first gradient

src/main.rs

@@ -1,19 +1,57 @@
-use std::{io::{BufWriter, Write}, fs::File};
+pub mod vec3;
+pub mod color;
+pub mod ray;
 
-const IMAGE_WIDTH: usize = 512;
-const IMAGE_HEIGHT: usize = 512;
+use std::{io::{BufWriter, Write}, fs::File};
+use crate::{
+    vec3::*,
+    color::*,
+    ray::*
+};
+
+fn ray_color(r: &Ray) -> Color {
+    let unit_direction: Vec3 = r.direction().unit_vector();
+    let t = 0.5 * (unit_direction.y() + 1.0);
+    //println!("{}", t);
+    ((1.0 - t) * Color::new(1.0, 1.0, 1.0)) + (t * Color::new(0.5, 0.7, 1.0))
+}
 
 fn main() {
+    // Image
+    let aspect_ratio: f64 = 1.0 / 1.0;
+    let image_width: i32 = 400;
+    let image_height: i32 = (image_width as f64 / aspect_ratio as f64) as i32;
 
-    println!();
+    // Camera
+
+    let viewport_height: f64 = 2.0;
+    let viewport_width: f64 = aspect_ratio * viewport_height;
+    let focal_length: f64 = 1.0;
+
+    let origin = Point3::new(0.0,0.0,0.0);
+    let horizontal = Vec3::new(viewport_width, 0.0, 0.0);
+    let vertical = Vec3::new(0.0, viewport_height, 0.0);
+    let lower_left_corner = origin - horizontal/2.0 - vertical/2.0 - Vec3::new(0.0,0.0, focal_length);
+
+    // Render
 
     let mut file = BufWriter::new(File::create("img.ppm").expect("File creation failed"));
 
-    writeln!(file, "P3\n{IMAGE_WIDTH} {IMAGE_HEIGHT}\n255").expect("Error while writing Magicbyte");
+    writeln!(file, "P3\n{image_width} {image_height}\n255").expect("Error while writing Magic Byte");
 
-    for _i in 0..IMAGE_WIDTH {
-        for _j in 0..IMAGE_HEIGHT {
-            writeln!(file, "234 100 255").expect("Error while writing Pixel X: {_i} Y: {_j}");
+    for j in (0..image_width).rev() {
+        //println!("{}", j);
+        //println!("Rows remaining: {j}");
+        write!(file, "\n").expect("grr");
+        for i in (0..image_height).rev() {
+            //println!("{}", i);
+            let u: f64 = i as f64 / image_width as f64;
+            let v: f64 = j as f64 / image_height as f64;
+            let r = Ray::new(origin, lower_left_corner + u * horizontal + v * vertical - origin);
+
+            let pixel_color = ray_color(&r);
+
+            write_color(&mut file, pixel_color);    
         }
     }
 }