feat(3d): Implement basic OBJ mesh asset pipeline

Added support for loading and rendering OBJ meshes.
- Updated asset_packer to parse .obj files into a binary format.
- Added MeshAsset and GetMeshAsset helper to asset_manager.
- Extended Object3D with mesh_asset_id and ObjectType::MESH.
- Implemented mesh rasterization pipeline in Renderer3D.
- Added a sample cube mesh and verified in test_3d_render.

1 files changed, 7 insertions, 3 deletions

diff --git a/src/3d/object.h b/src/3d/object.h
index 6d21393..0c8edd8 100644
--- a/src/3d/object.h
+++ b/src/3d/object.h
@@ -5,6 +5,7 @@
 #pragma once
 
 #include "util/mini_math.h"
+#include "util/asset_manager.h"
 
 enum class ObjectType {
   CUBE,
@@ -12,7 +13,8 @@ enum class ObjectType {
   PLANE,
   TORUS,
   BOX,
-  SKYBOX
+  SKYBOX,
+  MESH
   // Add more SDF types here
 };
 
@@ -37,10 +39,12 @@ class Object3D {
   float restitution;
   bool is_static;
 
+  AssetId mesh_asset_id;
+
   Object3D(ObjectType t = ObjectType::CUBE)
       : position(0, 0, 0), rotation(0, 0, 0, 1), scale(1, 1, 1), type(t),
         color(1, 1, 1, 1), velocity(0, 0, 0), mass(1.0f), restitution(0.5f),
-        is_static(false) {
+        is_static(false), mesh_asset_id((AssetId)0) {
   }
 
   mat4 get_model_matrix() const {
@@ -59,4 +63,4 @@ class Object3D {
     // Simple defaults for unit primitives
     return {{-1, -1, -1}, {1, 1, 1}};
   }
-};
+};
\ No newline at end of file