entityx_lua's Introduction

Lua Bindings for EntityX

This system adds the ability to extend entity logic with Lua scripts.

It has only been tested with entityx 0.1.0. 1.0.0 compatible version is still work in process.

Example

To use this system, first include the header entityx_lua.h. Create a component Position and export it to lua.

using namespace entityx;
using namespace entityx::lua;

struct Position : entityx::Component<Position> {
	Position(float x = 0.0f, float y = 0.0f) : x(x), y(y) {}

	float x, y;
};

export_component<Position>("Position",
	// Use wrapped constructor to create an object from lua
	wrap_ctor<Position, float, float>([](float x, float y) {
		return Position(x, y);
	}),
	// Make x and y accessible from lua
	[](MemberRegister<Position>& m) {
		m.add("x", &Position::x);
		m.add("y", &Position::y);
	}
);

Create the lua state and export the entity manager.

lua_State* L = luaL_newstate();
luaL_openlibs(L);
setup_entityx_api(L);

ptr<EventManager> events(new EventManager());
ptr<EntityManager> entities(new EntityManager(events));

new_entity_manager(L, entities, "manager");

Then you can use the entityx and the component Position in lua.

-- create a entity class
Player = entityx.manager:new()
function Player:init(o)
	o = o or {}
	-- this class has a component "Position"
	self.position = self:component("Position", o.position or {0, 0})
end
-- create an instance of this class
p = Player:instance({position = {10, 20}})
-- set Position.x to 5
p.position.x(5)
-- this will print 5, 20
print(p.position.x(), p.position.y())