Change Anyhow usage to ThisError

Cargo.lock

@@ -343,6 +343,7 @@ version = "0.1.0"
 dependencies = [
  "bytemuck",
  "log",
+ "thiserror",
  "wgpu",
  "winit",
 ]

Cargo.toml

@@ -8,5 +8,6 @@ edition = "2021"
 [dependencies]
 bytemuck = "1.15.0"
 log = "0.4.21"
+thiserror = "1.0.59"
 wgpu     = "0.19.4"
 winit    = "0.29.15"

src/bind_group.rs

@@ -1,9 +1,15 @@
 use std::num::NonZeroU32;
 
-use anyhow::{Context as _, Result};
+use thiserror::Error;
 
 use super::Context;
 
+#[derive(Error, Debug)]
+pub enum BindGroupError {
+    #[error("Cannot build BindGroup without a layout")]
+    NoLayout,
+}
+
 #[derive(Debug, Default)]
 pub struct BindGroupLayoutBuilder<'a> {
     next_binding: u32,
@@ -125,12 +131,17 @@ impl<'a> BindGroupBuilder<'a> {
     }
 
     #[inline]
-    pub fn build(self, context: &Context) -> Result<wgpu::BindGroup> {
+    pub fn build(self, context: &Context) -> Result<wgpu::BindGroup, BindGroupError> {
+        let layout = match self.layout {
+            Some(val) => val,
+            None => return Err(BindGroupError::NoLayout),
+        };
+
         Ok(context
             .device
             .create_bind_group(&wgpu::BindGroupDescriptor {
                 label: self.label,
-                layout: self.layout.context("BindGroupBuilder has no layout.")?,
+                layout,
                 entries: self.entries.as_slice(),
             }))
     }

src/context.rs

@@ -1,10 +1,22 @@
 use std::sync::Arc;
 
-use anyhow::{Context as _, Result};
+use thiserror::Error;
 use winit::{
     dpi::PhysicalSize, event::WindowEvent, event_loop::EventLoopWindowTarget, window::Window,
 };
 
+#[derive(Error, Debug)]
+pub enum ContextError {
+    #[error("Surface creation failed: {0}")]
+    Surface(#[from] wgpu::CreateSurfaceError),
+    #[error("Surface configuration failed: {0}")]
+    SurfaceConfig(String),
+    #[error("No compatible adapter found")]
+    Adapter,
+    #[error("Device request failed: {0}")]
+    Device(#[from] wgpu::RequestDeviceError),
+}
+
 pub struct Context<'window> {
     pub window: Arc<Window>,
     pub instance: wgpu::Instance,
@@ -17,7 +29,7 @@ pub struct Context<'window> {
 }
 
 impl<'window> Context<'window> {
-    pub async fn new(window: Arc<Window>, limits: wgpu::Limits) -> Result<Self> {
+    pub async fn new(window: Arc<Window>, limits: wgpu::Limits) -> Result<Self, ContextError> {
         log::info!("Initialising WGPU context...");
         let instance = wgpu::Instance::new(wgpu::InstanceDescriptor {
             backends: wgpu::Backends::VULKAN,
@@ -33,14 +45,17 @@ impl<'window> Context<'window> {
         let surface = instance.create_surface(window.clone())?;
 
         log::info!("Requesting GPU adapter...");
-        let adapter = instance
+        let adapter = match instance
             .request_adapter(&wgpu::RequestAdapterOptions {
                 power_preference: wgpu::PowerPreference::HighPerformance,
                 force_fallback_adapter: false,
                 compatible_surface: Some(&surface),
             })
             .await
-            .context("Failed to find suitable GPU adapter")?;
+        {
+            Some(val) => val,
+            None => return Err(ContextError::Adapter),
+        };
 
         log::info!("Checking GPU adapter meets requirements");
         log::info!("Requesting GPU device...");
@@ -57,9 +72,14 @@ impl<'window> Context<'window> {
 
         log::info!("Configuring window surface...");
         let size = window.inner_size();
-        let surface_config = surface
-            .get_default_config(&adapter, size.width, size.height)
-            .context("Surface configuration unsupported by adapter")?;
+        let surface_config = match surface.get_default_config(&adapter, size.width, size.height) {
+            Some(val) => val,
+            None => {
+                return Err(ContextError::SurfaceConfig(
+                    "Surface configuration unsupported by adapter".to_string(),
+                ))
+            }
+        };
         surface.configure(&device, &surface_config);
 
         Ok(Self {

src/texture.rs

@@ -1,7 +1,15 @@
-use anyhow::Result;
+use thiserror::Error;
+
+use crate::bind_group::BindGroupError;
 
 use super::{BindGroupBuilder, BindGroupLayoutBuilder, Context};
 
+#[derive(Error, Debug)]
+pub enum TextureError {
+    #[error("BindGroup failed to build: {0}")]
+    InvalidBindGroup(#[from] BindGroupError),
+}
+
 // TODO: Support mip-mapping and multi-sampling
 #[derive(Debug, Clone)]
 pub struct TextureAttributes {
@@ -99,7 +107,7 @@ impl TextureBuilder {
     }
 
     #[inline]
-    pub fn build(self, context: &Context) -> Result<Texture> {
+    pub fn build(self, context: &Context) -> Result<Texture, TextureError> {
         Texture::new(context, self.attributes)
     }
 }
@@ -115,7 +123,7 @@ pub struct Texture {
 }
 
 impl Texture {
-    pub fn new(context: &Context, attributes: TextureAttributes) -> Result<Self> {
+    pub fn new(context: &Context, attributes: TextureAttributes) -> Result<Self, TextureError> {
         let texture = context.device.create_texture(&wgpu::TextureDescriptor {
             label: None,
             size: attributes.size,