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Added basic structure of the project from ria-weekend project

1. Added Motion Blur Demo
This commit is contained in:
Ishan Jain 2020-03-14 23:03:07 +05:30
commit 35259ad16d
16 changed files with 1366 additions and 0 deletions

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# Ray Tracing the Next Week
This is my attempt at Ray Tracing the Next Week book by Peter Shirley.
# Demo Renders
![[1] Motion Blur](https://dl.ishanjain.me/images/motion_blur-2000x1000.png)
[1] Motion Blur

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use {
crate::types::{Ray, Vec3},
rand::Rng,
};
pub struct Camera {
origin: Vec3,
horizontal: Vec3,
vertical: Vec3,
lower_left_corner: Vec3,
lens_radius: f32,
// position vectors
u: Vec3,
v: Vec3,
w: Vec3,
shutter_open: f32,
shutter_close: f32,
}
impl Camera {
// vertical_fov is the viewable angle from top->bottom
// look_from is basically camera position
// look_at is the point where camera is looking
// v_up is camera's up vector. i.e. it points upwards from the camera
// orthogonal to look_from - look_at vector
pub fn new(
look_from: Vec3,
look_at: Vec3,
v_up: Vec3,
vertical_fov: f32,
aspect: f32,
aperture: f32,
focus_distance: f32,
shutter_open: f32,
shutter_close: f32,
) -> Self {
// convert degree to radian
let angle = vertical_fov * std::f32::consts::PI / 180.0;
let half_height = (angle / 2.0).tan();
let half_width = aspect * half_height;
let origin = look_from;
let w = (look_from - look_at).unit_vector();
let u = v_up.cross(&w).unit_vector();
let v = w.cross(&u);
let lower_left_corner = origin
- u * focus_distance * half_width
- v * focus_distance * half_height
- w * focus_distance;
let horizontal = u * half_width * focus_distance * 2.0;
let vertical = v * half_height * focus_distance * 2.0;
let lens_radius = aperture / 2.0;
Self {
lens_radius,
lower_left_corner,
horizontal,
vertical,
origin,
u,
v,
w,
shutter_open,
shutter_close,
}
}
pub fn get_ray(&self, u: f32, v: f32) -> Ray {
let mut rng = rand::thread_rng();
let rd = random_in_unit_disk(&mut rng) * self.lens_radius;
let offset = self.u * rd.x() + self.v * rd.y();
let time = self.shutter_open + rng.gen::<f32>() * (self.shutter_close - self.shutter_open);
Ray::new(
self.origin + offset,
self.lower_left_corner + self.horizontal * u + self.vertical * v - self.origin - offset,
time,
)
}
}
fn random_in_unit_disk(rng: &mut rand::rngs::ThreadRng) -> Vec3 {
let mut p = Vec3::new(rng.gen::<f32>(), rng.gen::<f32>(), 0.0) * 2.0 - Vec3::new(1.0, 1.0, 0.0);
while p.dot(&p) >= 1.0 {
p = Vec3::new(rng.gen::<f32>(), rng.gen::<f32>(), 0.0) * 2.0 - Vec3::new(1.0, 0.0, 0.0);
}
p
}

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use {
crate::{
types::{HitableList, Vec3},
Camera, HORIZONTAL_PARTITION, VERTICAL_PARTITION,
},
rayon::prelude::*,
std::{
fs::File,
io::Write,
sync::{Arc, Mutex},
},
};
mod motion_blur;
pub use motion_blur::MotionBlur;
pub struct Chunk {
x: usize,
y: usize,
nx: usize,
ny: usize,
start_x: usize,
start_y: usize,
buffer: Vec<u8>,
}
pub trait Demo: std::marker::Sync {
fn render(&self, buf: &mut Vec<u8>, width: usize, height: usize, samples: u8) {
let nx = width / VERTICAL_PARTITION;
let ny = height / HORIZONTAL_PARTITION;
let world = self.world();
let camera = self.camera(nx as f32 / ny as f32);
let buf = Arc::new(Mutex::new(buf));
(0..VERTICAL_PARTITION).into_par_iter().for_each(|j| {
let buf = buf.clone();
(0..HORIZONTAL_PARTITION).into_par_iter().for_each(|i| {
let start_y = j * ny;
let start_x = i * nx;
let x = width;
let y = height;
let mut chunk = Chunk {
x,
y,
nx,
ny,
start_x,
start_y,
buffer: vec![0; nx * ny * 4],
};
self.render_chunk(&mut chunk, camera.as_ref(), world.as_ref(), samples);
let mut buf = buf.lock().unwrap();
let mut temp_offset = 0;
for j in start_y..start_y + ny {
let real_offset = ((y - j - 1) * x + start_x) * 4;
buf[real_offset..real_offset + nx * 4]
.copy_from_slice(&chunk.buffer[temp_offset..temp_offset + nx * 4]);
temp_offset += nx * 4;
}
})
});
}
fn world(&self) -> Option<HitableList> {
None
}
fn camera(&self, aspect_ratio: f32) -> Option<Camera> {
let lookfrom = Vec3::new(0.0, 0.0, 0.0);
let lookat = Vec3::new(0.0, 0.0, -1.0);
Some(Camera::new(
lookfrom,
lookat,
Vec3::new(0.0, 1.0, 0.0),
90.0,
aspect_ratio,
0.0, //aperture
1.0, // focus_distance
0.0, // shutter open time
1.0, // shutter close time
))
}
fn render_chunk(
&self,
chunk: &mut Chunk,
camera: Option<&Camera>,
world: Option<&HitableList>,
samples: u8,
);
fn name(&self) -> &'static str;
fn save_as_ppm(&self, buf: &[u8], width: usize, height: usize) {
let header = format!("P3\n{} {}\n255\n", width, height);
let mut file = match File::create(&format!("{}-{}x{}.ppm", self.name(), width, height)) {
Ok(file) => file,
Err(e) => panic!("couldn't create {}: {}", self.name(), e),
};
file.write_all(header.as_bytes())
.expect("error in writing file header");
for i in buf.chunks(4) {
match file.write_all(format!("{} {} {}\n", i[0], i[1], i[2]).as_bytes()) {
Ok(_) => (),
Err(e) => panic!("couldn't write to {}: {}", self.name(), e),
}
}
}
}

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use {
crate::{
demos::{Chunk, Demo},
types::{
material::{Dielectric, Lambertian, Metal},
Hitable, HitableList, MovingSphere, Ray, Sphere, Vec3,
},
Camera,
},
rand::Rng,
};
const RANGE: i32 = 10;
pub struct MotionBlur;
impl Demo for MotionBlur {
fn name(&self) -> &'static str {
"motion_blur"
}
fn world(&self) -> Option<HitableList> {
let mut world = HitableList {
list: Vec::with_capacity(500),
};
world.push(Box::new(Sphere::new(
Vec3::new(0.0, -1000.0, 0.0),
1000.0,
Box::new(Lambertian::new(Vec3::new(0.5, 0.5, 0.5))),
)));
let mut rng = rand::thread_rng();
let radius = 0.2;
let l = Vec3::new(4.0, 0.2, 0.0);
for a in -RANGE..RANGE {
let a = a as f32;
for b in -RANGE..RANGE {
let b = b as f32;
let choose_material_probability = rng.gen::<f32>();
let center = Vec3::new(a + 0.9 * rng.gen::<f32>(), 0.2, b + 0.9 * rng.gen::<f32>());
if (center - l).length() > 0.9 {
if choose_material_probability < 0.8 {
// diffuse material
world.push(Box::new(MovingSphere::new(
center,
center + Vec3::new(0.0, 0.5 * rng.gen::<f32>(), 0.0),
0.0,
1.0,
radius,
Box::new(Lambertian::new(Vec3::new(
rng.gen::<f32>() * rng.gen::<f32>(),
rng.gen::<f32>() * rng.gen::<f32>(),
rng.gen::<f32>() * rng.gen::<f32>(),
))),
)));
} else if choose_material_probability < 0.95 {
// metal material
world.push(Box::new(Sphere::new(
center,
radius,
Box::new(Metal::with_fuzz(
Vec3::new(
(1.0 + rng.gen::<f32>()) * 0.5,
(1.0 + rng.gen::<f32>()) * 0.5,
(1.0 + rng.gen::<f32>()) * 0.5,
),
0.5 * rng.gen::<f32>(),
)),
)));
} else {
// glass material
world.push(Box::new(Sphere::new(
center,
radius,
Box::new(Dielectric::new(1.5)),
)));
}
}
}
}
world.push(Box::new(Sphere::new(
Vec3::new(0.0, 1.0, 0.0),
1.0,
Box::new(Dielectric::new(1.5)),
)));
world.push(Box::new(Sphere::new(
Vec3::new(-4.0, 1.0, 0.0),
1.0,
Box::new(Lambertian::new(Vec3::new(0.4, 0.2, 0.1))),
)));
world.push(Box::new(Sphere::new(
Vec3::new(4.0, 1.0, 0.0),
1.0,
Box::new(Metal::with_fuzz(Vec3::new(0.7, 0.6, 0.5), 0.0)),
)));
Some(world)
}
fn camera(&self, aspect_ratio: f32) -> Option<Camera> {
let lookfrom = Vec3::new(13.0, 2.0, 3.0);
let lookat = Vec3::new(0.0, 0.0, 0.0);
let aperture = 0.1;
let focus_distance = 10.0;
let camera = Camera::new(
lookfrom,
lookat,
Vec3::new(0.0, 1.0, 0.0),
20.0,
aspect_ratio,
aperture,
focus_distance,
0.0,
1.0,
);
Some(camera)
}
fn render_chunk(
&self,
chunk: &mut Chunk,
camera: Option<&Camera>,
world: Option<&HitableList>,
samples: u8,
) {
let &mut Chunk {
x,
y,
nx,
ny,
start_x,
start_y,
ref mut buffer,
} = chunk;
let camera = camera.unwrap();
let world = world.unwrap();
let mut rng = rand::thread_rng();
let mut offset = 0;
for j in start_y..start_y + ny {
for i in start_x..start_x + nx {
let mut color = Vec3::new(0.0, 0.0, 0.0);
for _s in 0..samples {
let u = (i as f32 + rng.gen::<f32>()) / x as f32;
let v = (j as f32 + rng.gen::<f32>()) / y as f32;
let ray = camera.get_ray(u, v);
color += calc_color(ray, &world, 0);
}
color /= samples as f32;
// gamma 2 corrected
buffer[offset] = (255.99 * color.r().sqrt()) as u8;
buffer[offset + 1] = (255.99 * color.g().sqrt()) as u8;
buffer[offset + 2] = (255.99 * color.b().sqrt()) as u8;
offset += 4;
}
}
}
}
fn calc_color(ray: Ray, world: &HitableList, depth: u32) -> Vec3 {
if let Some(hit_rec) = world.hit(&ray, 0.001, std::f32::MAX) {
if depth >= 50 {
Vec3::new(0.0, 0.0, 0.0)
} else {
let material = hit_rec.material;
if let (attenuation, Some(scattered_ray)) = material.scatter(&ray, &hit_rec) {
calc_color(scattered_ray, &world, depth + 1) * attenuation
} else {
Vec3::new(0.0, 0.0, 0.0)
}
}
} else {
let unit_direction = ray.direction().unit_vector();
let t = 0.5 * (unit_direction.y() + 1.0);
Vec3::new(1.0, 1.0, 1.0) * (1.0 - t) + Vec3::new(0.5, 0.7, 1.0) * t
}
}

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#![allow(clippy::suspicious_arithmetic_impl)]
#![feature(test)]
extern crate test;
mod camera;
mod demos;
mod types;
pub use camera::Camera;
use {
demos::Demo,
sdl2::{
event::{Event, WindowEvent},
keyboard::Keycode,
pixels::PixelFormatEnum,
},
std::time::Instant,
};
const NUM_SAMPLES: u8 = 100;
const VERTICAL_PARTITION: usize = 8;
const HORIZONTAL_PARTITION: usize = 8;
fn main() -> Result<(), String> {
let sdl_ctx = sdl2::init()?;
let video_subsys = sdl_ctx.video()?;
let (mut width, mut height): (usize, usize) = (2000, 1000);
let window = video_subsys
.window("Ray tracing in a weekend", width as u32, height as u32)
.position_centered()
.build()
.map_err(|e| e.to_string())?;
let mut event_pump = sdl_ctx.event_pump()?;
let mut canvas = window
.into_canvas()
.target_texture()
.build()
.map_err(|e| e.to_string())?;
// RGBA framebuffer
let mut buffer = vec![0; height * width * 4];
let texture_creator = canvas.texture_creator();
let mut texture = texture_creator
.create_texture_static(PixelFormatEnum::BGR888, width as u32, height as u32)
.map_err(|e| e.to_string())?;
//println!("{:?} {:?} {:?}", texture.query(), texture.color_mod(), texture.alpha_mod());
let mut active_demo: &dyn Demo = &demos::MotionBlur;
// TODO: Should update when window is unfocus since the project window retains
// data from overlapped window
// TODO: Maybe consider using condition variable to make loop {} not run at full
// speed at all times pinning a core at 100%
let mut should_update = true;
loop {
for event in event_pump.poll_iter() {
match event {
Event::Quit { .. }
| Event::KeyDown {
keycode: Some(Keycode::Escape),
..
} => return Ok(()),
Event::KeyUp { keycode, .. } => {
match keycode {
Some(Keycode::S) => {
active_demo.save_as_ppm(&buffer, width, height);
should_update = false;
}
None => unreachable!(),
_ => (),
};
}
Event::Window {
win_event: WindowEvent::Resized(w, h),
..
} => {
width = w as usize;
height = h as usize;
buffer.resize(width * height * 4, 0);
texture = texture_creator
.create_texture_static(PixelFormatEnum::BGR888, width as u32, height as u32)
.expect("error in resizing texture");
should_update = true;
}
_ => {}
};
}
if should_update {
let now = Instant::now();
active_demo.render(&mut buffer, width, height, NUM_SAMPLES);
println!(
"Demo {} Time Taken(s) = {}",
active_demo.name(),
now.elapsed().as_secs_f32()
);
texture.update(None, &buffer, width * 4).unwrap();
canvas.copy(&texture, None, None).unwrap();
canvas.present();
should_update = false;
}
}
}

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use {
crate::types::Vec3,
crate::types::{Material, Ray},
};
pub struct HitRecord<'a> {
/// Rays are represented by A + t * B
/// where A is the source point and B destination point
/// by adjusting t we can move forward/back on the ray
///
/// t is the point at which a ray intersected another object.
/// As in, If we put this value of t in A + t * B equation, We'll get the exact
/// point at which a ray intersects some other object
pub t: f32,
/// Ray object otherwise is represented by the Source/Destination points
/// p is what we get when we perform the operation, A + t * B
/// i.e. A vector from Ray source to the point t
pub p: Vec3,
/// unit outward facing normal
pub normal: Vec3,
/// material if any of the surface
pub material: &'a Box<dyn Material>,
}
pub trait Hitable: Send + Sync {
fn hit(&self, _ray: &Ray, _t_min: f32, _t_max: f32) -> Option<HitRecord> {
None
}
}

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use crate::types::{HitRecord, Hitable, Ray};
pub struct HitableList {
pub list: Vec<Box<dyn Hitable>>,
}
impl Hitable for HitableList {
fn hit(&self, ray: &Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
let mut closest_so_far = t_max;
let mut hit_rec: Option<HitRecord> = None;
for obj in &self.list {
if let Some(l_hit_rec) = obj.hit(ray, t_min, closest_so_far) {
closest_so_far = l_hit_rec.t;
hit_rec = Some(l_hit_rec);
}
}
hit_rec
}
}
impl HitableList {
pub fn push(&mut self, obj: Box<dyn Hitable>) {
self.list.push(obj);
}
}

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use {
crate::types::{HitRecord, Ray, Vec3},
rand::Rng,
};
pub trait Material: Send + Sync {
fn scatter(&self, ray: &Ray, hit_rec: &HitRecord) -> (Vec3, Option<Ray>);
}
pub struct Lambertian {
albedo: Vec3,
}
impl Lambertian {
pub fn new(a: Vec3) -> Self {
Self { albedo: a }
}
}
impl Material for Lambertian {
fn scatter(&self, ray: &Ray, hit_rec: &HitRecord) -> (Vec3, Option<Ray>) {
let mut rng = rand::thread_rng();
let target = hit_rec.p + hit_rec.normal + random_point_in_unit_sphere(&mut rng);
let scattered_ray = Ray::new(hit_rec.p, target - hit_rec.p, ray.time());
(self.albedo, Some(scattered_ray))
}
}
pub struct Metal {
albedo: Vec3,
fuzz: f32,
}
impl Metal {
pub fn new(albedo: Vec3) -> Self {
Self { albedo, fuzz: 0.0 }
}
pub fn with_fuzz(albedo: Vec3, fuzz: f32) -> Self {
Self { albedo, fuzz }
}
}
impl Material for Metal {
fn scatter(&self, ray_in: &Ray, hit_rec: &HitRecord) -> (Vec3, Option<Ray>) {
let mut rng = rand::thread_rng();
let reflected_ray = reflect(ray_in.direction().unit_vector(), hit_rec.normal);
let scattered_ray = Ray::new(
hit_rec.p,
reflected_ray + random_point_in_unit_sphere(&mut rng) * self.fuzz,
ray_in.time(),
);
if scattered_ray.direction().dot(&hit_rec.normal) > 0.0 {
(self.albedo, Some(scattered_ray))
} else {
(self.albedo, None)
}
}
}
pub struct Dielectric {
reflection_index: f32,
}
impl Dielectric {
pub fn new(reflection_index: f32) -> Self {
Self { reflection_index }
}
}
impl Material for Dielectric {
fn scatter(&self, ray_in: &Ray, hit_rec: &HitRecord) -> (Vec3, Option<Ray>) {
let reflected_ray = reflect(ray_in.direction(), hit_rec.normal);
// Glass absorbs nothing! So, Attenuation is always going to be 1.0 for this
let attenuation = Vec3::new(1.0, 1.0, 1.0);
let mut rng = rand::thread_rng();
let (outward_normal, ni_over_nt, cosine) = if ray_in.direction().dot(&hit_rec.normal) > 0.0
{
(
-hit_rec.normal,
self.reflection_index,
(ray_in.direction().dot(&hit_rec.normal) * self.reflection_index)
/ ray_in.direction().length(),
)
} else {
(
hit_rec.normal,
1.0 / self.reflection_index,
(-ray_in.direction().dot(&hit_rec.normal)) / ray_in.direction().length(),
)
};
if let Some(refracted_ray) = refract(ray_in.direction(), outward_normal, ni_over_nt) {
let reflect_prob = schlick(cosine, self.reflection_index);
if rng.gen::<f32>() < reflect_prob {
(
attenuation,
Some(Ray::new(hit_rec.p, reflected_ray, ray_in.time())),
)
} else {
(
attenuation,
Some(Ray::new(hit_rec.p, refracted_ray, ray_in.time())),
)
}
} else {
(
attenuation,
Some(Ray::new(hit_rec.p, reflected_ray, ray_in.time())),
)
}
}
}
// Christophe Schlick's Polynomial approximation to figure out reflectivity as the angle changes
// See Fresnel Equations, https://en.wikipedia.org/wiki/Fresnel_equations
fn schlick(cosine: f32, reflection_index: f32) -> f32 {
let mut r0 = (1.0 - reflection_index) / (1.0 + reflection_index);
r0 = r0 * r0;
r0 + (1.0 - r0) * (1.0 - cosine).powf(5.0)
}
fn reflect(incident: Vec3, normal: Vec3) -> Vec3 {
incident - normal * incident.dot(&normal) * 2.0
}
// Snell's Law
fn refract(incident: Vec3, normal: Vec3, ni_over_nt: f32) -> Option<Vec3> {
let uv = incident.unit_vector();
let dt = uv.dot(&normal);
let discriminant = 1.0 - ni_over_nt * ni_over_nt * (1.0 - dt * dt);
if discriminant > 0.0 {
Some((uv - normal * dt) * ni_over_nt - normal * discriminant.sqrt())
} else {
None
}
}
fn random_point_in_unit_sphere(rng: &mut rand::rngs::ThreadRng) -> Vec3 {
let mut point = Vec3::new(rng.gen::<f32>(), rng.gen::<f32>(), rng.gen::<f32>()) * 2.0
- Vec3::new(1.0, 1.0, 1.0);
while point.sq_len() >= 1.0 {
point = Vec3::new(rng.gen::<f32>(), rng.gen::<f32>(), rng.gen::<f32>()) * 2.0
- Vec3::new(1.0, 1.0, 1.0);
}
point
}

15
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mod hitable;
mod hitable_list;
pub mod material;
mod moving_sphere;
mod ray;
mod sphere;
mod vec3;
pub use hitable::{HitRecord, Hitable};
pub use hitable_list::HitableList;
pub use material::Material;
pub use moving_sphere::MovingSphere;
pub use ray::Ray;
pub use sphere::Sphere;
pub use vec3::Vec3;

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use crate::types::{HitRecord, Hitable, Material, Ray, Vec3};
pub struct MovingSphere {
radius: f32,
center_start: Vec3,
center_end: Vec3,
time_start: f32,
time_end: f32,
material: Box<dyn Material>,
}
impl MovingSphere {
pub fn new(
center_start: Vec3,
center_end: Vec3,
time_start: f32,
time_end: f32,
radius: f32,
material: Box<dyn Material>,
) -> Self {
Self {
center_start,
center_end,
time_start,
time_end,
radius,
material,
}
}
fn center(&self, time: f32) -> Vec3 {
self.center_start
+ (self.center_end - self.center_start)
* ((time - self.time_start) / (self.time_end - self.time_start))
}
}
impl Hitable for MovingSphere {
fn hit(&self, ray: &Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
let oc = ray.origin() - self.center(ray.time());
let a = ray.direction().dot(&ray.direction());
let b = oc.dot(&ray.direction());
let c = oc.dot(&oc) - self.radius * self.radius;
let discriminant = b * b - a * c;
let discriminant_root = discriminant.sqrt();
if discriminant > 0.0 {
let root = (-b - discriminant_root) / a;
if root < t_max && root > t_min {
let p = ray.point_at_parameter(root);
return Some(HitRecord {
t: root,
p,
normal: (p - self.center(ray.time())) / self.radius,
material: &self.material,
});
}
let root = (-b + discriminant_root) / a;
if root < t_max && root > t_min {
let p = ray.point_at_parameter(root);
return Some(HitRecord {
t: root,
p,
normal: (p - self.center(ray.time())) / self.radius,
material: &self.material,
});
}
}
None
}
}

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use crate::types::Vec3;
pub struct Ray {
a: Vec3,
b: Vec3,
time: f32,
}
impl Ray {
pub fn new(a: Vec3, b: Vec3, time: f32) -> Ray {
Ray { a, b, time }
}
#[inline]
pub const fn origin(&self) -> Vec3 {
self.a
}
#[inline]
pub const fn direction(&self) -> Vec3 {
self.b
}
#[inline]
pub fn point_at_parameter(&self, t: f32) -> Vec3 {
self.a + self.b * t
}
#[inline]
pub const fn time(&self) -> f32 {
self.time
}
}

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use crate::types::{HitRecord, Hitable, Material, Ray, Vec3};
pub struct Sphere {
center: Vec3,
radius: f32,
material: Box<dyn Material>,
}
impl Sphere {
pub fn new(center: Vec3, radius: f32, material: Box<dyn Material>) -> Self {
Self {
center,
radius,
material,
}
}
}
impl Hitable for Sphere {
fn hit(&self, ray: &Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
let oc = ray.origin() - self.center;
let a = ray.direction().dot(&ray.direction());
let b = oc.dot(&ray.direction());
let c = oc.dot(&oc) - self.radius * self.radius;
// The discriminant is calculated using b^2 - 4 * a * c
// but in this specific case, If we put the equation in the
// formula to find quadratic roots, We can get this shorter
// formula to find the discriminant.
// Check this for detailed proof
// https://vchizhov.github.io/resources/ray%20tracing/ray%20tracing%20tutorial%20series%20vchizhov/ray_casting/part1/intersecting_a_sphere.md.html#appendix
let discriminant = b * b - a * c;
let discriminant_root = discriminant.sqrt();
if discriminant > 0.0 {
let root = (-b - discriminant_root) / a;
if root < t_max && root > t_min {
let p = ray.point_at_parameter(root);
return Some(HitRecord {
t: root,
p,
normal: (p - self.center) / self.radius,
material: &self.material,
});
}
let root = (-b + discriminant_root) / a;
if root < t_max && root > t_min {
let p = ray.point_at_parameter(root);
return Some(HitRecord {
t: root,
p,
normal: (p - self.center) / self.radius,
material: &self.material,
});
}
}
None
}
}

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use std::{
fmt::{Display, Formatter, Result as FmtResult},
ops::{Add, AddAssign, Div, DivAssign, Index, IndexMut, Mul, MulAssign, Neg, Sub, SubAssign},
};
#[derive(Copy, Clone)]
pub struct Vec3([f32; 3]);
impl Vec3 {
#[inline]
pub const fn new(a: f32, b: f32, c: f32) -> Vec3 {
Vec3([a, b, c])
}
#[inline]
pub fn x(&self) -> f32 {
self[0]
}
#[inline]
pub fn y(&self) -> f32 {
self[1]
}
#[inline]
pub fn z(&self) -> f32 {
self[2]
}
#[inline]
pub fn r(&self) -> f32 {
self[0]
}
#[inline]
pub fn g(&self) -> f32 {
self[1]
}
#[inline]
pub fn b(&self) -> f32 {
self[2]
}
#[inline]
pub fn length(&self) -> f32 {
self.sq_len().sqrt()
}
#[inline]
pub fn sq_len(&self) -> f32 {
self[0] * self[0] + self[1] * self[1] + self[2] * self[2]
}
#[inline]
pub fn dot(&self, v: &Vec3) -> f32 {
self[0] * v[0] + self[1] * v[1] + self[2] * v[2]
}
#[inline]
pub fn cross(&self, v: &Vec3) -> Vec3 {
Vec3([
self[1] * v[2] - self[2] * v[1],
self[2] * v[0] - self[0] * v[2],
self[0] * v[1] - self[1] * v[0],
])
}
#[inline]
pub fn make_unit_vector(&mut self) {
let k = 1.0f32 / (self[0] * self[0] + self[1] * self[1] + self[2] * self[2]);
self[0] *= k;
self[1] *= k;
self[2] *= k;
}
#[inline]
pub fn unit_vector(&self) -> Vec3 {
let length = self.length();
Vec3([self[0] / length, self[1] / length, self[2] / length])
}
}
impl Add for Vec3 {
type Output = Vec3;
fn add(self, o: Vec3) -> Vec3 {
Vec3([self[0] + o[0], self[1] + o[1], self[2] + o[2]])
}
}
impl AddAssign for Vec3 {
fn add_assign(&mut self, o: Vec3) {
self.0[0] += o.0[0];
self.0[1] += o.0[1];
self.0[2] += o.0[2];
}
}
impl Sub for Vec3 {
type Output = Vec3;
fn sub(self, o: Vec3) -> Vec3 {
Vec3([self[0] - o[0], self[1] - o[1], self[2] - o[2]])
}
}
impl SubAssign for Vec3 {
fn sub_assign(&mut self, o: Vec3) {
self[0] -= o[0];
self[1] -= o[1];
self[2] -= o[2];
}
}
impl Neg for Vec3 {
type Output = Vec3;
fn neg(self) -> Vec3 {
Vec3([-self[0], -self[1], -self[2]])
}
}
impl MulAssign<Vec3> for Vec3 {
fn mul_assign(&mut self, o: Vec3) {
self[0] *= o[0];
self[1] *= o[1];
self[2] *= o[2];
}
}
impl MulAssign<f32> for Vec3 {
fn mul_assign(&mut self, o: f32) {
self[0] *= o;
self[1] *= o;
self[2] *= o;
}
}
impl Mul<f32> for Vec3 {
type Output = Vec3;
fn mul(self, o: f32) -> Vec3 {
Vec3([self[0] * o, self[1] * o, self[2] * o])
}
}
impl Mul<Vec3> for Vec3 {
type Output = Vec3;
fn mul(self, o: Vec3) -> Vec3 {
Vec3([self[0] * o[0], self[1] * o[1], self[2] * o[2]])
}
}
impl Div<Vec3> for Vec3 {
type Output = Vec3;
fn div(self, o: Vec3) -> Vec3 {
Vec3([self[0] / o[0], self[1] / o[1], self[2] / o[2]])
}
}
impl Div<f32> for Vec3 {
type Output = Vec3;
fn div(self, o: f32) -> Vec3 {
let o = 1.0 / o;
Vec3([self[0] * o, self[1] * o, self[2] * o])
}
}
impl DivAssign<f32> for Vec3 {
fn div_assign(&mut self, o: f32) {
let o = 1.0 / o;
self.0[0] *= o;
self.0[1] *= o;
self.0[2] *= o;
}
}
impl Index<usize> for Vec3 {
type Output = f32;
fn index(&self, q: usize) -> &f32 {
&self.0[q]
}
}
impl IndexMut<usize> for Vec3 {
fn index_mut(&mut self, q: usize) -> &mut f32 {
&mut self.0[q]
}
}
impl Display for Vec3 {
fn fmt(&self, f: &mut Formatter) -> FmtResult {
f.write_fmt(format_args!("{} {} {}", self[0], self[1], self[2]))
}
}