[none] Create random balls in parallel

- Use rayon par_iter to create the random balls
using random material.
- Extend worlds to add the balls

%SOFTWARE

src/main.rs

@@ -8,11 +8,12 @@ use lib::utilities::{
     point::Point3,
     vector3::Vector3,
 };
+use rayon::prelude::*;
 
 const NUMBER_BALLS: i32 = 5;
 
 const ASPECT_RATIO: f64 = 16.0 / 9.0;
-const IMAGE_WIDTH: i32 = 1600;
+const IMAGE_WIDTH: i32 = 800;
 const SAMPLES_PER_PIXEL: i32 = 200;
 const MAX_DEPTH: i32 = 50;
 const VERTICAL_FOV: f64 = 40.0;
@@ -32,40 +33,54 @@ fn main() {
     )));
 
     // Scene - small balls (random)
-    for x_index in -NUMBER_BALLS..NUMBER_BALLS {
-        for y_index in -NUMBER_BALLS..NUMBER_BALLS {
-            let choose_material_random: f64 = rand::thread_rng().r#gen::<f64>();
-            let center = Point3::new(
-                (x_index as f64) + (0.9 * rand::thread_rng().r#gen::<f64>()),
-                0.2,
-                (y_index as f64) + (0.9 * rand::thread_rng().r#gen::<f64>()),
-            );
-            if choose_material_random < 0.6 {
-                // Lambertian
-                let material_lambertian = Box::new(Lambertian::new(Color::new(
-                    rand::thread_rng().r#gen::<f64>(),
-                    rand::thread_rng().r#gen::<f64>(),
-                    rand::thread_rng().r#gen::<f64>(),
-                )));
-                world.push(Box::new(Sphere::new(center, 0.2, material_lambertian)));
-            } else if choose_material_random < 0.85 {
-                // Metal
-                let material_metal = Box::new(Metal::new(
-                    Color::new(
-                        rand::thread_rng().r#gen::<f64>(),
-                        rand::thread_rng().r#gen::<f64>(),
-                        rand::thread_rng().r#gen::<f64>(),
-                    ),
-                    rand::thread_rng().r#gen::<f64>(),
-                ));
-                world.push(Box::new(Sphere::new(center, 0.2, material_metal)));
-            } else {
-                // Glass
-                let material_glass = Box::new(Dielectric::new(1.33));
-                world.push(Box::new(Sphere::new(center, 0.2, material_glass)));
-            }
-        }
-    }
+    let spheres_scene: Vec<Box<dyn Hittable>> = (-NUMBER_BALLS..NUMBER_BALLS)
+        .into_par_iter()
+        .flat_map(|x_index| {
+            (-NUMBER_BALLS..NUMBER_BALLS)
+                .into_par_iter()
+                .map(|y_index| {
+                    let choose_material_random: f64 = rand::thread_rng().r#gen::<f64>();
+                    let center = Point3::new(
+                        (x_index as f64) + (0.9 * rand::thread_rng().r#gen::<f64>()),
+                        0.2,
+                        (y_index as f64) + (0.9 * rand::thread_rng().r#gen::<f64>()),
+                    );
+                    if choose_material_random < 0.4 {
+                        // Lambertian
+                        let material_lambertian = Box::new(Lambertian::new(Color::new(
+                            rand::thread_rng().r#gen::<f64>(),
+                            rand::thread_rng().r#gen::<f64>(),
+                            rand::thread_rng().r#gen::<f64>(),
+                        )));
+                        return Box::new(Sphere::new(center, 0.2, material_lambertian))
+                            as Box<dyn Hittable>;
+                    } else if choose_material_random < 0.8 {
+                        // Metal
+                        let material_metal = Box::new(Metal::new(
+                            Color::new(
+                                rand::thread_rng().r#gen::<f64>(),
+                                rand::thread_rng().r#gen::<f64>(),
+                                rand::thread_rng().r#gen::<f64>(),
+                            ),
+                            rand::thread_rng().r#gen::<f64>(),
+                        ));
+                        return Box::new(Sphere::new(center, 0.2, material_metal))
+                            as Box<dyn Hittable>;
+                    } else {
+                        // Glass
+                        let material_glass = Box::new(Dielectric::new(1.33));
+                        return Box::new(Sphere::new(center, 0.2, material_glass))
+                            as Box<dyn Hittable>;
+                    }
+                })
+                .collect::<Vec<Box<dyn Hittable>>>()
+        })
+        .collect();
+
+    world.extend(spheres_scene);
+    // If you don't need to use spheres_scene after pushing its contents to world, you can move the entire vector.
+    // Explanation: world.extend(spheres_scene) moves the contents of spheres_scene into world. The extend method consumes the vector, avoiding the need for cloning or referencing, and effectively transfers ownership of each Box<dyn Hittable> to world.
+    // Use moving (via extend) if you want to transfer ownership and don't need to use spheres_scene afterward, which is more efficient because it avoids unnecessary duplication.
 
     // Scene - big balls with Glass material
     let material_glass = Box::new(Dielectric::new(1.0 / 1.55));