src/bin/minitracer/main.rs

@@ -2,7 +2,7 @@ use std::error::Error;
 
 use glam::uvec2;
 use raytracing3::present::{self, Presenter};
-use raytracing3::scene::{Renderer, SceneParams};
+use raytracing3::scene::{load_envmap, Renderer, SceneParams};
 use winit::{
 	event::{Event, WindowEvent},
 	event_loop::EventLoop,
@@ -21,12 +21,13 @@ fn main() {
 		.unwrap();
 
 	let (device, queue, surface) = pollster::block_on(init_gpu(window)).unwrap();
+	let envmap = load_envmap(&device, &queue);
 	queue.submit([]);
 
 	let output_format = wgpu::TextureFormat::Bgra8UnormSrgb;
 	let hdr_format = wgpu::TextureFormat::Rgba16Float;
 	let scene = SceneParams::new(N_SPHERES);
-	let renderer = Renderer::new(&device);
+	let renderer = Renderer::new(&device, envmap);
 	let presenter = Presenter::new(&device, output_format);
 
 	let mut frame = 0;

src/bin/rec.rs

@@ -8,7 +8,7 @@ use std::{fs, io};
 use glam::{uvec2, UVec2};
 use image::buffer::ConvertBuffer;
 use raytracing3::present::{self, Presenter};
-use raytracing3::scene::{Renderer, SceneParams};
+use raytracing3::scene::{load_envmap, Renderer, SceneParams};
 
 const SIZE: UVec2 = uvec2(1920, 1080);
 const FRAME_RATE: u32 = 60;
@@ -82,6 +82,7 @@ fn do_work(img_sender: async_channel::Sender<Frame>, start_frame: u32, stop_fram
 	let img_sender = Arc::new(img_sender);
 
 	let (device, queue) = pollster::block_on(init_gpu()).unwrap();
+	let envmap = load_envmap(&device, &queue);
 	queue.submit([]);
 
 	let texsize = wgpu::Extent3d {
@@ -94,7 +95,7 @@ fn do_work(img_sender: async_channel::Sender<Frame>, start_frame: u32, stop_fram
 	let hdr_format = wgpu::TextureFormat::Rgba16Float;
 
 	let scene = SceneParams::new(N_SPHERES);
-	let renderer = Renderer::new(&device);
+	let renderer = Renderer::new(&device, envmap);
 	let presenter = Presenter::new(&device, output_format);
 
 	println!("Rendering...");

src/scene.rs

@@ -1,10 +1,9 @@
 use crate::anim::{self, SphereParams};
-use crate::trace::{self, Tracer, TracerData};
-use crate::Sphere;
+use crate::trace::{self, Tracer, TracerData, TracerEnv};
 use glam::{mat3, uvec2, vec3, UVec2, Vec3};
+use image::ImageReader;
 use std::f32::consts::PI;
 
-#[derive(Debug, Clone, Copy)]
 struct CamLoc {
 	eye: Vec3,
 	forward: Vec3,
@@ -34,39 +33,47 @@ const CAMERA_LAG: f32 = 0.03;
 
 pub struct Renderer {
 	tracer: Tracer,
+	env: TracerEnv,
 }
 
 impl Renderer {
-	pub fn new(device: &wgpu::Device) -> Self {
+	pub fn new(device: &wgpu::Device, env: wgpu::TextureView) -> Self {
 		let hdr_format = wgpu::TextureFormat::Rgba16Float;
 		let tracer = Tracer::new(&device, hdr_format);
-		Self { tracer }
+		let env = TracerEnv::new(&device, &tracer, &env);
+		Self { tracer, env }
 	}
 }
 
 pub struct SceneParams {
-	spheres: Vec<Sphere>,
-	camera: CamLoc,
+	pub spheres: Vec<SphereParams>,
+	pub camera: SphereParams,
+	pub target: SphereParams,
 }
 
 impl SceneParams {
 	pub fn new(n_spheres: u32) -> Self {
 		let mut rng = rand_pcg::Pcg32::new(42, 0);
-		const R: f32 = 100.;
-		let sphere = Sphere {
-			center: vec3(0., 0., -R),
-			radius: R,
-			emit_color: vec3(0., 0., 0.),
-			reflect_color: Vec3::splat(0.3),
-			glossiness: 0.,
+		let spheres: Vec<_> = {
+			let distr = anim::distr();
+			(0..n_spheres).map(|_| distr(&mut rng)).collect()
 		};
-		let spheres = vec![sphere];
-		let camera = CamLoc {
-			eye: vec3(-1., -1., 1.),
-			forward: vec3(1., 1., 0.).normalize(),
-			right: vec3(1., -1., 0.).normalize(),
+		let camera = {
+			let mut p = anim::distr()(&mut rng);
+			p.amplitudes *= 2.0;
+			p.frequencies *= 0.1;
+			p
 		};
-		Self { spheres, camera }
+		let target = {
+			let mut p = spheres[0];
+			p.phases -= 2. * PI * CAMERA_LAG * p.frequencies;
+			p
+		};
+		Self {
+			spheres,
+			camera,
+			target,
+		}
 	}
 }
 
@@ -96,12 +103,18 @@ impl Renderer {
 		time: f32,
 		seed: u32,
 	) {
+		let target = scene.target.to_sphere(time).center;
+		let eye = scene.camera.to_sphere(time).center;
+		let right = scene.camera.deriv(time);
+		let forward = target - eye;
 		let viewport = make_viewport(size.x, size.y);
-		let location = convert_location(scene.camera);
-		let data = TracerData::new(&device, &self.tracer, &scene.spheres);
+		let location = convert_location(CamLoc { eye, forward, right });
+		let spheres: Vec<_> = scene.spheres.iter().map(|p| p.to_sphere(time)).collect();
+		let data = TracerData::new(&device, &self.tracer, &spheres);
 		self.tracer.render(
 			&mut render_pass.0,
 			&data,
+			&self.env,
 			trace::Params {
 				max_reflections: 3,
 				min_strength: 0.1,
@@ -112,8 +125,82 @@ impl Renderer {
 			trace::Aperture {
 				radius: 0.0003,
 				focal_distance: std::f32::INFINITY,
+				glare_strength: 0.1,
+				glare_radius: 0.1,
 			},
 			location,
 		);
 	}
 }
+
+pub fn load_envmap(device: &wgpu::Device, queue: &wgpu::Queue) -> wgpu::TextureView {
+	let imgs = std::thread::scope(|s| {
+		[0, 1, 2, 3, 4, 5]
+			.map(|face| {
+				s.spawn(move || {
+					let img = ImageReader::open(format!("textures/env{face}.webp"))
+						.unwrap()
+						.with_guessed_format()
+						.unwrap()
+						.decode()
+						.unwrap();
+					img.to_rgba8()
+				})
+			})
+			.map(|t| t.join().unwrap())
+	});
+	let size = imgs[0].width();
+	for img in &imgs {
+		assert!(img.width() == size);
+		assert!(img.height() == size);
+	}
+	let texture = device.create_texture(&wgpu::TextureDescriptor {
+		label: None,
+		size: wgpu::Extent3d {
+			width: size,
+			height: size,
+			depth_or_array_layers: 6,
+		},
+		mip_level_count: 1,
+		sample_count: 1,
+		dimension: wgpu::TextureDimension::D2,
+		format: wgpu::TextureFormat::Rgba8UnormSrgb,
+		usage: wgpu::TextureUsages::TEXTURE_BINDING | wgpu::TextureUsages::COPY_DST,
+		view_formats: &[],
+	});
+	for (face, img) in imgs.iter().enumerate() {
+		queue.write_texture(
+			wgpu::ImageCopyTexture {
+				texture: &texture,
+				mip_level: 0,
+				origin: wgpu::Origin3d {
+					x: 0,
+					y: 0,
+					z: face as u32,
+				},
+				aspect: wgpu::TextureAspect::All,
+			},
+			img.as_raw(),
+			wgpu::ImageDataLayout {
+				offset: 0,
+				bytes_per_row: Some(4 * size),
+				rows_per_image: Some(size),
+			},
+			wgpu::Extent3d {
+				width: size,
+				height: size,
+				depth_or_array_layers: 1,
+			},
+		);
+	}
+	texture.create_view(&wgpu::TextureViewDescriptor {
+		label: None,
+		format: None,
+		dimension: Some(wgpu::TextureViewDimension::Cube),
+		aspect: wgpu::TextureAspect::All,
+		base_mip_level: 0,
+		mip_level_count: None,
+		base_array_layer: 0,
+		array_layer_count: None,
+	})
+}

src/trace.rs

@@ -22,6 +22,8 @@ pub struct Viewport {
 pub struct Aperture {
 	pub radius: f32,
 	pub focal_distance: f32, // from 0 (exclusive) to +∞ (inclusive)
+	pub glare_strength: f32,
+	pub glare_radius: f32, // at distance 1
 }
 
 #[derive(Debug, Clone, Copy)]
@@ -48,6 +50,8 @@ struct CameraData {
 	aperture: f32,
 	eye: Vec3,
 	antifocal: f32,
+	glare_strength: f32,
+	glare_radius: f32,
 }
 
 impl From<(Viewport, CameraLocation, Aperture)> for CameraData {
@@ -61,6 +65,8 @@ impl From<(Viewport, CameraLocation, Aperture)> for CameraData {
 			height: value.0.corner.y / value.0.corner.z,
 			aperture: value.2.radius,
 			antifocal: 1. / value.2.focal_distance,
+			glare_strength: value.2.glare_strength,
+			glare_radius: value.2.glare_radius,
 		}
 	}
 }
@@ -113,6 +119,10 @@ pub struct TracerData {
 	bindings: wgpu::BindGroup,
 }
 
+pub struct TracerEnv {
+	bindings: wgpu::BindGroup,
+}
+
 static SHADER: &str = include_str!("trace.wgsl");
 
 impl Tracer {
@@ -140,9 +150,30 @@ impl Tracer {
 				count: None,
 			}],
 		});
+		let envmap_bgl = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+			label: None,
+			entries: &[
+				wgpu::BindGroupLayoutEntry {
+					binding: 0,
+					visibility: wgpu::ShaderStages::FRAGMENT,
+					ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Filtering),
+					count: None,
+				},
+				wgpu::BindGroupLayoutEntry {
+					binding: 1,
+					visibility: wgpu::ShaderStages::FRAGMENT,
+					ty: wgpu::BindingType::Texture {
+						sample_type: wgpu::TextureSampleType::Float { filterable: true },
+						view_dimension: wgpu::TextureViewDimension::Cube,
+						multisampled: false,
+					},
+					count: None,
+				},
+			],
+		});
 		let pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
 			label: None,
-			bind_group_layouts: &[&spheres_bgl],
+			bind_group_layouts: &[&spheres_bgl, &envmap_bgl],
 			push_constant_ranges: &[wgpu::PushConstantRange {
 				stages: wgpu::ShaderStages::FRAGMENT,
 				range: 0..mem::size_of::<ParamsData>() as u32,
@@ -227,6 +258,7 @@ impl Tracer {
 		&self,
 		pass: &mut wgpu::RenderPass,
 		data: &TracerData,
+		env: &TracerEnv,
 		params: Params,
 		viewport: Viewport,
 		aperture: Aperture,
@@ -243,6 +275,7 @@ impl Tracer {
 		);
 		pass.set_vertex_buffer(0, self.view_buf.slice(..));
 		pass.set_bind_group(0, &data.bindings, &[]);
+		pass.set_bind_group(1, &env.bindings, &[]);
 		pass.draw(0..4, 0..1);
 	}
 }
@@ -266,3 +299,24 @@ impl TracerData {
 		Self { bindings }
 	}
 }
+
+impl TracerEnv {
+	pub fn new(device: &wgpu::Device, tracer: &Tracer, view: &wgpu::TextureView) -> Self {
+		let sampler = device.create_sampler(&wgpu::SamplerDescriptor::default());
+		let bindings = device.create_bind_group(&wgpu::BindGroupDescriptor {
+			label: None,
+			layout: &tracer.pipeline.get_bind_group_layout(1),
+			entries: &[
+				wgpu::BindGroupEntry {
+					binding: 0,
+					resource: wgpu::BindingResource::Sampler(&sampler),
+				},
+				wgpu::BindGroupEntry {
+					binding: 1,
+					resource: wgpu::BindingResource::TextureView(view),
+				},
+			],
+		});
+		Self { bindings }
+	}
+}

src/trace.wgsl

@@ -12,6 +12,9 @@ struct Params {
 	aperture: f32,
 	eye: vec3f,
 	antifocal: f32,
+
+	glare_strength: f32,
+	glare_radius: f32,
 }
 
 struct Sphere {
@@ -33,6 +36,8 @@ struct Varying {
 
 var<push_constant> params: Params;
 @group(0) @binding(1) var<storage, read> spheres: array<Sphere>;
+@group(1) @binding(0) var env_sampler: sampler;
+@group(1) @binding(1) var env_texture: texture_cube<f32>;
 
 @vertex
 fn on_vertex(in: Vertex) -> Varying {
@@ -79,7 +84,13 @@ fn trace_fragment(in: Varying) -> vec3f {
 	pos = params.eye + aperture_offset_abs;
 	let off_px = vec2(rand_float(), rand_float()) - .5;
 	let off_w = mat2x3(dpdx(in.dir), dpdy(in.dir));
-	let dir = in.dir + off_w * off_px;
+	var dir = in.dir + off_w * off_px;
+	if (rand_float() < params.glare_strength) {
+		let p = rand_float();
+		let d = params.glare_radius * pow(p, 2.);
+		let glare_off = d * rand_disc();
+		dir += view_mtx * vec3(glare_off, 0.);
+	}
 	ray = normalize(dir - params.antifocal * aperture_offset_abs);
 
 	for (var k = 0; k < params.max_reflections; k++) {
@@ -93,28 +104,8 @@ fn trace_fragment(in: Varying) -> vec3f {
 			}
 		}
 		if (sphere == -1) {
-			let theta = dot(ray, normalize(vec3(1., 2., 1.)));
-			var env: vec3f; // in kilonits
-
-			const ILLUMINANCE_LUX = 1e5;
-			const ANGULAR_DIAMETER_DEG = 20.0; // Sun: 0.5°
-
-			const PI = 3.141592653589793;
-
-			const ANGULAR_DIAMETER_RAD = PI / 180.0 * ANGULAR_DIAMETER_DEG;
-			const THETA = 0.5 * ANGULAR_DIAMETER_RAD;
-			const COS_THETA = 1.0 - 0.5 * THETA * THETA; // approximately
-
-			const SOLID_ANGLE_SR = PI * THETA * THETA; // approximately
-			const LUMINANCE_NIT = ILLUMINANCE_LUX / SOLID_ANGLE_SR;
-			const LUMINANCE_KNIT = 1e-3 * LUMINANCE_NIT;
-
-			if (theta > COS_THETA) {
-				env = vec3(1.0, 0.9, 0.6) * LUMINANCE_KNIT;
-			} else {
-				env = mix(vec3(0.5, 1.0, 2.0), vec3(2.0, 3.0, 4.0), 0.5 * theta + 0.5);
-			}
-			result += color * env.xyz;
+			let env = textureSampleLevel(env_texture, env_sampler, ray, 0.0);
+			result += 3.0 * color * env.xyz;
 			break;
 		}
 		let s = spheres[sphere];