3 - add vector and color type

Cargo.toml

@@ -6,3 +6,4 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+nalgebra = "0.32.3"

src/main.rs

@@ -1,6 +1,15 @@
 use std::fs::File;
 use std::io::prelude::*;
 
+extern crate nalgebra as na;
+use na::Vector3;
+
+type Color = Vector3<i32>;
+
+fn write_color(dst: &mut dyn Write, color: Color) {
+    writeln!(dst, "{} {} {}", color[0], color[1], color[2]).unwrap();
+}
+
 fn main() {
     // Image params
     let image_width = 256;
@@ -13,9 +22,8 @@ fn main() {
     writeln!(image_file, "P3\n{} {}\n255", image_width, image_height).unwrap();
 
     for j in 0..image_height {
-        println!("\rScanlines remaining: {}", (image_height-j));
+        println!("\rScanlines remaining: {}", (image_height - j));
         for i in 0..image_width {
-
             let r = i as f64 / (image_width - 1) as f64;
             let g = j as f64 / (image_height - 1) as f64;
             let b = 0 as f64;
@@ -24,7 +32,8 @@ fn main() {
             let ig = (255.999 * g) as i32;
             let ib = (255.999 * b) as i32;
 
-            writeln!(image_file, "{} {} {}", ir, ig, ib).unwrap();
+            let pixel = Color::new(ir, ig, ib);
+            write_color(&mut image_file, pixel);
         }
     }
     println!("Done");