From e23a4aacab045045f49ac5d02305a8e618d899b3 Mon Sep 17 00:00:00 2001
From: Savanni D'Gerinel <savanni@luminescent-dreams.com>
Date: Sun, 9 Jun 2024 13:19:47 -0400
Subject: [PATCH] Add primitive math operations

---
 ray-tracer/src/types.rs | 202 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 198 insertions(+), 4 deletions(-)

diff --git a/ray-tracer/src/types.rs b/ray-tracer/src/types.rs
index b253756..5174656 100644
--- a/ray-tracer/src/types.rs
+++ b/ray-tracer/src/types.rs
@@ -1,10 +1,10 @@
-
 const EPSILON: f64 = 0.00001;
 
 fn eq_f64(l: f64, r: f64) -> bool {
-    (l-r).abs() < EPSILON
+    (l - r).abs() < EPSILON
 }
 
+#[derive(Debug)]
 struct Tuple {
     x: f64,
     y: f64,
@@ -20,11 +20,55 @@ impl PartialEq for Tuple {
     }
 }
 
+impl std::ops::Add for Tuple {
+    type Output = Tuple;
+    fn add(self, r: Tuple) -> Self::Output {
+        return Self::Output {
+            x: self.x + r.x,
+            y: self.y + r.y,
+            z: self.z + r.z,
+            w: self.w + r.w,
+        };
+    }
+}
+
+impl std::ops::Sub for Tuple {
+    type Output = Tuple;
+    fn sub(self, r: Tuple) -> Self::Output {
+        return Self::Output {
+            x: self.x - r.x,
+            y: self.y - r.y,
+            z: self.z - r.z,
+            w: self.w - r.w,
+        };
+    }
+}
+
+impl std::ops::Neg for Tuple {
+    type Output = Tuple;
+    fn neg(self) -> Self::Output {
+        return Self::Output {
+            x: -self.x,
+            y: -self.y,
+            z: -self.z,
+            w: -self.w,
+        };
+    }
+}
+
+#[derive(Debug, PartialEq)]
 struct Point(Tuple);
 
 impl Point {
     fn new(x: f64, y: f64, z: f64) -> Self {
-        Self(Tuple{ x, y, z, w: 1.0 })
+        Self(Tuple { x, y, z, w: 1.0 })
+    }
+}
+
+impl From<Tuple> for Point {
+    fn from(tuple: Tuple) -> Self {
+        assert_eq!(tuple.w, 1.0);
+        Self(tuple)
     }
 }
 
@@ -34,11 +78,42 @@ impl Default for Point {
     }
 }
 
+impl std::ops::Add<Vector> for Point {
+    type Output = Point;
+    fn add(self, r: Vector) -> Self::Output {
+        Point::from(self.0 + r.0)
+    }
+}
+
+impl std::ops::Sub for Point {
+    type Output = Vector;
+    fn sub(self, r: Point) -> Self::Output {
+        Vector::from(self.0 - r.0)
+    }
+}
+
+impl std::ops::Sub<Vector> for Point {
+    type Output = Point;
+    fn sub(self, r: Vector) -> Self::Output {
+        Point::from(self.0 - r.0)
+    }
+}
+
+impl std::ops::Neg for Point {
+    type Output = Point;
+    fn neg(self) -> Self::Output {
+        let mut t = -self.0;
+        t.w = 1.;
+        Point::from(t)
+    }
+}
+
+#[derive(Debug, PartialEq)]
 struct Vector(Tuple);
 
 impl Vector {
     fn new(x: f64, y: f64, z: f64) -> Self {
-        Self(Tuple{ x, y, z, w: 0.0 })
+        Self(Tuple { x, y, z, w: 0.0 })
     }
 }
 
@@ -48,6 +123,29 @@ impl Default for Vector {
     }
 }
 
+impl From<Tuple> for Vector {
+    fn from(tuple: Tuple) -> Self {
+        assert_eq!(tuple.w, 0.0);
+        Self(tuple)
+    }
+}
+
+impl std::ops::Sub for Vector {
+    type Output = Vector;
+    fn sub(self, r: Self) -> Self {
+        Vector::from(self.0 - r.0)
+    }
+}
+
+impl std::ops::Neg for Vector {
+    type Output = Vector;
+    fn neg(self) -> Self::Output {
+        let mut t = -self.0;
+        t.w = 0.;
+        Vector::from(t)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -59,4 +157,100 @@ mod tests {
         assert!(eq_f64(0.9999994, 0.9999995));
         assert!(!eq_f64(0.9995, 0.9994));
     }
+
+    #[test]
+    fn add_two_tuples() {
+        let a = Tuple {
+            x: 3.,
+            y: -2.,
+            z: 5.,
+            w: 1.,
+        };
+        let b = Tuple {
+            x: -2.,
+            y: 3.,
+            z: 1.,
+            w: 0.,
+        };
+        assert_eq!(
+            a + b,
+            Tuple {
+                x: 1.,
+                y: 1.,
+                z: 6.,
+                w: 1.
+            }
+        );
+    }
+
+    #[test]
+    fn subtracts_two_tuples() {
+        let a = Tuple {
+            x: 3.,
+            y: 2.,
+            z: 1.,
+            w: 1.,
+        };
+        let b = Tuple {
+            x: 5.,
+            y: 6.,
+            z: 7.,
+            w: 1.,
+        };
+        assert_eq!(
+            a - b,
+            Tuple {
+                x: -2.,
+                y: -4.,
+                z: -6.,
+                w: 0.
+            }
+        );
+    }
+
+    #[test]
+    fn adds_point_and_vector() {
+        let a = Point::new(3., -2., 5.);
+        let b = Vector::new(-2., 3., 1.);
+        assert_eq!(a + b, Point::new(1., 1., 6.,));
+    }
+
+    #[test]
+    fn subtracts_two_points() {
+        let a = Point::new(3., 2., 1.);
+        let b = Point::new(5., 6., 7.);
+        assert_eq!(a - b, Vector::new(-2., -4., -6.,));
+    }
+
+    #[test]
+    fn subtracts_vector_from_point() {
+        let a = Point::new(3., 2., 1.);
+        let b = Vector::new(5., 6., 7.);
+        assert_eq!(a - b, Point::new(-2., -4., -6.));
+    }
+
+    #[test]
+    fn subtracts_two_vectors() {
+        let a = Vector::new(3., 2., 1.);
+        let b = Vector::new(5., 6., 7.);
+        assert_eq!(a - b, Vector::new(-2., -4., -6.));
+    }
+
+    #[test]
+    fn it_negates_primitives() {
+        assert_eq!(
+            -Tuple {
+                x: 1.,
+                y: 2.,
+                z: 3.,
+                w: 4.
+            },
+            Tuple {
+                x: -1.,
+                y: -2.,
+                z: -3.,
+                w: -4.
+            },
+        );
+    }
 }