public static IEnumerable <Actor> FindActorsInBox(this World world, WPos tl, WPos br)
{
var a = PPos.FromWPos(tl);
var b = PPos.FromWPos(br);
var u = PPos.Min(a, b);
var v = PPos.Max(a, b);
return(world.WorldActor.Trait <SpatialBins>().ActorsInBox(u, v));
}
