Question

I am working on a 2D game engine at the moment and have hit a stumbling block whilst implementing the LUA scripting / Interpreter.

I’m using SWIG and have got the basics all working fine.

In the engine I use the GLM (OpenGL Mathematics Libary http://glm.g-truc.net/) for all Vector and Matrix related areas.

I really need to expose glm (at a basic level) to the via SWIG to LUA so I can call methods in LUA like:

actor:GetPosition()  <- Which returns a glm::vec2

GLM is quite a complex library (possibly an understatement lol) and I do not require the whole thing exposed, that would be ridiculous amounts of work I assume. I simply want to be able to access the xy components of the glm::vec2 class.

I’m sure this must be easy as SWIG doesn’t require a full class definition and there must be a way to let SWIG just assume that the glm::vec2 class just has x,y params.

I’m not sure If using Proxy classes in SWIG is the way to do this ? or some other method ? I’m quite new to LUA integration and SWIG also.

One route I really don’t want to go down is ditching GLM and writing my own Vector/Matrix library which is much more simple, no templates etc and I can then simply wrap with SWIG, but I feel this would be a waste of time and I would ultimately end up with a less powerful Math Library :(.

Thanks in advance and I can provide more info if necessary.

Answer 1

A solution in luabind would look like this:

#include <luabind/luabind.hpp>


extern "C" int init(lua_State* L)
{
    using namespace luabind;
    using namespace glm;

    open(L);

    module(L)
    [
        class_<dvec2>("dvec2")
            .def_readwrite("x", &dvec2::x)
            .def_readwrite("y", &dvec2::y)
    ];

    return 0;
}