Added luasnap checkpointing mechanism

luprex/cpp/world.hpp

@@ -8,6 +8,7 @@
 #include "animqueue.hpp"
 #include "source.hpp"
 #include "gui.hpp"
+#include "luasnap.hpp"
 #include <memory>
 #include <unordered_map>
 
@@ -43,10 +44,10 @@ public:
 
 class World {
 public:
-    // A pointer to the lua State.
+    // A lua intepreter with snapshot function.
     //
-    lua_State *lua_state_;
-
+    LuaSnap lua_snap_;
+    
     // The Global ID Pool.
     //
     IdGlobalPool id_global_pool_;
@@ -81,7 +82,7 @@ public:
     //
     // Get the lua interpreter associated with this world model.
     //
-    lua_State *get_lua_state() { return lua_state_; }
+    lua_State *state() { return lua_snap_.state(); }
 
     // get_near
     //