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Lua OOP question

Started by pine3 Jun 29, 2006 at 12:45 AM 1 replies 1.1k views

Original Post

Jun 29, 2006 at 12:45 AM

Hi, I'm using Lunar for binding Lua with c++. Is it possible for Lua and C++ to access the same object? Member functions and variables are not static. Lua has a pointer to an object created in C++ or vice versa.

rileyriley

Jun 29, 2006 at 12:05 PM

I have a system set up that is working quite nicely (also using lunar). Lua and C++ can both access objects (complete with non-static member variables and functions).

Here is an example of how I have my classes declared:

#pragma once#include "lunar.h"class GameObject;class GameObjectManager;class GameObjectLuaProxy{	friend GameObjectManager;	friend GameObject;	DECLARE_SCRIPT_CLASS(GameObjectLuaProxy);private:	GameObject * gameObject;	int luaObjectReference;public:		GameObjectLuaProxy(lua_State * L);	GameObjectLuaProxy(const GameObjectLuaProxy &);	~GameObjectLuaProxy();	const GameObject * getGameObject() const { return gameObject; }	int getLuaReference();	SCRIPT_FUNCTION(GetPosition);	SCRIPT_FUNCTION(SetPosition);	SCRIPT_FUNCTION(GetVelocity);	SCRIPT_FUNCTION(SetVelocity);	SCRIPT_FUNCTION(ApplyForce);	SCRIPT_FUNCTION(SetLook);	SCRIPT_FUNCTION(SetColor);	SCRIPT_FUNCTION(GetColor);	SCRIPT_FUNCTION(SetPhysicsShape);	SCRIPT_FUNCTION(SetLabel);	SCRIPT_FUNCTION(SetReactive);	SCRIPT_FUNCTION(Destroy);	SCRIPT_FUNCTION(GetNetworkID);};

I also have to let Lua know about the class by registering it:

	REGISTER_CLASS(l, GameObjectLuaProxy);

With that done, from Lua I can call GameObjectLuaProxy:new() to get a new object in Lua. I can access the object from C++ with the userdata functionality built into the lua C++ API.

Hope this helps ~

pine3

Author

pine3

Jun 30, 2006 at 12:49 AM

Thanks that really helps!

So I just have to make a function in Lua that returns the pointer to the object.

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