M1+M2: gr2 -> Skeleton3D/ArrayMesh/Skin + libgr2-driven animation

- gr2_bridge: gr2 Mat4 (row-major) -> Godot Transform3D (4x4 transpose);
  build_skeleton (rest from local_transform, initial_placement folded into
  roots), build_skin (bind i -> bone i, pose = inverse_world), build_mesh
  (surface per gr2 mesh, ARRAY_BONES = skeleton idx via bone_bindings,
  rigid meshes bound to bone_bindings[0]).
- dxt: DDS DXT1/3/5 decoder ported from xrender-poc.
- Metin2Model: load_gr2 -> Skeleton3D + MeshInstance3D + StandardMaterial3D
  (runtime DDS albedo, face/body split by surface name). Z-up cm -> Y-up m
  conversion on the node transform (unit_scale, flip_z, flip_winding props).
- Metin2AnimPlayer: _process samples a (separate) anim .gr2 with
  gr2::sample_pose(model.skeleton, anim, t) -> set_bone_global_pose per bone;
  Godot GPU-skins via skin_matrix = global_pose(i) * bind_pose(i) == gr2
  deformer matrix. selfcheck() NaN-scans all anims.

Verified: warrior_cheongrin renders (75 bones, 5 surfaces, 3324 verts,
textured, upright). dance01 (dur 28.3s, 74 tracks) plays, 0 NaN over 25
samples, distinct poses at t=2/9/16/23. Screenshots in test/golden/.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WaHYEY9rwLWt21PULiYjeJ

extension/src/metin2_model.h

@@ -3,14 +3,24 @@
 #include <godot_cpp/classes/node3d.hpp>
 #include <godot_cpp/variant/string.hpp>
 
+#include <gr2/gr2.h>
+
+#include <memory>
+#include <optional>
+
+namespace godot {
+class Skeleton3D;
+class MeshInstance3D;
+} // namespace godot
+
 namespace mtgodot {
 
-// M0' placeholder node.
+// Loads a Metin2 .gr2 and builds a Godot subtree:
+//   Metin2Model (transform = Z-up/cm -> Y-up/m conversion)
+//     └─ Skeleton3D          (rest pose from gr2 bones)
+//     └─ MeshInstance3D      (ArrayMesh, one surface per gr2 mesh; skinned)
 //
-// Purpose at this milestone: prove the GDExtension registers a class the Godot
-// editor can instantiate, and that libgr2 is linked in and callable from here.
-// M1 replaces the body with real Skeleton3D / ArrayMesh construction
-// (see docs/GODOT-POC-PLAN.md §M1).
+// M1: static bind-pose render. M2's Metin2AnimPlayer drives the Skeleton3D.
 class Metin2Model : public godot::Node3D {
 	GDCLASS(Metin2Model, godot::Node3D)
 
@@ -18,14 +28,55 @@ public:
 	Metin2Model();
 	~Metin2Model() override;
 
-	// One-line tag proving libgr2 symbols resolved at link time.
-	godot::String libgr2_info() const;
+	void _ready() override;
 
-	// Parse a .gr2 with libgr2 and report a couple of counts (no scene build yet).
+	// --- inspector properties ---
+	void set_gr2_path(const godot::String &p);
+	godot::String get_gr2_path() const { return gr2_path; }
+
+	void set_texture_dir(const godot::String &p);
+	godot::String get_texture_dir() const { return texture_dir; }
+
+	void set_unit_scale(double s);
+	double get_unit_scale() const { return unit_scale; }
+
+	void set_flip_z(bool v);
+	bool get_flip_z() const { return flip_z; }
+
+	void set_flip_winding(bool v);
+	bool get_flip_winding() const { return flip_winding; }
+
+	// Rebuild the subtree from the current properties.
+	void reload();
+
+	// One-line summary (bones / meshes / verts / bounds).
+	godot::String get_info() const;
+
+	// --- C++ accessors for Metin2AnimPlayer (same extension) ---
+	const gr2::Skeleton *gr2_skeleton() const;
+	godot::Skeleton3D *skeleton_node() const { return skel; }
+
+	// libgr2 sanity probe (kept from M0').
 	godot::String probe_gr2(const godot::String &path) const;
 
 protected:
 	static void _bind_methods();
+
+private:
+	godot::String gr2_path;
+	godot::String texture_dir;
+	double unit_scale = 0.01;
+	bool flip_z = false;
+	bool flip_winding = false;
+
+	std::shared_ptr<std::optional<gr2::File>> file; // shared_ptr so accessor stays valid
+	godot::Skeleton3D *skel = nullptr;
+	godot::MeshInstance3D *mi = nullptr;
+	godot::String last_info;
+
+	void _clear_children();
+	void _apply_materials();
+	godot::String _guess_texture_dir() const;
 };
 
 } // namespace mtgodot