2nd

src/main.rs

@@ -1,3 +1,6 @@
+mod vec3;
+use vec3::Vec3;
+
 fn main() {
     let image_width = 256;
     let image_height = 256;
@@ -19,4 +22,7 @@ fn main() {
         }
     }
     eprintln!("\nDone!");
+
+    let v = Vec3::new(1.0,2.0,3.0);
+    println!("{:?}",v)
 }

src/vec3.rs

@@ -1,5 +1,9 @@
-struct Vec3 {
-    pub e: [f64: 3],
+use std::ops::*;
+use std::io::Write;
+
+#[derive(Clone, Copy, Debug)]
+pub struct Vec3 {
+    pub e: [f64; 3],
 }
 
 type Color = Vec3;
@@ -11,7 +15,7 @@ impl Vec3 {
         Vec3 { e: [x, y, z] }
     }
 
-    pub fn length() -> f64 {
+    pub fn length(&self) -> f64 {
         self.length_squared().sqrt()
     }
 
@@ -21,6 +25,20 @@ impl Vec3 {
         + self.e[2]*self.e[2]
     }
 
+    pub fn cross(a: Vec3, b: Vec3) -> Vec3 {
+        Vec3::new(a.y()*b.z() - a.z()*b.y(),
+            a.z()*b.x() - a.x()*b.z(),
+            a.x()*b.y() - a.y()*b.x())
+    }
+
+    pub fn dot(a: Vec3, b: Vec3) -> f64 {
+        a.x()*b.x() + a.y()*b.y() + a.z()*b.z()
+    }
+
+    pub fn unit_vector(a: Vec3) -> Vec3 {
+        a / a.length()
+    }
+
     pub fn x(&self) -> f64 { self.e[0] }
     pub fn y(&self) -> f64 { self.e[1] }
     pub fn z(&self) -> f64 { self.e[2] }
@@ -30,7 +48,7 @@ impl Add for Vec3 {
     type Output = Vec3;
 
     fn add(self, rhs: Self) -> Vec3 {
-        Vec3::new(self.x()+rhs.x(), self.y()+rhs.y(), self.z()+rhs.z());
+        Vec3::new(self.x()+rhs.x(), self.y()+rhs.y(), self.z()+rhs.z())
     }
 }
 
@@ -50,11 +68,19 @@ impl Sub for Vec3 {
     }
 }
 
+impl SubAssign for Vec3 {
+    fn sub_assign(&mut self, rhs: Self) {
+        self.e[0] -= rhs.x();
+        self.e[1] -= rhs.y();
+        self.e[2] -= rhs.z();
+    }
+}
+
 impl Mul<Vec3> for f64 {
     type Output = Vec3;
 
     fn mul(self, rhs: Vec3) -> Vec3 {
-        Vec3::new(self*rhs.x(), self*rhs.y(), self*rhs.z());
+        Vec3::new(self*rhs.x(), self*rhs.y(), self*rhs.z())
     }
 }
 
@@ -67,10 +93,21 @@ impl MulAssign<f64> for Vec3 {
 }
 
 impl DivAssign<f64> for Vec3 {
-    fn div_assign(&mul self, rhs: f64) {
+    fn div_assign(&mut self, rhs: f64) {
         self.e[0] /= rhs;
         self.e[1] /= rhs;
         self.e[2] /= rhs;
     }
 }
 
+impl Div<f64> for Vec3 {
+    type Output = Vec3;
+
+    fn div(self, rhs: f64) -> Vec3 {
+        Vec3::new(self.x()/rhs, self.y()/rhs, self.z()/rhs)
+    }
+}
+
+fn write_color(out: &mut impl Write, pixel_color: Color) {
+    write!(out, "{} {} {}\n", 255.999*pixel_color.x(), 255.999*pixel_color.y(), 255.999*pixel_color.z());
+}