Minor cleanup

src/main.rs

@@ -174,10 +174,10 @@ pub async fn run() -> Result<()> {
 			Event::RedrawRequested(window_id) if window_id == gpu.window().id() => {
 				gpu.update();
 				game.update();
-				match gpu.render(&game.sprites(), game.camera) {
+				match gpu.render(&game) {
 					Ok(_) => {}
 					// Reconfigure the surface if lost
-					Err(wgpu::SurfaceError::Lost) => gpu.resize(gpu.size),
+					Err(wgpu::SurfaceError::Lost) => gpu.resize(gpu.window_size),
 					// The system is out of memory, we should probably quit
 					Err(wgpu::SurfaceError::OutOfMemory) => *control_flow = ControlFlow::Exit,
 					// All other errors (Outdated, Timeout) should be resolved by the next frame

src/render/gpustate.rs

@@ -1,11 +1,11 @@
 use anyhow::Result;
 use bytemuck;
-use cgmath::{EuclideanSpace, Point2};
+use cgmath::{EuclideanSpace, Point2, Vector2};
 use std::{iter, rc::Rc};
 use wgpu;
-use winit::{self, window::Window};
+use winit::{self, dpi::PhysicalSize, window::Window};
 
-use crate::{Camera, Sprite};
+use crate::Game;
 
 use super::{
 	pipeline::PipelineBuilder,
@@ -13,7 +13,7 @@ use super::{
 	util::Transform,
 	vertexbuffer::{
 		data::{SPRITE_INDICES, SPRITE_VERTICES},
-		types::{PlainVertex, SpriteInstance, StarInstance, TexturedVertex},
+		types::{PlainVertex, SpriteInstance, StarfieldInstance, TexturedVertex},
 		VertexBuffer,
 	},
 };
@@ -25,7 +25,8 @@ pub struct GPUState {
 	queue: wgpu::Queue,
 
 	pub window: Window,
-	pub size: winit::dpi::PhysicalSize<u32>,
+	pub window_size: winit::dpi::PhysicalSize<u32>,
+	window_aspect: f32,
 
 	sprite_pipeline: wgpu::RenderPipeline,
 	starfield_pipeline: wgpu::RenderPipeline,
@@ -42,11 +43,12 @@ struct VertexBuffers {
 impl GPUState {
 	// We can draw at most this many sprites on the screen.
 	// TODO: compile-time option
-	pub const SPRITE_LIMIT: u64 = 100;
+	pub const SPRITE_INSTANCE_LIMIT: u64 = 100;
-	pub const STAR_LIMIT: u64 = 100;
+	pub const STARFIELD_INSTANCE_LIMIT: u64 = 100;
 
 	pub async fn new(window: Window) -> Result<Self> {
-		let size = window.inner_size();
+		let window_size = window.inner_size();
+		let window_aspect = window_size.width as f32 / window_size.height as f32;
 
 		let instance = wgpu::Instance::new(wgpu::InstanceDescriptor {
 			backends: wgpu::Backends::all(),
@@ -97,8 +99,8 @@ impl GPUState {
 			config = wgpu::SurfaceConfiguration {
 				usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
 				format: surface_format,
-				width: size.width,
+				width: window_size.width,
-				height: size.height,
+				height: window_size.height,
 				present_mode: surface_caps.present_modes[0],
 				alpha_mode: surface_caps.alpha_modes[0],
 				view_formats: vec![],
@@ -113,15 +115,15 @@ impl GPUState {
 				&device,
 				Some(SPRITE_VERTICES),
 				Some(SPRITE_INDICES),
-				Self::SPRITE_LIMIT,
+				Self::SPRITE_INSTANCE_LIMIT,
 			)),
 
-			starfield: Rc::new(VertexBuffer::new::<PlainVertex, StarInstance>(
+			starfield: Rc::new(VertexBuffer::new::<PlainVertex, StarfieldInstance>(
 				"starfield",
 				&device,
 				None,
 				None,
-				Self::STAR_LIMIT,
+				Self::STARFIELD_INSTANCE_LIMIT,
 			)),
 		};
 
@@ -159,7 +161,8 @@ impl GPUState {
 			queue,
 
 			window,
-			size,
+			window_size,
+			window_aspect,
 
 			sprite_pipeline,
 			starfield_pipeline,
@@ -173,9 +176,10 @@ impl GPUState {
 		&self.window
 	}
 
-	pub fn resize(&mut self, new_size: winit::dpi::PhysicalSize<u32>) {
+	pub fn resize(&mut self, new_size: PhysicalSize<u32>) {
 		if new_size.width > 0 && new_size.height > 0 {
-			self.size = new_size;
+			self.window_size = new_size;
+			self.window_aspect = new_size.width as f32 / new_size.height as f32;
 			self.config.width = new_size.width;
 			self.config.height = new_size.height;
 			self.surface.configure(&self.device, &self.config);
@@ -184,56 +188,20 @@ impl GPUState {
 
 	pub fn update(&mut self) {}
 
-	pub fn render(
+	/// Make a SpriteInstance for each of the game's visible sprites.
-		&mut self,
+	/// Will panic if SPRITE_INSTANCE_LIMIT is exceeded.
-		sprites: &Vec<Sprite>,
+	///
-		camera: Camera,
+	/// This is only called inside self.render()
-	) -> Result<(), wgpu::SurfaceError> {
+	fn make_sprite_instances(&self, game: &Game) -> Vec<SpriteInstance> {
-		let output = self.surface.get_current_texture()?;
+		let mut instances: Vec<SpriteInstance> = Vec::new();
-		let view = output
-			.texture
-			.create_view(&wgpu::TextureViewDescriptor::default());
-
-		let mut encoder = self
-			.device
-			.create_command_encoder(&wgpu::CommandEncoderDescriptor {
-				label: Some("sprite render encoder"),
-			});
-
-		let mut render_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
-			label: Some("sprite render pass"),
-
-			color_attachments: &[Some(wgpu::RenderPassColorAttachment {
-				view: &view,
-				resolve_target: None,
-				ops: wgpu::Operations {
-					load: wgpu::LoadOp::Clear(wgpu::Color {
-						r: 0.0,
-						g: 0.0,
-						b: 0.0,
-						a: 1.0,
-					}),
-					store: wgpu::StoreOp::Store,
-				},
-			})],
-			depth_stencil_attachment: None,
-			occlusion_query_set: None,
-			timestamp_writes: None,
-		});
-
-		// Correct for screen aspect ratio
-		// (it may not be square!)
-		let screen_aspect = self.size.width as f32 / self.size.height as f32;
 
 		// Game coordinates (relative to camera) of ne and sw corners of screen.
 		// Used to skip off-screen sprites.
-		let clip_ne = Point2::from((-1.0, 1.0)) * camera.zoom;
+		let clip_ne = Point2::from((-1.0, 1.0)) * game.camera.zoom;
-		let clip_sw = Point2::from((1.0, -1.0)) * camera.zoom;
+		let clip_sw = Point2::from((1.0, -1.0)) * game.camera.zoom;
 
-		let mut instances: Vec<SpriteInstance> = Vec::new();
+		for s in game.sprites() {
-
+			let pos = s.post_parallax_position(game.camera) - game.camera.pos.to_vec();
-		for s in sprites {
-			let pos = s.post_parallax_position(camera) - camera.pos.to_vec();
 			let texture = self.texture_array.get_texture(&s.name[..]);
 
 			// Game dimensions of this sprite post-scale.
@@ -261,14 +229,14 @@ impl GPUState {
 			//
 			// We can't use screen_pos to exclude off-screen sprites because
 			// it can't account for height and width.
-			let scale = height / camera.zoom;
+			let scale = height / game.camera.zoom;
-			let screen_pos: Point2<f32> = pos / camera.zoom;
+			let screen_pos: Point2<f32> = pos / game.camera.zoom;
 
 			instances.push(SpriteInstance {
 				transform: Transform {
 					pos: screen_pos,
-					aspect: texture.aspect,
+					sprite_aspect: texture.aspect,
-					screen_aspect,
+					window_aspect: self.window_aspect,
 					rotate: s.angle,
 					scale,
 				}
@@ -279,46 +247,101 @@ impl GPUState {
 		}
 
 		// Enforce sprite limit
-		if sprites.len() as u64 > Self::SPRITE_LIMIT {
+		if instances.len() as u64 > Self::SPRITE_INSTANCE_LIMIT {
 			// TODO: no panic, handle this better.
-			panic!("Sprite limit exceeded!")
+			unreachable!("Sprite limit exceeded!")
 		}
 
-		// Write new sprite data to buffer
+		return instances;
-		self.queue.write_buffer(
+	}
-			&self.vertex_buffers.sprite.instances,
-			0,
-			bytemuck::cast_slice(&instances),
-		);
 
-		render_pass.set_bind_group(0, &self.texture_array.bind_group, &[]);
+	/// Make a StarfieldInstance for each star that needs to be drawn.
-
+	/// Will panic if STARFIELD_INSTANCE_LIMIT is exceeded.
-		let nstances: Vec<StarInstance> = (-10..10)
+	///
-			.map(|x| StarInstance {
+	/// This is only called inside self.render()
-				transform: cgmath::Matrix4::from_translation(cgmath::Vector3 {
+	fn make_starfield_instances(&self, _game: &Game) -> Vec<StarfieldInstance> {
+		let instances: Vec<StarfieldInstance> = (-10..10)
+			.map(|x| StarfieldInstance {
+				position: Vector2 {
 					x: x as f32 / 10.0,
 					y: 0.0,
-					z: 0.0,
+				}
-				})
 				.into(),
 			})
 			.collect();
 
+		// Enforce starfield limit
+		if instances.len() as u64 > Self::STARFIELD_INSTANCE_LIMIT {
+			// TODO: no panic, handle this better.
+			unreachable!("Starfield limit exceeded!")
+		}
+		return instances;
+	}
+
+	pub fn render(&mut self, game: &Game) -> Result<(), wgpu::SurfaceError> {
+		let output = self.surface.get_current_texture()?;
+		let view = output
+			.texture
+			.create_view(&wgpu::TextureViewDescriptor::default());
+
+		let mut encoder = self
+			.device
+			.create_command_encoder(&wgpu::CommandEncoderDescriptor {
+				label: Some("render encoder"),
+			});
+
+		let mut render_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
+			label: Some("render pass"),
+
+			color_attachments: &[Some(wgpu::RenderPassColorAttachment {
+				view: &view,
+				resolve_target: None,
+				ops: wgpu::Operations {
+					load: wgpu::LoadOp::Clear(wgpu::Color {
+						r: 0.0,
+						g: 0.0,
+						b: 0.0,
+						a: 1.0,
+					}),
+					store: wgpu::StoreOp::Store,
+				},
+			})],
+			depth_stencil_attachment: None,
+			occlusion_query_set: None,
+			timestamp_writes: None,
+		});
+
+		// Create sprite instances
+		let sprite_instances = self.make_sprite_instances(game);
+		self.queue.write_buffer(
+			&self.vertex_buffers.sprite.instances,
+			0,
+			bytemuck::cast_slice(&sprite_instances),
+		);
+
+		// Create starfield instances
+		let starfield_instances = self.make_starfield_instances(game);
 		self.queue.write_buffer(
 			&self.vertex_buffers.starfield.instances,
 			0,
-			bytemuck::cast_slice(&nstances),
+			bytemuck::cast_slice(&starfield_instances),
 		);
 
+		render_pass.set_bind_group(0, &self.texture_array.bind_group, &[]);
+
 		// Starfield pipeline
 		self.vertex_buffers.starfield.set_in_pass(&mut render_pass);
 		render_pass.set_pipeline(&self.starfield_pipeline);
-		render_pass.draw(0..1, 0..nstances.len() as _);
+		render_pass.draw(0..1, 0..starfield_instances.len() as _);
 
 		// Sprite pipeline
 		self.vertex_buffers.sprite.set_in_pass(&mut render_pass);
 		render_pass.set_pipeline(&self.sprite_pipeline);
-		render_pass.draw_indexed(0..SPRITE_INDICES.len() as u32, 0, 0..instances.len() as _);
+		render_pass.draw_indexed(
+			0..SPRITE_INDICES.len() as u32,
+			0,
+			0..sprite_instances.len() as _,
+		);
 
 		// begin_render_pass borrows encoder mutably, so we can't call finish()
 		// without dropping this variable.

src/render/shaders/starfield.wgsl

@@ -1,9 +1,6 @@
 // Vertex shader
 struct InstanceInput {
-	@location(2) transform_matrix_0: vec4<f32>,
+	@location(2) position: vec2<f32>,
-	@location(3) transform_matrix_1: vec4<f32>,
-	@location(4) transform_matrix_2: vec4<f32>,
-	@location(5) transform_matrix_3: vec4<f32>,
 };
 
 struct VertexOutput {
@@ -14,19 +11,10 @@ struct VertexOutput {
 fn vertex_shader_main(
 	instance: InstanceInput,
 ) -> VertexOutput {
-	let transform_matrix = mat4x4<f32>(
-		instance.transform_matrix_0,
-		instance.transform_matrix_1,
-		instance.transform_matrix_2,
-		instance.transform_matrix_3,
-	);
-
 	// Stars consist of only one vertex, so we don't need to pass a buffer into this shader.
 	// We need one instance per star, and that's it!
-	let pos = vec4<f32>(0.0, 0.0, 0.0, 1.0);
-
 	var out: VertexOutput;
-	out.clip_position = transform_matrix * pos;
+	out.clip_position = vec4<f32>(instance.position, 0.0, 1.0);
 	return out;
 }
 

src/render/util.rs

@@ -8,8 +8,8 @@ use super::OPENGL_TO_WGPU_MATRIX;
 // to put it in the right place, at the right angle, with the right scale.
 pub struct Transform {
 	pub pos: Point2<f32>,   // position on screen
-	pub screen_aspect: f32, // width / height. Screen aspect ratio.
+	pub window_aspect: f32, // width / height. Screen aspect ratio.
-	pub aspect: f32,        // width / height. Sprite aspect ratio.
+	pub sprite_aspect: f32, // width / height. Sprite aspect ratio.
 	pub scale: f32,         // if scale = 1, this sprite will be as tall as the screen.
 	pub rotate: Deg<f32>,   // Around this object's center, in degrees measured ccw from vertical
 }
@@ -26,14 +26,14 @@ impl Transform {
 		//
 		// We apply the provided scale here as well as a minor optimization
 		let sprite_aspect_and_scale =
-			Matrix4::from_nonuniform_scale(self.aspect * self.scale, self.scale, 1.0);
+			Matrix4::from_nonuniform_scale(self.sprite_aspect * self.scale, self.scale, 1.0);
 
 		// Apply rotation
 		let rotate = Matrix4::from_angle_z(self.rotate);
 
 		// Apply screen aspect ratio, again preserving height.
 		// This must be done AFTER rotation... think about it!
-		let screen_aspect = Matrix4::from_nonuniform_scale(1.0 / self.screen_aspect, 1.0, 1.0);
+		let screen_aspect = Matrix4::from_nonuniform_scale(1.0 / self.window_aspect, 1.0, 1.0);
 
 		// After finishing all op, translate.
 		// This must be done last, all other operations

src/render/vertexbuffer/types.rs

@@ -53,46 +53,25 @@ impl BufferObject for PlainVertex {
 	}
 }
 
-// Represents a star instance in WGSL
+// Represents a point in the starfield instance in WGSL
 #[repr(C)]
 #[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
-pub struct StarInstance {
+pub struct StarfieldInstance {
-	// All transformations we need to put this star in its place
+	// All transformations we need to put this dot in its place
-	pub transform: [[f32; 4]; 4],
+	// TODO: we don't need that much data
+	pub position: [f32; 2],
 }
 
-impl BufferObject for StarInstance {
+impl BufferObject for StarfieldInstance {
 	fn layout() -> wgpu::VertexBufferLayout<'static> {
 		wgpu::VertexBufferLayout {
 			array_stride: Self::SIZE,
-			// We need to switch from using a step mode of TexturedVertex to Instance
-			// This means that our shaders will only change to use the next
-			// instance when the shader starts processing a new instance
 			step_mode: wgpu::VertexStepMode::Instance,
-			attributes: &[
+			attributes: &[wgpu::VertexAttribute {
-				// A mat4 takes up 4 Texturedvertex slots as it is technically 4 vec4s. We need to define a slot
+				offset: 0,
-				// for each vec4. We'll have to reassemble the mat4 in the shader.
+				shader_location: 2,
-				wgpu::VertexAttribute {
+				format: wgpu::VertexFormat::Float32x2,
-					offset: 0,
+			}],
-					shader_location: 2,
-					format: wgpu::VertexFormat::Float32x4,
-				},
-				wgpu::VertexAttribute {
-					offset: mem::size_of::<[f32; 4]>() as wgpu::BufferAddress,
-					shader_location: 3,
-					format: wgpu::VertexFormat::Float32x4,
-				},
-				wgpu::VertexAttribute {
-					offset: mem::size_of::<[f32; 8]>() as wgpu::BufferAddress,
-					shader_location: 4,
-					format: wgpu::VertexFormat::Float32x4,
-				},
-				wgpu::VertexAttribute {
-					offset: mem::size_of::<[f32; 12]>() as wgpu::BufferAddress,
-					shader_location: 5,
-					format: wgpu::VertexFormat::Float32x4,
-				},
-			],
 		}
 	}
 }
@@ -113,7 +92,7 @@ impl BufferObject for SpriteInstance {
 	fn layout() -> wgpu::VertexBufferLayout<'static> {
 		wgpu::VertexBufferLayout {
 			array_stride: Self::SIZE,
-			// We need to switch from using a step mode of TexturedVertex to Instance
+			// Switch to a step mode of Vertex to Instance.
 			// This means that our shaders will only change to use the next
 			// instance when the shader starts processing a new instance
 			step_mode: wgpu::VertexStepMode::Instance,