Struct Ray

pub struct Ray { /* private fields */ }

This structure conceptually represents a half-line (which also known as “Ray”).

A ray has a “start vertex” r₀, that is, r₀ is a part of the ray itself, but we cannot make a disk of radius ε which contained in the ray around r₀ for arbitrary ε > 0.

If we consider the vectors from r₀ to each point on the ray, then they are all pairwise parallel. Therefore, there exists a “direction vector” v and we can represent each point on ray by the parameterized equation:

r₀ + tv (t ≥ 0),

where t is the parameter which is greater than or equal to zero.

We can also think of a ray as the locus of a moving point at a constant velocity from the starting point r₀ as time passes. In this case, the location of the point after time t (t ≥ 0) is equal to r₀ + tv.

Implementations

impl Ray

pub fn new(src: Coordinate, dst: Coordinate) -> Self

Creates and returns a Ray w.r.t. the given arguments.

Arguments

• src: The starting point of the ray.
• dst: The point for which src is heading.

Return

A Ray that starts from src towards dst with arrival time 1.

Example

use geo_buffer::{Coordinate, Ray};
 
let c1 = (1., 2.).into();
let c2 = (2., 3.).into();
let r1 = Ray::new(c1, c2);
 

pub fn point(&self) -> Coordinate

Returns the “starting point” of the given ray.

Example

use geo_buffer::{Coordinate, Ray};
 
let c1 = (1., 2.).into();
let c2 = (2., 3.).into();
let r1 = Ray::new(c1, c2);
 
assert!(c1.eq(&r1.point()));
 

pub fn point_by_ratio(&self, ratio: f64) -> Coordinate

Returns the value of parameterized equation r₀ + tv by the given ratio t.

Example

use geo_buffer::{Coordinate, Ray};
 
let c1 = (1., 2.).into();
let c2 = (2., 3.).into();
let r1 = Ray::new(c1, c2);
 
assert!(r1.point_by_ratio(2.).eq(&(3., 4.).into()));

pub fn is_contain(&self, rhs: &Coordinate) -> bool

Checks whether self contains the given Cartesian coordinate.

Note that this function considers self as a open-ended line. That is, if the given point lies on the extended line of self, this function returns true.

Return

• true if the given point lies on self,
• false otherwise.

Example

use geo_buffer::{Coordinate, Ray};
 
let c1 = (1., 2.).into();
let c2 = (2., 3.).into();
let r1 = Ray::new(c1, c2);
 
assert!(r1.is_contain(&(3., 4.).into()));

pub fn is_intersect(&self, rhs: &Ray) -> bool

Checks whether the given two rays are intersecting with each other. More precisely, it checks whether they have one or more common points.

Return

• true if the given rays have one or more common points,
• false otherwise.

Example

use geo_buffer::{Coordinate, Ray};
 
let c1 = (1., 2.).into();
let c2 = (2., 3.).into();
let r1 = Ray::new(c1, c2);
 
assert!(r1.is_contain(&(3., 4.).into()));

pub fn intersect(&self, rhs: &Ray) -> Coordinate

Returns a common point of the given rays. If they have more than 2 common points, then returns a middle point of the starting points of the given rays.

Note that this function considers the rays as a open-ended line. That is, if the common point lies on the extended line(s) of them, this function returns the point.

Example

use geo_buffer::{Coordinate, Ray};
 
let c1 = (0., 0.).into();
let c2 = (1., 1.).into();
let c3 = (4., 0.).into();
let c4 = (0., 4.).into();
let r1 = Ray::new(c1, c2);
let r2 = Ray::new(c3, c4);
 
assert!(r1.intersect(&r2).eq(&(2., 2.).into()));
 

pub fn is_parallel(&self, rhs: &Ray) -> bool

Checks whether the given two rays are parallel. If they have more than 2 common points, they are not considered as parallel.

Return

• true if the given rays are parallel,
• false otherwise.

Example

use geo_buffer::{Coordinate, Ray};
 
let c1 = (0., 0.).into();
let c2 = (1., 1.).into();
let c3 = (0., 1.).into();
let c4 = (1., 2.).into();
let r1 = Ray::new(c1, c2);
let r2 = Ray::new(c3, c4);
 
assert!(r1.is_parallel(&r2));

pub fn normalize(&mut self)

Normalizes the given Ray. The magnitude of the ‘velocity’ becomes 1. Does nothing if it is 0.

Example

use geo_buffer::{Coordinate, Ray};
 
let c1 = (0., 0.).into();
let c2 = (3., 4.).into();
let mut r1 = Ray::new(c1, c2);
r1.normalize();
 
assert!(r1.point_by_ratio(1.).eq(&(0.6, 0.8).into()));

pub fn reverse(&self) -> Self

Returns the reversed ray of the given ray. The returned ray has the same starting point and the opposite direction to the given ray.

Example

use geo_buffer::{Coordinate, Ray};
 
let c1 = (0., 0.).into();
let c2 = (3., 4.).into();
let r1 = Ray::new(c1, c2);
let r2 = r1.reverse();
 
assert!(r2.point_by_ratio(1.).eq(&(-3., -4.).into()));

pub fn rotate_by(&self, angle: f64) -> Self

Returns a ray which performs a rotation of the given vector through the given angle (in radian). The direction of rotation is counter-clockwise direction and the center of rotation is the starting point of the given vector.

Example

use geo_buffer::{Coordinate, Ray};
 
let c1 = (0., 0.).into();
let c2 = (3., 4.).into();
let r1 = Ray::new(c1, c2);
let r2 = r1.rotate_by(std::f64::consts::PI/2.);
 
assert!(r2.point_by_ratio(1.).eq(&(-4., 3.).into()));

Trait Implementations

impl Clone for Ray

fn clone(&self) -> Ray

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Ray

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Ray

fn default() -> Ray

Returns the “default value” for a type.

impl Display for Ray

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Copy for Ray