RE: Attach Lua script To C++ class!

Hi all!

I have pretty much the same dilemma atm…

The problem with one script per actor is that they can’t share variables and functions!

And the problem having only one lua_state* is that you can’t duplicate the same script several time without sharing the same variables and functions for all actors assigned to this script!

Is that right?

If yes … having the possibility to make global and local script make sense?

thx

-----Original Message-----
From: lua-bounces@bazar2.conectiva.com.br [mailto:lua-bounces@bazar2.conectiva.com.br] On Behalf Of herviou
Sent: Tuesday, July 19, 2005 3:24 AM
To: Lua list
Subject: Re: Attach Lua script To C++ class!

Hello,
I have choosen the same solution as Jason. Here is a (simple) example you can do to register lua script inside a C++ class (store has a filename)
In C++ pseudo-code:
class LuaAI {
    void acting (void); //the method called to animate your buddy at each frame
    StlString _filename; //the AI script
    bool _first;
    lua_state* L;
}

void
LuaAI::acting(void){
    if (_first){
    lua_dofile(L,_fileName.c_str());
    first=false;
    }
    lua_pcall(L,0,0,0);
}
Something interresting can be done with this solution, instead of testing the boolean _first you can have a method that checks if the _filename has been modify since its last execution, this way you can modify "on the fly" the behavior of your character!

Personnally I have choosen to have one lua_state for each character, this way each one has its own stack of execution,but again that's a personnal choice...

david.

Ive wrote:

O interesting!

Can u be more precise on this and/or point me to some example?

thx

-----Original Message-----

From: lua-bounces@bazar2.conectiva.com.br

[mailto:lua-bounces@bazar2.conectiva.com.br] On Behalf Of Jason Murdick

Sent: Monday, July 18, 2005 3:35 PM

To: Lua list

Subject: Re: Attach Lua script To C++ class!

Sure it is!  The two ways I've stored scripts inside C++ classes is to

simply store the script as a string or as a filename/path.

Jason

On 7/18/05, Ive <neosettlers@sympatico.ca> wrote:

Am I at the right place to discuss this?

...

Alright!

What I m trying to do is to assign to each actor in a game environment

script ai!

I m wondering if I must do:

lua_State *m_lua;

       if ((m_lua = lua_open()) == NULL)

               Trace("ERROR: LUA initialization failed!\n\n");

       else

               Trace("TELL: LUA initialization successful!\n\n");

               luaopen_base(m_lua);

               luaopen_table(m_lua);

               luaopen_io(m_lua);

               luaopen_string(m_lua);

               luaopen_math(m_lua);

               luaopen_debug(m_lua);

               RegisterFunction(); /// register all functions

       Int l_status = luaL_loadfile(m_lua, in_name.GetName());

       lua_settop(m_lua, 0);

       if (l_status != 0)

               lua_error(m_lua);

to each of the script!

Then update them individually each frame with:

lua_pcall(m_lua, 0, 0, 0);

or

my first guest is to have only one lua_State instance and register all

functions once and then keep track with a pointer to each

luaL_loadfile... but I cant find the way to retrieve them... can

anyone

clear this up please?

Is lua_open() should be call once (then register all possible

functions

once) or to all attached scripts? What is the ultimate way to do this

with out unnecessary overheads?

thx