first diffused sphere

src/main.rs

@@ -8,7 +8,6 @@ pub mod rtweekend;
 pub mod camera;
 
 use std::{io::{BufWriter, Write}, fs::File};
-use camera::Camera;
 
 use crate::{
     color::*,
@@ -18,12 +17,20 @@ use crate::{
     vec3::*,
     ray::*,
     hittable::*,
+    camera::*,
 };
 
-fn ray_color(r: &Ray, world: &mut dyn Hittable) -> Color {
+fn ray_color(r: &Ray, world: &mut dyn Hittable, depth: i32) -> Color {
     let mut rec = HitRecord::new_empty();
+
+    // Limit the bounces
+    if depth <= 0 {
+        return Color::new(0.0, 0.0, 0.0);
+    }
+
     if world.hit(r, 0.0, INFINITY, &mut rec) {
-        return 0.5 * (rec.normal + Color::new(1.0, 1.0, 1.0))
+        let target = rec.p + rec.normal + random_in_unit_sphere();
+        return 0.5 * ray_color(&Ray::new(rec.p, target - rec.p), world, depth - 1)
     }
 
     let unit_direction: Vec3 = r.direction().unit_vector();
@@ -37,7 +44,8 @@ fn main() {
     let aspect_ratio: f64 = 1.0 / 1.0;
     let image_width: i32 = 512;
     let image_height: i32 = (image_width as f64 / aspect_ratio as f64) as i32;
-    let samples_per_pixel = 100;
+    let samples_per_pixel: i32 = 100;
+    let max_depth: i32 = 4;
 
     // World
     let mut world = HittableList::new_empty();
@@ -45,25 +53,25 @@ fn main() {
     world.add(Box::new(Sphere::new(Point3::new(0.0, -100.5, -1.0), 100.0)));
 
     // Camera
-    let mut cam = Camera::new();
+    let cam = Camera::new();
 
     // Render
-
+    //let mut rng = rand::thread_rng();
     let mut file = BufWriter::new(File::create("img.ppm").expect("File creation failed"));
 
     write!(file, "P3\n{image_width} {image_height}\n255").expect("Error while writing Magic Byte");
 
     for j in (0..image_width).rev() {
-        write!(file, "\n").expect("grr");
+        write!(file, "\n").expect("Error writing to File");
 
         for i in 0..image_height {
             let mut pixel_color = Color::new(0.0, 0.0, 0.0);
             
-            for s in 0..samples_per_pixel {
+            for _s in 0..samples_per_pixel {
                 let u = (i as f64 + random_f64()) / (image_width - 1) as f64;
                 let v = (j as f64 + random_f64()) / (image_height - 1) as f64;
                 let r: Ray = cam.get_ray(u, v);
-                pixel_color += ray_color(&r, &mut world)
+                pixel_color += ray_color(&r, &mut world, max_depth)
             }
             write_color(&mut file, pixel_color, samples_per_pixel);
         }

src/rtweekend.rs

@@ -1,4 +1,4 @@
-use rand::prelude::*;
+use rand::Rng;
 
 // Constants
 pub const INFINITY: f64 = std::f64::INFINITY;

src/vec3.rs

@@ -1,5 +1,7 @@
 use std::{ops::{Add, Sub, AddAssign, SubAssign, Mul, Div, MulAssign, DivAssign}};
 
+use crate::rtweekend::{random_f64, random_range_f64};
+
 #[derive(Debug, Clone, Copy)]
 pub struct Vec3 {
     pub elements: [f64; 3],
@@ -49,6 +51,14 @@ impl Vec3 {
     pub fn unit_vector(self) -> Self {
         self / self.length()
     }
+
+    pub fn random() -> Self {
+        Vec3::new(random_f64(), random_f64(), random_f64())
+    }
+
+    pub fn random_range(min: f64, max: f64) -> Self {
+        Vec3::new(random_range_f64(min, max), random_range_f64(min, max), random_range_f64(min, max))
+    }
 }
 
 impl Add for Vec3 {
@@ -165,4 +175,14 @@ impl DivAssign<f64> for Vec3 {
 }
 
 pub type Color = Vec3;
-pub type Point3 = Vec3;
+pub type Point3 = Vec3;
+
+pub fn random_in_unit_sphere() -> Vec3 {
+    loop {
+        let p = Vec3::random_range(-1.0, 1.0);
+        if p.length_squared() >= 1.0 {
+            continue;
+        }
+        return p;
+    }
+}