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Add Vec2::LEFT,RIGHT,UP,DOWN and Vec2::angle

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This commit is contained in:
Emil Ernerfeldt 2021-04-20 23:04:04 +02:00
parent 58ebb217dc
commit cb14e8571f
1 changed files with 59 additions and 0 deletions
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59
emath/src/vec2.rs
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@ -87,6 +87,11 @@ impl Vec2 {
pub const X: Vec2 = Vec2 { x: 1.0, y: 0.0 };
pub const Y: Vec2 = Vec2 { x: 0.0, y: 1.0 };
pub const RIGHT: Vec2 = Vec2 { x: 1.0, y: 0.0 };
pub const LEFT: Vec2 = Vec2 { x: -1.0, y: 0.0 };
pub const UP: Vec2 = Vec2 { x: 0.0, y: -1.0 };
pub const DOWN: Vec2 = Vec2 { x: 0.0, y: 1.0 };
pub const ZERO: Self = Self { x: 0.0, y: 0.0 };
pub const INFINITY: Self = Self::splat(f32::INFINITY);
@ -140,9 +145,38 @@ impl Vec2 {
self.x * self.x + self.y * self.y
}
/// Measures the angle of the vector.
///
/// ```
/// # use emath::Vec2;
/// use std::f32::consts::TAU;
///
/// assert_eq!(Vec2::ZERO.angle(), 0.0);
/// assert_eq!(Vec2::angled(0.0).angle(), 0.0);
/// assert_eq!(Vec2::angled(1.0).angle(), 1.0);
/// assert_eq!(Vec2::X.angle(), 0.0);
/// assert_eq!(Vec2::Y.angle(), 0.25 * TAU);
///
/// assert_eq!(Vec2::RIGHT.angle(), 0.0);
/// assert_eq!(Vec2::DOWN.angle(), 0.25 * TAU);
/// assert_eq!(Vec2::UP.angle(), -0.25 * TAU);
/// ```
#[inline(always)]
pub fn angle(self) -> f32 {
self.y.atan2(self.x)
}
/// Create a unit vector with the given angle (in radians).
/// * An angle of zero gives the unit X axis.
/// * An angle of 𝞃/4 = 90° gives the unit Y axis.
///
/// ```
/// # use emath::Vec2;
/// use std::f32::consts::TAU;
///
/// assert_eq!(Vec2::angled(0.0), Vec2::X);
/// assert!((Vec2::angled(0.25 * TAU) - Vec2::Y).length() < 1e-5);
/// ```
#[inline(always)]
pub fn angled(angle: f32) -> Self {
vec2(angle.cos(), angle.sin())
@ -368,3 +402,28 @@ impl std::fmt::Debug for Vec2 {
write!(f, "[{:.1} {:.1}]", self.x, self.y)
}
}
#[test]
fn test_vec2() {
#![allow(clippy::float_cmp)]
macro_rules! almost_eq {
($left:expr, $right:expr) => {
let left = $left;
let right = $right;
assert!((left - right).abs() < 1e-6, "{} != {}", left, right);
};
}
use std::f32::consts::TAU;
assert_eq!(Vec2::ZERO.angle(), 0.0);
assert_eq!(Vec2::angled(0.0).angle(), 0.0);
assert_eq!(Vec2::angled(1.0).angle(), 1.0);
assert_eq!(Vec2::X.angle(), 0.0);
assert_eq!(Vec2::Y.angle(), 0.25 * TAU);
assert_eq!(Vec2::RIGHT.angle(), 0.0);
assert_eq!(Vec2::DOWN.angle(), 0.25 * TAU);
almost_eq!(Vec2::LEFT.angle(), 0.50 * TAU);
assert_eq!(Vec2::UP.angle(), -0.25 * TAU);
}