From 899f81eed6c221dce22333ad03704b12d7634a54 Mon Sep 17 00:00:00 2001
From: Sakarias Johansson <sakarias.johansson@goodbyekansas.com>
Date: Sun, 8 Jan 2023 17:51:44 +0100
Subject: =?UTF-8?q?=F0=9F=8C=8D=20Add=20Geometry?=
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- Created a trait for all geometry that has to implement a hit
  function. Depending on if the ray hits or not it returns an option
  with the color.

- Add support for multiple samples per pixel

Current issues:
- Using cooperative multitasking which isn't that
  helpful in this situation since it's like running without async but
  without overhead. Should switch to rayon.

- All data gets copied once per job. Will decide later what to
  do (copy or put locks and share data between jobs).
---
 racer-tracer/src/main.rs | 76 ++++++++++++++++++++++++++++++++++++------------
 1 file changed, 58 insertions(+), 18 deletions(-)

(limited to 'racer-tracer/src/main.rs')

diff --git a/racer-tracer/src/main.rs b/racer-tracer/src/main.rs
index 1951da5..9d45762 100644
--- a/racer-tracer/src/main.rs
+++ b/racer-tracer/src/main.rs
@@ -1,51 +1,86 @@
 #[macro_use]
 mod error;
 mod camera;
+mod geometry;
 mod image;
 mod ray;
+mod scene;
 mod util;
 mod vec3;
 
-use crate::vec3::Vec3;
 use std::vec::Vec;
 
 use futures::{select, stream::FuturesUnordered, stream::StreamExt};
+use geometry::Hittable;
 use minifb::{Key, Window, WindowOptions};
 
-fn ray_color(ray: &ray::Ray) -> Vec3 {
-    let unit_direction = vec3::unit_vector(ray.direction());
+use crate::camera::Camera;
+use crate::geometry::sphere::Sphere;
+use crate::image::Image;
+use crate::ray::Ray;
+use crate::scene::Scene;
+use crate::util::random_double;
+use crate::vec3::Vec3;
+
+fn ray_color(scene: &Scene, ray: &Ray) -> Vec3 {
+    if let Some(hit_record) = scene.hit(ray, 0.0, std::f64::INFINITY) {
+        //return hit_record.color;
+        return 0.5 * (hit_record.normal + Vec3::new(1.0, 1.0, 1.0));
+    }
+
+    // Sky
+    let unit_direction = ray.direction().unit_vector();
     let t = 0.5 * (unit_direction.y() + 1.0);
     (1.0 - t) * Vec3::new(1.0, 1.0, 1.0) + t * Vec3::new(0.5, 0.7, 1.0)
 }
 
+// TODO: Rustify
 async fn raytrace(
-    camera: camera::Camera,
-    image: image::Image,
+    scene: Scene,
+    camera: Camera,
+    image: Image,
     row: usize,
 ) -> Result<(usize, Vec<u32>), error::TracerError> {
     let mut buffer: Vec<u32> = vec![0; image.width as usize];
+    let mut colors: Vec<Vec3> = vec![Vec3::default(); image.width as usize];
 
     for i in 0..buffer.len() {
-        let u: f64 = i as f64 / (image.width - 1) as f64;
-        let v: f64 = row as f64 / (image.height - 1) as f64;
-        let ray = ray::Ray::new(
-            camera.origin,
-            camera.lower_left_corner + u * camera.horizontal + v * camera.vertical - camera.origin,
-        );
-        let col = ray_color(&ray);
-        buffer[i] = col.as_color();
+        for _ in 0..image.samples_per_pixel {
+            let u: f64 = (i as f64 + random_double()) / (image.width - 1) as f64;
+            let v: f64 = (row as f64 + random_double()) / (image.height - 1) as f64;
+            colors[i] += ray_color(&scene, &camera.get_ray(u, v));
+        }
+    }
+
+    for i in 0..image.width {
+        buffer[i] = (colors[i] / image.samples_per_pixel as f64).as_color();
     }
 
     Ok((row, buffer))
 }
 
+fn create_scene() -> Scene {
+    let mut scene = Scene::new();
+    let sphere1 = Sphere::new(Vec3::new(0.0, 0.0, -1.0), 0.5, Vec3::new(0.0, 1.0, 0.0));
+    let sphere2 = Sphere::new(
+        Vec3::new(0.0, -100.5, -1.0),
+        100.0,
+        Vec3::new(0.0, 1.0, 0.0),
+    );
+    scene.add(Box::new(sphere1));
+    scene.add(Box::new(sphere2));
+    scene
+}
+
 async fn run(
     rows_per_update: u32,
     aspect_ratio: f64,
-    screen_height: usize,
+    screen_width: usize,
+    samples: usize,
 ) -> Result<(), error::TracerError> {
-    let image = image::Image::new(aspect_ratio, screen_height);
+    let image = image::Image::new(aspect_ratio, screen_width, samples);
     let camera = camera::Camera::new(&image, 2.0, 1.0);
+    let scene = create_scene();
 
     let mut screen_buffer: Vec<u32> = vec![0; image.width * image.height];
     let mut window = Window::new(
@@ -61,13 +96,18 @@ async fn run(
     // One future per row is a bit high.
     // Could do something less spammy.
     for h in 0..image.height {
-        futs.push(raytrace(camera.clone(), image.clone(), h));
+        // TODO: Either clone all or lock em all.
+        futs.push(raytrace(scene.clone(), camera.clone(), image.clone(), h));
     }
 
+    // TODO: use rayon
+    // Since it's cooperative multitasking this is not really helpful at the moment.
+    // You will get pretty much get the same result without the tokio asyncness.
+    // using rayon with threads is a different matter.
     let mut complete = false;
     while window.is_open() && !window.is_key_down(Key::Escape) {
         if !complete {
-            for _ in 1..rows_per_update {
+            for _ in 0..rows_per_update {
                 select! {
                     res = futs.select_next_some() => {
                         let row_buffer = res.expect("Expected to get data");
@@ -95,7 +135,7 @@ async fn run(
 
 #[tokio::main]
 async fn main() {
-    if let Err(e) = run(50, 16.0 / 9.0, 1200).await {
+    if let Err(e) = run(100, 16.0 / 9.0, 1200, 100).await {
         eprintln!("{}", e);
         std::process::exit(e.into())
     }
-- 
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