Various fixes and improvements

MeshDecimatorCore/MeshDecimatorCore.csproj

@@ -3,7 +3,7 @@
     <PropertyGroup>
         <TargetFramework>net10.0</TargetFramework>
         <ImplicitUsings>enable</ImplicitUsings>
-        <Nullable>enable</Nullable>
+        <Nullable>disable</Nullable>
     </PropertyGroup>
 
 </Project>

Obj2Gltf/Converter.cs

@@ -391,7 +391,13 @@ private List<Primitive> AddVertexAttributes(GltfModel gltfModel,
                 var hasColors = objModel.Colors.Count == objModel.Vertices.Count;
 
                 var materialIndex = GetMaterialIndexOrDefault(gltfModel, objModel, f.MatName);
-                var material = materialIndex < objModel.Materials.Count ? objModel.Materials[materialIndex] : null;
+                // Fix Issue #36: look up the OBJ material by name instead of relying
+                // on the gltfModel index, which can diverge from objModel.Materials
+                // when the default material is inserted at index 0.
+                var material = !string.IsNullOrEmpty(f.MatName)
+                    ? objModel.Materials.FirstOrDefault(m => m.Name == f.MatName)
+                      ?? (materialIndex < objModel.Materials.Count ? objModel.Materials[materialIndex] : null)
+                    : objModel.Materials.FirstOrDefault();
                 var materialHasTexture = material?.DiffuseTextureFile != null;
 
                 // every primitive needs their own vertex indices(v,t,n)

Obj2Gltf/WaveFront/ObjParser.cs

@@ -74,7 +74,7 @@ public ObjModel Parse(string objFilePath, bool removeDegenerateFaces = false, En
 
             using (_reader)
             {
-                model.Materials.Add(new Material() { Ambient = new Reflectivity(new FactorColor(1)) });
+                model.Materials.Add(new Material() { Name = "default", Ambient = new Reflectivity(new FactorColor(1)) });
                 var currentMaterialName = "default";
                 var currentGeometries = model.GetOrAddGeometries("default");
                 Face currentFace = null;

Obj2Tiles.Common/CommonUtils.cs

@@ -62,7 +62,7 @@ public static bool FilesAreEqual(FileInfo first, FileInfo second)
             return true;
         }
 
-        public static TValue SafeGetValue<TKey, TValue>(this IDictionary<TKey, TValue> dictionary, TKey key)
+        public static TValue? SafeGetValue<TKey, TValue>(this IDictionary<TKey, TValue> dictionary, TKey key)
         {
             return !dictionary.TryGetValue(key, out var value) ? default : value;
         }
@@ -74,7 +74,7 @@ public static TValue SafeGetValue<TKey, TValue>(this IDictionary<TKey, TValue> d
         }
 
         /// <summary>
-        /// Ensures that the sqlite database folder exists 
+        /// Ensures that the sqlite database folder exists
         /// </summary>
         /// <param name="connstr"></param>
         public static void EnsureFolderCreated(string connstr)
@@ -93,7 +93,7 @@ public static void EnsureFolderCreated(string connstr)
 
                     if (folder != null)
                         Directory.CreateDirectory(folder);
-                }   
+                }
             }
         }
 
@@ -125,7 +125,7 @@ public static string ComputeFileHash(string filePath)
 
         private static string ConvertBytesToString(byte[] bytes)
         {
-            // Convert byte array to a string   
+            // Convert byte array to a string
             var builder = new StringBuilder();
             foreach (var t in bytes)
                 builder.Append(t.ToString("x2"));
@@ -202,7 +202,7 @@ public static bool SafeDelete(string path)
                 return false;
             }
         }
-        
+
         public static bool SafeCopy(string source, string dest, bool overwrite = true)
         {
             try
@@ -316,7 +316,7 @@ public static string[] SafeTreeDelete(string baseTempFolder, int rounds = 3, int
                     }
                 }
 
-                if (!entries.Any()) 
+                if (!entries.Any())
                     return [];
 
                 Thread.Sleep(delay);
@@ -363,7 +363,7 @@ public static string[] SafeTreeDelete(string baseTempFolder, int rounds = 3, int
 
         // Credit https://stackoverflow.com/a/11124118
         /// <summary>
-        /// Returns the human-readable file size for an arbitrary, 64-bit file size 
+        /// Returns the human-readable file size for an arbitrary, 64-bit file size
         /// </summary>
         /// <param name="i"></param>
         /// <returns></returns>
@@ -420,7 +420,7 @@ public static bool Validate<T>(T obj, out ICollection<ValidationResult> results)
         {
             results = new List<ValidationResult>();
 
-            return Validator.TryValidateObject(obj, new ValidationContext(obj), results, true);
+            return Validator.TryValidateObject(obj!, new ValidationContext(obj!), results, true);
         }
 
         public static string ToErrorString(this IEnumerable<ValidationResult> results)
@@ -448,7 +448,7 @@ public static async Task<FileStream> WaitForFile(string fullPath, FileMode mode,
             int hops = 15, int baseDelay = 10, int incrementDelay = 2)
         {
             int delay = baseDelay;
-            
+
             for (var hop = 0; hop < hops; hops++)
             {
                 FileStream fs = null;
@@ -472,13 +472,13 @@ public static async Task<FileStream> WaitForFile(string fullPath, FileMode mode,
             return null;
         }*/
 
-        public static async Task<FileStream> WaitForFile(string fullPath, FileMode mode, FileAccess access,
+        public static async Task<FileStream?> WaitForFile(string fullPath, FileMode mode, FileAccess access,
             FileShare share,
             int delay = 50, int retries = 1200)
         {
             for (var numTries = 0; numTries < retries; numTries++)
             {
-                FileStream fs = null;
+                FileStream? fs = null;
                 try
                 {
                     fs = new FileStream(fullPath, mode, access, share);

Obj2Tiles.Common/TestArea.cs

@@ -19,7 +19,7 @@ public TestArea(string name)
 
     }
 
-    public TestArea() : this(new StackFrame(1).GetMethod()?.Name)
+    public TestArea() : this(new StackFrame(1).GetMethod()?.Name ?? "Unknown")
     {
         //
     }

Obj2Tiles.Common/TestFS.cs

@@ -24,7 +24,7 @@ public class TestFS : IDisposable
         /// </summary>
         public string BaseTestFolder { get; }
 
-        private readonly string _oldCurrentDirectory = null;
+        private readonly string? _oldCurrentDirectory = null;
 
         /// <summary>
         /// Creates a new instance of TestFS

Obj2Tiles.Library.Test/BoundsTests.cs

@@ -0,0 +1,146 @@
+using System.IO;
+using NUnit.Framework;
+using Obj2Tiles.Library.Geometry;
+using Shouldly;
+
+namespace Obj2Tiles.Library.Test;
+
+/// <summary>
+/// Tests for Box3 bounding box and mesh Bounds calculation.
+/// </summary>
+public class BoundsTests
+{
+    private const string TestDataPath = "TestData";
+
+    [Test]
+    public void Bounds_Triangle_Correct()
+    {
+        var mesh = MeshUtils.LoadMesh(Path.Combine(TestDataPath, "triangle.obj"));
+        var bounds = mesh.Bounds;
+
+        bounds.Min.X.ShouldBe(0.0);
+        bounds.Min.Y.ShouldBe(0.0);
+        bounds.Min.Z.ShouldBe(0.0);
+        bounds.Max.X.ShouldBe(1.0);
+        bounds.Max.Y.ShouldBe(1.0);
+        bounds.Max.Z.ShouldBe(0.0);
+    }
+
+    [Test]
+    public void Bounds_Cube3D_SymmetricAroundOrigin()
+    {
+        var mesh = MeshUtils.LoadMesh(Path.Combine(TestDataPath, "cube-3d.obj"));
+        var bounds = mesh.Bounds;
+
+        bounds.Min.X.ShouldBe(-1.0);
+        bounds.Min.Y.ShouldBe(-1.0);
+        bounds.Min.Z.ShouldBe(-1.0);
+        bounds.Max.X.ShouldBe(1.0);
+        bounds.Max.Y.ShouldBe(1.0);
+        bounds.Max.Z.ShouldBe(1.0);
+
+        bounds.Width.ShouldBe(2.0);
+        bounds.Height.ShouldBe(2.0);
+        bounds.Depth.ShouldBe(2.0);
+    }
+
+    [Test]
+    public void Bounds_Center_IsCorrect()
+    {
+        var mesh = MeshUtils.LoadMesh(Path.Combine(TestDataPath, "cube-3d.obj"));
+        var center = mesh.Bounds.Center;
+
+        center.X.ShouldBe(0.0);
+        center.Y.ShouldBe(0.0);
+        center.Z.ShouldBe(0.0);
+    }
+
+    [Test]
+    public void Bounds_AfterSplit_SubsetsOfOriginal()
+    {
+        var mesh = MeshUtils.LoadMesh(Path.Combine(TestDataPath, "cube-3d.obj"));
+        var originalBounds = mesh.Bounds;
+        var xutils = new VertexUtilsX();
+
+        mesh.Split(xutils, 0.0, out var left, out var right);
+
+        var lb = left.Bounds;
+        lb.Min.X.ShouldBeGreaterThanOrEqualTo(originalBounds.Min.X - 1e-9);
+        lb.Max.X.ShouldBeLessThanOrEqualTo(0.0 + 1e-9);
+
+        var rb = right.Bounds;
+        rb.Min.X.ShouldBeGreaterThanOrEqualTo(0.0 - 1e-9);
+        rb.Max.X.ShouldBeLessThanOrEqualTo(originalBounds.Max.X + 1e-9);
+    }
+
+    // --- Box3 Split ---
+
+    [Test]
+    public void Box3_SplitX_CoversFull()
+    {
+        var box = new Box3(-1, -1, -1, 1, 1, 1);
+        var halves = box.Split(Axis.X);
+
+        halves.Length.ShouldBe(2);
+        halves[0].Min.X.ShouldBe(-1.0);
+        halves[0].Max.X.ShouldBe(0.0);
+        halves[1].Min.X.ShouldBe(0.0);
+        halves[1].Max.X.ShouldBe(1.0);
+
+        // Y and Z unchanged
+        halves[0].Min.Y.ShouldBe(-1.0);
+        halves[0].Max.Y.ShouldBe(1.0);
+    }
+
+    [Test]
+    public void Box3_SplitY_CoversFull()
+    {
+        var box = new Box3(-1, -1, -1, 1, 1, 1);
+        var halves = box.Split(Axis.Y);
+
+        halves[0].Max.Y.ShouldBe(0.0);
+        halves[1].Min.Y.ShouldBe(0.0);
+    }
+
+    [Test]
+    public void Box3_SplitZ_CoversFull()
+    {
+        var box = new Box3(-1, -1, -1, 1, 1, 1);
+        var halves = box.Split(Axis.Z);
+
+        halves[0].Max.Z.ShouldBe(0.0);
+        halves[1].Min.Z.ShouldBe(0.0);
+    }
+
+    [Test]
+    public void Box3_SplitAtPosition_Correct()
+    {
+        var box = new Box3(0, 0, 0, 10, 10, 10);
+        var halves = box.Split(Axis.X, 3.0);
+
+        halves[0].Max.X.ShouldBe(3.0);
+        halves[1].Min.X.ShouldBe(3.0);
+    }
+
+    [Test]
+    public void Box3_Center_Calculation()
+    {
+        var box = new Box3(2, 4, 6, 8, 10, 12);
+        var center = box.Center;
+
+        center.X.ShouldBe(5.0);
+        center.Y.ShouldBe(7.0);
+        center.Z.ShouldBe(9.0);
+    }
+
+    [Test]
+    public void Box3_Equality()
+    {
+        var a = new Box3(0, 0, 0, 1, 1, 1);
+        var b = new Box3(0, 0, 0, 1, 1, 1);
+        var c = new Box3(0, 0, 0, 2, 1, 1);
+
+        (a == b).ShouldBeTrue();
+        (a != c).ShouldBeTrue();
+    }
+}