Create the basic Tuple, Point, and Vector types

Cargo.lock

@@ -3331,6 +3331,10 @@ dependencies = [
  "rand_core 0.6.4",
 ]
 
+[[package]]
+name = "ray-tracer"
+version = "0.1.0"
+
 [[package]]
 name = "rayon"
 version = "1.8.0"

Cargo.toml

@@ -27,5 +27,5 @@ members = [
     "sgf",
     "timezone-testing",
     "tree",
-    "visions/server",
+    "visions/server", "ray-tracer",
 ]

ray-tracer/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "ray-tracer"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

ray-tracer/src/lib.rs

@@ -0,0 +1,2 @@
+mod types;
+

ray-tracer/src/types.rs

@@ -0,0 +1,62 @@
+
+const EPSILON: f64 = 0.00001;
+
+fn eq_f64(l: f64, r: f64) -> bool {
+    (l-r).abs() < EPSILON
+}
+
+struct Tuple {
+    x: f64,
+    y: f64,
+    z: f64,
+    w: f64, // Used for very low-level math. w = 1.0 indicates a point, w = 0.0 indicates a vector.
+            // Theoretically the type system should make this redundant, so operations on points
+            // and vectors can always assert the correct value.
+}
+
+impl PartialEq for Tuple {
+    fn eq(&self, r: &Tuple) -> bool {
+        eq_f64(self.x, r.x) && eq_f64(self.y, r.y) && eq_f64(self.z, r.z) && eq_f64(self.w, r.w)
+    }
+}
+
+struct Point(Tuple);
+
+impl Point {
+    fn new(x: f64, y: f64, z: f64) -> Self {
+        Self(Tuple{ x, y, z, w: 1.0 })
+    }
+}
+
+impl Default for Point {
+    fn default() -> Self {
+        Self::new(0., 0., 0.)
+    }
+}
+
+struct Vector(Tuple);
+
+impl Vector {
+    fn new(x: f64, y: f64, z: f64) -> Self {
+        Self(Tuple{ x, y, z, w: 0.0 })
+    }
+}
+
+impl Default for Vector {
+    fn default() -> Self {
+        Self::new(0., 0., 0.)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn eq_f64_compares_values() {
+        assert!(eq_f64(1.0, 1.0));
+        assert!(eq_f64(0.9994, 0.9994));
+        assert!(eq_f64(0.9999994, 0.9999995));
+        assert!(!eq_f64(0.9995, 0.9994));
+    }
+}