552c0cb966
This necessitated to rework how light properties for a material were given. A material can have either reflectivity or transparency. This changes the parsing of materials, using a `LightProperty` structure at its core. This is does not implement the true Fresnel equations to take into account the amount of reflection that an incident goes through when encountering a transparent object.
333 lines
10 KiB
Rust
333 lines
10 KiB
Rust
use super::{light_aggregate::LightAggregate, object::Object};
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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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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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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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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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self.diffraction_index,
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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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// NOTE(Bruno): should be written using iterators
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let mut shot_obj: Option<&Object> = None;
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let mut t = std::f32::INFINITY;
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// NOTE: we don't care about all objects... Only the closest one
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for object in self.bvh.traverse(&ray, &self.objects).iter() {
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match object.shape.intersect(&ray) {
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Some(dist) if dist < t => {
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t = dist;
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shot_obj = Some(&object);
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}
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_ => {}
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}
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}
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shot_obj.map(|obj| (t, obj))
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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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diffraction_index: f32,
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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 = reflected(incident_ray, normal);
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let lighting = self.illuminate(point, object_color, &properties, normal, reflected);
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match properties.refl_trans {
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None => lighting,
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Some(ReflTransEnum::Transparency { coef, index }) => {
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// Calculate the refracted ray, if it was refracted
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refracted(incident_ray, normal, diffraction_index, index).map_or_else(
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// Total reflection
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|| self.reflection(point, 1., reflected, reflection_limit, diffraction_index),
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// Refraction
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|r| {
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self.refraction(point, coef, r, reflection_limit, index)
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+ lighting * (1. - coef)
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},
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)
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}
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Some(ReflTransEnum::Reflectivity { coef }) => {
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self.reflection(point, coef, reflected, reflection_limit, diffraction_index)
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+ lighting * (1. - coef)
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}
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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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new_index: f32,
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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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new_index,
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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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reflectivity: f32,
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reflected: Vector,
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reflection_limit: u32,
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diffraction_index: f32,
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) -> LinearColor {
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// FIXME: use fresnel reflection too
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if reflectivity > 1e-5 && 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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diffraction_index,
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);
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return color * reflectivity;
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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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fn reflected(incident: Vector, normal: Vector) -> Vector {
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let proj = incident.dot(&normal);
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let delt = normal * (proj * 2.);
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incident - delt
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}
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fn refracted(incident: Vector, normal: Vector, n_1: f32, n_2: f32) -> Option<Vector> {
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let cos = incident.dot(&normal);
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let normal = if cos < 0. { normal } else { -normal };
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let eta = n_1 / n_2;
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let k = 1. - eta * eta * (1. - cos * cos);
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if k < 0. {
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None
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} else {
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Some(eta * incident + (eta * cos.abs() - f32::sqrt(k)) * normal)
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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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}
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