library: render: pathtracer: basic pathtracing

This commit is contained in:
Bruno BELANYI 2020-04-06 15:40:34 +02:00
parent ddebd55fcd
commit a10fd07f43

View file

@ -1,7 +1,11 @@
use super::super::utils::{buffer_to_image, prepare_buffer}; use super::super::utils::{buffer_to_image, prepare_buffer, sample_hemisphere};
use super::super::Renderer; use super::super::Renderer;
use crate::core::LinearColor; use crate::{
use crate::scene::{Object, Scene}; core::LinearColor,
material::Material,
scene::{Object, Scene},
shape::Shape,
};
use beevee::ray::Ray; use beevee::ray::Ray;
use image::RgbImage; use image::RgbImage;
@ -61,12 +65,38 @@ impl Pathtracer {
let ray = self.scene.camera.ray_with_ratio(x, y); let ray = self.scene.camera.ray_with_ratio(x, y);
self.cast_ray(ray).map_or_else( self.cast_ray(ray).map_or_else(
|| self.scene.background.clone(), || self.scene.background.clone(),
|(t, obj)| { |(t, obj)| self.radiance(ray, t, obj, self.scene.reflection_limit),
LinearColor::new(1., 1., 1.) // FIXME: calculate real color
},
) )
} }
fn radiance(&self, ray: Ray, t: f32, obj: &Object, limit: u32) -> LinearColor {
// This doesn't look great, but it works ¯\_(ツ)_/¯
let hit_pos = ray.origin + ray.direction.as_ref() * t;
let texel = obj.shape.project_texel(&hit_pos);
let properties = obj.material.properties(texel);
// If we are the at recursion limit, return the light emitted by the object
if limit == 0 {
return properties.emitted;
};
// Get BRDF
// FIXME: what about the material's albedo ?
let brdf = properties.diffuse;
// Pick a new direction
let normal = obj.shape.normal(&hit_pos);
let (new_direction, weight) = sample_hemisphere(normal);
let cos_new_ray = new_direction.dot(&normal);
// Calculate the incoming light along the new ray
let new_ray = Ray::new(hit_pos + new_direction.as_ref() * 0.001, new_direction);
let incoming = self
.cast_ray(new_ray)
.map_or_else(LinearColor::black, |(t, obj)| {
self.radiance(new_ray, t, obj, limit - 1)
});
// Put it all together
properties.emitted + (brdf * incoming * cos_new_ray * weight)
}
fn cast_ray(&self, ray: Ray) -> Option<(f32, &Object)> { fn cast_ray(&self, ray: Ray) -> Option<(f32, &Object)> {
self.scene.bvh.walk(&ray, &self.scene.objects) self.scene.bvh.walk(&ray, &self.scene.objects)
} }