Calculate primary BoundingBox

Penumbra/Import/Models/Import/BoundingBox.cs

@@ -0,0 +1,33 @@
+using Lumina.Data.Parsing;
+
+namespace Penumbra.Import.Models.Import;
+
+/// <summary> Mutable representation of the bounding box surrouding a collection of vertices. </summary>
+public class BoundingBox
+{
+    private Vector3 _minimum = Vector3.Zero;
+    private Vector3 _maximum = Vector3.Zero;
+
+    /// <summary> Use the specified position to update this bounding box, expanding it if necessary. </summary>
+    public void Merge(Vector3 position)
+    {
+        _minimum = Vector3.Min(_minimum, position);
+        _maximum = Vector3.Max(_maximum, position);
+    }
+
+    /// <summary> Merge the provided bounding box into this one, expanding it if necessary. </summary>
+    /// <param name="other"></param>
+    public void Merge(BoundingBox other)
+    {
+        _minimum = Vector3.Min(_minimum, other._minimum);
+        _maximum = Vector3.Max(_maximum, other._maximum);
+    }
+
+    /// <summary> Convert this bounding box to the struct format used in .mdl data structures. </summary>
+    public MdlStructs.BoundingBoxStruct ToStruct()
+        => new MdlStructs.BoundingBoxStruct
+        {
+            Min = [_minimum.X, _minimum.Y, _minimum.Z, 1],
+            Max = [_maximum.X, _maximum.Y, _maximum.Z, 1],
+        };
+}

Penumbra/Import/Models/Import/MeshImporter.cs

@@ -19,6 +19,8 @@ public class MeshImporter(IEnumerable<Node> nodes)
 
         public List<string>? Bones;
 
+        public BoundingBox BoundingBox;
+
         public List<string> MetaAttributes;
 
         public List<MeshShapeKey> ShapeKeys;
@@ -50,6 +52,8 @@ public class MeshImporter(IEnumerable<Node> nodes)
 
     private List<string>? _bones;
 
+    private readonly BoundingBox _boundingBox = new BoundingBox();
+
     private readonly List<string> _metaAttributes = [];
 
     private readonly Dictionary<string, List<MdlStructs.ShapeValueStruct>> _shapeValues = [];
@@ -87,6 +91,7 @@ public class MeshImporter(IEnumerable<Node> nodes)
             VertexBuffer      = _streams[0].Concat(_streams[1]).Concat(_streams[2]),
             Indices           = _indices,
             Bones             = _bones,
+            BoundingBox       = _boundingBox,
             MetaAttributes    = _metaAttributes,
             ShapeKeys = _shapeValues
                 .Select(pair => new MeshShapeKey()
@@ -154,6 +159,8 @@ public class MeshImporter(IEnumerable<Node> nodes)
             }));
         }
 
+        _boundingBox.Merge(subMesh.BoundingBox);
+
         // And finally, merge in the sub-mesh struct itself.
         _subMeshes.Add(subMesh.SubMeshStruct with
         {

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 BoundingBox _boundingBox = new BoundingBox();
+
     private readonly List<string> _metaAttributes = [];
 
     private readonly Dictionary<string, List<MdlStructs.ShapeMeshStruct>> _shapeMeshes = [];
@@ -95,9 +97,10 @@ public partial class ModelImporter(ModelRoot model)
 
             Materials = [.. materials],
 
+            BoundingBoxes = _boundingBox.ToStruct(),
+
             // TODO: Would be good to calculate all of this up the tree.
             Radius            = 1,
-            BoundingBoxes     = MdlFile.EmptyBoundingBox,
             BoneBoundingBoxes = Enumerable.Repeat(MdlFile.EmptyBoundingBox, _bones.Count).ToArray(),
             RemainingData     = [.._vertexBuffer, ..indexBuffer],
         };
@@ -156,6 +159,8 @@ public partial class ModelImporter(ModelRoot model)
                 .ToArray(),
         });
 
+        _boundingBox.Merge(mesh.BoundingBox);
+
         _subMeshes.AddRange(mesh.SubMeshStructs.Select(m => m with
         {
             AttributeIndexMask = Utility.GetMergedAttributeMask(

Penumbra/Import/Models/Import/SubMeshImporter.cs

@@ -21,6 +21,8 @@ public class SubMeshImporter
 
         public ushort[] Indices;
 
+        public BoundingBox BoundingBox;
+
         public string[] MetaAttributes;
 
         public Dictionary<string, List<MdlStructs.ShapeValueStruct>> ShapeValues;
@@ -44,6 +46,8 @@ public class SubMeshImporter
 
     private ushort[]? _indices;
 
+    private BoundingBox _boundingBox = new BoundingBox();
+
     private string[]? _metaAttributes;
 
     private readonly List<string>?                                          _morphNames;
@@ -90,9 +94,11 @@ public class SubMeshImporter
     private SubMesh Create()
     {
         // Build all the data we'll need.
+        // TODO: This structure is verging on a little silly. Reconsider.
         BuildIndices();
         BuildVertexAttributes();
         BuildVertices();
+        BuildBoundingBox();
         BuildMetaAttributes();
 
         ArgumentNullException.ThrowIfNull(_indices);
@@ -133,6 +139,7 @@ public class SubMeshImporter
             Strides     = _strides,
             Streams     = _streams,
             Indices     = _indices,
+            BoundingBox = _boundingBox,
             MetaAttributes  = _metaAttributes, 
             ShapeValues = _shapeValues,
         };
@@ -255,6 +262,13 @@ public class SubMeshImporter
         _shapeValues = morphShapeValues;
     }
 
+    private void BuildBoundingBox()
+    {
+        var positions = _primitive.VertexAccessors["POSITION"].AsVector3Array();
+        foreach (var position in positions)
+            _boundingBox.Merge(position);
+    }
+
     private void BuildMetaAttributes()
     {
         // We consider any "extras" key with a boolean value set to `true` to be an attribute.