static opacity_default opc_default = opacity_default();

static opacity_default opc_default;
// Default LOS rules, but only consider fully opaque features blocking.
// In particular, clouds don't affect the result.
struct opacity_fullyopaque : opacity_func
{
    opacity_type operator()(const coord_def& p) const;
};
static opacity_fullyopaque opc_fullyopaque;

static opacity_solid opc_solid = opacity_solid();

static opacity_solid opc_solid;

static bounds_los_radius bds_default = bounds_los_radius();

static bounds_los_radius bds_default;

    else
        return OPC_CLEAR;
}
opacity_type opacity_fullyopaque::operator()(const coord_def& p) const
{
    if (grid_is_opaque(env.grid(p)))
        return OPC_OPAQUE;

// Is p2 visible from p1, disregarding clouds?
// XXX: Horribly inefficient since we do an entire LOS calculation;
//      needs to be rewritten if it is used more.

// Is p2 visible from p1, disregarding half-opaque objects?

    env_show_grid show;
    losight(show, p1);
    return see_grid(show, p1, p2);

    return exists_ray(p1, p2, opc_fullyopaque);