1 files changed, 66 insertions, 10 deletions

diff --git a/src/camera.rs b/src/camera.rs
index 22f9837..65d1d43 100644
--- a/src/camera.rs
+++ b/src/camera.rs
@@ -1,14 +1,18 @@
+use std::mem::size_of;
+
 use cgmath::{Matrix4, Vector2};
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Debug)]
 pub struct Camera {
 	position: (f32, f32),
 	zoom: f32,
 	rotation: f32,
 	inverse_aspect_ratio: f32,
+	buffer: wgpu::Buffer,
+	bind_group: wgpu::BindGroup,
 }
 
-pub(crate) type CameraUniform = [[f32; 4]; 4];
+type CameraUniform = [[f32; 4]; 4];
 
 #[allow(clippy::cast_precision_loss)]
 fn inverse_aspect_ratio(width: u32, height: u32) -> f32 {
@@ -17,13 +21,53 @@ fn inverse_aspect_ratio(width: u32, height: u32) -> f32 {
 
 impl Camera {
 	/// Create a new camera, with a position of (0, 0), and a zoom of 1.0
-	pub(crate) fn from_size(width: u32, height: u32) -> Self {
-		Self {
-			position: (0.0, 0.0),
-			zoom: 1.0,
-			rotation: 0.0,
-			inverse_aspect_ratio: inverse_aspect_ratio(width, height),
-		}
+	// TODO this can still be a little smaller
+	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
@@ -89,7 +133,7 @@ impl Camera {
 	}
 
 	#[allow(clippy::wrong_self_convention)]
-	pub(crate) fn to_matrix(&mut self) -> CameraUniform {
+	fn to_matrix(&self) -> CameraUniform {
 		let cos = self.rotation.cos();
 		let sin = self.rotation.sin();
 
@@ -120,4 +164,16 @@ impl Camera {
 		let transform = projection_matrix * view_matrix;
 		transform.into()
 	}
+
+	pub(crate) const fn bind_group(&self) -> &wgpu::BindGroup {
+		&self.bind_group
+	}
+
+	pub(crate) fn refresh(&self, queue: &wgpu::Queue) {
+		queue.write_buffer(
+			&self.buffer,
+			0 as wgpu::BufferAddress,
+			bytemuck::cast_slice(&self.to_matrix()),
+		);
+	}
 }