worker.js

import { add, mul, Color, Point3, Vec3, unit_vector } from "./vec3.js";
import { writeColor } from "./color.js";
import { Sphere } from "./sphere.js";
import { HittableList } from "./hittable-list.js";
import { Camera } from "./camera.js";
import { Dielectric, Lambertian, Metal } from "./material.js";

function ray_color(r, world, depth) {
  if (depth <= 0) {
    return new Color(0, 0, 0);
  }

  let t;
  const hitRecord = world.hit(r, 0.001, Number.POSITIVE_INFINITY);

  if (hitRecord) {
    const scattering = hitRecord.material.scatter(r, hitRecord);
    if (scattering) {
      const { attenuation, scattered } = scattering;
      return mul(attenuation, ray_color(scattered, world, depth - 1));
    } else {
      return new Color(0, 0, 0);
    }
  }

  const unit_direction = unit_vector(r.direction);
  t = 0.5 * (unit_direction.y + 1);
  return add(mul(1 - t, new Color(1, 1, 1)), mul(t, new Color(0.5, 0.7, 1)));
}

onmessage = function (e) {
  const {
    image_width,
    image_height,
    pixels,
    samples_per_pixel,
    world,
  } = e.data;
  // Image
  const aspect_ratio = image_width / image_height;
  const max_depth = 50;

  // Camera
  const lookfrom = new Point3(13, 2, 3);
  const lookat = new Point3(0, 0, 0);
  const vup = new Vec3(0, 1, 0);
  const dist_to_focus = 10;
  const aperture = 0.1;
  const cam = new Camera(
    lookfrom,
    lookat,
    vup,
    20,
    aspect_ratio,
    aperture,
    dist_to_focus
  );

  // World
  Object.setPrototypeOf(world, HittableList.prototype);

  for (let sphere of world.objects) {
    Object.setPrototypeOf(sphere, Sphere.prototype);
    Object.setPrototypeOf(sphere.center, Vec3.prototype);

    if (sphere.material._type === "Lambertian") {
      Object.setPrototypeOf(sphere.material, Lambertian.prototype);
      Object.setPrototypeOf(sphere.material.albedo, Vec3.prototype);
    } else if (sphere.material._type === "Metal") {
      Object.setPrototypeOf(sphere.material, Metal.prototype);
      Object.setPrototypeOf(sphere.material.albedo, Vec3.prototype);
    } else if (sphere.material._type === "Dielectric") {
      Object.setPrototypeOf(sphere.material, Dielectric.prototype);
    }
  }

  let idx = 0;
  for (let j = image_height - 1; j >= 0; --j) {
    if (j % Math.round(image_height / 10) === 0) {
      postMessage({
        progress: Math.round((100 * (image_height - j)) / image_height),
      });
    }
    for (let i = 0; i < image_width; ++i) {
      const color = new Color(0, 0, 0);
      for (let s = 0; s < samples_per_pixel; ++s) {
        const u = (i + Math.random()) / (image_width - 1);
        const v = (j + Math.random()) / (image_height - 1);

        const r = cam.get_ray(u, v);
        color.addInPlace(ray_color(r, world, max_depth));
      }

      idx = writeColor(pixels, idx, color, samples_per_pixel);
    }
  }

  postMessage({ progress: 100, pixels }, [pixels.buffer]);
};