Function rltk::field_of_view_set

pub fn field_of_view_set(
    start: Point, 
    range: i32, 
    fov_check: &dyn Algorithm2D
) -> HashSet<Point, RandomState>

Calculates field-of-view for a map that supports Algorithm2D, returning a HashSet. This is a bit faster than coercing the results into a vector, since internally it uses the set for de-duplication.