feat(scene): make render loop parallelized

Cargo.lock

@@ -513,6 +513,7 @@ dependencies = [
  "image",
  "nalgebra",
  "nix",
+ "rayon",
 ]
 
 [[package]]

Cargo.toml

@@ -24,3 +24,4 @@ futures = "0.3.30"
 image = "0.25.5"
 nalgebra = "0.33.2"
 nix = "0.29.0"
+rayon = "1.10.0"

rust-toolchain.toml

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly"
+channel = "1.80.1"
 components = [ "rustfmt", "rustc-dev", "rust-analyzer", "rust-src"]

src/bin/rt_demo.rs

@@ -6,6 +6,7 @@ use lispers::raytracer::{
     types::{Color, Light, Material, Point3, Vector3},
 };
 extern crate nalgebra as na;
+use std::sync::Arc;
 
 fn main() {
     let mut scene = Scene::new();
@@ -21,7 +22,7 @@ fn main() {
         color: Color::new(1.0, 1.0, 1.0),
     });
 
-    scene.add_object(Box::new(Plane::new(
+    scene.add_object(Arc::new(Plane::new(
         Point3::new(0.0, -1.0, 0.0),
         Vector3::new(0.0, 1.0, 0.0),
         Material::new(
@@ -33,7 +34,7 @@ fn main() {
         ),
     )));
 
-    scene.add_object(Box::new(Sphere::new(
+    scene.add_object(Arc::new(Sphere::new(
         Point3::new(-2.0, 0.0, 1.0),
         1.0,
         Material::new(
@@ -45,7 +46,7 @@ fn main() {
         ),
     )));
 
-    scene.add_object(Box::new(Sphere::new(
+    scene.add_object(Arc::new(Sphere::new(
         Point3::new(0.2, -0.5, -0.2),
         0.5,
         Material::new(
@@ -57,7 +58,7 @@ fn main() {
         ),
     )));
 
-    scene.add_object(Box::new(Sphere::new(
+    scene.add_object(Arc::new(Sphere::new(
         Point3::new(-0.5, 0.5, -2.0),
         1.5,
         Material::new(

src/raytracer/camera.rs

@@ -3,6 +3,7 @@ use super::{
     types::{Color, Point3, Ray, Scalar, Vector3},
 };
 use image::RgbImage;
+use rayon::prelude::*;
 
 /// A camera that can render a scene.
 pub struct Camera {
@@ -77,26 +78,31 @@ impl Camera {
     /// - `subp` is the number of subpixels to use for antialiasing.
     pub fn render(&self, scene: &Scene, depth: u32, subp: u32) -> RgbImage {
         let dx = 1.0 / self.width as Scalar;
-        let dy = 1.0 / self.width as Scalar;
+        let dy = 1.0 / self.height as Scalar;
         let dsx = dx / subp as Scalar;
         let dsy = dy / subp as Scalar;
-        RgbImage::from_fn(self.width as u32, self.height as u32, |x, y| {
-            let x = x as Scalar * dx;
-            let y = y as Scalar * dy;
-            let mut color = Color::new(0.0, 0.0, 0.0);
-            for sx in 0..subp {
-                for sy in 0..subp {
-                    color += scene.trace(
-                        &self.ray_at_relative(
-                            x + sx as Scalar * dsx,
-                            1.0 - (y + sy as Scalar * dsy),
-                        ),
-                        depth,
-                    );
+        let mut img = RgbImage::new(self.width as u32, self.height as u32);
+
+        img.enumerate_rows_mut().par_bridge().for_each(|(_, row)| {
+            for (x, y, pixel) in row {
+                let y = y as Scalar * dy;
+                let x = x as Scalar * dx;
+                let mut color = Color::new(0.0, 0.0, 0.0);
+                for sx in 0..subp {
+                    for sy in 0..subp {
+                        color += scene.trace(
+                            &self.ray_at_relative(
+                                x + sx as Scalar * dsx,
+                                1.0 - (y + sy as Scalar * dsy),
+                            ),
+                            depth,
+                        );
+                    }
                 }
+                color *= 255.0 / (subp * subp) as Scalar;
+                *pixel = [color.x as u8, color.y as u8, color.z as u8].into();
             }
-            color *= 255.0 / (subp * subp) as Scalar;
-            [color.x as u8, color.y as u8, color.z as u8].into()
-        })
+        });
+        img
     }
 }

src/raytracer/scene.rs

@@ -7,6 +7,7 @@ use super::types::Ray;
 use super::types::Vector3;
 use super::vec::mirror;
 use super::vec::reflect;
+use std::sync::Arc;
 extern crate nalgebra as na;
 
 /// A scene is a collection of objects and lights, and provides a method to trace a ray through the scene.
@@ -14,7 +15,7 @@ pub struct Scene {
     /// The ambient light of the scene
     ambient: Color,
     /// The objects in the scene
-    objects: Vec<Box<dyn Intersect>>,
+    objects: Vec<Arc<dyn Intersect + Send + Sync>>,
     /// The lights in the scene
     lights: Vec<Light>,
 }
@@ -35,7 +36,7 @@ impl Scene {
     }
 
     /// Add an object to the scene
-    pub fn add_object(&mut self, obj: Box<dyn Intersect>) {
+    pub fn add_object(&mut self, obj: Arc<dyn Intersect + Send + Sync>) {
         self.objects.push(obj);
     }