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fix: Corrected the distributions

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I had been carrying the distributions around with the SmallRng object so
that I can provide whatever bounds needed. It turns out that the book
only takes advantage of this a couple of times.

The functions accepting a Uniform struct no longer do. They instead
construct their own temporary one -- hopefully the optimizer can see
through the loops and construct it just once. :l

The change exposed all the uses of the distributions (duh!) and now they
are correct. The effect is most pronounced on the dielectric spheres.
This commit is contained in:
Robert Garrett
2023-06-06 20:47:32 -05:00
parent 0c9949bbb8
commit 0b31f66bbf
5 changed files with 19 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
src/camera.rs
View File

@@ -15,14 +15,13 @@ use crate::ray::Ray;
use crate::degrees_to_radians;
use rand::rngs::SmallRng;
use rand::distributions::Uniform;
pub struct Camera {
origin: Vec3,
lower_left_corner: Vec3,
horizontal: Vec3,
vertical: Vec3,
u: Vec3, v: Vec3, w: Vec3,
u: Vec3, v: Vec3, /*w: Vec3,*/
lens_radius: f32,
}
@@ -55,13 +54,13 @@ impl Camera {
lower_left_corner,
horizontal: horiz,
vertical: verti,
u, v, w,
u, v, /* w,*/
lens_radius: aperture / 2.0,
}
}
pub fn get_ray(&self, s: f32, t: f32, srng: &mut SmallRng, distrib: Uniform<f32>) -> Ray {
let rd = Vec3::rand_in_unit_disk(srng, distrib) * self.lens_radius;
pub fn get_ray(&self, s: f32, t: f32, srng: &mut SmallRng) -> Ray {
let rd = Vec3::rand_in_unit_disk(srng) * self.lens_radius;
let offset = self.u * rd.x + self.v * rd.y;
let dir = self.lower_left_corner

6
src/hittable.rs
View File

@@ -35,9 +35,9 @@ impl HittableList{
pub fn add(&mut self, hittable: Box<dyn Hittable> ) -> () {
self.hittables.push(hittable);
}
pub fn clear(&mut self) -> () {
self.hittables.clear();
}
// pub fn clear(&mut self) -> () {
// self.hittables.clear();
// }
}
impl Hittable for HittableList{

6
src/main.rs
View File

@@ -65,7 +65,7 @@ fn main() {
for _ in 0..samples_per_pixel {
let u = ((x as f32) + small_rng.sample(distrib_zero_one)) / ((image.0 - 1) as f32);
let v = ((y as f32) + small_rng.sample(distrib_zero_one)) / ((image.1 - 1) as f32);
let ray = cam.get_ray(u, v, &mut small_rng, distrib_plusminus_one);
let ray = cam.get_ray(u, v, &mut small_rng);
color+= ray_color(ray, &world, max_depth, &mut small_rng, distrib_plusminus_one);
}
println!("{}", color.print_ppm(samples_per_pixel));
@@ -88,7 +88,7 @@ fn ray_color(r: Ray, world: &dyn Hittable, depth: u32, srng: &mut SmallRng, dist
let mut attenuation = Vec3::zero();
match rec.material {
Some(mat) => {
if mat.scatter(r, rec, &mut attenuation, &mut scattered, srng, distrib) {
if mat.scatter(r, rec, &mut attenuation, &mut scattered, srng) {
return attenuation * ray_color(scattered, world, depth-1, srng, distrib);
};
},
@@ -108,8 +108,6 @@ fn random_scene(srng: &mut SmallRng) -> HittableList {
world.add( Box::new( Sphere::new(0.0, -1000.0, 0.0, 1000.0, Some(mat_ground) )));
let distrib_zero_one = Uniform::new(0.0, 1.0);
let distrib_plusminus_one = Uniform::new(-1.0, 1.0);
for a in -11..11 {
for b in -11..11 {
let choose_mat = srng.sample(distrib_zero_one);

8
src/material.rs
View File

@@ -25,11 +25,10 @@ impl Material {
attenuation: &mut Vec3,
scattered: &mut Ray,
srng: &mut SmallRng,
distrib: Uniform<f32>,
) -> bool {
match self {
Material::Lambertian { albedo } => {
let scatter_dir = rec.normal + Vec3::rand_unit_vector(srng, distrib);
let scatter_dir = rec.normal + Vec3::rand_unit_vector(srng);
// The compiler might be smart enough to compute this ^^^ just once. In which case,
// I don't need to do this weird dance. Oh well. It'll work.
let scatter_dir = if scatter_dir.near_zero() { // if near zero,
@@ -55,7 +54,7 @@ impl Material {
);
*scattered = Ray{
orig: rec.p,
dir: reflected + Vec3::rand_in_unit_sphere(srng, distrib) * *fuzz,
dir: reflected + Vec3::rand_in_unit_sphere(srng) * *fuzz,
};
*attenuation = *albedo;
return Vec3::dot(scattered.dir, rec.normal) > 0.0;
@@ -69,7 +68,8 @@ impl Material {
let sin_theta = (1.0 - cos_theta * cos_theta).sqrt();
let cannot_refract = refraction_ratio * sin_theta > 1.0;
let direction = if cannot_refract || Material::reflectance(cos_theta, refraction_ratio) > srng.sample(distrib) {
let distrib_zero_one = Uniform::new(0.0, 1.0);
let direction = if cannot_refract || Material::reflectance(cos_theta, refraction_ratio) > srng.sample(distrib_zero_one) {
Vec3::reflect(unit_direction, rec.normal)
} else {
Vec3::refract(unit_direction, rec.normal, refraction_ratio)

10
src/vec3.rs
View File

@@ -53,7 +53,8 @@ impl Vec3{
}
}
pub fn rand_in_unit_sphere(srng: &mut SmallRng, distrib: Uniform<f32>) -> Vec3 {
pub fn rand_in_unit_sphere(srng: &mut SmallRng) -> Vec3 {
let distrib = Uniform::new(-1.0, 1.0);
loop {
let p = Vec3::rand(srng, distrib);
if p.length_squared() >= 1.0 { continue; }
@@ -61,7 +62,8 @@ impl Vec3{
}
}
pub fn rand_in_unit_disk(srng: &mut SmallRng, distrib: Uniform<f32>) -> Vec3 {
pub fn rand_in_unit_disk(srng: &mut SmallRng) -> Vec3 {
let distrib = Uniform::new(-1.0, 1.0);
loop {
let p = Vec3 {
x: srng.sample(distrib),
@@ -73,8 +75,8 @@ impl Vec3{
}
}
pub fn rand_unit_vector(srng: &mut SmallRng, distrib: Uniform<f32>) -> Vec3 {
return Vec3::as_unit(Vec3::rand_in_unit_sphere(srng, distrib));
pub fn rand_unit_vector(srng: &mut SmallRng) -> Vec3 {
return Vec3::as_unit(Vec3::rand_in_unit_sphere(srng));
}
pub fn length(&self) -> f32 {