use std::marker::PhantomData;
use rust_num::{Zero, One};
use num::{BaseNum, BaseFloat};
use point::{Point, Point2, Point3};
use vector::{Vector, Vector2, Vector3};
use ray::{Ray2};
use intersect::Intersect;
#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable)]
pub struct Line<S, V, P> {
pub origin: P,
pub dest: P,
phantom_s: PhantomData<S>,
phantom_v: PhantomData<V>
}
impl<S: BaseNum, V: Vector<S>, P: Point<S, V>> Line<S, V, P> {
pub fn new(origin: P, dest: P) -> Line<S, V, P> {
Line {
origin: origin,
dest: dest,
phantom_v: PhantomData,
phantom_s: PhantomData
}
}
}
pub type Line2<S> = Line<S, Vector2<S>, Point2<S>>;
pub type Line3<S> = Line<S, Vector3<S>, Point3<S>>;
impl<S: BaseFloat> Intersect<Option<Point2<S>>> for (Ray2<S>, Line2<S>) {
fn intersection(&self) -> Option<Point2<S>> {
let (ref ray, ref line) = *self;
let p = ray.origin;
let q = line.origin;
let r = ray.direction;
let s = Vector2::new(line.dest.x - line.origin.x, line.dest.y - line.origin.y);
let cross_1 = r.perp_dot(&s);
let qmp = Vector2::new(q.x - p.x, q.y - p.y);
let cross_2 = qmp.perp_dot(&r);
if cross_1 == S::zero() {
if cross_2 != S::zero() {
return None;
}
let q2mp = Vector2::new(line.dest.x - p.x, line.dest.y - p.y);
let dot_1 = qmp.dot(&r);
let dot_2 = q2mp.dot(&r);
if (dot_1 <= S::zero() && dot_2 >= S::zero()) || (dot_1 >= S::zero() && dot_2 <= S::zero()) {
return Some(p);
}
else if dot_1 >= S::zero() && dot_2 >= S::zero() {
if dot_1 <= dot_2 {
return Some(q);
}
else {
return Some(line.dest);
}
}
return None;
}
let t = qmp.perp_dot(&s) / cross_1;
let u = cross_2 / cross_1;
if S::zero() <= t && u >= S::zero() && u <= S::one() {
return Some(Point2::new(p.x + t*r.x, p.y + t*r.y));
}
return None;
}
}