364 lines
12 KiB
Rust
364 lines
12 KiB
Rust
//! Scene rendering logic
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use std::cmp::Ordering;
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use super::{light_aggregate::LightAggregate, object::Object, utils::*};
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use crate::{
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core::{Camera, LightProperties, LinearColor, ReflTransEnum},
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material::Material,
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shape::Shape,
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texture::Texture,
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{Point, Vector},
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};
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use bvh::{bvh::BVH, ray::Ray};
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use image::RgbImage;
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use rand::prelude::thread_rng;
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use rand::Rng;
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use serde::{Deserialize, Deserializer};
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/// Represent the scene being rendered.
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pub struct Scene {
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camera: Camera,
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lights: LightAggregate,
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objects: Vec<Object>,
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bvh: BVH,
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aliasing_limit: u32,
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reflection_limit: u32,
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diffraction_index: f32,
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}
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impl Scene {
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/// Creates a new `Scene`.
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///
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/// # Examples
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///
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/// ```
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/// # use pathtracer::core::{Camera, LightProperties, LinearColor};
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/// # use pathtracer::material::UniformMaterial;
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/// # use pathtracer::render::{LightAggregate, Object, Scene};
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/// # use pathtracer::shape::Sphere;
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/// # use pathtracer::texture::UniformTexture;
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/// # use pathtracer::Point;
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/// #
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/// let scene = Scene::new(
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/// Camera::default(),
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/// LightAggregate::empty(),
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/// vec![
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/// Object::new(
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/// Sphere::new(Point::origin(), 1.0).into(),
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/// UniformMaterial::new(
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/// LightProperties::new(
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/// LinearColor::new(1.0, 0.0, 0.0), // diffuse component
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/// LinearColor::new(0.0, 0.0, 0.0), // specular component
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/// None,
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/// ),
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/// ).into(),
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/// UniformTexture::new(LinearColor::new(0.5, 0.5, 0.5)).into(),
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/// ),
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/// ],
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/// 5, // aliasing limit
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/// 3, // reflection recursion limit
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/// 0.0, // diffraction index
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/// );
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/// ```
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pub fn new(
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camera: Camera,
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lights: LightAggregate,
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mut objects: Vec<Object>,
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aliasing_limit: u32,
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reflection_limit: u32,
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diffraction_index: f32,
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) -> Self {
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// NOTE(Antoine): fun fact: BVH::build stack overflows when given an empty slice :)
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let bvh = BVH::build(&mut objects);
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Scene {
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camera,
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lights,
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objects,
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bvh,
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aliasing_limit,
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reflection_limit,
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diffraction_index,
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}
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}
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/// Render the scene into an image.
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pub fn render(&self) -> RgbImage {
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let mut image = RgbImage::new(self.camera.film().width(), self.camera.film().height());
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let total = (image.width() * image.height()) as u64;
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let pb = indicatif::ProgressBar::new(total);
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pb.set_draw_delta(total / 10000);
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pb.set_style(indicatif::ProgressStyle::default_bar().template(
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"{spinner:.green} [{elapsed_precise}] [{wide_bar:.cyan/blue}] {percent:>3}%: {pos}/{len} pixels (ETA: {eta})",
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));
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let pixel_func = if self.aliasing_limit > 0 {
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Self::anti_alias_pixel
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} else {
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Self::pixel
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};
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rayon::scope(|s| {
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// FIXME(Bruno): it would go even faster to cut the image in blocks of rows, leading to
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// better cache-line behaviour...
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for (_, row) in image.enumerate_rows_mut() {
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s.spawn(|_| {
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for (x, y, pixel) in row {
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*pixel = pixel_func(&self, x as f32, y as f32).into();
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pb.inc(1);
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}
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})
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}
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});
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pb.finish();
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image
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}
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/// Get pixel color for (x, y) a pixel **coordinate**
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fn pixel(&self, x: f32, y: f32) -> LinearColor {
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let (x, y) = self.camera.film().pixel_ratio(x, y);
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let pixel = self.camera.film().pixel_at_ratio(x, y);
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let direction = (pixel - self.camera.origin()).normalize();
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let indices = RefractionInfo::with_index(self.diffraction_index);
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self.cast_ray(Ray::new(pixel, direction))
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.map_or_else(LinearColor::black, |(t, obj)| {
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self.color_at(
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pixel + direction * t,
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obj,
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direction,
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self.reflection_limit,
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indices,
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)
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})
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}
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/// Get pixel color with anti-aliasing
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fn anti_alias_pixel(&self, x: f32, y: f32) -> LinearColor {
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let range = 0..self.aliasing_limit;
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let mut rng = thread_rng();
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let acc: LinearColor = range
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.map(|_| {
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let random_x: f32 = rng.gen();
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let random_y: f32 = rng.gen();
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self.pixel(x + random_x, y + random_y)
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})
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.map(LinearColor::clamp)
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.sum();
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acc / self.aliasing_limit as f32
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}
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fn cast_ray(&self, ray: Ray) -> Option<(f32, &Object)> {
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self.bvh
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.traverse(&ray, &self.objects)
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.iter()
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.filter_map(|obj| obj.shape.intersect(&ray).map(|distance| (distance, *obj)))
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.min_by(|(dist_a, _), (dist_b, _)| {
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dist_a.partial_cmp(dist_b).unwrap_or(Ordering::Equal)
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})
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}
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fn color_at(
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&self,
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point: Point,
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object: &Object,
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incident_ray: Vector,
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reflection_limit: u32,
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mut indices: RefractionInfo,
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) -> LinearColor {
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let texel = object.shape.project_texel(&point);
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let properties = object.material.properties(texel);
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let object_color = object.texture.texel_color(texel);
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let normal = object.shape.normal(&point);
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let reflected_ray = reflected(incident_ray, normal);
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let lighting = self.illuminate(point, object_color, &properties, normal, reflected_ray);
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if properties.refl_trans.is_none() {
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// Avoid calculating reflection when not needed
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return lighting;
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}
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let reflected = self.reflection(point, reflected_ray, reflection_limit, indices.clone());
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// We can unwrap safely thanks to the check for None before
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match properties.refl_trans.unwrap() {
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ReflTransEnum::Transparency { coef, index } => {
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// Calculate the refracted ray, if it was refracted, and mutate indices accordingly
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refracted(incident_ray, normal, &mut indices, index).map_or_else(
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// Total reflection
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|| reflected.clone(),
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// Refraction (refracted ray, amount of *reflection*)
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|(r, refl_t)| {
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let refracted = self.refraction(point, coef, r, reflection_limit, indices);
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let refr_light = refracted * (1. - refl_t) + reflected.clone() * refl_t;
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refr_light * coef + lighting * (1. - coef)
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},
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)
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}
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ReflTransEnum::Reflectivity { coef } => reflected * coef + lighting * (1. - coef),
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}
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}
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fn refraction(
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&self,
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point: Point,
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transparency: f32,
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refracted: Vector,
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reflection_limit: u32,
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indices: RefractionInfo,
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) -> LinearColor {
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if transparency > 1e-5 && reflection_limit > 0 {
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let refraction_start = point + refracted * 0.001;
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if let Some((t, obj)) = self.cast_ray(Ray::new(refraction_start, refracted)) {
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let resulting_position = refraction_start + refracted * t;
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let refracted = self.color_at(
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resulting_position,
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obj,
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refracted,
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reflection_limit - 1,
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indices,
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);
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return refracted * transparency;
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}
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}
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LinearColor::black()
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}
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fn reflection(
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&self,
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point: Point,
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reflected: Vector,
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reflection_limit: u32,
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indices: RefractionInfo,
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) -> LinearColor {
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if reflection_limit > 0 {
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let reflection_start = point + reflected * 0.001;
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if let Some((t, obj)) = self.cast_ray(Ray::new(reflection_start, reflected)) {
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let resulting_position = reflection_start + reflected * t;
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let color = self.color_at(
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resulting_position,
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obj,
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reflected,
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reflection_limit - 1,
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indices,
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);
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return color;
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}
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};
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LinearColor::black()
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}
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fn illuminate(
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&self,
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point: Point,
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object_color: LinearColor,
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properties: &LightProperties,
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normal: Vector,
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reflected: Vector,
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) -> LinearColor {
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let ambient = self.illuminate_ambient(object_color.clone());
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let spatial = self.illuminate_spatial(point, properties, normal, reflected);
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ambient + object_color * spatial
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}
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fn illuminate_ambient(&self, color: LinearColor) -> LinearColor {
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self.lights
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.ambient_lights_iter()
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.map(|light| color.clone() * light.illumination(&Point::origin()))
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.map(LinearColor::clamp)
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.sum()
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}
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fn illuminate_spatial(
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&self,
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point: Point,
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properties: &LightProperties,
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normal: Vector,
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reflected: Vector,
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) -> LinearColor {
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self.lights
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.spatial_lights_iter()
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.map(|light| {
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let (direction, t) = light.to_source(&point);
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let light_ray = Ray::new(point + 0.001 * direction, direction);
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match self.cast_ray(light_ray) {
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// Take shadows into account
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Some((obstacle_t, _)) if obstacle_t < t => return LinearColor::black(),
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_ => {}
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}
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let lum = light.illumination(&point);
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let diffused = properties.diffuse.clone() * normal.dot(&direction);
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let specular = properties.specular.clone() * reflected.dot(&direction);
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lum * (diffused + specular)
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})
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.map(LinearColor::clamp)
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.sum()
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}
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}
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#[derive(Debug, PartialEq, Deserialize)]
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struct SerializedScene {
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camera: Camera,
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#[serde(default)]
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lights: LightAggregate,
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#[serde(default)]
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objects: Vec<Object>,
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#[serde(default)]
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aliasing_limit: u32,
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#[serde(default)]
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reflection_limit: u32,
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#[serde(default = "crate::serialize::default_identity")]
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starting_diffraction: f32,
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}
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impl From<SerializedScene> for Scene {
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fn from(scene: SerializedScene) -> Self {
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Scene::new(
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scene.camera,
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scene.lights,
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scene.objects,
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scene.aliasing_limit,
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scene.reflection_limit,
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scene.starting_diffraction,
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)
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}
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}
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impl<'de> Deserialize<'de> for Scene {
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fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
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where
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D: Deserializer<'de>,
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{
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let cam: SerializedScene = Deserialize::deserialize(deserializer)?;
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Ok(cam.into())
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}
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}
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#[cfg(test)]
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mod test {
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use super::*;
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#[test]
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fn deserialization_works() {
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let yaml = std::include_str!("../../examples/scene.yaml");
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let _: Scene = serde_yaml::from_str(yaml).unwrap();
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// FIXME: actually test the equality ?
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}
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#[test]
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#[ignore] // stack overflow because of BVH :(
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fn bvh_fails() {
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use crate::core::Camera;
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use crate::render::{LightAggregate, Scene};
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let _scene = Scene::new(
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Camera::default(),
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LightAggregate::empty(),
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Vec::new(), // Objects list
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5, // aliasing limit
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3, // reflection recursion limit
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0.0, // diffraction index
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);
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}
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}
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