Multithreading

Cargo.lock

@@ -59,6 +59,51 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "crossbeam-channel"
+version = "0.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5aaa7bd5fb665c6864b5f963dd9097905c54125909c7aa94c9e18507cdbe6c53"
+dependencies = [
+ "cfg-if",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6455c0ca19f0d2fbf751b908d5c55c1f5cbc65e03c4225427254b46890bdde1e"
+dependencies = [
+ "cfg-if",
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1145cf131a2c6ba0615079ab6a638f7e1973ac9c2634fcbeaaad6114246efe8c"
+dependencies = [
+ "autocfg",
+ "cfg-if",
+ "crossbeam-utils",
+ "lazy_static",
+ "memoffset",
+ "scopeguard",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0bf124c720b7686e3c2663cf54062ab0f68a88af2fb6a030e87e30bf721fcb38"
+dependencies = [
+ "cfg-if",
+ "lazy_static",
+]
+
 [[package]]
 name = "deflate"
 version = "1.0.0"
@@ -68,6 +113,12 @@ dependencies = [
  "adler32",
 ]
 
+[[package]]
+name = "either"
+version = "1.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
+
 [[package]]
 name = "getrandom"
 version = "0.2.6"
@@ -79,6 +130,15 @@ dependencies = [
  "wasi",
 ]
 
+[[package]]
+name = "hermit-abi"
+version = "0.1.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "image"
 version = "0.24.2"
@@ -101,12 +161,27 @@ version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9478aa10f73e7528198d75109c8be5cd7d15fb530238040148d5f9a22d4c5b3b"
 
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
 [[package]]
 name = "libc"
 version = "0.2.126"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "349d5a591cd28b49e1d1037471617a32ddcda5731b99419008085f72d5a53836"
 
+[[package]]
+name = "memoffset"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5aa361d4faea93603064a027415f07bd8e1d5c88c9fbf68bf56a285428fd79ce"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "miniz_oxide"
 version = "0.5.3"
@@ -157,6 +232,16 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "num_cpus"
+version = "1.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "19e64526ebdee182341572e50e9ad03965aa510cd94427a4549448f285e957a1"
+dependencies = [
+ "hermit-abi",
+ "libc",
+]
+
 [[package]]
 name = "png"
 version = "0.17.5"
@@ -205,14 +290,45 @@ dependencies = [
  "getrandom",
 ]
 
+[[package]]
+name = "rayon"
+version = "1.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bd99e5772ead8baa5215278c9b15bf92087709e9c1b2d1f97cdb5a183c933a7d"
+dependencies = [
+ "autocfg",
+ "crossbeam-deque",
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "258bcdb5ac6dad48491bb2992db6b7cf74878b0384908af124823d118c99683f"
+dependencies = [
+ "crossbeam-channel",
+ "crossbeam-deque",
+ "crossbeam-utils",
+ "num_cpus",
+]
+
 [[package]]
 name = "renderer"
 version = "0.1.0"
 dependencies = [
  "image",
  "rand",
+ "rayon",
 ]
 
+[[package]]
+name = "scopeguard"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
+
 [[package]]
 name = "wasi"
 version = "0.10.2+wasi-snapshot-preview1"

Cargo.toml

@@ -8,3 +8,4 @@ edition = "2021"
 [dependencies]
 image = { version = "0.24.2", default-features = false, features = ["jpeg", "png", "pnm"] }
 rand = { version = "0.8.5", features = ["small_rng"] }
+rayon = "1.5.3"

src/hittable.rs

@@ -14,7 +14,7 @@ pub struct Sphere {
     radius: f64,
 }
 
-pub trait Hittable {
+pub trait Hittable: Sync+Send {
     fn hit(&self, r: &Ray, t_min: f64, t_max: f64, rec: &mut HitRecord) -> bool;
 }
 

src/main.rs

@@ -9,6 +9,7 @@ mod utility;
 mod vec3;
 
 use std::env;
+use std::sync::atomic::AtomicU32;
 //use std::fs::File;
 //use std::io::BufWriter;
 //use std::io::Write;
@@ -18,6 +19,7 @@ use hittable_list::HittableList;
 use image::{Rgb, RgbImage};
 use ray::Ray;
 use vec3::{Color, Point3, Vec3};
+use rayon::prelude::*;
 
 fn ray_color(r: &Ray, world: &HittableList, depth: u32) -> Color {
     let mut rec = HitRecord::empty();
@@ -91,27 +93,38 @@ fn main() {
     //let mut file = BufWriter::new(File::create(default_file).unwrap());
     //writeln!(&mut file, "P3\n{image_width} {image_height}\n255\n").unwrap();
 
-    for j in (0..image_height).rev() {
+    let mut atomic_counter = AtomicU32::new(image_height);
-        eprint!("\rScanlines remaining: {j:5}");
+    let color_lines: Vec<_> = (0..image_height).into_par_iter().rev().map(|j| {
+        eprint!("\rScanlines remaining: {:5}", *atomic_counter.get_mut());
+        let mut colors = Vec::new();
         for i in 0..image_width {
             let mut pixel_color = Color::new(0.0, 0.0, 0.0);
             for _ in 0..samples_per_pixel {
                 let u = (i as f64 + utility::random_f64()) / (image_width - 1) as f64;
                 let v = (j as f64 + utility::random_f64()) / (image_height - 1) as f64;
                 let r = cam.get_ray(u, v);
-                pixel_color += ray_color(&r, &mut world, max_depth);
+                pixel_color += ray_color(&r, &world, max_depth);
             }
+            colors.push(pixel_color);
+        }
+        *atomic_counter.get_mut() -= 1;
 
+        return colors;
+    } ).collect();
+
+    (0..image_height).into_iter().rev().for_each(|j| {
+        (0..image_width).into_iter().for_each(|i| {
             //color::write_color(&mut file, &pixel_color);
             color::put_color(
                 &mut image,
-                &pixel_color,
+                &color_lines[(image_height - j - 1) as usize][i as usize],
                 i,
                 image_height - j - 1,
                 samples_per_pixel,
             );
-        }
+        })
-    }
+    });
+
     image.save(default_file).unwrap();
     eprintln!("\nDone!");
 }