From 758f94acdec7b23cf7147af5607a9776ef92fe50 Mon Sep 17 00:00:00 2001
From: Bill Thiede <git@xinu.tv>
Date: Thu, 24 Jun 2021 14:47:53 -0700
Subject: [PATCH] Implement Add, Div, Mul, Neg, Sub traits for tuple.

---
 rtchallenge/src/tuples.rs | 126 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 125 insertions(+), 1 deletion(-)

diff --git a/rtchallenge/src/tuples.rs b/rtchallenge/src/tuples.rs
index 75f2fe2..2a68103 100644
--- a/rtchallenge/src/tuples.rs
+++ b/rtchallenge/src/tuples.rs
@@ -1,4 +1,5 @@
-#[derive(Debug, PartialEq)]
+use std::ops::{Add, Div, Mul, Neg, Sub};
+#[derive(Debug, PartialEq, Copy, Clone)]
 struct Tuple {
     x: f32,
     y: f32,
@@ -16,6 +17,77 @@ impl Tuple {
     }
 }
 
+impl Add for Tuple {
+    type Output = Self;
+    fn add(self, other: Self) -> Self {
+        Self {
+            x: self.x + other.x,
+            y: self.y + other.y,
+            z: self.z + other.z,
+            w: self.w + other.w,
+        }
+    }
+}
+
+impl Div<f32> for Tuple {
+    type Output = Self;
+    fn div(self, rhs: f32) -> Self::Output {
+        Self::Output {
+            x: self.x / rhs,
+            y: self.y / rhs,
+            z: self.z / rhs,
+            w: self.w / rhs,
+        }
+    }
+}
+
+impl Mul<f32> for Tuple {
+    type Output = Self;
+    fn mul(self, rhs: f32) -> Self::Output {
+        Self::Output {
+            x: self.x * rhs,
+            y: self.y * rhs,
+            z: self.z * rhs,
+            w: self.w * rhs,
+        }
+    }
+}
+
+impl Mul<Tuple> for f32 {
+    type Output = Tuple;
+    fn mul(self, rhs: Tuple) -> Self::Output {
+        Self::Output {
+            x: self * rhs.x,
+            y: self * rhs.y,
+            z: self * rhs.z,
+            w: self * rhs.w,
+        }
+    }
+}
+
+impl Neg for Tuple {
+    type Output = Self;
+    fn neg(self) -> Self::Output {
+        Self {
+            x: -self.x,
+            y: -self.y,
+            z: -self.z,
+            w: -self.w,
+        }
+    }
+}
+impl Sub for Tuple {
+    type Output = Self;
+    fn sub(self, other: Self) -> Self {
+        Self {
+            x: self.x - other.x,
+            y: self.y - other.y,
+            z: self.z - other.z,
+            w: self.w - other.w,
+        }
+    }
+}
+
 fn point(x: f32, y: f32, z: f32) -> Tuple {
     tuple(x, y, z, 1.0)
 }
@@ -61,4 +133,56 @@ mod tests {
     fn vector_tuple() {
         assert_eq!(vector(4., -4., 3.), tuple(4., -4., 3., 0.))
     }
+    #[test]
+    fn add_two_tuples() {
+        let a1 = tuple(3., -2., 5., 1.);
+        let a2 = tuple(-2., 3., 1., 0.);
+        assert_eq!(a1 + a2, tuple(1., 1., 6., 1.));
+    }
+    #[test]
+    fn sub_two_points() {
+        let p1 = point(3., 2., 1.);
+        let p2 = point(5., 6., 7.);
+        assert_eq!(p1 - p2, vector(-2., -4., -6.));
+    }
+    #[test]
+    fn sub_vector_point() {
+        let p = point(3., 2., 1.);
+        let v = vector(5., 6., 7.);
+        assert_eq!(p - v, point(-2., -4., -6.));
+    }
+    #[test]
+    fn sub_two_vectors() {
+        let v1 = vector(3., 2., 1.);
+        let v2 = vector(5., 6., 7.);
+        assert_eq!(v1 - v2, vector(-2., -4., -6.));
+    }
+    #[test]
+    fn sub_zero_vector() {
+        let zero = vector(0., 0., 0.);
+        let v = vector(1., -2., 3.);
+        assert_eq!(zero - v, vector(-1., 2., -3.));
+    }
+    #[test]
+    fn negate_tuple() {
+        let a = tuple(1., -2., 3., -4.);
+        assert_eq!(-a, tuple(-1., 2., -3., 4.));
+    }
+    #[test]
+    fn mul_tuple_scalar() {
+        let a = tuple(1., -2., 3., -4.);
+        assert_eq!(a * 3.5, tuple(3.5, -7., 10.5, -14.));
+        assert_eq!(3.5 * a, tuple(3.5, -7., 10.5, -14.));
+    }
+    #[test]
+    fn mul_tuple_fraction() {
+        let a = tuple(1., -2., 3., -4.);
+        assert_eq!(a * 0.5, tuple(0.5, -1., 1.5, -2.));
+        assert_eq!(0.5 * a, tuple(0.5, -1., 1.5, -2.));
+    }
+    #[test]
+    fn div_tuple_scalar() {
+        let a = tuple(1., -2., 3., -4.);
+        assert_eq!(a / 2., tuple(0.5, -1., 1.5, -2.));
+    }
 }