摄像机系统，和子对象绑定

include/config.hpp

@@ -21,11 +21,14 @@ struct MeshConfig {
 
 struct ActorConfig {
     std::string name;
+    std::string type = "actor";
     std::string init_function;
     std::string tick_function;
     std::array<float, 2> position{0.0F, 0.0F};
     std::array<float, 2> facing{1.0F, 0.0F};
+    float zoom = 1.0F;
     MeshConfig mesh;
+    std::vector<ActorConfig> children;
 };
 
 struct InputBindingConfig {
@@ -38,6 +41,8 @@ struct SceneConfig {
     std::string name;
     std::string path;
     std::vector<ActorConfig> actors;
+    std::string default_camera;
+    bool grid_background = false;
 };
 
 struct GameConfig {