#math #geometry #vector #2D

vector2math

Traits for doing 2D vector geometry operations using standard types

12 releases (5 breaking)

✓ Uses Rust 2018 edition

0.6.0 Sep 8, 2019
0.5.0 Apr 29, 2019
0.4.0 Mar 28, 2019
0.3.5 Mar 20, 2019
0.1.1 Jan 16, 2019

#86 in Math

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Used in 1 crate

MIT license

34KB
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Description

This library provides traits for doing 2D vector geometry operations using either Rust's built-in types or custom types.

For examples and usage details, check out the API Documentation


lib.rs:

This crate provides traits for doing 2D vector geometry operations using standard types

Usage

Simple vector math is implemented for vectors with the following scalar types:

  • u8-u128
  • usize
  • i8-i128
  • isize
  • f32
  • f64
  • Any type that implements one or more of this crate's Scalar traits

Vectors can be of the following forms:

  • [T; 2]
  • (T, T)
  • Any type that implements one or more of this crate's Vector2 traits

Many 2D Vector operations are supported. Vectors do not necessarily need to be the same type to allow operation. They need only have the same Scalar type. The output type will be the same as the first argument.

use vector2math::*;

let a = [2, 6];
let b = (4, -1);
assert_eq!(2, a.x());
assert_eq!(-1, b.y());
assert_eq!([-2, -6], a.neg());
assert_eq!([6, 5], a.add(b));
assert_eq!([-2, 7], a.sub(b));
assert_eq!((12, -3), b.mul(3));
assert_eq!((8, -6), b.mul2(a));
assert_eq!([1, 3], a.div(2));
assert_eq!([0, -6], a.div2(b));

Floating-point vectors have additional operations:

use vector2math::*;

assert_eq!(5.0, [3.0, 4.0].mag());
assert_eq!(10.0, [-1.0, -2.0].dist([5.0, 6.0]));
let rotation_calculation = [1.0, 0.0].rotate_about([0.0; 2], std::f64::consts::PI / 4.0);
let rotation_solution = [2f64.powf(0.5) / 2.0; 2];
assert!(rotation_calculation.sub(rotation_solution).mag() < std::f64::EPSILON);

Many types can be used to define axis-aligned rectangles:

  • [[T; 2]; 2]
  • [(T, T); 2]
  • ((T, T), (T, T))
  • ([T; 2], [T; 2])
  • [T; 4]
  • (T, T, T, T)
  • Any type that implements this crate's Pair trait where the associated Item type implements Vector2.
use vector2math::*;

let rect = [1i32, 2, 4, 6];
assert_eq!([1, 2], rect.top_left());
assert_eq!([4, 6], rect.size());
assert_eq!([3, 5], rect.center());
assert_eq!(20, rect.perimeter());
assert_eq!(24, rect.area());
assert!(rect.contains([3, 5]));

A few types can be used to define circles:

  • ([T; 2], T)
  • ((T, T), T)
  • Any pair of types where the first implements FloatingVector2 and the second is the vector's scalar type.
use vector2math::*;
use std::f64;

let circle = ([2.0, 3.0], 4.0);
assert!((circle.circumference() - 25.132_741_228_718_345).abs() < f64::EPSILON);
assert!((circle.area() - 50.265_482_457_436_69).abs() < f64::EPSILON);
assert!(circle.contains([0.0, 1.0]));
assert!(!circle.contains([5.0, 6.0]));

Vector, rectangle, and circle types can be easily mapped to different types:

use vector2math::*;

let arrayf32: [f32; 2] = [1.0, 2.0];
let arrayf64: [f64; 2] = arrayf32.map();
let pairf64: (f64, f64) = arrayf64.map();
let arrayi16: [i16; 2] = pairf64.map_with(|f| f as i16);
assert_eq!(arrayf32, arrayi16.map::<[f32; 2]>());

let weird_rect = [(0.0, 1.0), (2.0, 5.0)];
let normal_rectf32: [f32; 4] = weird_rect.map();
let normal_rectf64: [f32; 4] = normal_rectf32.map();
let normal_rectu8: [u8; 4] = normal_rectf32.map_with(|f| f as u8);
assert_eq!([0, 1, 2, 5], normal_rectu8);

let pair_circlef32 = ((0.0, 1.0), 2.0);
let array_circlef32 = ([0.0, 1.0], 2.0);
assert_eq!(((0.0, 1.0), 2.0), array_circlef32.map::<((f64, f64), f64)>());

Implementing these traits for your own types is simple. Just make sure that your type is Copy

use vector2math::*;

#[derive(Clone, Copy)]
struct MyVector {
x: f64,
y: f64,
}

impl Vector2 for MyVector {
type Scalar = f64;
fn new(x: f64, y: f64) -> Self {
MyVector { x, y }
}
fn x(self) -> f64 {
self.x
}
fn y(self) -> f64 {
self.y
}
}

#[derive(Clone, Copy)]
struct MyRectangle {
top_left: MyVector,
size: MyVector,
}

impl Rectangle for MyRectangle {
type Scalar = f64;
type Vector = MyVector;
fn new(top_left: MyVector, size: MyVector) -> Self {
MyRectangle { top_left, size }
}
fn top_left(self) -> MyVector {
self.top_left
}
fn size(self) -> MyVector {
self.size
}
}

let rect: MyRectangle = [1, 2, 3, 4].map();
assert_eq!(12.0, rect.area());
assert_eq!(6.0, rect.bottom());

No runtime deps