pathtracer/pathtracer/src/render/raytrace/raytracer.rs

253 lines
8.5 KiB
Rust

use super::super::utils::*;
use super::super::Renderer;
use crate::scene::{Object, Scene};
use crate::{
core::{LightProperties, LinearColor, ReflTransEnum},
material::Material,
shape::Shape,
texture::Texture,
{Point, Vector},
};
use beevee::ray::Ray;
use image::RgbImage;
use nalgebra::Unit;
use rand::prelude::thread_rng;
use rand::Rng;
/// Render the [`Scene`] using Raytracing.
///
/// [`Scene`]: ../scene/scene/struct.Scene.html
pub struct Raytracer {
scene: Scene,
}
impl Raytracer {
/// Create a [`Raytracer`] renderer with the given [`Scene`]
///
/// [`Raytracer`]: struct.Raytracer.html
/// [`Scene`]: ../scene/scene/struct.Scene.html
pub fn new(scene: Scene) -> Self {
Raytracer { scene }
}
/// Render the [`Scene`] using Raytracing.
///
/// [`Scene`]: ../scene/scene/struct.Scene.html
pub fn render(&self) -> RgbImage {
let mut image = RgbImage::new(
self.scene.camera.film().width(),
self.scene.camera.film().height(),
);
let total = (image.width() * image.height()) as u64;
let pb = super::super::progress::get_pixels_progressbar(total);
let pixel_func = if self.scene.shot_rays > 0 {
Self::anti_alias_pixel
} else {
Self::pixel
};
rayon::scope(|s| {
// FIXME(Bruno): it would go even faster to cut the image in blocks of rows, leading to
// better cache-line behaviour...
for (_, row) in image.enumerate_rows_mut() {
s.spawn(|_| {
for (x, y, pixel) in row {
*pixel = pixel_func(&self, x as f32, y as f32).into();
pb.inc(1);
}
})
}
});
pb.finish();
image
}
/// Get pixel color for (x, y) a pixel **coordinate**
fn pixel(&self, x: f32, y: f32) -> LinearColor {
let (x, y) = self.scene.camera.film().pixel_ratio(x, y);
let indices = RefractionInfo::with_index(self.scene.diffraction_index);
let ray = self.scene.camera.ray_with_ratio(x, y);
self.cast_ray(ray).map_or_else(
|| self.scene.background.clone(),
|(t, obj)| {
self.color_at(
ray.origin + ray.direction.as_ref() * t,
obj,
ray.direction,
self.scene.reflection_limit,
indices,
)
},
)
}
/// Get pixel color with anti-aliasing
fn anti_alias_pixel(&self, x: f32, y: f32) -> LinearColor {
let range = 0..self.scene.shot_rays;
let mut rng = thread_rng();
let acc: LinearColor = range
.map(|_| {
let random_x: f32 = rng.gen();
let random_y: f32 = rng.gen();
self.pixel(x + random_x, y + random_y)
})
.map(LinearColor::clamp)
.sum();
acc / self.scene.shot_rays as f32
}
fn cast_ray(&self, ray: Ray) -> Option<(f32, &Object)> {
self.scene.bvh.walk(&ray, &self.scene.objects)
}
fn color_at(
&self,
point: Point,
object: &Object,
incident_ray: Unit<Vector>,
reflection_limit: u32,
mut indices: RefractionInfo,
) -> LinearColor {
let texel = object.shape.project_texel(&point);
let properties = object.material.properties(texel);
let object_color = object.texture.texel_color(texel);
let normal = object.shape.normal(&point);
let reflected_ray = reflected(incident_ray, normal);
// FIXME: change this to averaged sampled rays instead of visiting every light ?
// Indeed the path-tracing algorithm is good for calculating the radiance at a point
// But it should be used for reflection and refraction too...
let lighting = self.illuminate(point, object_color, &properties, normal, reflected_ray);
if properties.refl_trans.is_none() {
// Avoid calculating reflection when not needed
return lighting;
}
let reflected = self.reflection(point, reflected_ray, reflection_limit, indices.clone());
// We can unwrap safely thanks to the check for None before
match properties.refl_trans.unwrap() {
ReflTransEnum::Transparency { coef, index } => {
// Calculate the refracted ray, if it was refracted, and mutate indices accordingly
refracted(incident_ray, normal, &mut indices, index).map_or_else(
// Total reflection
|| reflected.clone(),
// Refraction (refracted ray, amount of *reflection*)
|(r, refl_t)| {
let refracted = self.refraction(point, coef, r, reflection_limit, indices);
let refr_light = refracted * (1. - refl_t) + reflected.clone() * refl_t;
refr_light * coef + lighting * (1. - coef)
},
)
}
ReflTransEnum::Reflectivity { coef } => reflected * coef + lighting * (1. - coef),
}
}
fn refraction(
&self,
point: Point,
transparency: f32,
refracted: Unit<Vector>,
reflection_limit: u32,
indices: RefractionInfo,
) -> LinearColor {
if transparency > 1e-5 && reflection_limit > 0 {
let refraction_start = point + refracted.as_ref() * 0.001;
if let Some((t, obj)) = self.cast_ray(Ray::new(refraction_start, refracted)) {
let resulting_position = refraction_start + refracted.as_ref() * t;
let refracted = self.color_at(
resulting_position,
obj,
refracted,
reflection_limit - 1,
indices,
);
return refracted * transparency;
}
}
LinearColor::black()
}
fn reflection(
&self,
point: Point,
reflected: Unit<Vector>,
reflection_limit: u32,
indices: RefractionInfo,
) -> LinearColor {
if reflection_limit > 0 {
let reflection_start = point + reflected.as_ref() * 0.001;
if let Some((t, obj)) = self.cast_ray(Ray::new(reflection_start, reflected)) {
let resulting_position = reflection_start + reflected.as_ref() * t;
let color = self.color_at(
resulting_position,
obj,
reflected,
reflection_limit - 1,
indices,
);
return color;
}
};
LinearColor::black()
}
fn illuminate(
&self,
point: Point,
object_color: LinearColor,
properties: &LightProperties,
normal: Unit<Vector>,
reflected: Unit<Vector>,
) -> LinearColor {
let ambient = self.illuminate_ambient(object_color.clone());
let spatial = self.illuminate_spatial(point, properties, normal, reflected);
ambient + object_color * spatial
}
fn illuminate_ambient(&self, color: LinearColor) -> LinearColor {
self.scene
.lights
.ambient_lights_iter()
.map(|light| color.clone() * light.illumination(&Point::origin()))
.map(LinearColor::clamp)
.sum()
}
fn illuminate_spatial(
&self,
point: Point,
properties: &LightProperties,
normal: Unit<Vector>,
reflected: Unit<Vector>,
) -> LinearColor {
self.scene
.lights
.spatial_lights_iter()
.map(|light| {
let (direction, t) = light.to_source(&point);
let light_ray = Ray::new(point + direction.as_ref() * 0.001, direction);
match self.cast_ray(light_ray) {
// Take shadows into account
Some((obstacle_t, _)) if obstacle_t < t => return LinearColor::black(),
_ => {}
}
let lum = light.illumination(&point);
let diffused = properties.diffuse.clone() * normal.dot(&direction);
let specular = properties.specular.clone() * reflected.dot(&direction);
lum * (diffused + specular)
})
.map(LinearColor::clamp)
.sum()
}
}
impl Renderer for Raytracer {
fn render(&self) -> RgbImage {
self.render()
}
}