stretch_road_usage.rs

let road_width = 10.0f32;
let main_road = Road::new();

let bezier1 = Bezier::new(control_points1);
let bezier2 = Bezier::new(control_points2);
// compute connection curve from other road stretch
let hermite = HermiteSpline::from_curves(&bezier1, &bezier2);

let stretch1 = StretchRoad::from_curve(bezier1, road_width);
let stretch2 = StretchRoad::from_curve(bezier2, road_width);
let connection = StretchRoad::from_curve(hermite, road_width);

// push stretch of road in the right order
main_road.push_front(stretch1);
main_road.push_front(connection);
main_road.push_front(stretch2);

// when cars doesn't need road stretch anymore
main_road.pop_back(); // it's a VecDeqeu