Moved files into workspace

14 files changed, 1505 insertions, 0 deletions

diff --git a/alligator_render/Cargo.toml b/alligator_render/Cargo.toml
new file mode 100644
index 0000000..01c5738
--- /dev/null
+++ b/alligator_render/Cargo.toml
@@ -0,0 +1,33 @@
+[package]
+name = "alligator_render"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+winit = "0.27"
+log = "0.4"
+wgpu = "0.14"
+thiserror = "1"
+pollster = "0.2"
+bytemuck = { version = "1.4", features = ["derive"] }
+cgmath = "0.18"
+image = "0.24"
+texture_packer = "0.24"
+profiling = "1"
+tracy-client = { version = "0.14", optional = true }
+dhat = "0.3"
+
+[lib]
+crate-type = ["cdylib", "lib"]
+
+[features]
+dhat = []
+profile-with-tracy = ["tracy-client", "profiling/profile-with-tracy"]
+
+[[example]]
+name = "black"
+
+[[example]]
+name = "bmp"
diff --git a/alligator_render/examples/black.rs b/alligator_render/examples/black.rs
new file mode 100644
index 0000000..c66b080
--- /dev/null
+++ b/alligator_render/examples/black.rs
@@ -0,0 +1,21 @@
+#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
+
+use alligator_render::{RenderWindowConfig, Renderer};
+
+fn update(_renderer: &mut Renderer) {}
+
+fn main() {
+	let start = std::time::Instant::now();
+	// configure the render window
+	let config = RenderWindowConfig {
+		//vsync: false,
+		//mode: alligator_render::config::WindowMode::BorderlessFullscreen,
+		title: "Black Screen.exe",
+		..Default::default()
+	};
+
+	let renderer = Renderer::new(&config).unwrap();
+	println!("Startup time: {:?}", start.elapsed());
+
+	renderer.run(&update);
+}
diff --git a/alligator_render/examples/bmp.rs b/alligator_render/examples/bmp.rs
new file mode 100644
index 0000000..af71863
--- /dev/null
+++ b/alligator_render/examples/bmp.rs
@@ -0,0 +1,88 @@
+#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
+
+use std::num::NonZeroU32;
+
+use alligator_render::{ImageFormat, Instance, RenderWindowConfig, Renderer};
+
+#[profiling::function]
+fn update(renderer: &mut Renderer) {
+	let camera = renderer.camera_mut();
+	camera.set_rotation(camera.rotation() + 0.01);
+}
+
+fn main() {
+	// configure the render window
+	let config = RenderWindowConfig {
+		title: "Bumper Stickers",
+		instance_capacity: 2,
+		default_width: NonZeroU32::new(1280).unwrap(),
+		default_height: NonZeroU32::new(720).unwrap(),
+		//mode: alligator_render::config::WindowMode::BorderlessFullscreen,
+		//vsync: false,
+		..Default::default()
+	};
+
+	let mut renderer = Renderer::new(&config).unwrap();
+
+	// render the alligator
+	let gator = include_bytes!("res/gator.ff");
+	let gator_id = renderer
+		.textures_mut()
+		.load_from_memory(gator, ImageFormat::Farbfeld)
+		.unwrap();
+	let gator_width = renderer.textures().texture_width(gator_id).unwrap();
+	let gator_height = renderer.textures().texture_height(gator_id).unwrap();
+	let gator_x = renderer.textures().texture_x(gator_id).unwrap();
+	let gator_y = renderer.textures().texture_y(gator_id).unwrap();
+
+	renderer.instances_mut().push_instance(Instance {
+		position: [-0.5, 0.5],
+		size: [1.5; 2],
+		z_index: 1.0,
+		texture_size: [gator_width, gator_height],
+		texture_coordinates: [gator_x, gator_y],
+		..Default::default()
+	});
+
+	// render the ghost
+	let icon = include_bytes!("res/ghost.ico");
+	let icon_id = renderer
+		.textures_mut()
+		.load_from_memory(icon, ImageFormat::Ico)
+		.unwrap();
+	let icon_width = renderer.textures().texture_width(icon_id).unwrap();
+	let icon_height = renderer.textures().texture_height(icon_id).unwrap();
+	let icon_x = renderer.textures().texture_x(icon_id).unwrap();
+	let icon_y = renderer.textures().texture_y(icon_id).unwrap();
+
+	renderer.instances_mut().push_instance(Instance {
+		position: [0.5, 0.5],
+		size: [0.75; 2],
+		rotation: 0.5,
+		z_index: 1.0,
+		texture_size: [icon_width, icon_height],
+		texture_coordinates: [icon_x, icon_y],
+		..Default::default()
+	});
+
+	// render the bitmap alligator
+	let gator = include_bytes!("res/gator.bmp");
+	let gator_id = renderer
+		.textures_mut()
+		.load_from_memory(gator, ImageFormat::Bmp)
+		.unwrap();
+	let gator_width = renderer.textures().texture_width(gator_id).unwrap();
+	let gator_height = renderer.textures().texture_height(gator_id).unwrap();
+	let gator_x = renderer.textures().texture_x(gator_id).unwrap();
+	let gator_y = renderer.textures().texture_y(gator_id).unwrap();
+
+	renderer.instances_mut().push_instance(Instance {
+		position: [0.0, -0.5],
+		size: [1.5; 2],
+		texture_size: [gator_width, gator_height],
+		texture_coordinates: [gator_x, gator_y],
+		..Default::default()
+	});
+
+	renderer.run(&update);
+}
diff --git a/alligator_render/examples/res/gator.bmp b/alligator_render/examples/res/gator.bmp
new file mode 100644
index 0000000..e752b56
--- /dev/null
+++ b/alligator_render/examples/res/gator.bmp
diff --git a/alligator_render/examples/res/gator.ff b/alligator_render/examples/res/gator.ff
new file mode 100644
index 0000000..aac1bcb
--- /dev/null
+++ b/alligator_render/examples/res/gator.ff
diff --git a/alligator_render/examples/res/ghost.ico b/alligator_render/examples/res/ghost.ico
new file mode 100644
index 0000000..102de00
--- /dev/null
+++ b/alligator_render/examples/res/ghost.ico
diff --git a/alligator_render/shaders/sprite.wgsl b/alligator_render/shaders/sprite.wgsl
new file mode 100644
index 0000000..60b5773
--- /dev/null
+++ b/alligator_render/shaders/sprite.wgsl
@@ -0,0 +1,62 @@
+
+@group(0) @binding(0)
+var<uniform> camera: mat4x4<f32>;
+
+struct VertexInput {
+	@location(0) position: vec2<f32>
+}
+
+struct InstanceInput {
+	@location(1) position: vec2<f32>,
+	@location(2) size: vec2<f32>,
+	@location(3) texture_coordinates: vec2<f32>,
+	@location(4) texture_size: vec2<f32>,
+	@location(5) texture_atlas_index: u32,
+	@location(6) rotation: f32,
+	@location(7) z_index: f32,
+}
+
+struct VertexOutput {
+	@builtin(position) clip_position: vec4<f32>,
+	@location(0) texture_coordinates: vec2<f32>,
+	@location(1) texture_atlas_index: u32
+}
+
+@vertex
+fn vs_main(model: VertexInput, instance: InstanceInput) -> VertexOutput {
+	var out: VertexOutput;
+
+	// rotate the sprite
+	let rotation = -instance.rotation;
+	let a = vec2<f32>(cos(rotation), sin(rotation));
+	let b = vec2<f32>(-a[1], a[0]);
+	let rotation = mat2x2<f32>(a, b);
+	let rotated = rotation * model.position;
+
+	// scale the sprite
+	let scaled = rotated * instance.size;
+
+	// move the sprite
+	let position2d = scaled + instance.position;
+
+	// camera stuff
+	let position4d = vec4<f32>(position2d, instance.z_index, 1.0);
+	let position = camera * position4d;
+
+	let tex_coords = vec2<f32>(model.position[0] + 0.5, 1.0 - (model.position[1] + 0.5));
+
+	out.clip_position = position;
+	out.texture_atlas_index = instance.texture_atlas_index;
+	out.texture_coordinates = tex_coords * instance.texture_size + instance.texture_coordinates;
+	return out;
+}
+
+@group(1) @binding(0)
+var t_diffuse: texture_2d<f32>;
+@group(1) @binding(1)
+var s_diffuse: sampler;
+
+@fragment
+fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
+	return textureSample(t_diffuse, s_diffuse, in.texture_coordinates);
+}
\ No newline at end of file
diff --git a/alligator_render/src/camera.rs b/alligator_render/src/camera.rs
new file mode 100644
index 0000000..ecece90
--- /dev/null
+++ b/alligator_render/src/camera.rs
@@ -0,0 +1,187 @@
+use std::mem::size_of;
+
+use cgmath::{Matrix4, Vector2};
+
+#[derive(Debug)]
+pub struct Camera {
+	position: (f32, f32),
+	zoom: f32,
+	rotation: f32,
+	inverse_aspect_ratio: f32,
+	buffer: wgpu::Buffer,
+	bind_group: wgpu::BindGroup,
+}
+
+type CameraUniform = [[f32; 4]; 4];
+
+#[allow(clippy::cast_precision_loss)]
+fn inverse_aspect_ratio(width: u32, height: u32) -> f32 {
+	(height as f32) / (width as f32)
+}
+
+impl Camera {
+	/// Create a new camera, with a position of (0, 0), and a zoom of 1.0
+	pub(crate) fn new(
+		device: &wgpu::Device,
+		width: u32,
+		height: u32,
+	) -> (Self, wgpu::BindGroupLayout) {
+		let buffer = device.create_buffer(&wgpu::BufferDescriptor {
+			label: Some("Camera Uniform"),
+			size: size_of::<CameraUniform>() as wgpu::BufferAddress,
+			usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
+			mapped_at_creation: false,
+		});
+
+		let bind_group_layout = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+			label: Some("Camera Bind Group Layout"),
+			entries: &[wgpu::BindGroupLayoutEntry {
+				binding: 0,
+				visibility: wgpu::ShaderStages::VERTEX,
+				ty: wgpu::BindingType::Buffer {
+					ty: wgpu::BufferBindingType::Uniform,
+					has_dynamic_offset: false,
+					min_binding_size: None,
+				},
+				count: None,
+			}],
+		});
+
+		let bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
+			label: Some("Camera Bind Group"),
+			layout: &bind_group_layout,
+			entries: &[wgpu::BindGroupEntry {
+				binding: 0,
+				resource: buffer.as_entire_binding(),
+			}],
+		});
+
+		(
+			Self {
+				position: (0.0, 0.0),
+				zoom: 1.0,
+				rotation: 0.0,
+				inverse_aspect_ratio: inverse_aspect_ratio(width, height),
+				buffer,
+				bind_group,
+			},
+			bind_group_layout,
+		)
+	}
+
+	/// Get the camera's current x position
+	#[must_use]
+	pub const fn x(&self) -> f32 {
+		self.position.0
+	}
+
+	/// Get the camera's current y position
+	#[must_use]
+	pub const fn y(&self) -> f32 {
+		self.position.1
+	}
+
+	/// Get the camera's current zoom
+	#[must_use]
+	pub const fn zoom(&self) -> f32 {
+		self.zoom
+	}
+
+	/// Get the camera's current rotation, in radians
+	#[must_use]
+	pub const fn rotation(&self) -> f32 {
+		self.rotation
+	}
+
+	/// Set the position of the camera
+	pub fn set_position(&mut self, x: f32, y: f32) {
+		#[cfg(debug_assertions)]
+		if !(-1000.0..1000.0).contains(&x) || !(-1000.0..1000.0).contains(&y) {
+			log::warn!(
+				"The position of the camera is (x: {}, y: {}). \
+				Please keep both the x and y positions above -1000 and below 1000 units. \
+				Otherwise, everything will look crazy. \
+				For an explanation, see https://www.youtube.com/watch?v=Q2OGwnRik24",
+				x,
+				y
+			);
+		}
+
+		self.position = (x, y);
+	}
+
+	/// Set the zoom of the camera
+	pub fn set_zoom(&mut self, zoom: f32) {
+		#[cfg(debug_assertions)]
+		if !(-1000.0..1000.0).contains(&zoom) {
+			log::warn!(
+				"The zoom of the camera is {}. \
+				Please keep above -1000, and below 1000, or else smooth zoom may be difficult. \
+				For an explanation, see https://www.youtube.com/watch?v=Q2OGwnRik24",
+				zoom
+			);
+		}
+
+		self.zoom = zoom;
+	}
+
+	/// Set the camera rotation, in radians
+	pub fn set_rotation(&mut self, rotation: f32) {
+		self.rotation = rotation % std::f32::consts::TAU;
+	}
+
+	/// Set the aspect ratio of the camera
+	pub(crate) fn set_size(&mut self, width: u32, height: u32) {
+		self.inverse_aspect_ratio = inverse_aspect_ratio(width, height);
+	}
+
+	/// Create a matrix that can be multiplied by any vector to transform it
+	/// according to the current camera
+	#[allow(clippy::wrong_self_convention)]
+	fn to_matrix(&self) -> CameraUniform {
+		let cos = self.rotation.cos();
+		let sin = self.rotation.sin();
+
+		let x_axis = Vector2::new(cos, -sin);
+		let y_axis = Vector2::new(sin, cos);
+
+		let eye = Vector2::new(self.position.0, self.position.1);
+		let x_dot = -cgmath::dot(x_axis, eye);
+		let y_dot = -cgmath::dot(y_axis, eye);
+
+		#[rustfmt::skip]
+		let view_matrix = Matrix4::new(
+			x_axis.x, y_axis.x, 0.0, 0.0,
+			x_axis.y, y_axis.y, 0.0, 0.0,
+			0.0, 0.0, 1.0, 0.0,
+			x_dot, y_dot, 0.0, 1.0
+		);
+
+		#[rustfmt::skip]
+		// TODO implement more scaling coordinate systems
+		let projection_matrix = Matrix4::new(
+			self.inverse_aspect_ratio * self.zoom, 0.0, 0.0, 0.0,
+			0.0, self.zoom, 0.0, 0.0,
+			0.0, 0.0, 1.0 / 256.0, 0.0,
+			0.0, 0.0, 0.0, 1.0
+		);
+
+		let transform = projection_matrix * view_matrix;
+		transform.into()
+	}
+
+	/// Get the bind group for the camera
+	pub(crate) const fn bind_group(&self) -> &wgpu::BindGroup {
+		&self.bind_group
+	}
+
+	/// Refresh the camera buffer for the next frame
+	#[profiling::function]
+	pub(crate) fn refresh(&self, queue: &wgpu::Queue) {
+		queue.write_buffer(
+			&self.buffer,
+			0 as wgpu::BufferAddress,
+			bytemuck::cast_slice(&self.to_matrix()),
+		);
+	}
+}
diff --git a/alligator_render/src/config.rs b/alligator_render/src/config.rs
new file mode 100644
index 0000000..c73c357
--- /dev/null
+++ b/alligator_render/src/config.rs
@@ -0,0 +1,193 @@
+use std::num::NonZeroU32;
+
+use winit::dpi::{LogicalPosition, LogicalSize};
+use winit::window::{Fullscreen, WindowBuilder};
+
+/// Describes how a window may be resized
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Hash)]
+pub struct Resizable {
+	/// The minimum width of the window, or None if unconstrained
+	pub min_width: Option<NonZeroU32>,
+	/// The minimum height of the window, or None if unconstrained
+	pub min_height: Option<NonZeroU32>,
+	/// The maximum width of the window, or None if unconstrained
+	pub max_width: Option<NonZeroU32>,
+	/// The maximum height of the window, or None if unconstrained
+	pub max_height: Option<NonZeroU32>,
+}
+
+/// Information about a window, that is not fullscreened
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct WindowInfo {
+	pub default_x: i32,
+	pub default_y: i32,
+	pub resizable: Option<Resizable>,
+	pub default_maximized: bool,
+}
+
+impl Default for WindowInfo {
+	fn default() -> Self {
+		Self {
+			default_x: 100,
+			default_y: 100,
+			resizable: Some(Resizable::default()),
+			default_maximized: false,
+		}
+	}
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum WindowMode {
+	Windowed(WindowInfo),
+	// TODO support choosing a monitor
+	BorderlessFullscreen, // TODO exclusive fullscreen
+}
+
+impl Default for WindowMode {
+	fn default() -> Self {
+		Self::Windowed(WindowInfo::default())
+	}
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+// TODO window icon
+pub struct RenderWindowConfig<'a> {
+	/// The width of the window, once initialized
+	pub default_width: NonZeroU32,
+	/// The height of the window, once initialized
+	pub default_height: NonZeroU32,
+	/// The window may be fullscreen
+	pub mode: WindowMode,
+	/// The title for the window
+	pub title: &'a str,
+	/// If true, a low-power device will be selected as the GPU, if possible
+	pub low_power: bool,
+	/// If true, Fifo mode is used to present frames. If false, then Mailbox or
+	/// Immediate will be used if available. Otherwise, Fifo will be used.
+	pub vsync: bool,
+	/// The initial capacity of the instance buffer. The size will increase if
+	/// it's not large enough. Increasing this value may improve performance
+	/// towards the beginning, if a lot of instances are being created.
+	pub instance_capacity: usize,
+}
+
+impl<'a> Default for RenderWindowConfig<'a> {
+	fn default() -> Self {
+		Self {
+			default_width: NonZeroU32::new(640).unwrap(),
+			default_height: NonZeroU32::new(480).unwrap(),
+			mode: WindowMode::default(),
+			title: "Alligator Game",
+			low_power: true,
+			vsync: true,
+			instance_capacity: 0, // TODO this should probably be bigger
+		}
+	}
+}
+
+impl<'a> RenderWindowConfig<'a> {
+	/// Based on the vsync settings, choose a presentation mode
+	pub(crate) fn present_mode(
+		vsync: bool,
+		supported_modes: &[wgpu::PresentMode],
+	) -> wgpu::PresentMode {
+		if vsync {
+			wgpu::PresentMode::Fifo
+		} else if supported_modes.contains(&wgpu::PresentMode::Mailbox) {
+			wgpu::PresentMode::Mailbox
+		} else if supported_modes.contains(&wgpu::PresentMode::Immediate) {
+			wgpu::PresentMode::Immediate
+		} else {
+			wgpu::PresentMode::Fifo
+		}
+	}
+
+	/// Pick an alpha mode
+	fn alpha_mode(supported_modes: &[wgpu::CompositeAlphaMode]) -> wgpu::CompositeAlphaMode {
+		if supported_modes.contains(&wgpu::CompositeAlphaMode::PostMultiplied) {
+			wgpu::CompositeAlphaMode::PostMultiplied
+		} else {
+			wgpu::CompositeAlphaMode::Auto
+		}
+	}
+
+	/// Create a `WindowBuilder` from the configuration given. This window is
+	/// initially invisible and must later be made visible.
+	pub(crate) fn to_window(&self) -> WindowBuilder {
+		// start building the window
+		let mut builder = WindowBuilder::new()
+			.with_title(self.title)
+			.with_visible(false)
+			.with_inner_size(LogicalSize::new(
+				self.default_width.get(),
+				self.default_height.get(),
+			));
+
+		match self.mode {
+			WindowMode::Windowed(window_info) => {
+				builder = builder.with_maximized(window_info.default_maximized);
+
+				if let Some(resizing_options) = window_info.resizable {
+					if resizing_options.max_height.is_some() || resizing_options.max_width.is_some()
+					{
+						builder = builder.with_max_inner_size(LogicalSize::new(
+							resizing_options.max_width.unwrap_or(NonZeroU32::MAX).get(),
+							resizing_options.max_height.unwrap_or(NonZeroU32::MAX).get(),
+						));
+					}
+
+					if resizing_options.min_height.is_some() || resizing_options.min_width.is_some()
+					{
+						builder = builder.with_min_inner_size(LogicalSize::new(
+							resizing_options.min_width.unwrap_or(NonZeroU32::MAX).get(),
+							resizing_options.min_height.unwrap_or(NonZeroU32::MAX).get(),
+						));
+					}
+				} else {
+					builder = builder.with_resizable(false);
+				}
+
+				// TODO clamp the position to the monitor's size
+				builder = builder.with_position(LogicalPosition::new(
+					window_info.default_x,
+					window_info.default_y,
+				));
+			}
+			WindowMode::BorderlessFullscreen => {
+				builder = builder.with_fullscreen(Some(Fullscreen::Borderless(None)));
+			}
+		}
+
+		builder
+	}
+
+	/// Gets a surface configuration out of the config.
+	pub(crate) fn to_surface_configuration(
+		&self,
+		supported_present_modes: &[wgpu::PresentMode],
+		supported_alpha_modes: &[wgpu::CompositeAlphaMode],
+		texture_format: wgpu::TextureFormat,
+	) -> wgpu::SurfaceConfiguration {
+		let present_mode = Self::present_mode(self.vsync, supported_present_modes);
+		let alpha_mode = Self::alpha_mode(supported_alpha_modes);
+
+		// configuration for the surface
+		wgpu::SurfaceConfiguration {
+			usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
+			format: texture_format,
+			width: self.default_width.get(),
+			height: self.default_height.get(),
+			alpha_mode,
+			present_mode,
+		}
+	}
+
+	/// Get the power preference
+	pub(crate) const fn power_preference(&self) -> wgpu::PowerPreference {
+		if self.low_power {
+			wgpu::PowerPreference::LowPower
+		} else {
+			wgpu::PowerPreference::HighPerformance
+		}
+	}
+}
diff --git a/alligator_render/src/instance.rs b/alligator_render/src/instance.rs
new file mode 100644
index 0000000..2d1808f
--- /dev/null
+++ b/alligator_render/src/instance.rs
@@ -0,0 +1,163 @@
+use std::mem::size_of;
+
+use bytemuck::{Pod, Zeroable};
+
+/// The ID for an instance
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub struct InstanceId(usize);
+
+/// A sprite, that can be used by the alligator shader
+#[repr(C)]
+#[derive(Copy, Clone, Debug, PartialEq, Pod, Zeroable)]
+pub struct Instance {
+	/// Position on the screen
+	pub position: [f32; 2],
+	/// Relative size
+	pub size: [f32; 2],
+	/// The location of the texture in the texture atlas
+	pub texture_coordinates: [f32; 2],
+	/// The size of the sprite's texture
+	pub texture_size: [f32; 2],
+	/// The index of the texture atlas to use
+	pub texture_atlas_index: u32,
+	/// Rotation, in radians
+	pub rotation: f32,
+	/// z-index
+	pub z_index: f32,
+}
+
+impl Default for Instance {
+	fn default() -> Self {
+		Self {
+			position: [0.0; 2],
+			size: [1.0; 2],
+			rotation: 0.0,
+			z_index: 0.0,
+			texture_coordinates: [0.0; 2],
+			texture_size: [1.0; 2],
+			texture_atlas_index: 0,
+		}
+	}
+}
+
+impl Instance {
+	// whenever this is updated, please also update `sprite.wgsl`
+	const ATTRIBUTES: [wgpu::VertexAttribute; 7] = wgpu::vertex_attr_array![
+		1 => Float32x2, 2 => Float32x2, 3 => Float32x2, 4 => Float32x2,
+		5 => Uint32, 6 => Float32, 7 => Float32
+	];
+
+	pub(crate) fn desc<'a>() -> wgpu::VertexBufferLayout<'a> {
+		// make sure these two don't conflict
+		debug_assert_eq!(
+			Self::ATTRIBUTES[0].shader_location as usize,
+			crate::Vertex::ATTRIBUTES.len()
+		);
+		wgpu::VertexBufferLayout {
+			array_stride: size_of::<Self>() as wgpu::BufferAddress,
+			step_mode: wgpu::VertexStepMode::Instance,
+			attributes: &Self::ATTRIBUTES,
+		}
+	}
+}
+
+/// A buffer of sprites, for both CPU and GPU memory
+pub struct InstanceBuffer {
+	instances: Vec<Instance>,
+	instance_buffer: wgpu::Buffer,
+	instance_buffer_size: usize,
+}
+
+fn create_buffer(device: &wgpu::Device, instances: &Vec<Instance>) -> wgpu::Buffer {
+	device.create_buffer(&wgpu::BufferDescriptor {
+		label: Some("Sprite Instance Buffer"),
+		size: (instances.capacity() * size_of::<Instance>()) as wgpu::BufferAddress,
+		usage: wgpu::BufferUsages::VERTEX | wgpu::BufferUsages::COPY_DST,
+		mapped_at_creation: false,
+	})
+}
+
+impl InstanceBuffer {
+	/// Create a new buffer with the given capacity
+	pub(crate) fn new(device: &wgpu::Device, capacity: usize) -> Self {
+		let instances = Vec::with_capacity(capacity);
+		let instance_buffer_size = instances.capacity();
+		let instance_buffer = create_buffer(device, &instances);
+
+		Self {
+			instances,
+			instance_buffer,
+			instance_buffer_size,
+		}
+	}
+
+	/// The number of sprites
+	pub fn len(&self) -> u32 {
+		self.instances
+			.len()
+			.try_into()
+			.expect("expected less than 3 billion instances")
+	}
+
+	/// Returns `true` if there are no sprites
+	pub fn is_empty(&self) -> bool {
+		self.instances.is_empty()
+	}
+
+	/// The capacity of the buffer
+	pub const fn buffer_size(&self) -> usize {
+		self.instance_buffer_size
+	}
+
+	/// Get a slice containing the entire buffer
+	pub(crate) fn buffer_slice(&self) -> wgpu::BufferSlice {
+		self.instance_buffer.slice(..)
+	}
+
+	/// Add a new sprite. The new sprite's `InstanceId` is returned. This ID
+	/// becomes invalid if the buffer is cleared.
+	pub fn push_instance(&mut self, instance: Instance) -> InstanceId {
+		let index = self.instances.len();
+		self.instances.push(instance);
+		InstanceId(index)
+	}
+
+	/// Get a specific instance
+	pub fn get_instance(&self, id: InstanceId) -> Option<&Instance> {
+		self.instances.get(id.0)
+	}
+
+	/// Get a mutable reference to a specific sprite
+	pub fn get_instance_mut(&mut self, id: InstanceId) -> Option<&mut Instance> {
+		self.instances.get_mut(id.0)
+	}
+
+	/// Clear the instance buffer. This invalidates all `InstanceId`'s
+	pub fn clear(&mut self) {
+		self.instances.clear();
+	}
+
+	/// Increase the capacity of the buffer
+	fn expand_buffer(&mut self, device: &wgpu::Device) {
+		self.instance_buffer_size = self.instances.capacity();
+		self.instance_buffer = create_buffer(device, &self.instances);
+	}
+
+	/// Fill the GPU buffer with the sprites in the CPU buffer.
+	#[profiling::function]
+	pub(crate) fn fill_buffer(&mut self, device: &wgpu::Device, queue: &wgpu::Queue) {
+		if self.instances.len() > self.instance_buffer_size {
+			self.expand_buffer(device);
+		}
+
+		// the instances must be sorted by z-index before being handed to the GPU
+		let mut sorted = self.instances.clone();
+		sorted.sort_by(|a, b| a.z_index.total_cmp(&b.z_index));
+
+		queue.write_buffer(
+			&self.instance_buffer,
+			0 as wgpu::BufferAddress,
+			bytemuck::cast_slice(&sorted),
+		);
+	}
+}
diff --git a/alligator_render/src/lib.rs b/alligator_render/src/lib.rs
new file mode 100644
index 0000000..f5403f2
--- /dev/null
+++ b/alligator_render/src/lib.rs
@@ -0,0 +1,22 @@
+#![feature(let_else)]
+#![feature(nonzero_min_max)]
+#![feature(type_alias_impl_trait)]
+#![warn(clippy::pedantic)]
+#![warn(clippy::nursery)]
+#![allow(clippy::module_name_repetitions)]
+
+mod camera;
+pub mod config;
+pub mod instance;
+pub mod renderer;
+mod texture;
+mod vertex;
+
+pub(crate) use camera::Camera;
+pub use config::RenderWindowConfig;
+pub use instance::Instance;
+pub(crate) use instance::InstanceBuffer;
+pub use renderer::Renderer;
+pub use texture::ImageFormat;
+pub(crate) use texture::TextureAtlas;
+pub(crate) use vertex::Vertex;
diff --git a/alligator_render/src/renderer.rs b/alligator_render/src/renderer.rs
new file mode 100644
index 0000000..afcb92b
--- /dev/null
+++ b/alligator_render/src/renderer.rs
@@ -0,0 +1,410 @@
+use std::{convert::TryInto, num::NonZeroU32};
+
+use crate::{
+	vertex::SQUARE, Camera, Instance, InstanceBuffer, RenderWindowConfig, TextureAtlas, Vertex,
+};
+use pollster::FutureExt;
+use thiserror::Error;
+use wgpu::{include_wgsl, util::DeviceExt};
+use winit::{
+	dpi::PhysicalSize,
+	error::OsError,
+	event::{Event, WindowEvent},
+	event_loop::{ControlFlow, EventLoop},
+	window::Window,
+};
+
+/// No device could be found which supports the given surface
+#[derive(Clone, Copy, Debug, Error)]
+#[error("No GPU could be found on this machine")]
+pub struct NoGpuError {
+	/// Prevents this type from being constructed
+	_priv: (),
+}
+
+impl NoGpuError {
+	/// Create a new error
+	const fn new() -> Self {
+		Self { _priv: () }
+	}
+}
+
+#[derive(Debug, Error)]
+pub enum NewRendererError {
+	#[error(transparent)]
+	NoGpu(#[from] NoGpuError),
+	#[error(transparent)]
+	// TODO better error
+	WindowInitError(#[from] OsError),
+}
+
+// TODO make this Debug
+pub struct Renderer {
+	// TODO move some of this data elsewhere
+	surface: wgpu::Surface,
+	surface_config: wgpu::SurfaceConfiguration,
+	supported_present_modes: Box<[wgpu::PresentMode]>,
+	device: wgpu::Device,
+	queue: wgpu::Queue,
+	render_pipeline: wgpu::RenderPipeline,
+	square_vertex_buffer: wgpu::Buffer,
+	square_vertices: u32,
+	instances: InstanceBuffer,
+	camera: Camera,
+	textures: TextureAtlas,
+	event_loop: Option<EventLoop<()>>,
+	window: Window,
+}
+
+fn get_adapter(
+	instance: &wgpu::Instance,
+	surface: &wgpu::Surface,
+	power_preference: wgpu::PowerPreference,
+) -> Result<wgpu::Adapter, NoGpuError> {
+	let adapter = instance
+		.request_adapter(&wgpu::RequestAdapterOptions {
+			power_preference,
+			compatible_surface: Some(surface),
+			force_fallback_adapter: false,
+		})
+		.block_on(); // TODO this takes too long
+
+	let adapter = adapter.or_else(|| {
+		instance
+			.enumerate_adapters(wgpu::Backends::PRIMARY)
+			.find(|adapter| !surface.get_supported_formats(adapter).is_empty())
+	});
+
+	adapter.ok_or(NoGpuError::new())
+}
+
+fn sprite_render_pipeline(
+	device: &wgpu::Device,
+	texture_format: wgpu::TextureFormat,
+	render_pipeline_layout: &wgpu::PipelineLayout,
+) -> wgpu::RenderPipeline {
+	let shader = device.create_shader_module(include_wgsl!("../shaders/sprite.wgsl"));
+
+	device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+		label: Some("Sprite Render Pipeline"),
+		layout: Some(render_pipeline_layout),
+		// information about the vertex shader
+		vertex: wgpu::VertexState {
+			module: &shader,
+			entry_point: "vs_main",
+			buffers: &[Vertex::desc(), Instance::desc()],
+		},
+		// information about the fragment shader
+		fragment: Some(wgpu::FragmentState {
+			module: &shader,
+			entry_point: "fs_main",
+			targets: &[Some(wgpu::ColorTargetState {
+				format: texture_format,
+				blend: Some(wgpu::BlendState::ALPHA_BLENDING),
+				write_mask: wgpu::ColorWrites::ALL,
+			})],
+		}),
+		primitive: wgpu::PrimitiveState {
+			// don't render the back of a sprite
+			cull_mode: Some(wgpu::Face::Back),
+			..Default::default()
+		},
+		depth_stencil: None,
+		multisample: wgpu::MultisampleState::default(),
+		multiview: None,
+	})
+}
+
+impl Renderer {
+	/// Initializes the renderer
+	///
+	/// # Errors
+	///
+	/// Returns a [`NoGpu`] error if no device could be detected that can
+	/// display to the window
+	///
+	/// # Panics
+	///
+	/// This function **must** be called on the main thread, or else it may
+	/// panic on some platforms.
+	// TODO make it possible to use without a window (ie, use a bitmap in memory as a surface)
+	// TODO this function needs to be smaller
+	pub fn new(config: &RenderWindowConfig) -> Result<Self, NewRendererError> {
+		#[cfg(feature = "profile-with-tracy")]
+		profiling::tracy_client::Client::start();
+		profiling::register_thread!("main");
+
+		// build the window
+		let event_loop = EventLoop::new();
+		let window = config.to_window().build(&event_loop)?;
+		let event_loop = Some(event_loop);
+
+		// the instance's main purpose is to create an adapter and a surface
+		let instance = wgpu::Instance::new(wgpu::Backends::VULKAN);
+
+		// the surface is the part of the screen we'll draw to
+		let surface = unsafe { instance.create_surface(&window) };
+
+		let power_preference = config.power_preference();
+
+		// the adapter is the handle to the GPU
+		let adapter = get_adapter(&instance, &surface, power_preference)?;
+
+		// gets a connection to the device, as well as a handle to its command queue
+		// the options chosen here ensure that this is guaranteed to not panic
+		let (device, queue) = adapter
+			.request_device(
+				&wgpu::DeviceDescriptor {
+					features: wgpu::Features::empty(),
+					..Default::default()
+				},
+				None,
+			)
+			.block_on()
+			.expect("there was no device with the selected features");
+
+		// configuration for the surface
+		let supported_present_modes = surface
+			.get_supported_present_modes(&adapter)
+			.into_boxed_slice();
+		let supported_alpha_modes = surface
+			.get_supported_alpha_modes(&adapter)
+			.into_boxed_slice();
+		let surface_config = config.to_surface_configuration(
+			&supported_present_modes,
+			&supported_alpha_modes,
+			surface.get_supported_formats(&adapter)[0],
+		);
+		surface.configure(&device, &surface_config);
+
+		// create the camera
+		let width = window.inner_size().width;
+		let height = window.inner_size().height;
+		let (camera, camera_bind_group_layout) = Camera::new(&device, width, height);
+
+		// the vertex buffer used for rendering squares
+		let square_vertices = SQUARE
+			.len()
+			.try_into()
+			.expect("expected fewer than 3 billion vertices in a square");
+		let square_vertex_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
+			label: Some("Square Vertex Buffer"),
+			contents: bytemuck::cast_slice(&SQUARE),
+			usage: wgpu::BufferUsages::VERTEX,
+		});
+
+		// create the instance buffer
+		let instances = InstanceBuffer::new(&device, config.instance_capacity);
+
+		// TODO make this configurable
+		let (textures, texture_layout) = TextureAtlas::new(
+			&device,
+			window.inner_size().width,
+			window.inner_size().height,
+		);
+
+		let render_pipeline_layout =
+			device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
+				label: Some("Sprite Render Pipeline Layout"),
+				bind_group_layouts: &[&camera_bind_group_layout, &texture_layout],
+				push_constant_ranges: &[],
+			});
+
+		// set up a pipeline for sprite rendering
+		let render_pipeline =
+			sprite_render_pipeline(&device, surface_config.format, &render_pipeline_layout);
+
+		Ok(Self {
+			surface,
+			surface_config,
+			supported_present_modes,
+			device,
+			queue,
+			render_pipeline,
+			square_vertex_buffer,
+			square_vertices,
+			instances,
+			camera,
+			textures,
+			event_loop,
+			window,
+		})
+	}
+
+	/// Reconfigure the surface
+	fn reconfigure(&mut self) {
+		self.surface.configure(&self.device, &self.surface_config);
+	}
+
+	/// Resize just the renderer. The window will remain unchanged
+	fn resize_renderer(&mut self, size: PhysicalSize<u32>) {
+		if size.width == 0 || size.height == 0 {
+			log::error!("The window was somehow set to a size of zero");
+			return;
+		}
+
+		self.surface_config.height = size.height;
+		self.surface_config.width = size.width;
+		self.camera.set_size(size.width, size.height);
+		self.reconfigure();
+	}
+
+	/// Set the physical window and renderer size
+	pub fn resize(&mut self, width: NonZeroU32, height: NonZeroU32) {
+		let size = PhysicalSize::new(width.get(), height.get());
+		self.window.set_inner_size(size);
+		self.resize_renderer(size);
+	}
+
+	/// Set vsync on or off. See `[RenderWindowConfig::present_mode]` for more details.
+	pub fn set_vsync(&mut self, vsync: bool) {
+		self.surface_config.present_mode =
+			RenderWindowConfig::present_mode(vsync, &self.supported_present_modes);
+		self.reconfigure();
+	}
+
+	/// Set the window's title
+	pub fn set_title(&mut self, title: &str) {
+		self.window.set_title(title);
+	}
+
+	/// The reference buffer
+	pub const fn instances(&self) -> &InstanceBuffer {
+		&self.instances
+	}
+
+	/// The reference buffer
+	pub fn instances_mut(&mut self) -> &mut InstanceBuffer {
+		&mut self.instances
+	}
+
+	/// Get the camera information
+	pub const fn camera(&self) -> &Camera {
+		&self.camera
+	}
+
+	/// Get a mutable reference to the camera
+	pub fn camera_mut(&mut self) -> &mut Camera {
+		&mut self.camera
+	}
+
+	/// Get a reference to the texture atlas
+	pub const fn textures(&self) -> &TextureAtlas {
+		&self.textures
+	}
+
+	/// Get a mutable reference to the texture atlas
+	pub fn textures_mut(&mut self) -> &mut TextureAtlas {
+		&mut self.textures
+	}
+
+	/// Renders a new frame to the window
+	///
+	/// # Errors
+	///
+	/// A number of problems could occur here. A timeout could occur while
+	/// trying to acquire the next frame. There may also be no more memory left
+	/// that can be used for the new frame.
+	#[profiling::function]
+	fn render(&mut self) -> Result<(), wgpu::SurfaceError> {
+		// the new texture we can render to
+		let output = self.surface.get_current_texture()?;
+		let view = output
+			.texture
+			.create_view(&wgpu::TextureViewDescriptor::default());
+
+		// this will allow us to send commands to the gpu
+		let mut encoder = self
+			.device
+			.create_command_encoder(&wgpu::CommandEncoderDescriptor {
+				label: Some("Render Encoder"),
+			});
+
+		let num_instances = self.instances.len();
+		self.instances.fill_buffer(&self.device, &self.queue);
+		self.camera.refresh(&self.queue);
+		self.textures.fill_textures(&self.queue);
+
+		{
+			profiling::scope!("encode render pass");
+			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::BLACK),
+						store: true,
+					},
+				})],
+				depth_stencil_attachment: None,
+			});
+
+			render_pass.set_pipeline(&self.render_pipeline);
+			render_pass.set_bind_group(0, self.camera.bind_group(), &[]);
+			render_pass.set_bind_group(1, self.textures.bind_group(), &[]);
+			render_pass.set_vertex_buffer(0, self.square_vertex_buffer.slice(..));
+			render_pass.set_vertex_buffer(1, self.instances.buffer_slice());
+			render_pass.draw(0..self.square_vertices, 0..num_instances);
+		}
+		// the encoder can't finish building the command buffer until the
+		// render pass is dropped
+
+		// submit the command buffer to the GPU
+		profiling::scope!("submit render");
+		self.queue.submit(std::iter::once(encoder.finish()));
+		output.present();
+
+		Ok(())
+	}
+
+	/// Take the event loop out of the Renderer, without moving it
+	///
+	/// # Panics
+	///
+	/// This method must only be called once
+	// TODO This is a quick fix to get the event loop inside the renderer.
+	//      In the future, we should make a separate struct that contains the
+	//      renderer and the event loop, which we move the event loop out of
+	//      while still being able to move the renderer.
+	fn event_loop(&mut self) -> EventLoop<()> {
+		self.event_loop.take().unwrap()
+	}
+
+	/// Run the renderer indefinitely
+	pub fn run(mut self, f: &'static dyn Fn(&mut Self)) -> ! {
+		self.window.set_visible(true);
+		let event_loop = self.event_loop();
+		event_loop.run(move |event, _, control_flow| match event {
+			Event::WindowEvent { window_id, event } => {
+				if window_id == self.window.id() {
+					match event {
+						WindowEvent::Resized(size) => self.resize_renderer(size),
+						WindowEvent::CloseRequested => {
+							*control_flow = ControlFlow::ExitWithCode(0);
+						}
+						_ => (),
+					}
+				}
+			}
+			Event::MainEventsCleared => {
+				f(&mut self);
+				match self.render() {
+					Ok(_) => {}
+					// reconfigure the surface if it's been lost
+					Err(wgpu::SurfaceError::Lost) => {
+						self.reconfigure();
+					}
+					// if we ran out of memory, then we'll die
+					Err(wgpu::SurfaceError::OutOfMemory) => {
+						*control_flow = ControlFlow::ExitWithCode(1);
+					}
+					// otherwise, we'll just log the error
+					Err(e) => log::error!("{}", e),
+				};
+				profiling::finish_frame!();
+			}
+			_ => {}
+		});
+	}
+}
diff --git a/alligator_render/src/texture.rs b/alligator_render/src/texture.rs
new file mode 100644
index 0000000..e343508
--- /dev/null
+++ b/alligator_render/src/texture.rs
@@ -0,0 +1,287 @@
+use std::error::Error;
+use std::num::NonZeroU32;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+use image::error::DecodingError;
+use image::{EncodableLayout, GenericImage, ImageError, RgbaImage};
+use texture_packer::TexturePacker;
+use texture_packer::{
+	exporter::{ExportResult, ImageExporter},
+	TexturePackerConfig,
+};
+use thiserror::Error;
+
+static NEXT_TEXTURE_ID: AtomicUsize = AtomicUsize::new(0);
+
+/// The unique ID for a subtexture
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct TextureId(usize);
+
+impl TextureId {
+	#[allow(clippy::new_without_default)]
+	pub fn new() -> Self {
+		Self(NEXT_TEXTURE_ID.fetch_add(1, Ordering::Relaxed))
+	}
+}
+
+/// These are the formats supported by the renderer.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+#[non_exhaustive]
+pub enum ImageFormat {
+	Bmp,
+	Ico,
+	Farbfeld,
+}
+
+impl ImageFormat {
+	const fn format(self) -> image::ImageFormat {
+		match self {
+			Self::Bmp => image::ImageFormat::Bmp,
+			Self::Ico => image::ImageFormat::Ico,
+			Self::Farbfeld => image::ImageFormat::Farbfeld,
+		}
+	}
+}
+
+/// The texture did not fit in the texture atlas
+#[derive(Debug, Error)]
+#[error("{:?}", .0)]
+pub struct PackError(PackErrorInternal);
+
+// TODO this can be removed when a new texture packer is made
+type PackErrorInternal = impl std::fmt::Debug;
+
+#[derive(Error, Debug)]
+pub enum TextureError {
+	#[error("{:?}", .0)]
+	TextureTooLarge(
+		#[source]
+		#[from]
+		PackError,
+	),
+	#[error("{}", .0)]
+	BadImage(
+		#[source]
+		#[from]
+		DecodingError,
+	), // TODO don't export this
+	#[error("Unexpected Error (this is a bug in alligator_render): {}", .0)]
+	Unexpected(#[source] Box<dyn Error>),
+}
+
+impl From<ImageError> for TextureError {
+	fn from(ie: ImageError) -> Self {
+		match ie {
+			ImageError::Decoding(de) => de.into(),
+			_ => Self::Unexpected(Box::new(ie)),
+		}
+	}
+}
+
+/// Simpler constructor for a wgpu extent3d
+const fn extent_3d(width: u32, height: u32) -> wgpu::Extent3d {
+	wgpu::Extent3d {
+		width,
+		height,
+		depth_or_array_layers: 1,
+	}
+}
+
+/// A texture atlas, usable by the renderer
+// TODO make this Debug
+// TODO make these resizable
+pub struct TextureAtlas {
+	packer: TexturePacker<'static, image::RgbaImage, TextureId>,
+	diffuse_texture: wgpu::Texture,
+	diffuse_bind_group: wgpu::BindGroup,
+	image: RgbaImage,
+	width: u32,
+	height: u32,
+	changed: bool,
+}
+
+macro_rules! texture_info {
+	($name: ident, $prop: ident, $divisor: ident) => {
+		pub fn $name(&self, id: TextureId) -> Option<f32> {
+			let frame = self.texture_frame(id)?;
+			let property = frame.frame.$prop;
+			let value = property as f32 / self.$divisor as f32;
+			Some(value)
+		}
+	};
+}
+
+impl TextureAtlas {
+	/// Creates a new texture atlas, with the given size
+	// TODO why is this u32?
+	// TODO this is still too large
+	pub fn new(device: &wgpu::Device, width: u32, height: u32) -> (Self, wgpu::BindGroupLayout) {
+		let atlas_size = extent_3d(width, height);
+		let diffuse_texture = device.create_texture(&wgpu::TextureDescriptor {
+			label: Some("Diffuse Texture"),
+			size: atlas_size,
+			mip_level_count: 1,
+			sample_count: 1,
+			dimension: wgpu::TextureDimension::D2,
+			format: wgpu::TextureFormat::Rgba8UnormSrgb,
+			usage: wgpu::TextureUsages::TEXTURE_BINDING | wgpu::TextureUsages::COPY_DST,
+		});
+
+		// TODO I don't think this refreshes anything
+		let diffuse_texture_view =
+			diffuse_texture.create_view(&wgpu::TextureViewDescriptor::default());
+
+		let diffuse_sampler = device.create_sampler(&wgpu::SamplerDescriptor::default());
+
+		let texture_bind_group_layout =
+			device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+				label: Some("Texture Bind Group Layout"),
+				entries: &[
+					wgpu::BindGroupLayoutEntry {
+						binding: 0,
+						visibility: wgpu::ShaderStages::FRAGMENT,
+						ty: wgpu::BindingType::Texture {
+							sample_type: wgpu::TextureSampleType::Float { filterable: true },
+							view_dimension: wgpu::TextureViewDimension::D2,
+							multisampled: false,
+						},
+						count: None,
+					},
+					wgpu::BindGroupLayoutEntry {
+						binding: 1,
+						visibility: wgpu::ShaderStages::FRAGMENT,
+						ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Filtering),
+						count: None,
+					},
+				],
+			});
+
+		let diffuse_bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
+			label: Some("Diffuse Bind Group"),
+			layout: &texture_bind_group_layout,
+			entries: &[
+				wgpu::BindGroupEntry {
+					binding: 0,
+					resource: wgpu::BindingResource::TextureView(&diffuse_texture_view),
+				},
+				wgpu::BindGroupEntry {
+					binding: 1,
+					resource: wgpu::BindingResource::Sampler(&diffuse_sampler),
+				},
+			],
+		});
+
+		(
+			Self {
+				packer: TexturePacker::new_skyline(TexturePackerConfig {
+					max_width: width,
+					max_height: height,
+					allow_rotation: false,
+					trim: false,
+					texture_padding: 0,
+					..Default::default()
+				}),
+				diffuse_texture,
+				diffuse_bind_group,
+				width,
+				height,
+				image: RgbaImage::from_raw(
+					width,
+					height,
+					vec![0; 4 * width as usize * height as usize],
+				)
+				.unwrap(),
+				changed: true,
+			},
+			texture_bind_group_layout,
+		)
+	}
+
+	/// get the bind group for the texture
+	pub(crate) const fn bind_group(&self) -> &wgpu::BindGroup {
+		&self.diffuse_bind_group
+	}
+
+	/// Load a new subtexture from memory
+	// TODO support RGBA16
+	pub fn load_from_memory(
+		&mut self,
+		buf: &[u8],
+		format: ImageFormat,
+	) -> Result<TextureId, TextureError> {
+		let img = image::load_from_memory_with_format(buf, format.format())?.into_rgba8();
+		let id = TextureId::new();
+		self.packer.pack_own(id, img).map_err(PackError)?;
+		Ok(id)
+	}
+
+	/// Get the frame for s particular subtexture
+	fn texture_frame(&self, id: TextureId) -> Option<&texture_packer::Frame<TextureId>> {
+		self.packer.get_frame(&id)
+	}
+
+	texture_info!(texture_width, w, width);
+	texture_info!(texture_height, h, height);
+	texture_info!(texture_x, x, width);
+	texture_info!(texture_y, y, height);
+
+	/// Fill the cached image
+	fn fill_image(&mut self) -> ExportResult<()> {
+		let atlas = {
+			profiling::scope!("export atlas");
+			ImageExporter::export(&self.packer)?
+		};
+		profiling::scope!("copy image");
+		self.image
+			.copy_from(&atlas, 0, 0)
+			.expect("image cache is too small");
+		Ok(())
+	}
+
+	/// Clear the texture atlas
+	pub fn clear(&mut self) {
+		self.packer = TexturePacker::new_skyline(TexturePackerConfig {
+			max_width: self.width,
+			max_height: self.height,
+			..Default::default()
+		});
+	}
+
+	/// Fill the GPU texture atlas
+	#[profiling::function]
+	pub fn fill_textures(&mut self, queue: &wgpu::Queue) {
+		// saves time if nothing changed since the last time we did this
+		// FIXME This doesn't do much good once we get procedurally generated animation
+		//       We'll have to create our own texture packer, with mutable subtextures,
+		//       and more efficient algorithms. This'll also make frame times more consistent
+		if !self.changed {
+			return;
+		}
+
+		let atlas_size = extent_3d(self.width, self.height);
+
+		// put the packed texture into the base image
+		if let Err(e) = self.fill_image() {
+			log::error!("{}", e);
+		}
+
+		// copy that to the gpu
+		queue.write_texture(
+			wgpu::ImageCopyTexture {
+				texture: &self.diffuse_texture,
+				mip_level: 0,
+				origin: wgpu::Origin3d::ZERO,
+				aspect: wgpu::TextureAspect::All,
+			},
+			self.image.as_bytes(),
+			wgpu::ImageDataLayout {
+				offset: 0,
+				bytes_per_row: NonZeroU32::new(atlas_size.width * 4),
+				rows_per_image: NonZeroU32::new(atlas_size.height),
+			},
+			atlas_size,
+		);
+
+		self.changed = false;
+	}
+}
diff --git a/alligator_render/src/vertex.rs b/alligator_render/src/vertex.rs
new file mode 100644
index 0000000..570eec4
--- /dev/null
+++ b/alligator_render/src/vertex.rs
@@ -0,0 +1,39 @@
+use std::mem::size_of;
+
+use bytemuck::{Pod, Zeroable};
+
+/// The vertices needed to form a square
+pub const SQUARE: [Vertex; 6] = [
+	Vertex::new(-0.5, -0.5),
+	Vertex::new(0.5, -0.5),
+	Vertex::new(-0.5, 0.5),
+	Vertex::new(0.5, 0.5),
+	Vertex::new(-0.5, 0.5),
+	Vertex::new(0.5, -0.5),
+];
+
+/// A vertex that is usable by the alligator shader
+#[repr(C)]
+#[derive(Copy, Clone, Debug, PartialEq, Pod, Zeroable)]
+pub struct Vertex {
+	position: [f32; 2],
+}
+
+impl Vertex {
+	// whenever this is updated, please also update `sprite.wgsl`
+	pub(crate) const ATTRIBUTES: [wgpu::VertexAttribute; 1] =
+		wgpu::vertex_attr_array![0 => Float32x2];
+
+	/// Create a new vertex
+	const fn new(x: f32, y: f32) -> Self {
+		Self { position: [x, y] }
+	}
+
+	pub(crate) const fn desc<'a>() -> wgpu::VertexBufferLayout<'a> {
+		wgpu::VertexBufferLayout {
+			array_stride: size_of::<Self>() as wgpu::BufferAddress,
+			step_mode: wgpu::VertexStepMode::Vertex,
+			attributes: &Self::ATTRIBUTES,
+		}
+	}
+}