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[makerimages]

Hi,

So. i've decided to do a project with C++ this year, to gain some more knowledge in how it works. Right now I'm working on implementing Lua integration to it. I've already gotten simple C++ functions to be called from Lua, when I can't find a good tutorial on, however is extending classes to Lua, specifically - classes that have constructors that take parameters. Say something like this.

Code:

SpecterApp::SpecterApp(std::string title, int width, int height, bool vsync, int frames)

How should I go about extending these(and any other class, for that matter), to Lua?

Solution

[makerimages]

Figured it out already.

[oahda]

Then you should post your solution in case somebody else with the same problem finds this thread.

[InfiniteStateMachine]

Then you should post your solution in case somebody else with the same problem finds this thread.

Required :

 

[oahda]

Yep. D:

[makerimages]

Will do as soon as I get the code cleaned up a bit and/or am more awake than at 11:30PM.

[makerimages]

OK, here goes the solution

This actually proved to be simpler than expected.

I've got a class with a constructor like this:

Code:

SpecterApp::SpecterApp(std::string title, int width, int height, bool vsync, int frames)

Registering this is simple, at least with Lua 5.1. Every function to be registered needs a Lua equivalent in C++.
Like so, for the constructor.

Code:

int l_SpecterApp_constructor(lua_State * l)
{
    const char * name = luaL_checkstring(l, 1);
    int width = luaL_checkint(l, 2);
    int height = luaL_checkint(l,3);
    bool vsync = lua_toboolean(l,4);
    int frames = luaL_checkint(l,5);


    SpecterApp** udata = (SpecterApp **)lua_newuserdata(l, sizeof(SpecterApp *));
    *udata = new SpecterApp(name,width,height,vsync, frames);
    luaL_getmetatable(l, "luaL_SpecterApp");
    lua_setmetatable(l, -2);
    return 1;
}

And, in some other function that initializes the Lua stack.

Code:

 luaL_Reg sSpecterAppRegs[] =
    {
        { "create", l_SpecterApp_constructor },
        { NULL, NULL }
    };

    luaL_newmetatable(L, "luaL_SpecterApp");
    luaL_register(L, NULL, sSpecterAppRegs);
    lua_pushvalue(L, -1);
    lua_setfield(L, -1, "__index");
    lua_setglobal(L, "SpecterApp");

With this, A SpecterApp can be created from Lua as such:

Code:

local app = SpecterApp.create("An app",1280,720,true,60)