From 9b3f6f0595083bceca1164348dbfedb119e4b603 Mon Sep 17 00:00:00 2001
From: Bob van der Linden <bobvanderlinden@gmail.com>
Date: Sat, 28 Dec 2024 22:17:41 +0100
Subject: [PATCH] add Angle struct

This is to represent Angle and translate between radians, degrees and
Vec2D.
---
 src/math.rs | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/src/math.rs b/src/math.rs
index f41a6b1..799a162 100644
--- a/src/math.rs
+++ b/src/math.rs
@@ -10,6 +10,38 @@ pub struct Vec2D {
     pub y: f32,
 }
 
+#[derive(Default, Debug, Copy, Clone, PartialEq)]
+pub struct Angle {
+    pub radians: f32,
+}
+impl Angle {
+    pub fn from_radians(radians: f32) -> Self {
+        Self { radians }
+    }
+
+    pub fn from_degrees(degrees: f32) -> Self {
+        Self {
+            radians: degrees * PI / 180.0,
+        }
+    }
+
+    pub fn cos(&self) -> f32 {
+        self.radians.cos()
+    }
+
+    pub fn sin(&self) -> f32 {
+        self.radians.sin()
+    }
+}
+
+impl Mul<f32> for Angle {
+    type Output = Angle;
+
+    fn mul(self, rhs: f32) -> Self::Output {
+        Angle::from_radians(self.radians * rhs)
+    }
+}
+
 impl Vec2D {
     pub fn zero() -> Self {
         Self { x: 0.0, y: 0.0 }
@@ -27,6 +59,24 @@ impl Vec2D {
         self.x * self.x + self.y * self.y
     }
 
+    /**
+     * Get the angle of the vector.
+     * Angle of 0 is the positive x-axis.
+     * Angle of PI/2 is the positive y-axis.
+     */
+    pub fn angle(&self) -> Angle {
+        Angle::from_radians(self.y.atan2(self.x))
+    }
+
+    /**
+     * Create a vector from an angle.
+     * Angle of 0 is the positive x-axis.
+     * Angle of PI/2 is the positive y-axis.
+     */
+    pub fn from_angle(angle: Angle) -> Vec2D {
+        Vec2D::new(angle.cos(), angle.sin())
+    }
+
     pub fn snapped_vector_15deg(&self) -> Vec2D {
         let current_angle = (self.y / self.x).atan();
         let current_norm2 = self.norm2();