extern crate specs;
use specs::prelude::*;
use super::{Viewshed, Position};

pub struct VisibilitySystem {}

impl<'a> System<'a> for VisibilitySystem {
    type SystemData = ( WriteStorage<'a, Viewshed>, 
                        WriteStorage<'a, Position>);

    fn run(&mut self, (mut viewshed, pos) : Self::SystemData) {
        for (viewshed,pos) in (&mut viewshed, &pos).join() {
        }
    }
}