From 58720ce44ec38ac9a98300697a39ef2965ca259c Mon Sep 17 00:00:00 2001
From: waridh <waridh@proton.me>
Date: Sun, 8 Sep 2024 17:53:35 -0400
Subject: [PATCH] added parallel processing using rayon

---
 Cargo.toml    |  2 +-
 src/camera.rs | 48 +++++++++++++++++++++++++++---------------------
 src/color.rs  | 23 ++++++++++++++++++++++-
 3 files changed, 50 insertions(+), 23 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index b9c62e7..9dd8580 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,6 @@ edition = "2021"
 
 [dependencies]
 anyhow = "1.0.86"
-indicatif = "0.17.8"
+indicatif = { version = "*", features = ["rayon"] }
 rand = "0.8.5"
 rayon = "1.10.0"
diff --git a/src/camera.rs b/src/camera.rs
index 6fbcbf1..c711a47 100644
--- a/src/camera.rs
+++ b/src/camera.rs
@@ -4,7 +4,7 @@ use crate::{
     ray::{self},
     vec3::{self, Point3, Vec3},
 };
-use indicatif::{ProgressBar, ProgressStyle};
+use indicatif::{ParallelProgressIterator, ProgressBar, ProgressIterator, ProgressStyle};
 use rand::{self, Rng};
 use rayon::prelude::*;
 use std::f32::INFINITY;
@@ -127,24 +127,35 @@ impl Camera {
 
         println!("P3\n{} {}\n255", self.image_width, self.image_height);
 
-        for j in 0..self.image_height {
-            for i in 0..self.image_width {
-                let mut pixel = Color::black();
-                for _ in 0..self.samples_per_pixel {
-                    let r = self.get_ray(i, j);
-                    pixel += Camera::ray_color(r, self.reflection_depth, world);
-                }
-
-                println!("{}", pixel * self.pixel_sample_scale);
-            }
-            bar.inc(1);
-        }
-        bar.finish();
+        let pixels = (0..self.image_height)
+            .into_par_iter()
+            .progress_with(bar)
+            .flat_map(|j| {
+                (0..self.image_width)
+                    .map(|i| {
+                        (0..self.samples_per_pixel)
+                            .map(|_| {
+                                let r = self.get_ray(i, j);
+                                Camera::ray_color(r, self.reflection_depth, world)
+                            })
+                            .sum::<Color>()
+                    })
+                    .collect::<Vec<Color>>()
+            })
+            .collect::<Vec<Color>>();
+
+        let spinner = ProgressBar::new_spinner();
+        spinner.enable_steady_tick(std::time::Duration::from_millis(100));
+
+        pixels
+            .iter()
+            .progress_with(spinner)
+            .for_each(|e| println!("{}", self.pixel_sample_scale * e));
     }
 
     /// Create a ray from the defocus lens in the camera center, and direct
     /// it at the pixel square
-    fn get_ray(&mut self, i: usize, j: usize) -> ray::Ray {
+    fn get_ray(&self, i: usize, j: usize) -> ray::Ray {
         let offset = self.sample_square();
         let pixel_center = self.pixel00
             + (self.pixel_delta_u * ((i as f32) + offset[0]))
@@ -161,7 +172,7 @@ impl Camera {
         ray::Ray::new(raydir, ray_orig)
     }
 
-    fn sample_square(&mut self) -> vec3::Vec3 {
+    fn sample_square(&self) -> vec3::Vec3 {
         let mut rng = rand::thread_rng();
         vec3::Vec3(rng.gen_range(-0.5..0.5), rng.gen_range(-0.5..0.5), 0.)
     }
@@ -187,8 +198,3 @@ impl Camera {
         }
     }
 }
-
-#[cfg(test)]
-mod test {
-    use super::*;
-}
diff --git a/src/color.rs b/src/color.rs
index 99451bf..db2751b 100644
--- a/src/color.rs
+++ b/src/color.rs
@@ -1,5 +1,5 @@
 use crate::vec3;
-use std::{fmt, ops};
+use std::{fmt, iter, ops};
 
 pub fn linear_to_gamma(linear: f32) -> f32 {
     match linear {
@@ -35,6 +35,12 @@ impl From<(f32, f32, f32)> for Color {
     }
 }
 
+impl iter::Sum for Color {
+    fn sum<I: Iterator<Item = Self>>(iter: I) -> Self {
+        iter.fold(Color::new(0., 0., 0.), |a, e| a + e)
+    }
+}
+
 /// Used to clamp the color output
 fn clamp(legal_range: &ops::Range<f32>, val: f32) -> f32 {
     match val {
@@ -82,6 +88,14 @@ impl ops::Mul<f32> for Color {
     }
 }
 
+impl ops::Mul<f32> for &Color {
+    type Output = Color;
+    fn mul(self, rhs: f32) -> Self::Output {
+        let new_val = (self[0] * rhs, self[1] * rhs, self[2] * rhs);
+        Color::from(new_val)
+    }
+}
+
 impl ops::Mul<Color> for f32 {
     type Output = Color;
     fn mul(self, rhs: Color) -> Self::Output {
@@ -89,6 +103,13 @@ impl ops::Mul<Color> for f32 {
     }
 }
 
+impl ops::Mul<&Color> for f32 {
+    type Output = Color;
+    fn mul(self, rhs: &Color) -> Self::Output {
+        rhs * self
+    }
+}
+
 impl ops::Mul<Color> for Color {
     type Output = Color;
     fn mul(self, rhs: Color) -> Self::Output {