Working with Lua callbacks and more than one parameter in both directions

[Michael Bauroth <Michael.Bauroth@...>]

Hi,

I've implemented a working simple callback system between Lua and C++ 
(Lunar based). But now I have problems to implement some more 
sophisticated features. Google didn't help so far, but eventually can 
someone can give me some short hints, links or samples for the following
features ...

My code looks like this at the moment (Questions are located below):


Lua:

function onmousemove( comp )
    comp:doSomthing()
end

btn = Button:new()
btn.Callback = { onmousemove, 1 }; // will call SetCallback(L)



C++:

LRESULT FComponent::OnMouseMove( int x, int y )
{
    if ( m_CbOnMouseMove )
    {
        // Call lua function by stored Reference
        lua_State* L = GetLuaInstance();
        lua_pushvalue(L, 1);

        // push function
        lua_rawgeti( L, LUA_REGISTRYINDEX, m_CbOnMouseMove );
			
        // push parameter(s)
        pushLuaObject( L );

        // call function
        lua_pcall( L, 1, LUA_MULTRET, 0 )
        return 0;
    }

    return 1L;
}

int FComponent::SetCallback( lua_State *L )
{
    luaL_checktype( L, 1, LUA_TTABLE );

    lua_rawgeti( L, 1, 1 );
    int tType = lua_tonumber( L, -1 );
    lua_pop(L, 1);

    lua_rawgeti(L, 1, 2);
    int tCb = luaL_ref( L, LUA_REGISTRYINDEX );
    lua_pop(L, 1);

    switch ( tType )
    {
    case 1:
        m_CbOnMouseMove = tCb;
        break;
    ...
    }
	
    lua_pop( L, lua_gettop( L ) );
    return 0;
}


Question 1:
How can I register a callback with a optional parameter, e.g., if Button 
3 is pressed, call onmousedown with value 3.

sample:

function onmousedown( number )
  print( number )
end

btn1 = Button:new()
btn1.Callback = { onmousedown( 1 ), 1 }
btn2 = Button:new()
btn2.Callback = { onmousedown( 2 ), 1 }


Question2:
How can I pass more than one parameter (e.g. table based) from C++ side 
to Lua for callbacks (see above FComponent::OnMouseMove )

sample:

function onmousedown( event )
  print( event[ "x" ] )
  print( event[ "y" ] )
  print( event[ "component" ] )
end

Best Regards
Micha