feat: 测试覆盖扩展 + 文档更新

include/vde/foundation/io_obj.h

@@ -7,8 +7,26 @@ namespace vde::foundation {
 
 struct ObjMeshData {
     std::vector<Point3D> vertices;
+    std::vector<Point2D> texcoords;
     std::vector<Vector3D> normals;
-    std::vector<std::vector<int>> faces;  // vertex indices (1-based in file, 0-based here)
+
+    /// Vertex indices per face (0-based internally).
+    /// Always populated regardless of face format.
+    std::vector<std::vector<int>> faces;
+
+    /// Texcoord indices per face (0-based). Empty if the file had no vt data.
+    /// Same length as faces; each sub-vector same length as corresponding face.
+    std::vector<std::vector<int>> face_texcoords;
+
+    /// Normal indices per face (0-based). Empty if the file had no vn data.
+    std::vector<std::vector<int>> face_normals;
+
+    /// Material name per face group (appears before the faces that use it).
+    /// The i-th entry gives the material active for the i-th face.
+    std::vector<std::string> face_materials;
+
+    /// Helpers
+    [[nodiscard]] bool has_texcoords() const { return !texcoords.empty(); }
 };
 
 ObjMeshData read_obj(const std::string& filepath);