Add Sqrt trait and Vec2::length

Author: fwcd

lighthouse-protocol/src/utils/mod.rs

@@ -3,6 +3,7 @@ mod direction;
 mod rect;
 mod rem_euclid;
 mod rotation;
+mod sqrt;
 mod unity;
 mod vec2;
 mod zero;
@@ -12,6 +13,7 @@ pub use direction::*;
 pub use rect::*;
 pub use rem_euclid::*;
 pub use rotation::*;
+pub use sqrt::*;
 pub use unity::*;
 pub use vec2::*;
 pub use zero::*;

lighthouse-protocol/src/utils/sqrt.rs

@@ -0,0 +1,19 @@
+/// A type whose values have a square root.
+pub trait Sqrt {
+    /// The square root.
+    fn sqrt(self) -> Self;
+}
+
+macro_rules! impl_sqrt {
+    ($($tys:ty),*) => {
+        $(impl Sqrt for $tys {
+            fn sqrt(self) -> Self {
+                <$tys>::sqrt(self)
+            }
+        })*
+    };
+}
+
+impl_sqrt!(
+    f32, f64
+);

lighthouse-protocol/src/utils/vec2.rs

@@ -1,9 +1,9 @@
-use std::{fmt, ops::{Add, AddAssign, Neg, Sub, SubAssign}};
+use std::{fmt, ops::{Add, AddAssign, Mul, Neg, Sub, SubAssign}};
 
 use rand::{thread_rng, Rng};
 use serde::{Deserialize, Serialize};
 
-use super::{Unity, Zero};
+use super::{Sqrt, Unity, Zero};
 
 /// A 2D vector.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
@@ -59,6 +59,13 @@ impl<T> Vec2<T> where T: Zero + Unity {
     }
 }
 
+impl<T> Vec2<T> where T: Add<Output = T> + Mul<Output = T> + Sqrt + Copy {
+    /// The vector's length.
+    pub fn length(&self) -> T {
+        (self.x * self.x + self.y * self.y).sqrt()
+    }
+}
+
 impl<T> fmt::Display for Vec2<T> where T: fmt::Display {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "({}, {})", self.x, self.y)