            // TODO: Would be good to populate from gltf material names.
-            Materials = ["/NO_MATERIAL"],
+            Materials = [.. materials],
 
             // TODO: Would be good to calculate all of this up the tree.
             Radius            = 1,
@@ -130,15 +133,20 @@ public partial class ModelImporter(ModelRoot _model)
         var mesh           = MeshImporter.Import(subMeshNodes);
         var meshStartIndex = (uint)(mesh.MeshStruct.StartIndex + indexOffset);
 
+        ushort materialIndex = 0;
+        if (mesh.Material != null)
+            materialIndex = GetMaterialIndex(mesh.Material);
+
         // If no bone table is used for a mesh, the index is set to 255.
-        var boneTableIndex = 255;
+        ushort boneTableIndex = 255;
         if (mesh.Bones != null)
             boneTableIndex = BuildBoneTable(mesh.Bones);
 
         _meshes.Add(mesh.MeshStruct with
         {
+            MaterialIndex = materialIndex,
             SubMeshIndex = (ushort)(mesh.MeshStruct.SubMeshIndex + subMeshOffset),
-            BoneTableIndex = (ushort)boneTableIndex,
+            BoneTableIndex = boneTableIndex,
             StartIndex = meshStartIndex,
             VertexBufferOffset = mesh.MeshStruct.VertexBufferOffset
                 .Select(offset => (uint)(offset + vertexOffset))
@@ -173,6 +181,23 @@ public partial class ModelImporter(ModelRoot _model)
         }
     }
 
+    private ushort GetMaterialIndex(string materialName)
+    {
+        // If we already have this material, grab the current one
+        var index = _materials.IndexOf(materialName);
+        if (index >= 0)
+            return (ushort)index;
+
+        // If there's already 4 materials, we can't add any more.
+        // TODO: permit, with a warning to reduce, and validation in MdlTab.
+        var count = _materials.Count;
+        if (count >= 4)
+            return 0;
+
+        _materials.Add(materialName);
+        return (ushort)count;
+    }
+
     private ushort BuildBoneTable(List<string> boneNames)
     {
         var boneIndices = new List<ushort>();

Penumbra/Import/Models/Import/SubMeshImporter.cs

@@ -10,6 +10,8 @@ public class SubMeshImporter
     {
         public MdlStructs.SubmeshStruct SubMeshStruct;
 
+        public string? Material;
+
         public MdlStructs.VertexDeclarationStruct VertexDeclaration;
 
         public ushort       VertexCount;
@@ -81,6 +83,10 @@ public class SubMeshImporter
         ArgumentNullException.ThrowIfNull(_attributes);
         ArgumentNullException.ThrowIfNull(_shapeValues);
 
+        var material = _primitive.Material.Name;
+        if (material == "")
+            material = null;
+
         return new SubMesh()
         {
             SubMeshStruct = new MdlStructs.SubmeshStruct()
@@ -93,6 +99,7 @@ public class SubMeshImporter
                 BoneStartIndex = 0,
                 BoneCount      = 0,
             },
+            Material = material,
             VertexDeclaration = new MdlStructs.VertexDeclarationStruct()
             {
                 VertexElements = _attributes.Select(attribute => attribute.Element).ToArray(),