Move camera location into push constants

src/bin/minitracer/main.rs

@@ -1,9 +1,9 @@
 use std::error::Error;
 
-use glam::{mat3, uvec2, vec2, vec3, Vec3};
+use glam::{mat3, uvec2, Vec3};
 use image::ImageReader;
 use present::Presenter;
-use trace::{Tracer, TracerData, TracerEnv, Vertex};
+use trace::{Tracer, TracerData, TracerEnv};
 use winit::{
 	event::{Event, WindowEvent},
 	event_loop::EventLoop,
@@ -22,25 +22,19 @@ struct CamLoc {
 	right: Vec3,
 }
 
-fn make_viewport(cam: CamLoc, w: u32, h: u32) -> [Vertex; 4] {
+fn make_viewport(cam: CamLoc, w: u32, h: u32) -> trace::CameraLocation {
 	let size = uvec2(w, h).as_vec2();
 	let size = size.normalize();
 	let (w, h, d) = (size.x, size.y, 1.);
-	let screen_coord = [vec2(-1., -1.), vec2(1., -1.), vec2(-1., 1.), vec2(1., 1.)];
 
-	let eye = cam.eye;
-	let fwd = cam.forward.normalize();
-	let up = cam.right.cross(fwd).normalize();
-	let right = up.cross(fwd);
+	let fwd = d * cam.forward.normalize();
+	let up = h * cam.right.cross(fwd).normalize();
+	let right = w * up.cross(fwd).normalize();
 
-	let m = mat3(fwd, right, up);
-
-	let world_coord = [vec3(d, -w, -h), vec3(d, w, -h), vec3(d, -w, h), vec3(d, w, h)];
-	[0, 1, 2, 3].map(|k| Vertex {
-		eye,
-		world: eye + m * world_coord[k],
-		screen: screen_coord[k],
-	})
+	trace::CameraLocation {
+		eye: cam.eye,
+		view: mat3(fwd, right, up),
+	}
 }
 
 const N_SPHERES: u32 = 100;
@@ -60,7 +54,7 @@ fn main() {
 
 	let output_format = wgpu::TextureFormat::Bgra8UnormSrgb;
 	let hdr_format = wgpu::TextureFormat::Rgba16Float;
-	let mut tracer = Tracer::new(&device, hdr_format);
+	let tracer = Tracer::new(&device, hdr_format);
 	let mut rng = rand_pcg::Pcg32::new(42, 0);
 	let sphere_params: Vec<_> = {
 		let distr = anim::distr();
@@ -149,10 +143,7 @@ fn main() {
 							let eye = camera_params.to_sphere(time).center;
 							let right = camera_params.deriv(time);
 							let forward = target_params.to_sphere(time).center - eye;
-							tracer.set_view(
-								&queue,
-								&make_viewport(CamLoc { eye, forward, right }, size.width, size.height),
-							);
+							let view = make_viewport(CamLoc { eye, forward, right }, size.width, size.height);
 							let spheres: Vec<_> = sphere_params.iter().map(|p| p.to_sphere(time)).collect();
 							let data = TracerData::new(&device, &tracer, &spheres);
 							tracer.render(
@@ -165,6 +156,7 @@ fn main() {
 									sphere_count: N_SPHERES,
 									seed: frame,
 								},
+								view,
 							);
 						}
 					}
@@ -222,7 +214,7 @@ async fn init_gpu(wnd: &Window) -> Result<(wgpu::Device, wgpu::Queue, wgpu::Surf
 				label: None,
 				required_features: wgpu::Features::PUSH_CONSTANTS,
 				required_limits: wgpu::Limits {
-					max_push_constant_size: 32,
+					max_push_constant_size: 128,
 					..Default::default()
 				},
 				memory_hints: Default::default(),

src/bin/minitracer/trace.rs

@@ -1,7 +1,7 @@
-use std::mem::{self, offset_of};
+use std::mem;
 
 use bytemuck::{bytes_of, cast_slice, Pod, Zeroable};
-use glam::{Vec2, Vec3};
+use glam::{vec2, Mat3, Vec2, Vec3};
 use wgpu::util::DeviceExt;
 
 #[derive(Debug, Clone, Copy, Pod, Zeroable)]
@@ -13,6 +13,47 @@ pub struct Params {
 	pub seed: u32,
 }
 
+#[derive(Debug, Clone, Copy)]
+pub struct CameraLocation {
+	pub eye: Vec3,
+	pub view: Mat3,
+}
+
+#[derive(Debug, Clone, Copy, Pod, Zeroable)]
+#[repr(C)]
+struct ParamsData {
+	params: Params,
+	camera: CameraData,
+}
+
+#[derive(Debug, Clone, Copy, Pod, Zeroable)]
+#[repr(C)]
+struct CameraData {
+	u: Vec3,
+	pad1: f32,
+	v: Vec3,
+	pad2: f32,
+	w: Vec3,
+	pad3: f32,
+	eye: Vec3,
+	pad4: f32,
+}
+
+impl From<CameraLocation> for CameraData {
+	fn from(value: CameraLocation) -> Self {
+		CameraData {
+			u: value.view.x_axis,
+			v: value.view.y_axis,
+			w: value.view.z_axis,
+			eye: value.eye,
+			pad1: 0.,
+			pad2: 0.,
+			pad3: 0.,
+			pad4: 0.,
+		}
+	}
+}
+
 #[derive(Debug, Clone, Copy)]
 pub struct Sphere {
 	pub center: Vec3,
@@ -24,9 +65,7 @@ pub struct Sphere {
 
 #[derive(Debug, Clone, Copy, Pod, Zeroable)]
 #[repr(C)]
-pub struct Vertex {
-	pub eye: Vec3,
-	pub world: Vec3,
+struct Vertex {
 	pub screen: Vec2,
 }
 
@@ -71,11 +110,11 @@ static SHADER: &str = include_str!("trace.wgsl");
 
 impl Tracer {
 	pub fn new(device: &wgpu::Device, format: wgpu::TextureFormat) -> Self {
-		let view_buf = device.create_buffer(&wgpu::BufferDescriptor {
+		let screen_coord = [vec2(-1., -1.), vec2(1., -1.), vec2(-1., 1.), vec2(1., 1.)];
+		let view_buf = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
 			label: None,
-			size: (4 * mem::size_of::<Vertex>()) as u64,
-			usage: wgpu::BufferUsages::VERTEX | wgpu::BufferUsages::COPY_DST,
-			mapped_at_creation: false,
+			contents: cast_slice(&screen_coord),
+			usage: wgpu::BufferUsages::VERTEX,
 		});
 		let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
 			label: None,
@@ -120,7 +159,7 @@ impl Tracer {
 			bind_group_layouts: &[&spheres_bgl, &envmap_bgl],
 			push_constant_ranges: &[wgpu::PushConstantRange {
 				stages: wgpu::ShaderStages::FRAGMENT,
-				range: 0..16,
+				range: 0..mem::size_of::<ParamsData>() as u32,
 			}],
 		});
 		let pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
@@ -133,23 +172,11 @@ impl Tracer {
 				buffers: &[wgpu::VertexBufferLayout {
 					array_stride: size_of::<Vertex>() as u64,
 					step_mode: wgpu::VertexStepMode::Vertex,
-					attributes: &[
-						wgpu::VertexAttribute {
-							shader_location: 0,
-							offset: offset_of!(Vertex, eye) as u64,
-							format: wgpu::VertexFormat::Float32x3,
-						},
-						wgpu::VertexAttribute {
-							shader_location: 1,
-							offset: offset_of!(Vertex, world) as u64,
-							format: wgpu::VertexFormat::Float32x3,
-						},
-						wgpu::VertexAttribute {
-							shader_location: 2,
-							offset: offset_of!(Vertex, screen) as u64,
-							format: wgpu::VertexFormat::Float32x2,
-						},
-					],
+					attributes: &[wgpu::VertexAttribute {
+						shader_location: 0,
+						offset: 0,
+						format: wgpu::VertexFormat::Float32x2,
+					}],
 				}],
 			},
 			primitive: wgpu::PrimitiveState {
@@ -189,13 +216,23 @@ impl Tracer {
 		Self { view_buf, pipeline }
 	}
 
-	pub fn set_view(&mut self, queue: &wgpu::Queue, vertices: &[Vertex; 4]) {
-		queue.write_buffer(&self.view_buf, 0, bytes_of(vertices));
-	}
-
-	pub fn render(&self, pass: &mut wgpu::RenderPass, data: &TracerData, env: &TracerEnv, params: Params) {
+	pub fn render(
+		&self,
+		pass: &mut wgpu::RenderPass,
+		data: &TracerData,
+		env: &TracerEnv,
+		params: Params,
+		camera: CameraLocation,
+	) {
 		pass.set_pipeline(&self.pipeline);
-		pass.set_push_constants(wgpu::ShaderStages::FRAGMENT, 0, bytes_of(&params));
+		pass.set_push_constants(
+			wgpu::ShaderStages::FRAGMENT,
+			0,
+			bytes_of(&ParamsData {
+				params,
+				camera: camera.into(),
+			}),
+		);
 		pass.set_vertex_buffer(0, self.view_buf.slice(..));
 		pass.set_bind_group(0, &data.bindings, &[]);
 		pass.set_bind_group(1, &env.bindings, &[]);

src/bin/minitracer/trace.wgsl

@@ -3,6 +3,8 @@ struct Params {
 	min_strength: f32,
 	sphere_count: i32,
 	seed: u32,
+	view: mat3x3f,
+	eye: vec3f,
 }
 
 struct Sphere {
@@ -14,9 +16,7 @@ struct Sphere {
 }
 
 struct Vertex {
-	@location(0) eye: vec3f,
-	@location(1) world: vec3f,
-	@location(2) screen: vec2f,
+	@location(0) screen: vec2f,
 }
 
 struct Varying {
@@ -32,7 +32,7 @@ var<push_constant> params: Params;
 
 @vertex
 fn on_vertex(in: Vertex) -> Varying {
-	return Varying(in.eye, in.world, vec4(in.screen, 0.0, 1.0));
+	return Varying(params.eye, params.eye + params.view * vec3(1.0, in.screen), vec4(in.screen, 0.0, 1.0));
 }
 
 @fragment