chore: Release lemur version 0.15.0

- Support WGPU_FORCE_FALLBACK to run on CPU
 - Pass display when creating wgpu instance
 - Pass compatible surface when constructing adapter
 - Log some settings (at debug level)

Cargo.lock

@@ -232,6 +232,9 @@ name = "arrayvec"
 version = "0.7.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d3fb67a6e08acf24fdeccbac2cb6ac4305825bd1f117462e0e6f2f193345ad56"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "as-raw-xcb-connection"
@@ -1571,6 +1574,8 @@ dependencies = [
  "allocator-api2",
  "equivalent",
  "foldhash 0.2.0",
+ "serde",
+ "serde_core",
 ]
 
 [[package]]
@@ -2029,7 +2034,7 @@ checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
 
 [[package]]
 name = "lemur"
-version = "0.13.0"
+version = "0.15.0"
 dependencies = [
  "anyhow",
  "atoi",
@@ -2238,6 +2243,22 @@ dependencies = [
  "zerocopy-derive",
 ]
 
+[[package]]
+name = "macro_rules_attribute"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b3ae8f6d608c795738406608304d30a2dfbdc8e58e44f7ba43236da5208ded3c"
+dependencies = [
+ "macro_rules_attribute-proc_macro",
+ "pastey",
+]
+
+[[package]]
+name = "macro_rules_attribute-proc_macro"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc04a4c58212d57930a24bf47d3fa87485264a3a054e9c10e042eb373573ad3c"
+
 [[package]]
 name = "matchers"
 version = "0.2.0"
@@ -2999,6 +3020,12 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "pastey"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2ee67f1008b1ba2321834326597b8e186293b049a023cdef258527550b9935b4"
+
 [[package]]
 name = "pdb-addr2line"
 version = "0.11.2"
@@ -5094,6 +5121,7 @@ dependencies = [
  "hashbrown 0.16.1",
  "indexmap",
  "log",
+ "macro_rules_attribute",
  "naga",
  "once_cell",
  "parking_lot",
@@ -5101,6 +5129,7 @@ dependencies = [
  "profiling",
  "raw-window-handle",
  "rustc-hash 1.1.0",
+ "serde",
  "smallvec",
  "thiserror 2.0.18",
  "wgpu-core-deps-apple",
@@ -5223,6 +5252,7 @@ dependencies = [
  "js-sys",
  "log",
  "raw-window-handle",
+ "serde",
  "web-sys",
 ]
 

Cargo.toml

@@ -4,7 +4,7 @@ description = "An emulator for the Virtual Boy."
 repository = "https://git.virtual-boy.com/PVB/lemur"
 publish = false
 license = "MIT"
-version = "0.13.0"
+version = "0.15.0"
 edition = "2024"
 
 [dependencies]
@@ -44,9 +44,9 @@ serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 thread-priority = "3"
 tokio = { version = "1", features = ["io-util", "macros", "net", "rt", "sync", "time"] }
-tracing = { version = "0.1", features = ["release_max_level_info"] }
+tracing = { version = "0.1", features = ["release_max_level_debug"] }
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
-wgpu = "29"
+wgpu = { version = "29", features = ["serde"] }
 wholesym = "0.8"
 winit = { version = "0.30", features = ["serde"] }
 

src/app.rs

@@ -14,16 +14,16 @@ use egui::{
 use egui_wgpu::winit::Painter;
 use egui_winit::EventResponse;
 use gilrs::{EventType, Gilrs};
-use tracing::{error, warn};
+use tracing::{debug, error, warn};
 use winit::{
     application::ApplicationHandler,
     event::WindowEvent,
-    event_loop::{ActiveEventLoop, ControlFlow, EventLoopProxy},
+    event_loop::{ActiveEventLoop, ControlFlow, EventLoopProxy, OwnedDisplayHandle},
     window::{Window, WindowId},
 };
 
 use crate::{
-    config::CliArgs,
+    config::{AppConfig, CliArgs},
     controller::ControllerManager,
     emulator::{EmulatorClient, EmulatorCommand, SimId},
     images::ImageTextureLoader,
@@ -48,9 +48,30 @@ fn load_icon() -> anyhow::Result<IconData> {
 
 struct SharedViewportState {
     viewport_info: ViewportIdMap<ViewportInfo>,
-    painter: Painter,
+    wgpu: WgpuState,
+    painter: Option<Painter>,
     resized_viewport: Option<ViewportId>,
 }
+impl SharedViewportState {
+    fn init_painter(&mut self, ctx: &Context, window: &Window) -> &mut Painter {
+        if self.painter.is_none() {
+            let wgpu_config = egui_wgpu::WgpuConfiguration {
+                present_mode: wgpu::PresentMode::AutoVsync,
+                wgpu_setup: egui_wgpu::WgpuSetup::Existing(self.wgpu.init(window)),
+                ..egui_wgpu::WgpuConfiguration::default()
+            };
+
+            let options = egui_wgpu::RendererOptions::default();
+            let painter =
+                pollster::block_on(Painter::new(ctx.clone(), wgpu_config, false, options));
+            self.painter = Some(painter);
+        }
+        self.painter.as_mut().unwrap()
+    }
+    fn get_painter(&mut self) -> &mut Painter {
+        self.painter.as_mut().unwrap()
+    }
+}
 
 pub struct Application {
     client: EmulatorClient,
@@ -70,10 +91,12 @@ impl Application {
     pub fn new(
         client: EmulatorClient,
         proxy: EventLoopProxy<UserEvent>,
+        handle: OwnedDisplayHandle,
         persistence: Persistence,
         args: CliArgs,
+        config: AppConfig,
     ) -> Self {
-        let wgpu = WgpuState::new();
+        let wgpu = WgpuState::new(handle, config);
         let icon = load_icon().ok().map(Arc::new);
         let mappings = MappingProvider::new(persistence.clone(), args.player2_controller);
         let shortcuts = ShortcutProvider::new(persistence.clone());
@@ -131,20 +154,6 @@ impl Application {
             });
         }
 
-        let wgpu_config = egui_wgpu::WgpuConfiguration {
-            present_mode: wgpu::PresentMode::AutoVsync,
-            wgpu_setup: egui_wgpu::WgpuSetup::Existing(egui_wgpu::WgpuSetupExisting {
-                instance: wgpu.instance.clone(),
-                adapter: wgpu.adapter.clone(),
-                device: wgpu.device.clone(),
-                queue: wgpu.queue.clone(),
-            }),
-            ..egui_wgpu::WgpuConfiguration::default()
-        };
-
-        let options = egui_wgpu::RendererOptions::default();
-        let painter = pollster::block_on(Painter::new(ctx.clone(), wgpu_config, false, options));
-
         let mut initial_windows = vec![];
         if let Some(port) = args.debug_port {
             initial_windows.push(ChildWindow::Debugger { port: Some(port) });
@@ -184,7 +193,8 @@ impl Application {
             ctx,
             shared: SharedViewportState {
                 viewport_info: ViewportIdMap::default(),
-                painter,
+                wgpu,
+                painter: None,
                 resized_viewport: None,
             },
             icon,
@@ -289,7 +299,7 @@ impl Application {
             }
             let clipped_primitives = self.ctx.tessellate(output.shapes, output.pixels_per_point);
             viewport.window.pre_present_notify();
-            self.shared.painter.paint_and_update_textures(
+            self.shared.get_painter().paint_and_update_textures(
                 viewport.id,
                 output.pixels_per_point,
                 [0.0, 0.0, 0.0, 0.0],
@@ -325,7 +335,11 @@ impl Application {
                                 id,
                                 InitArgs {
                                     window: &manager.window,
-                                    render_state: &self.shared.painter.render_state().unwrap(),
+                                    render_state: &self
+                                        .shared
+                                        .get_painter()
+                                        .render_state()
+                                        .unwrap(),
                                 },
                             );
                             manager
@@ -341,7 +355,9 @@ impl Application {
         if !active_viewports.contains(&ViewportId::ROOT) {
             event_loop.exit();
         }
-        self.shared.painter.gc_viewports(&active_viewports);
+        if let Some(painter) = self.shared.painter.as_mut() {
+            painter.gc_viewports(&active_viewports);
+        }
     }
 }
 
@@ -359,7 +375,7 @@ impl ApplicationHandler<UserEvent> for Application {
             viewport_builder,
             &mut self.shared,
         );
-        let render_state = self.shared.painter.render_state().unwrap();
+        let render_state = self.shared.get_painter().render_state().unwrap();
         GameScreen::init_pipeline(&render_state);
         self.app.handle_init(
             ViewportId::ROOT,
@@ -408,6 +424,9 @@ impl ApplicationHandler<UserEvent> for Application {
                 {
                     self.controllers.handle_key_event(&event);
                 }
+                WindowEvent::DroppedFile(path) => {
+                    self.app.handle_dropped_file(viewport_id, path);
+                }
                 WindowEvent::Focused(new_focused) => {
                     self.focused = new_focused.then_some(viewport_id);
                 }
@@ -448,6 +467,9 @@ impl ApplicationHandler<UserEvent> for Application {
                     self.controllers.handle_gamepad_event(&event);
                 }
             }
+            UserEvent::LowBattery(sim_id, pwr) => {
+                self.controllers.handle_low_battery(sim_id, pwr);
+            }
             UserEvent::Quit(sim_id) => match sim_id {
                 SimId::Player1 => event_loop.exit(),
                 SimId::Player2 => self.app.close(ChildWindow::Player2),
@@ -480,47 +502,66 @@ impl ApplicationHandler<UserEvent> for Application {
 
 struct WgpuState {
     instance: wgpu::Instance,
-    adapter: wgpu::Adapter,
+    device_descriptor: Arc<dyn Fn(&wgpu::Adapter) -> wgpu::DeviceDescriptor<'static> + Send + Sync>,
-    device: wgpu::Device,
+    config: AppConfig,
-    queue: wgpu::Queue,
 }
 
 impl WgpuState {
-    fn new() -> Self {
+    fn new(handle: OwnedDisplayHandle, config: AppConfig) -> Self {
         #[allow(unused_variables)]
-        let egui_wgpu::WgpuConfiguration {
+        let egui_wgpu::WgpuSetupCreateNew {
-            wgpu_setup:
+            instance_descriptor: wgpu::InstanceDescriptor { backends, .. },
-                egui_wgpu::WgpuSetup::CreateNew(egui_wgpu::WgpuSetupCreateNew {
+            device_descriptor,
-                    instance_descriptor: wgpu::InstanceDescriptor { backends, .. },
-                    device_descriptor,
-                    ..
-                }),
             ..
-        } = egui_wgpu::WgpuConfiguration::default()
+        } = egui_wgpu::WgpuSetupCreateNew::without_display_handle();
-        else {
-            panic!("required fields not found")
-        };
         #[cfg(windows)]
         let backends = wgpu::Backends::from_env()
             .unwrap_or((wgpu::Backends::PRIMARY | wgpu::Backends::GL) - wgpu::Backends::VULKAN);
         let instance = wgpu::Instance::new(wgpu::InstanceDescriptor {
             backends,
-            ..wgpu::InstanceDescriptor::new_without_display_handle_from_env()
+            ..wgpu::InstanceDescriptor::new_with_display_handle_from_env(Box::new(handle))
         });
 
-        let adapter = pollster::block_on(instance.request_adapter(&wgpu::RequestAdapterOptions {
-            power_preference:
-                wgpu::PowerPreference::from_env().unwrap_or(wgpu::PowerPreference::LowPower),
-            compatible_surface: None,
-            force_fallback_adapter: false,
-        }))
-        .expect("could not create adapter");
-
-        let (device, queue) =
-            pollster::block_on(adapter.request_device(&(*device_descriptor)(&adapter)))
-                .expect("could not request device");
         Self {
             instance,
+            device_descriptor,
+            config,
+        }
+    }
+
+    fn init(&mut self, window: &Window) -> egui_wgpu::WgpuSetupExisting {
+        let power_preference =
+            wgpu::PowerPreference::from_env().unwrap_or(self.config.power_preference);
+        debug!("power preference: {power_preference:?}");
+
+        let force_fallback_adapter = std::env::var("WGPU_FORCE_FALLBACK")
+            .map_or(self.config.force_fallback, |f| {
+                f.eq_ignore_ascii_case("true") || f.eq_ignore_ascii_case("1")
+            });
+        debug!("force fallback: {force_fallback_adapter}");
+
+        let surface = self
+            .instance
+            .create_surface(window)
+            .expect("could not create surface");
+
+        let adapter =
+            pollster::block_on(self.instance.request_adapter(&wgpu::RequestAdapterOptions {
+                power_preference,
+                compatible_surface: Some(&surface),
+                force_fallback_adapter,
+            }))
+            .expect("could not create adapter");
+        debug!("selected adapter: {:?}", adapter.get_info());
+
+        drop(surface);
+
+        let (device, queue) =
+            pollster::block_on(adapter.request_device(&(*self.device_descriptor)(&adapter)))
+                .expect("could not request device");
+
+        egui_wgpu::WgpuSetupExisting {
+            instance: self.instance.clone(),
             adapter,
             device,
             queue,
@@ -544,14 +585,15 @@ impl ViewportManager {
         shared: &mut SharedViewportState,
     ) -> Self {
         let window = Arc::new(egui_winit::create_window(ctx, event_loop, &builder).unwrap());
-        pollster::block_on(shared.painter.set_window(viewport_id, Some(window.clone()))).unwrap();
+        let painter = shared.init_painter(ctx, &window);
+        pollster::block_on(painter.set_window(viewport_id, Some(window.clone()))).unwrap();
         let state = egui_winit::State::new(
             ctx.clone(),
             viewport_id,
             event_loop,
             Some(window.scale_factor() as f32),
             event_loop.system_theme(),
-            shared.painter.max_texture_side(),
+            painter.max_texture_side(),
         );
 
         let mut info = ViewportInfo {
@@ -588,9 +630,13 @@ impl ViewportManager {
         {
             if shared.resized_viewport != Some(self.id) {
                 shared.resized_viewport = Some(self.id);
-                shared.painter.on_window_resize_state_change(self.id, true);
+                shared
+                    .get_painter()
+                    .on_window_resize_state_change(self.id, true);
             }
-            shared.painter.on_window_resized(self.id, width, height);
+            shared
+                .get_painter()
+                .on_window_resized(self.id, width, height);
         }
         let response = self.state.on_window_event(&self.window, event);
         let info = shared.viewport_info.get_mut(&self.id).unwrap();
@@ -630,6 +676,7 @@ impl ViewportManager {
 pub enum UserEvent {
     GamepadEvent(gilrs::Event),
     Quit(SimId),
+    LowBattery(SimId, bool),
     RequestRedraw(ViewportId, Instant),
 }
 

src/audio.rs

@@ -1,12 +1,16 @@
 use std::time::Duration;
 
-use anyhow::{Result, bail};
+use anyhow::{Context, Result, bail};
 use audioadapter_buffers::direct::InterleavedSlice;
-use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
+use cpal::{
+    Device, FromSample, Sample, SampleFormat, SizedSample, StreamConfig,
+    traits::{DeviceTrait, HostTrait, StreamTrait},
+};
+use itertools::Itertools;
 use rubato::{Adjustable as _, Resampler};
 use tracing::warn;
 
-pub struct Audio {
+struct CpalAudio {
     #[allow(unused)]
     stream: cpal::Stream,
     sampler: rubato::Async<f32>,
@@ -17,19 +21,31 @@ pub struct Audio {
 
 const VB_FREQUENCY: usize = 41700;
 
-impl Audio {
+impl CpalAudio {
-    pub fn init() -> Result<Self> {
+    fn init() -> Result<Self> {
         let host = cpal::default_host();
-        let Some(device) = host.default_output_device() else {
+        let device = host
-            bail!("No output device available");
+            .default_output_device()
-        };
+            .context("no output device available")?;
         let default_rate = device.default_output_config()?.sample_rate();
-        let Some(config) = device.supported_output_configs()?.find(|c| {
+
-            c.channels() == 2 && c.sample_format().is_float() && c.contains_rate(default_rate)
+        let supported_config = device
-        }) else {
+            .supported_output_configs()?
-            bail!("No suitable output config available");
+            .filter(|c| {
-        };
+                c.contains_rate(default_rate)
-        let mut config = config.with_max_sample_rate().config();
+                    && matches!(
+                        c.sample_format(),
+                        SampleFormat::F32
+                            | SampleFormat::F64
+                            | SampleFormat::I32
+                            | SampleFormat::I16
+                    )
+            })
+            .max_by(|a, b| a.cmp_default_heuristics(b))
+            .context("no suitable output config available")?
+            .with_sample_rate(default_rate);
+        let mut config = supported_config.config();
+
         let resample_ratio = config.sample_rate as f64 / VB_FREQUENCY as f64;
         let chunk_size = (834.0 * resample_ratio) as usize;
         let sampler = rubato::Async::new_poly(
@@ -42,6 +58,23 @@ impl Audio {
         )?;
         config.buffer_size = cpal::BufferSize::Fixed(sampler.output_frames_max() as u32);
 
+        match supported_config.sample_format() {
+            SampleFormat::F32 if config.channels == 2 => {
+                Self::new_f32_stereo(device, config, sampler)
+            }
+            SampleFormat::F32 => Self::new::<f32>(device, config, sampler),
+            SampleFormat::F64 => Self::new::<f64>(device, config, sampler),
+            SampleFormat::I32 => Self::new::<i32>(device, config, sampler),
+            SampleFormat::I16 => Self::new::<i16>(device, config, sampler),
+            _ => bail!("unsupported sample format"),
+        }
+    }
+
+    fn new_f32_stereo(
+        device: Device,
+        config: StreamConfig,
+        sampler: rubato::Async<f32>,
+    ) -> Result<Self> {
         let input_buffer = Vec::with_capacity(sampler.nbr_channels() * sampler.input_frames_max());
         let output_buffer = vec![0.0; sampler.nbr_channels() * sampler.output_frames_max()];
         let (sample_sink, mut sample_source) =
@@ -79,7 +112,60 @@ impl Audio {
         })
     }
 
-    pub fn update(&mut self, mut samples: &[f32]) {
+    fn new<S: SizedSample + FromSample<f32>>(
+        device: Device,
+        config: StreamConfig,
+        sampler: rubato::Async<f32>,
+    ) -> Result<Self> {
+        let input_buffer = Vec::with_capacity(sampler.nbr_channels() * sampler.input_frames_max());
+        let output_buffer = vec![0.0; sampler.nbr_channels() * sampler.output_frames_max()];
+        let (sample_sink, mut sample_source) =
+            rtrb::RingBuffer::new(sampler.output_frames_max() * 4);
+
+        let channels = config.channels as usize;
+
+        let stream = device.build_output_stream(
+            config,
+            move |data: &mut [S], _| {
+                let requested = data.len() * 2 / channels;
+                let chunk = match sample_source.read_chunk(requested) {
+                    Ok(c) => c,
+                    Err(rtrb::chunks::ChunkError::TooFewSlots(n)) => {
+                        sample_source.read_chunk(n).unwrap()
+                    }
+                };
+                let (first, second) = chunk.as_slices();
+
+                let new_samples = first
+                    .iter()
+                    .chain(second)
+                    .map(|s: &f32| (*s).to_sample())
+                    .chunks(2);
+                let buffer = data.iter_mut().chunks(channels);
+                for (dst, samples) in buffer.into_iter().zip(&new_samples) {
+                    // channels beyond the first two are zeroed
+                    let src = samples.chain(std::iter::repeat(S::EQUILIBRIUM));
+                    for (d, s) in dst.zip(src) {
+                        *d = s;
+                    }
+                }
+
+                chunk.commit_all();
+            },
+            move |error| warn!(%error, "stream error"),
+            None,
+        )?;
+        stream.play()?;
+        Ok(Self {
+            stream,
+            sampler,
+            input_buffer,
+            output_buffer,
+            sample_sink,
+        })
+    }
+
+    fn update(&mut self, mut samples: &[f32]) {
         while self.input_buffer.len() + samples.len() >= self.sampler.input_frames_next() * 2 {
             let samples_needed =
                 (self.sampler.input_frames_next() * 2).saturating_sub(self.input_buffer.len());
@@ -117,9 +203,64 @@ impl Audio {
         }
     }
 
-    pub fn set_speed(&mut self, speed: f64) -> Result<()> {
+    fn set_speed(&mut self, speed: f64) -> Result<()> {
         self.sampler
             .set_resample_ratio_relative(1.0 / speed, false)?;
         Ok(())
     }
 }
+
+struct NoAudio {
+    speed: f64,
+}
+
+impl NoAudio {
+    fn new() -> Self {
+        Self { speed: 1.0 }
+    }
+
+    fn update(&mut self, samples: &[f32]) {
+        let samples = (samples.len() / 2) as f64;
+        let elapsed = Duration::from_secs_f64(samples / (VB_FREQUENCY as f64 * self.speed));
+        std::thread::sleep(elapsed);
+    }
+
+    fn set_speed(&mut self, speed: f64) -> Result<()> {
+        self.speed = speed;
+        Ok(())
+    }
+}
+
+#[allow(clippy::large_enum_variant)]
+enum AudioInner {
+    Cpal(CpalAudio),
+    None(NoAudio),
+}
+
+pub struct Audio(AudioInner);
+
+impl Audio {
+    pub fn init() -> Self {
+        match CpalAudio::init() {
+            Ok(a) => Self(AudioInner::Cpal(a)),
+            Err(e) => {
+                warn!("could not play audio: {e}");
+                Self(AudioInner::None(NoAudio::new()))
+            }
+        }
+    }
+
+    pub fn update(&mut self, samples: &[f32]) {
+        match &mut self.0 {
+            AudioInner::Cpal(a) => a.update(samples),
+            AudioInner::None(a) => a.update(samples),
+        }
+    }
+
+    pub fn set_speed(&mut self, speed: f64) -> Result<()> {
+        match &mut self.0 {
+            AudioInner::Cpal(a) => a.set_speed(speed),
+            AudioInner::None(a) => a.set_speed(speed),
+        }
+    }
+}

src/config.rs

@@ -1,5 +1,5 @@
 use anyhow::Result;
-use clap::Parser;
+use clap::{Parser, ValueEnum};
 use egui::{Color32, Pos2, Vec2};
 use serde::{Deserialize, Serialize};
 
@@ -47,6 +47,28 @@ pub struct CliArgs {
     /// Map the first connected controller to Player 2
     #[arg(long)]
     pub player2_controller: bool,
+    /// Force the application to render with CPU, rather than GPU.
+    #[arg(long)]
+    pub wgpu_force_fallback: Option<bool>,
+    /// Set a preference for whether to use a low-power or high-performance GPU adapter
+    #[arg(long)]
+    pub wgpu_power_preference: Option<PowerPreferenceWrapper>,
+}
+
+#[derive(ValueEnum, Clone, Copy)]
+pub enum PowerPreferenceWrapper {
+    Low,
+    High,
+    None,
+}
+impl From<PowerPreferenceWrapper> for wgpu::PowerPreference {
+    fn from(value: PowerPreferenceWrapper) -> Self {
+        match value {
+            PowerPreferenceWrapper::Low => wgpu::PowerPreference::LowPower,
+            PowerPreferenceWrapper::High => wgpu::PowerPreference::HighPerformance,
+            PowerPreferenceWrapper::None => wgpu::PowerPreference::None,
+        }
+    }
 }
 
 pub const COLOR_PRESETS: [[Color32; 2]; 3] = [
@@ -64,6 +86,49 @@ pub const COLOR_PRESETS: [[Color32; 2]; 3] = [
     ],
 ];
 
+const fn default_power_preference() -> wgpu::PowerPreference {
+    wgpu::PowerPreference::LowPower
+}
+
+#[derive(Serialize, Deserialize, Clone, PartialEq, Eq)]
+pub struct AppConfig {
+    #[serde(default = "default_power_preference")]
+    pub power_preference: wgpu::PowerPreference,
+    #[serde(default)]
+    pub force_fallback: bool,
+}
+
+impl AppConfig {
+    pub fn load(persistence: &Persistence) -> Self {
+        if let Ok(config) = persistence.load_config(APP_CONFIG_FILENAME) {
+            return config;
+        }
+        Self {
+            power_preference: default_power_preference(),
+            force_fallback: false,
+        }
+    }
+
+    pub fn save(&self, persistence: &Persistence) -> Result<()> {
+        persistence.save_config(APP_CONFIG_FILENAME, &self)
+    }
+
+    pub fn update(&mut self, args: &CliArgs) -> bool {
+        let mut updated = false;
+        if let Some(pref) = args.wgpu_power_preference {
+            self.power_preference = pref.into();
+            updated = true;
+        }
+        if let Some(force_fallback) = args.wgpu_force_fallback {
+            self.force_fallback = force_fallback;
+            updated = true;
+        }
+        updated
+    }
+}
+
+const APP_CONFIG_FILENAME: &str = "config";
+
 const fn default_audio_enabled() -> bool {
     true
 }
@@ -76,12 +141,16 @@ pub struct SimConfig {
     #[serde(default = "default_audio_enabled")]
     pub audio_enabled: bool,
     #[serde(default)]
+    pub low_battery: bool,
+    #[serde(default)]
+    pub watch_rom: bool,
+    #[serde(default)]
     pub position: Option<Pos2>,
 }
 
 impl SimConfig {
     pub fn load(persistence: &Persistence, sim_id: SimId) -> Self {
-        if let Ok(config) = persistence.load_config(config_filename(sim_id)) {
+        if let Ok(config) = persistence.load_config(sim_config_filename(sim_id)) {
             return config;
         }
         Self {
@@ -89,16 +158,18 @@ impl SimConfig {
             colors: COLOR_PRESETS[0],
             dimensions: DisplayMode::Anaglyph.proportions() + Vec2::new(0.0, 22.0),
             audio_enabled: true,
+            low_battery: false,
+            watch_rom: false,
             position: None,
         }
     }
 
     pub fn save(&self, persistence: &Persistence, sim_id: SimId) -> Result<()> {
-        persistence.save_config(config_filename(sim_id), self)
+        persistence.save_config(sim_config_filename(sim_id), self)
     }
 }
 
-fn config_filename(sim_id: SimId) -> &'static str {
+fn sim_config_filename(sim_id: SimId) -> &'static str {
     match sim_id {
         SimId::Player1 => "config_p1",
         SimId::Player2 => "config_p2",

src/controller.rs

@@ -77,6 +77,15 @@ impl Controller {
         self.update_state(pressed, released)
     }
 
+    pub fn low_battery(&mut self, pwr: bool) -> Option<VBKey> {
+        let (pressed, released) = if pwr {
+            (VBKey::PWR, VBKey::empty())
+        } else {
+            (VBKey::empty(), VBKey::PWR)
+        };
+        self.update_state(pressed, released)
+    }
+
     fn update_state(&mut self, pressed: VBKey, released: VBKey) -> Option<VBKey> {
         let old_state = self.state;
         self.state = self.state.union(pressed).difference(released);
@@ -133,6 +142,14 @@ impl ControllerManager {
             }
         }
     }
+
+    pub fn handle_low_battery(&mut self, sim_id: SimId, pwr: bool) {
+        let controller = &mut self.controllers[sim_id.to_index()];
+        if let Some(pressed) = controller.low_battery(pwr) {
+            self.client
+                .send_command(EmulatorCommand::SetKeys(controller.sim_id, pressed));
+        }
+    }
 }
 
 fn axis_presses(value: f32, pair_value: f32, neg: VBKey, pos: VBKey) -> (VBKey, VBKey) {

src/emulator.rs

@@ -138,7 +138,7 @@ impl EmulatorBuilder {
             self.audio_on,
             self.watch_rom,
             self.linked,
-        )?;
+        );
         if let Some(path) = self.rom {
             emulator.load_cart(SimId::Player1, &path)?;
         }
@@ -178,11 +178,11 @@ impl Emulator {
         audio_on: Arc<[AtomicBool; 2]>,
         watch_rom: Arc<[AtomicBool; 2]>,
         linked: Arc<AtomicBool>,
-    ) -> Result<Self> {
+    ) -> Self {
-        Ok(Self {
+        Self {
             sims: vec![],
             carts: [None, None],
-            audio: Audio::init()?,
+            audio: Audio::init(),
             commands,
             sim_state,
             state,
@@ -198,7 +198,7 @@ impl Emulator {
             eye_contents: [vec![0u8; 384 * 224 * 2], vec![0u8; 384 * 224 * 2]],
             audio_samples: Vec::with_capacity(EXPECTED_FRAME_SIZE),
             buffer: vec![],
-        })
+        }
     }
 
     pub fn reload_cart(&mut self, sim_id: SimId) -> Result<()> {
@@ -265,7 +265,8 @@ impl Emulator {
         } else if let Some(cart) = self.carts[index].as_mut()
             && cart.is_watching()
         {
-            cart.restart_watching();
+            cart.reload()?;
+            sim.load_cart(cart.rom.clone(), cart.sram.clone())?;
         }
         let mut profiling = false;
         if let Some(profiler) = self.profilers[sim_id.to_index()].as_ref()

src/emulator/cart.rs

@@ -22,10 +22,7 @@ pub struct Cart {
 
 impl Cart {
     pub fn load(file_path: &Path, sim_id: SimId, watch: bool) -> Result<Self> {
-        let rom = fs::read(file_path)?;
+        let (rom, info) = Self::read_rom(file_path)?;
-        let (rom, info) = try_parse_isx(file_path, &rom)
-            .or_else(|| try_parse_elf(file_path, &rom))
-            .unwrap_or_else(|| (rom, GameInfo::empty(file_path)));
 
         let mut sram_file = File::options()
             .read(true)
@@ -66,6 +63,16 @@ impl Cart {
         })
     }
 
+    pub fn reload(&mut self) -> Result<()> {
+        let (rom, info) = Self::read_rom(&self.file_path)?;
+        self.rom = rom;
+        self.info = Arc::new(info);
+        if self.is_watching() {
+            self.restart_watching();
+        }
+        Ok(())
+    }
+
     pub fn save_sram(&mut self) -> Result<()> {
         self.sram_file.seek(SeekFrom::Start(0))?;
         self.sram_file.write_all(&self.sram)?;
@@ -92,6 +99,14 @@ impl Cart {
         self.changed = Arc::new(AtomicBool::new(false));
         self.watcher = None;
     }
+
+    fn read_rom(file_path: &Path) -> Result<(Vec<u8>, GameInfo)> {
+        let rom = fs::read(file_path)?;
+        let (rom, info) = try_parse_isx(file_path, &rom)
+            .or_else(|| try_parse_elf(file_path, &rom))
+            .unwrap_or_else(|| (rom, GameInfo::empty(file_path)));
+        Ok((rom, info))
+    }
 }
 
 fn build_watcher(file_path: &Path, changed: Arc<AtomicBool>) -> Option<notify::RecommendedWatcher> {

src/filepicker.rs

@@ -0,0 +1,103 @@
+#[cfg(target_os = "linux")]
+use std::fmt::Write as _;
+use std::{
+    path::PathBuf,
+    sync::{Arc, Weak},
+};
+
+use winit::window::Window;
+
+pub struct FilePicker {
+    window: Option<Weak<Window>>,
+}
+
+impl FilePicker {
+    pub fn new() -> Self {
+        Self { window: None }
+    }
+
+    pub fn set_window(&mut self, window: &Arc<Window>) {
+        self.window = Some(Arc::downgrade(window));
+    }
+
+    pub fn pick_file_dialog(&self) -> FileDialogBuilder {
+        self.new_dialog(FileDialogAction::PickFile, false)
+    }
+
+    pub fn save_file_dialog(&self) -> FileDialogBuilder {
+        self.new_dialog(FileDialogAction::SaveFile, cfg!(not(target_os = "windows")))
+    }
+
+    fn new_dialog(&self, action: FileDialogAction, attach_window: bool) -> FileDialogBuilder {
+        #[cfg(not(target_os = "macos"))]
+        let mut dialog = rfd::AsyncFileDialog::new();
+        #[cfg(target_os = "macos")]
+        let mut dialog = rfd::FileDialog::new();
+
+        if attach_window && let Some(window) = self.window.as_ref().and_then(|w| w.upgrade()) {
+            dialog = dialog.set_parent(&window);
+        }
+        FileDialogBuilder { dialog, action }
+    }
+}
+
+pub struct FileDialogBuilder {
+    #[cfg(not(target_os = "macos"))]
+    dialog: rfd::AsyncFileDialog,
+    #[cfg(target_os = "macos")]
+    dialog: rfd::FileDialog,
+    action: FileDialogAction,
+}
+
+impl FileDialogBuilder {
+    pub fn add_filter(self, name: impl Into<String>, extensions: &[impl ToString]) -> Self {
+        #[cfg(target_os = "linux")]
+        let exts = extensions
+            .iter()
+            .map(|ext| {
+                let mut normalized = String::new();
+                for char in ext.to_string().chars() {
+                    if char.is_ascii_lowercase() {
+                        let _ = write!(&mut normalized, "[{char}{}]", char.to_ascii_uppercase());
+                    } else {
+                        normalized.push(char);
+                    }
+                }
+                normalized
+            })
+            .collect::<Vec<_>>();
+        #[cfg(target_os = "linux")]
+        let extensions = &exts;
+        Self {
+            dialog: self.dialog.add_filter(name, extensions),
+            ..self
+        }
+    }
+
+    pub fn set_file_name(self, file_name: impl Into<String>) -> Self {
+        Self {
+            dialog: self.dialog.set_file_name(file_name),
+            ..self
+        }
+    }
+
+    pub fn open(self) -> Option<PathBuf> {
+        #[cfg(not(target_os = "macos"))]
+        fn resolve(action: impl Future<Output = Option<rfd::FileHandle>>) -> Option<PathBuf> {
+            pollster::block_on(action).map(Into::into)
+        }
+        #[cfg(target_os = "macos")]
+        fn resolve(action: Option<PathBuf>) -> Option<PathBuf> {
+            action
+        }
+        match self.action {
+            FileDialogAction::PickFile => resolve(self.dialog.pick_file()),
+            FileDialogAction::SaveFile => resolve(self.dialog.save_file()),
+        }
+    }
+}
+
+enum FileDialogAction {
+    PickFile,
+    SaveFile,
+}

src/main.rs

@@ -13,7 +13,7 @@ use tracing_subscriber::{EnvFilter, Layer, layer::SubscriberExt, util::Subscribe
 use winit::event_loop::{ControlFlow, EventLoop};
 
 use crate::{
-    config::{CliArgs, SimConfig},
+    config::{AppConfig, CliArgs, SimConfig},
     emulator::SimId,
     persistence::Persistence,
 };
@@ -23,6 +23,7 @@ mod audio;
 mod config;
 mod controller;
 mod emulator;
+mod filepicker;
 mod gdbserver;
 mod graphics;
 mod images;
@@ -110,6 +111,10 @@ fn main() -> Result<()> {
     if args.profile {
         builder = builder.start_paused(true)
     }
+    let mut config = AppConfig::load(&persistence);
+    if config.update(&args) {
+        let _ = config.save(&persistence);
+    }
     let p1 = SimConfig::load(&persistence, SimId::Player1);
     let p2 = SimConfig::load(&persistence, SimId::Player2);
 
@@ -136,6 +141,14 @@ fn main() -> Result<()> {
     let event_loop = EventLoop::with_user_event().build().unwrap();
     event_loop.set_control_flow(ControlFlow::Poll);
     let proxy = event_loop.create_proxy();
-    event_loop.run_app(&mut Application::new(client, proxy, persistence, args))?;
+    let handle = event_loop.owned_display_handle();
+    event_loop.run_app(&mut Application::new(
+        client,
+        proxy,
+        handle,
+        persistence,
+        args,
+        config,
+    ))?;
     Ok(())
 }

src/window.rs

@@ -1,4 +1,4 @@
-use std::sync::Arc;
+use std::{path::PathBuf, sync::Arc};
 
 pub use about::AboutWindow;
 use egui::{Ui, ViewportBuilder};
@@ -47,6 +47,10 @@ pub trait AppWindow {
         let _ = event;
         false
     }
+    fn handle_dropped_file(&mut self, path: PathBuf) -> bool {
+        let _ = path;
+        false
+    }
 }
 
 pub struct InitArgs<'a> {

src/window/game.rs

@@ -1,5 +1,6 @@
 use std::{
     ops::{Deref, DerefMut},
+    path::PathBuf,
     sync::{Arc, Mutex, atomic::AtomicBool, mpsc},
     time::Duration,
 };
@@ -8,6 +9,7 @@ use crate::{
     app::UserEvent,
     config::{COLOR_PRESETS, SimConfig},
     emulator::{EmulatorClient, EmulatorCommand, EmulatorState, SimId, SimState},
+    filepicker::FilePicker,
     images::ImageTextureLoader,
     input::{Command, MappingProvider, ShortcutProvider},
     memory::MemoryClient,
@@ -46,7 +48,7 @@ pub struct GameWindow {
     messages: mpsc::Receiver<Toast>,
     message_sink: mpsc::Sender<Toast>,
     color_picker: Option<ColorPickerState>,
-    window: Option<Arc<winit::window::Window>>,
+    file_picker: FilePicker,
     memory: Arc<MemoryClient>,
     images: Arc<ImageTextureLoader>,
     mappings: MappingProvider,
@@ -70,6 +72,8 @@ impl GameWindow {
         sim_id: SimId,
     ) -> Self {
         let config = SimConfig::load(&persistence, sim_id);
+        let _ = proxy.send_event(UserEvent::LowBattery(sim_id, config.low_battery));
+        client.send_command(EmulatorCommand::WatchRom(sim_id, config.watch_rom));
         let toasts = Toasts::new()
             .with_anchor(Anchor::BottomLeft)
             .with_margin((10.0, 10.0).into())
@@ -88,7 +92,7 @@ impl GameWindow {
             messages,
             message_sink,
             color_picker: None,
-            window: None,
+            file_picker: FilePicker::new(),
             memory: memory.clone(),
             images: images.clone(),
             mappings: mappings.clone(),
@@ -180,6 +184,11 @@ impl GameWindow {
         let mut viewport = child.initial_viewport();
         let title = viewport.title.clone().unwrap();
         let sim_id = child.sim_id();
+        if let Some(sim_id) = sim_id
+            && self.show_player_name
+        {
+            viewport.title = Some(format!("{title} ({sim_id})"));
+        }
         if let Some(state) = self.child_states.get(&viewport_id) {
             viewport.position = Some(state.position);
             viewport.inner_size = Some(state.size);
@@ -208,6 +217,10 @@ impl GameWindow {
         self.handle_event(viewport_id, |window| window.handle_gamepad_event(event))
     }
 
+    pub fn handle_dropped_file(&mut self, viewport_id: ViewportId, path: PathBuf) -> bool {
+        self.handle_event(viewport_id, |window| window.handle_dropped_file(path))
+    }
+
     fn handle_event<F, R>(&mut self, viewport_id: ViewportId, cb: F) -> R
     where
         F: FnOnce(&mut dyn AppWindow) -> R,
@@ -244,9 +257,11 @@ impl GameWindow {
         for command in ui.input_mut(|input| self.shortcuts.consume_all(input)) {
             match command {
                 Command::OpenRom => {
-                    let rom = rfd::FileDialog::new()
+                    let rom = self
+                        .file_picker
+                        .pick_file_dialog()
                         .add_filter("Virtual Boy ROMs", &["vb", "vbrom", "elf", "isx"])
-                        .pick_file();
+                        .open();
                     if let Some(path) = rom {
                         self.client
                             .send_command(EmulatorCommand::LoadGame(self.sim_id, path));
@@ -300,9 +315,11 @@ impl GameWindow {
                 .add(self.button_for(ui.ctx(), "Open ROM", Command::OpenRom))
                 .clicked()
             {
-                let rom = rfd::FileDialog::new()
+                let rom = self
+                    .file_picker
+                    .pick_file_dialog()
                     .add_filter("Virtual Boy ROMs", &["vb", "vbrom", "elf", "isx"])
-                    .pick_file();
+                    .open();
                 if let Some(path) = rom {
                     self.client
                         .send_command(EmulatorCommand::LoadGame(self.sim_id, path));
@@ -317,6 +334,7 @@ impl GameWindow {
             }
             let watch_rom = self.client.is_rom_watched(self.sim_id);
             if ui.selectable_button(watch_rom, "Watch ROM").clicked() {
+                self.update_config(|c| c.watch_rom = !watch_rom);
                 self.client
                     .send_command(EmulatorCommand::WatchRom(self.sim_id, !watch_rom));
             }
@@ -374,6 +392,14 @@ impl GameWindow {
             {
                 pollster::block_on(self.take_screenshot());
             }
+            ui.separator();
+            let low_battery = self.config.low_battery;
+            if ui.selectable_button(low_battery, "Low Battery").clicked() {
+                self.update_config(|c| c.low_battery = !low_battery);
+                let _ = self
+                    .proxy
+                    .send_event(UserEvent::LowBattery(self.sim_id, !low_battery));
+            }
         });
         ui.menu_button("Options", |ui| self.show_options_menu(ui));
         ui.menu_button("Multiplayer", |ui| {
@@ -454,13 +480,12 @@ impl GameWindow {
         self.client
             .send_command(EmulatorCommand::Screenshot(self.sim_id, tx));
         let bytes = rx.await.context("Could not take screenshot")?;
-        let mut file_dialog = rfd::FileDialog::new()
+        let file = self
+            .file_picker
+            .save_file_dialog()
             .add_filter("PNG images", &["png"])
-            .set_file_name("screenshot.png");
+            .set_file_name("screenshot.png")
-        if let Some(window) = self.window.as_ref() {
+            .open();
-            file_dialog = file_dialog.set_parent(window);
-        }
-        let file = file_dialog.save_file();
         let Some(path) = file else {
             return Ok(None);
         };
@@ -754,7 +779,13 @@ impl AppWindow for GameWindow {
             ));
             self.screen = Some(screen);
         }
-        self.window = Some(args.window.clone());
+        self.file_picker.set_window(args.window);
+    }
+
+    fn handle_dropped_file(&mut self, path: PathBuf) -> bool {
+        self.client
+            .send_command(EmulatorCommand::LoadGame(self.sim_id, path));
+        true
     }
 }
 

src/window/profile.rs

@@ -1,12 +1,12 @@
-use std::{fs, sync::Arc, time::Duration};
+use std::{fs, time::Duration};
 
 use anyhow::Result;
 use egui::{Button, CentralPanel, Checkbox, Label, ViewportBuilder};
 use egui_notify::{Anchor, Toast, Toasts};
-use winit::window::Window;
 
 use crate::{
     emulator::{EmulatorClient, EmulatorCommand, EmulatorState, SimId},
+    filepicker::FilePicker,
     profiler::{Profiler, ProfilerStatus},
     window::{AppWindow, InitArgs},
 };
@@ -16,7 +16,7 @@ pub struct ProfileWindow {
     client: EmulatorClient,
     profiler: Profiler,
     toasts: Toasts,
-    window: Option<Arc<Window>>,
+    file_picker: FilePicker,
 }
 
 impl ProfileWindow {
@@ -29,7 +29,7 @@ impl ProfileWindow {
                 .with_anchor(Anchor::BottomLeft)
                 .with_margin((10.0, 10.0).into())
                 .reverse(true),
-            window: None,
+            file_picker: FilePicker::new(),
         }
     }
 
@@ -62,13 +62,12 @@ impl ProfileWindow {
 
     fn try_finish_recording(&mut self) -> Result<Option<String>> {
         let bytes_receiver = self.profiler.finish_recording();
-        let mut file_dialog = rfd::FileDialog::new()
+        let file = self
+            .file_picker
+            .save_file_dialog()
             .add_filter("Profiler files", &["json"])
-            .set_file_name("profile.json");
+            .set_file_name("profile.json")
-        if let Some(window) = self.window.as_ref() {
+            .open();
-            file_dialog = file_dialog.set_parent(window);
-        }
-        let file = file_dialog.save_file();
         if let Some(path) = file {
             let bytes = pollster::block_on(bytes_receiver)?;
             let _ = fs::remove_file(&path);
@@ -164,6 +163,6 @@ impl AppWindow for ProfileWindow {
     }
 
     fn on_init(&mut self, args: InitArgs) {
-        self.window = Some(args.window.clone());
+        self.file_picker.set_window(args.window);
     }
 }