chore: Release lemur version 0.15.1

- 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.toml

@@ -4,52 +4,54 @@ description = "An emulator for the Virtual Boy."
 repository = "https://git.virtual-boy.com/PVB/lemur"
 publish = false
 license = "MIT"
-version = "0.7.3"
+version = "0.15.1"
 edition = "2024"
 
 [dependencies]
 anyhow = "1"
-atoi = "2"
+atoi = "3"
+audioadapter-buffers = "5"
 atomic = "0.6"
 bitflags = { version = "2", features = ["serde"] }
 bytemuck = { version = "1", features = ["derive"] }
 clap = { version = "4", features = ["derive"] }
-cpal = { git = "https://github.com/sidit77/cpal.git", rev = "66ed6be" }
+cpal = "0.18"
 directories = "6"
-egui = { version = "0.32", features = ["serde"] }
-egui_extras = { version = "0.32", features = ["image"] }
-egui-notify = "0.20"
-egui-winit = "0.32"
-egui-wgpu = { version = "0.32", features = ["winit"] }
+egui = { version = "0.36", features = ["persistence", "serde"] }
+egui_extras = { version = "0.36", features = ["image"] }
+egui-notify = "0.23"
+egui-winit = "0.36"
+egui-wgpu = { version = "0.36", features = ["winit"] }
 fxprof-processed-profile = "0.8"
 fixed = { version = "1.28", features = ["num-traits"] }
 gilrs = { version = "0.11", features = ["serde-serialize"] }
-gimli = "0.32"
+gimli = "0.34"
 hex = "0.4"
 image = { version = "0.25", default-features = false, features = ["png"] }
-itertools = "0.14"
+itertools = "0.15"
 normpath = "1"
-num-derive = "0.4"
+notify = "8"
+num-derive = "0.5"
 num-traits = "0.2"
-object = "0.37"
-oneshot = "0.1"
-pollster = "0.4"
-rand = "0.9"
-rfd = { version = "0.15", default-features = false, features = ["xdg-portal", "async-std"]}
-rtrb = "0.3"
-rubato = "0.16"
+object = "0.40"
+oneshot = { version = "0.2", features = ["async", "std"] }
+pollster = "1"
+rand = "0.10"
+rfd = "0.17"
+rtrb = "0.4"
+rubato = "5"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
-thread-priority = "2"
+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 = "25"
+wgpu = { version = "30", features = ["serde"] }
 wholesym = "0.8"
 winit = { version = "0.30", features = ["serde"] }
 
 [target.'cfg(windows)'.dependencies]
-windows = { version = "0.61", features = ["Win32_System_Threading"] }
+windows = { version = "0.62", features = ["Win32_System_Threading"] }
 
 [build-dependencies]
 cc = "1"

build.Dockerfile

@@ -1,7 +1,7 @@
 # This Dockerfile produces a base image for builds.
 # It includes all dependencies necessary to cross-compile for Windows/MacOS/Linux.
 
-FROM debian:bookworm AS osxcross
+FROM debian:trixie AS osxcross
 ADD --chmod=644 "https://apt.llvm.org/llvm-snapshot.gpg.key" /etc/apt/trusted.gpg.d/apt.llvm.org.asc
 WORKDIR /build/osxcross
 ADD "https://github.com/tpoechtrager/osxcross.git#47936a512273bb3b414b5a2e83043c92eabc7ae7" .
@@ -10,30 +10,30 @@ RUN apt-get update && \
     apt-get install -y ca-certificates
 COPY llvm.sources /etc/apt/sources.list.d/llvm.sources
 RUN apt-get update && \
-    apt-get install -y bash bzip2 clang-20 git lld-20 llvm-20 make patch xz-utils && \
-    ln -s $(which clang-20) /usr/bin/clang && \
-    ln -s $(which clang++-20) /usr/bin/clang++ && \
-    ln -s $(which ld64.lld-20) /usr/bin/ld64.lld && \
+    apt-get install -y bash bzip2 clang-22 git lld-22 llvm-22 make patch xz-utils && \
+    ln -s $(which clang-22) /usr/bin/clang && \
+    ln -s $(which clang++-22) /usr/bin/clang++ && \
+    ln -s $(which ld64.lld-22) /usr/bin/ld64.lld && \
     SDK_VERSION=14.5 UNATTENDED=1 ENABLE_COMPILER_RT_INSTALL=1 TARGET_DIR=/osxcross ./build.sh
 
-FROM rust:1.89-bookworm
+FROM rust:1.98-trixie
 ADD --chmod=644 "https://apt.llvm.org/llvm-snapshot.gpg.key" /etc/apt/trusted.gpg.d/apt.llvm.org.asc
 COPY llvm.sources /etc/apt/sources.list.d/llvm.sources
 RUN rustup target add x86_64-pc-windows-msvc && \
     rustup target add x86_64-apple-darwin && \
     rustup target add aarch64-apple-darwin && \
     apt-get update && \
-    apt-get install -y clang-20 lld-20 libc6-dev libasound2-dev libudev-dev genisoimage mingw-w64 && \
+    apt-get install -y clang-22 lld-22 libc6-dev libasound2-dev libudev-dev genisoimage mingw-w64 && \
     cargo install cargo-bundle xwin && \
     xwin --accept-license splat --output xwin && \
     rm -rf .xwin-cache && \
-    ln -s $(which clang-20) /usr/bin/clang && \
-    ln -s $(which clang++-20) /usr/bin/clang++
+    ln -s $(which clang-22) /usr/bin/clang && \
+    ln -s $(which clang++-22) /usr/bin/clang++
 COPY --from=osxcross /osxcross /osxcross
 
 ENV PATH="/osxcross/bin:$PATH" \
     LD_LIBRARY_PATH="/osxcross/lib" \
-    CC="clang-20" CXX="clang++-20" AR="llvm-ar-20" \
+    CC="clang-22" CXX="clang++-22" AR="llvm-ar-22" \
     CC_x86_64-apple-darwin="o64-clang" \
     CXX_x86_64-apple-darwin="o64-clang++" \
     CC_aarch64-apple-darwin="oa64-clang" \
@@ -41,12 +41,13 @@ ENV PATH="/osxcross/bin:$PATH" \
     SHROOMS_CFLAGS_x86_64-unknown-linux-gnu="-flto" \
     CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUSTFLAGS="-Clinker-plugin-lto -Clinker=clang -Clink-arg=-fuse-ld=lld" \
     SHROOMS_CFLAGS_x86_64-pc-windows-msvc="-flto" \
+    CFLAGS_x86_64-pc-windows-msvc="-I/xwin/crt/include -I/xwin/sdk/include/ucrt -I/xwin/sdk/include/um -I/xwin/sdk/include/shared" \
     CARGO_TARGET_X86_64_PC_WINDOWS_MSVC_RUSTFLAGS="-Lnative=/xwin/crt/lib/x86_64 -Lnative=/xwin/sdk/lib/um/x86_64 -Lnative=/xwin/sdk/lib/ucrt/x86_64 -Clinker-plugin-lto -Clink-arg=-fuse-ld=lld" \
-    CARGO_TARGET_X86_64_PC_WINDOWS_MSVC_LINKER="lld-link-20" \
+    CARGO_TARGET_X86_64_PC_WINDOWS_MSVC_LINKER="lld-link-22" \
     CARGO_TARGET_X86_64_APPLE_DARWIN_LINKER="o64-clang" \
-    CARGO_TARGET_X86_64_APPLE_DARWIN_AR="llvm-ar-20" \
+    CARGO_TARGET_X86_64_APPLE_DARWIN_AR="llvm-ar-22" \
     CARGO_TARGET_AARCH64_APPLE_DARWIN_LINKER="oa64-clang" \
-    CARGO_TARGET_AARCH64_APPLE_DARWIN_AR="llvm-ar-20" \
-    RC_PATH="llvm-rc-20" \
+    CARGO_TARGET_AARCH64_APPLE_DARWIN_AR="llvm-ar-22" \
+    RC_PATH="llvm-rc-22" \
     MACOSX_DEPLOYMENT_TARGET="14.5"
 ENTRYPOINT ["bash"]

build.rs

@@ -18,8 +18,10 @@ fn main() -> Result<(), Box<dyn Error>> {
     };
     builder
         .include(Path::new("shrooms-vb-core/core"))
+        .include(Path::new("shrooms-vb-core/util"))
         .opt_level(opt_level)
         .flag_if_supported("-fno-strict-aliasing")
+        .define("_CRT_SECURE_NO_WARNINGS", None)
         .define("VB_LITTLE_ENDIAN", None)
         .define("VB_SIGNED_PROPAGATE", None)
         .define("VB_DIV_GENERIC", None)
@@ -29,7 +31,10 @@ fn main() -> Result<(), Box<dyn Error>> {
         .define("VB_DIRECT_FRAME", "on_frame")
         .define("VB_DIRECT_READ", "on_read")
         .define("VB_DIRECT_WRITE", "on_write")
+        .define("VBU_REALLOC", "vbu_realloc_shim")
         .file(Path::new("shrooms-vb-core/core/vb.c"))
+        .file(Path::new("shrooms-vb-core/util/isx.c"))
+        .file(Path::new("shrooms-vb-core/util/vbu.c"))
         .compile("vb");
 
     Ok(())

llvm.sources

@@ -1,4 +1,4 @@
 Types: deb deb-src
-URIs: http://apt.llvm.org/bookworm/
-Suites: llvm-toolchain-bookworm-20
+URIs: http://apt.llvm.org/trixie/
+Suites: llvm-toolchain-trixie-22
 Components: main

src/audio.rs

@@ -1,53 +1,87 @@
 use std::time::Duration;
 
-use anyhow::{Result, bail};
-use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
+use anyhow::{Context, Result, bail};
+use audioadapter_buffers::direct::InterleavedSlice;
+use cpal::{
+    Device, FromSample, Sample, SampleFormat, SizedSample, StreamConfig,
+    traits::{DeviceTrait, HostTrait, StreamTrait},
+};
 use itertools::Itertools;
-use rubato::{FastFixedOut, Resampler};
-use tracing::error;
+use rubato::{Adjustable as _, Resampler};
+use tracing::warn;
 
-pub struct Audio {
+struct CpalAudio {
     #[allow(unused)]
     stream: cpal::Stream,
-    sampler: FastFixedOut<f32>,
-    input_buffer: Vec<Vec<f32>>,
-    output_buffer: Vec<Vec<f32>>,
+    sampler: rubato::Async<f32>,
+    input_buffer: Vec<f32>,
+    output_buffer: Vec<f32>,
     sample_sink: rtrb::Producer<f32>,
 }
 
 const VB_FREQUENCY: usize = 41700;
 
-impl Audio {
-    pub fn init() -> Result<Self> {
+impl CpalAudio {
+    fn init() -> Result<Self> {
         let host = cpal::default_host();
-        let Some(device) = host.default_output_device() else {
-            bail!("No output device available");
-        };
-        let Some(config) = device
+        let device = host
+            .default_output_device()
+            .context("no output device available")?;
+        let default_rate = device.default_output_config()?.sample_rate();
+
+        let supported_config = device
             .supported_output_configs()?
-            .find(|c| c.channels() == 2 && c.sample_format().is_float())
-        else {
-            bail!("No suitable output config available");
-        };
-        let mut config = config.with_max_sample_rate().config();
-        let resample_ratio = config.sample_rate.0 as f64 / VB_FREQUENCY as f64;
+            .filter(|c| {
+                c.contains_rate(default_rate)
+                    && 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 = FastFixedOut::new(
+        let sampler = rubato::Async::new_poly(
             resample_ratio,
             64.0,
             rubato::PolynomialDegree::Cubic,
             chunk_size,
             2,
+            rubato::FixedAsync::Output,
         )?;
         config.buffer_size = cpal::BufferSize::Fixed(sampler.output_frames_max() as u32);
 
-        let input_buffer = sampler.input_buffer_allocate(true);
-        let output_buffer = sampler.output_buffer_allocate(true);
+        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) =
             rtrb::RingBuffer::new(sampler.output_frames_max() * 4);
 
         let stream = device.build_output_stream(
-            &config,
+            config,
             move |data: &mut [f32], _| {
                 let requested = data.len();
                 let chunk = match sample_source.read_chunk(data.len()) {
@@ -65,7 +99,7 @@ impl Audio {
                 }
                 chunk.commit_all();
             },
-            move |error| error!(%error, "stream error"),
+            move |error| warn!(%error, "stream error"),
             None,
         )?;
         stream.play()?;
@@ -78,43 +112,155 @@ impl Audio {
         })
     }
 
-    pub fn update(&mut self, samples: &[f32]) {
-        for sample in samples.chunks_exact(2) {
-            for (channel, value) in self.input_buffer.iter_mut().zip(sample) {
-                channel.push(*value);
-            }
-            if self.input_buffer[0].len() >= self.sampler.input_frames_next() {
-                let (_, output_samples) = self
-                    .sampler
-                    .process_into_buffer(&self.input_buffer, &mut self.output_buffer, None)
-                    .unwrap();
+    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 chunk = match self.sample_sink.write_chunk_uninit(output_samples * 2) {
+        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)) => {
-                        self.sample_sink.write_chunk_uninit(n).unwrap()
+                        sample_source.read_chunk(n).unwrap()
                     }
                 };
-                let interleaved = self.output_buffer[0]
-                    .iter()
-                    .interleave(self.output_buffer[1].iter())
-                    .cloned();
-                chunk.fill_from_iter(interleaved);
+                let (first, second) = chunk.as_slices();
 
-                for channel in &mut self.input_buffer {
-                    channel.clear();
+                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());
+            let (current_samples, future_samples) = samples.split_at(samples_needed);
+            self.input_buffer.extend_from_slice(current_samples);
+            samples = future_samples;
+
+            let buffer_in =
+                InterleavedSlice::new(&self.input_buffer, 2, self.sampler.input_frames_next())
+                    .unwrap();
+            let mut buffer_out = InterleavedSlice::new_mut(
+                &mut self.output_buffer,
+                2,
+                self.sampler.output_frames_next(),
+            )
+            .unwrap();
+            let (_, output_samples) = self
+                .sampler
+                .process_into_buffer(&buffer_in, &mut buffer_out, None)
+                .unwrap();
+            let chunk = match self.sample_sink.write_chunk_uninit(output_samples * 2) {
+                Ok(c) => c,
+                Err(rtrb::chunks::ChunkError::TooFewSlots(n)) => {
+                    self.sample_sink.write_chunk_uninit(n).unwrap()
+                }
+            };
+            chunk.fill_from_iter(self.output_buffer[..output_samples * 2].iter().copied());
+
+            self.input_buffer.clear();
         }
+        self.input_buffer.extend_from_slice(samples);
 
         while self.sample_sink.slots() < self.sampler.output_frames_max() * 2 {
             std::thread::sleep(Duration::from_micros(500));
         }
     }
 
-    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

@@ -0,0 +1,201 @@
+use anyhow::Result;
+use bytemuck::NoUninit;
+use clap::{Parser, ValueEnum};
+use egui::{Color32, Pos2, Vec2};
+use serde::{Deserialize, Serialize};
+
+use crate::{emulator::SimId, filesystem::Persistence, window::DisplayMode};
+use std::path::PathBuf;
+
+#[derive(Parser)]
+#[command(version, long_version = env!("CARGO_PKG_VERSION"))]
+pub struct CliArgs {
+    /// The path to a virtual boy ROM to run.
+    pub rom: Option<PathBuf>,
+    /// Start a GDB/LLDB debug server on this port.
+    #[arg(short, long)]
+    pub debug_port: Option<u16>,
+    /// Enable profiling a game
+    #[arg(short, long)]
+    pub profile: bool,
+    /// Open character data window
+    #[arg(short, long)]
+    pub character_data: bool,
+    /// Open bgmap data window
+    #[arg(short, long)]
+    pub bgmap_data: bool,
+    /// Open object data window
+    #[arg(short, long)]
+    pub object_data: bool,
+    /// Open worlds window
+    #[arg(long)]
+    pub worlds: bool,
+    /// Open frame buffers window
+    #[arg(short, long)]
+    pub frame_buffers: bool,
+    /// Open registers window
+    #[arg(short, long)]
+    pub registers: bool,
+    /// Open terminal
+    #[arg(short, long)]
+    pub terminal: bool,
+    /// Watch ROM files for changes, automatically reload
+    #[arg(short, long)]
+    pub watch: bool,
+    /// Automatically open Player 2 for multiplayer
+    #[arg(long)]
+    pub player2: bool,
+    /// 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>,
+    /// Choose whether save files are kept in the rom or the data directory
+    #[arg(long)]
+    pub save_data_location: Option<SaveDataLocation>,
+}
+
+#[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] = [
+    [
+        Color32::from_rgb(0xff, 0x00, 0x00),
+        Color32::from_rgb(0x00, 0xc6, 0xf0),
+    ],
+    [
+        Color32::from_rgb(0x00, 0xb4, 0x00),
+        Color32::from_rgb(0xc8, 0x00, 0xff),
+    ],
+    [
+        Color32::from_rgb(0xb4, 0x9b, 0x00),
+        Color32::from_rgb(0x00, 0x00, 0xff),
+    ],
+];
+
+const fn default_power_preference() -> wgpu::PowerPreference {
+    wgpu::PowerPreference::LowPower
+}
+
+#[derive(Serialize, Deserialize, Clone, Copy, PartialEq, Eq, ValueEnum, Debug, NoUninit)]
+#[repr(usize)]
+pub enum SaveDataLocation {
+    /// The same directory as the ROM
+    RomDirectory,
+    /// This application's data directory
+    DataDirectory,
+}
+
+const fn default_save_data_location() -> SaveDataLocation {
+    SaveDataLocation::RomDirectory
+}
+
+#[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,
+    #[serde(default = "default_save_data_location")]
+    pub save_data_location: SaveDataLocation,
+}
+
+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,
+            save_data_location: default_save_data_location(),
+        }
+    }
+
+    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;
+        }
+        if let Some(save_data_location) = args.save_data_location {
+            self.save_data_location = save_data_location;
+            updated = true;
+        }
+        updated
+    }
+}
+
+const APP_CONFIG_FILENAME: &str = "config";
+
+const fn default_audio_enabled() -> bool {
+    true
+}
+
+#[derive(Serialize, Deserialize, Clone, PartialEq, Eq)]
+pub struct SimConfig {
+    pub display_mode: DisplayMode,
+    pub colors: [Color32; 2],
+    pub dimensions: Vec2,
+    #[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(sim_config_filename(sim_id)) {
+            return config;
+        }
+        Self {
+            display_mode: DisplayMode::Anaglyph,
+            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(sim_config_filename(sim_id), self)
+    }
+}
+
+fn sim_config_filename(sim_id: SimId) -> &'static str {
+    match sim_id {
+        SimId::Player1 => "config_p1",
+        SimId::Player2 => "config_p2",
+    }
+}

src/controller.rs

@@ -1,4 +1,7 @@
-use std::sync::{Arc, RwLock};
+use std::{
+    collections::HashMap,
+    sync::{Arc, RwLock},
+};
 
 use gilrs::{Event as GamepadEvent, EventType, GamepadId, ev::Code};
 use winit::{
@@ -8,12 +11,13 @@ use winit::{
 
 use crate::{
     emulator::{EmulatorClient, EmulatorCommand, SimId, VBKey},
-    input::{InputMapping, MappingProvider},
+    input::{AxisMapping, InputMapping, MappingProvider},
 };
 
 pub struct Controller {
     pub sim_id: SimId,
     state: VBKey,
+    axis_values: HashMap<(GamepadId, Code), f32>,
     mapping: Arc<RwLock<InputMapping>>,
 }
 
@@ -22,6 +26,7 @@ impl Controller {
         Self {
             sim_id,
             state: VBKey::SGN,
+            axis_values: HashMap::new(),
             mapping: mappings.for_sim(sim_id).clone(),
         }
     }
@@ -45,20 +50,23 @@ impl Controller {
                 (VBKey::empty(), mappings)
             }
             EventType::AxisChanged(_, value, code) => {
-                let (neg, pos) = self.map_axis(&event.id, &code)?;
-                let mut pressed = VBKey::empty();
-                let mut released = VBKey::empty();
-                if value < -0.75 {
-                    pressed = pressed.union(neg);
-                }
-                if value > 0.75 {
-                    pressed = pressed.union(pos);
-                }
-                if value > -0.65 {
-                    released = released.union(neg);
-                }
-                if value < 0.65 {
-                    released = released.union(pos);
+                let mapping = self.map_axis(&event.id, &code)?;
+                self.axis_values.insert((event.id, code), value);
+
+                let pair_value = mapping
+                    .pair
+                    .and_then(|p| self.axis_values.get(&(event.id, p)))
+                    .copied()
+                    .unwrap_or_default();
+                let neg = mapping.neg;
+                let pos = mapping.pos;
+
+                let (mut pressed, mut released) = axis_presses(value, pair_value, neg, pos);
+                if let Some(other) = mapping.pair.and_then(|p| self.map_axis(&event.id, &p)) {
+                    let (other_pressed, other_released) =
+                        axis_presses(pair_value, value, other.neg, other.pos);
+                    pressed = pressed.union(other_pressed);
+                    released = released.union(other_released);
                 }
                 (pressed, released)
             }
@@ -69,6 +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);
@@ -87,7 +104,7 @@ impl Controller {
         self.mapping.read().unwrap().map_button(id, code)
     }
 
-    fn map_axis(&self, id: &GamepadId, code: &Code) -> Option<(VBKey, VBKey)> {
+    fn map_axis(&self, id: &GamepadId, code: &Code) -> Option<AxisMapping> {
         self.mapping.read().unwrap().map_axis(id, code)
     }
 }
@@ -125,4 +142,104 @@ 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) {
+    use std::f32::consts::FRAC_PI_3;
+
+    let mut pressed = VBKey::empty();
+    let mut released = VBKey::empty();
+
+    let magnitude = value.hypot(pair_value);
+    let abs_angle = pair_value.atan2(value).abs();
+
+    if magnitude < 0.65 {
+        released = released.union(neg).union(pos);
+    } else if abs_angle <= FRAC_PI_3 {
+        // stick tilted towards positive
+        released = released.union(neg);
+
+        if magnitude >= 0.75 {
+            pressed = pressed.union(pos);
+        }
+    } else if abs_angle >= 2.0 * FRAC_PI_3 {
+        // stick tilted towards negative
+        released = released.union(pos);
+
+        if magnitude >= 0.75 {
+            pressed = pressed.union(neg);
+        }
+    } else {
+        released = released.union(neg).union(pos);
+    }
+
+    (pressed, released)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{VBKey, axis_presses};
+
+    const NEG: VBKey = VBKey::LL;
+    const POS: VBKey = VBKey::LR;
+
+    const NONE: VBKey = VBKey::empty();
+    const BOTH: VBKey = NEG.union(POS);
+
+    #[test]
+    fn detects_no_input() {
+        let (pressed, released) = axis_presses(0.0, 0.0, NEG, POS);
+        assert_eq!(pressed, NONE);
+        assert_eq!(released, BOTH);
+    }
+
+    #[test]
+    fn detects_pos_input() {
+        let (pressed, released) = axis_presses(1.0, 0.0, NEG, POS);
+        assert_eq!(pressed, POS);
+        assert_eq!(released, NEG);
+    }
+
+    #[test]
+    fn detects_neg_input() {
+        let (pressed, released) = axis_presses(-1.0, 0.0, NEG, POS);
+        assert_eq!(pressed, NEG);
+        assert_eq!(released, POS);
+    }
+
+    #[test]
+    fn respects_dead_zone() {
+        let (pressed, released) = axis_presses(0.70, 0.0, NEG, POS);
+        assert_eq!(pressed, NONE);
+        assert_eq!(released, NEG);
+    }
+
+    #[test]
+    fn handles_diagonals_ok() {
+        let (pressed, released) = axis_presses(0.6, 0.6, NEG, POS);
+        assert_eq!(pressed, POS);
+        assert_eq!(released, NEG);
+    }
+
+    #[test]
+    fn ignores_diagonal_noise() {
+        let (pressed, released) = axis_presses(-1.0, -0.1484245, NEG, POS);
+        assert_eq!(pressed, NEG);
+        assert_eq!(released, POS);
+    }
+
+    #[test]
+    fn ignores_small_values() {
+        let (pressed, released) = axis_presses(-0.1484245, -1.0, NEG, POS);
+        assert_eq!(pressed, NONE);
+        assert_eq!(released, BOTH);
+    }
 }

src/emulator.rs

@@ -5,7 +5,7 @@ use std::{
     sync::{
         Arc, Weak,
         atomic::{AtomicBool, Ordering},
-        mpsc::{self, RecvError, TryRecvError},
+        mpsc::{self, RecvTimeoutError, TryRecvError},
     },
     time::Duration,
 };
@@ -18,6 +18,7 @@ use tracing::{error, warn};
 
 use crate::{
     audio::Audio,
+    config::SaveDataLocation,
     graphics::TextureSink,
     memory::{MemoryRange, MemoryRegion},
 };
@@ -33,6 +34,7 @@ mod cart;
 mod game_info;
 mod inline_stack_map;
 mod shrooms_vb_core;
+mod shrooms_vb_util;
 
 #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)]
 pub enum SimId {
@@ -73,11 +75,13 @@ pub struct EmulatorBuilder {
     state: Arc<Atomic<EmulatorState>>,
     audio_on: Arc<[AtomicBool; 2]>,
     linked: Arc<AtomicBool>,
+    save_data_location: Arc<Atomic<SaveDataLocation>>,
     start_paused: bool,
+    watch_rom: Arc<[AtomicBool; 2]>,
 }
 
 impl EmulatorBuilder {
-    pub fn new() -> (Self, EmulatorClient) {
+    pub fn new(save_data_location: SaveDataLocation) -> (Self, EmulatorClient) {
         let (queue, commands) = mpsc::channel();
         let builder = Self {
             rom: None,
@@ -89,14 +93,17 @@ impl EmulatorBuilder {
             state: Arc::new(Atomic::new(EmulatorState::Paused)),
             audio_on: Arc::new([AtomicBool::new(true), AtomicBool::new(true)]),
             linked: Arc::new(AtomicBool::new(false)),
+            save_data_location: Arc::new(Atomic::new(save_data_location)),
             start_paused: false,
+            watch_rom: Arc::new([AtomicBool::new(false), AtomicBool::new(false)]),
         };
         let client = EmulatorClient {
             queue,
             sim_state: builder.sim_state.clone(),
             state: builder.state.clone(),
-            audio_on: builder.audio_on.clone(),
             linked: builder.linked.clone(),
+            save_data_location: builder.save_data_location.clone(),
+            watch_rom: builder.watch_rom.clone(),
         };
         (builder, client)
     }
@@ -115,18 +122,55 @@ impl EmulatorBuilder {
         }
     }
 
+    pub fn with_audio_on(self, p1: bool, p2: bool) -> Self {
+        self.audio_on[0].store(p1, Ordering::Relaxed);
+        self.audio_on[1].store(p2, Ordering::Relaxed);
+        self
+    }
+
+    pub fn with_watch_rom(self, p1: bool, p2: bool) -> Self {
+        self.watch_rom[0].store(p1, Ordering::Relaxed);
+        self.watch_rom[1].store(p2, Ordering::Relaxed);
+        self
+    }
+
     pub fn build(self) -> Result<Emulator> {
-        let mut emulator = Emulator::new(
-            self.commands,
-            self.sim_state,
-            self.state,
-            self.audio_on,
-            self.linked,
-        )?;
-        if let Some(path) = self.rom {
+        let Self {
+            rom,
+            commands,
+            sim_state,
+            state,
+            audio_on,
+            watch_rom,
+            linked,
+            save_data_location,
+            start_paused,
+        } = self;
+        let mut emulator = Emulator {
+            sims: vec![],
+            carts: [None, None],
+            audio: Audio::init(),
+            commands,
+            sim_state,
+            state,
+            audio_on,
+            watch_rom,
+            linked,
+            save_data_location,
+            profilers: [None, None],
+            renderers: HashMap::new(),
+            messages: HashMap::new(),
+            debuggers: HashMap::new(),
+            stdouts: HashMap::new(),
+            watched_regions: HashMap::new(),
+            eye_contents: [vec![0u8; 384 * 224 * 2], vec![0u8; 384 * 224 * 2]],
+            audio_samples: Vec::with_capacity(EXPECTED_FRAME_SIZE),
+            buffer: vec![],
+        };
+        if let Some(path) = rom {
             emulator.load_cart(SimId::Player1, &path)?;
         }
-        if self.start_paused {
+        if start_paused {
             emulator.pause_sims()?;
         }
         Ok(emulator)
@@ -141,7 +185,9 @@ pub struct Emulator {
     sim_state: Arc<[Atomic<SimState>; 2]>,
     state: Arc<Atomic<EmulatorState>>,
     audio_on: Arc<[AtomicBool; 2]>,
+    watch_rom: Arc<[AtomicBool; 2]>,
     linked: Arc<AtomicBool>,
+    save_data_location: Arc<Atomic<SaveDataLocation>>,
     profilers: [Option<ProfileSender>; 2],
     renderers: HashMap<SimId, TextureSink>,
     messages: HashMap<SimId, mpsc::Sender<Toast>>,
@@ -154,37 +200,23 @@ pub struct Emulator {
 }
 
 impl Emulator {
-    fn new(
-        commands: mpsc::Receiver<EmulatorCommand>,
-        sim_state: Arc<[Atomic<SimState>; 2]>,
-        state: Arc<Atomic<EmulatorState>>,
-        audio_on: Arc<[AtomicBool; 2]>,
-        linked: Arc<AtomicBool>,
-    ) -> Result<Self> {
-        Ok(Self {
-            sims: vec![],
-            carts: [None, None],
-            audio: Audio::init()?,
-            commands,
-            sim_state,
-            state,
-            audio_on,
-            linked,
-            profilers: [None, None],
-            renderers: HashMap::new(),
-            messages: HashMap::new(),
-            debuggers: HashMap::new(),
-            stdouts: HashMap::new(),
-            watched_regions: HashMap::new(),
-            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<()> {
+        let Some(cart) = &self.carts[sim_id.to_index()] else {
+            return Ok(());
+        };
+        let path = cart.file_path.clone();
+        self.load_cart(sim_id, &path)
     }
 
     pub fn load_cart(&mut self, sim_id: SimId, path: &Path) -> Result<()> {
-        let cart = Cart::load(path, sim_id)?;
-        self.reset_sim(sim_id, Some(cart))?;
+        let watch = self.watch_rom[sim_id.to_index()].load(Ordering::Acquire);
+        let cart = Cart::load(
+            path,
+            sim_id,
+            self.save_data_location.load(Ordering::Acquire),
+            watch,
+        )?;
+        self.try_reset_sim(sim_id, Some(cart))?;
         Ok(())
     }
 
@@ -194,16 +226,31 @@ impl Emulator {
         } else {
             self.carts[0].as_ref().map(|c| c.file_path.clone())
         };
+        let watch = self.watch_rom[SimId::Player2.to_index()].load(Ordering::Acquire);
         let cart = match file_path {
-            Some(rom_path) => Some(Cart::load(&rom_path, SimId::Player2)?),
+            Some(rom_path) => Some(Cart::load(
+                &rom_path,
+                SimId::Player2,
+                self.save_data_location.load(Ordering::Acquire),
+                watch,
+            )?),
             None => None,
         };
-        self.reset_sim(SimId::Player2, cart)?;
+        self.try_reset_sim(SimId::Player2, cart)?;
         self.link_sims();
         Ok(())
     }
 
-    fn reset_sim(&mut self, sim_id: SimId, new_cart: Option<Cart>) -> Result<()> {
+    fn reset_sim(&mut self, sim_id: SimId, new_cart: Option<Cart>) -> bool {
+        if let Err(error) = self.try_reset_sim(sim_id, new_cart) {
+            self.report_error(sim_id, format!("Error resetting sim: {error}"));
+            false
+        } else {
+            true
+        }
+    }
+
+    fn try_reset_sim(&mut self, sim_id: SimId, new_cart: Option<Cart>) -> Result<()> {
         self.save_sram(sim_id)?;
 
         let index = sim_id.to_index();
@@ -224,6 +271,11 @@ impl Emulator {
             sim.load_cart(cart.rom.clone(), cart.sram.clone())?;
             self.carts[index] = Some(cart);
             self.sim_state[index].store(SimState::Ready, Ordering::Release);
+        } else if let Some(cart) = self.carts[index].as_mut()
+            && cart.is_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()
@@ -340,7 +392,7 @@ impl Emulator {
 
     fn start_profiling(&mut self, sim_id: SimId, sender: ProfileSender) -> Result<()> {
         self.profilers[sim_id.to_index()] = Some(sender);
-        self.reset_sim(sim_id, None)
+        self.try_reset_sim(sim_id, None)
     }
 
     fn start_debugging(&mut self, sim_id: SimId, sender: DebugSender) {
@@ -416,11 +468,30 @@ impl Emulator {
             let idle = self.tick();
             if idle {
                 // The game is paused, and we have output all the video/audio we have.
-                // Block the thread until a new command comes in.
-                match self.commands.recv() {
-                    Ok(command) => self.handle_command(command),
-                    Err(RecvError) => {
-                        return;
+                // Block the thread until a new command comes in, or a ROM changes.
+                loop {
+                    match self.commands.recv_timeout(Duration::from_millis(250)) {
+                        Ok(command) => {
+                            self.handle_command(command);
+                            break;
+                        }
+                        Err(RecvTimeoutError::Timeout) => {
+                            let mut changed = false;
+                            for sim_id in SimId::values() {
+                                let Some(cart) = self.carts[sim_id.to_index()].as_ref() else {
+                                    continue;
+                                };
+                                if cart.changed() {
+                                    changed |= self.reset_sim(sim_id, None);
+                                }
+                            }
+                            if changed {
+                                break;
+                            }
+                        }
+                        Err(RecvTimeoutError::Disconnected) => {
+                            return;
+                        }
                     }
                 }
             }
@@ -435,6 +506,14 @@ impl Emulator {
                     }
                 }
             }
+            for sim_id in SimId::values() {
+                let Some(cart) = self.carts[sim_id.to_index()].as_ref() else {
+                    continue;
+                };
+                if cart.changed() {
+                    self.reset_sim(sim_id, None);
+                }
+            }
             self.watched_regions.retain(|range, region| {
                 let Some(region) = region.upgrade() else {
                     return false;
@@ -601,6 +680,36 @@ impl Emulator {
                     self.report_error(sim_id, format!("Error loading rom: {error}"));
                 }
             }
+            EmulatorCommand::ReloadRom(sim_id) => {
+                if let Err(error) = self.reload_cart(sim_id) {
+                    self.report_error(sim_id, format!("Error loading rom: {error}"));
+                }
+            }
+            EmulatorCommand::WatchRom(sim_id, watch) => {
+                self.watch_rom[sim_id.to_index()].store(watch, Ordering::Release);
+                let Some(cart) = self.carts[sim_id.to_index()].as_mut() else {
+                    return;
+                };
+                if watch {
+                    cart.restart_watching();
+                } else {
+                    cart.stop_watching();
+                }
+            }
+            EmulatorCommand::SetSaveDataLocation(save_data_location) => {
+                self.save_data_location
+                    .store(save_data_location, Ordering::Release);
+                for sim_id in SimId::values() {
+                    if let Some(cart) = self.carts[sim_id.to_index()].as_mut()
+                        && let Err(error) = cart.change_save_data_location(save_data_location)
+                    {
+                        self.report_error(
+                            sim_id,
+                            format!("Error changing save data location: {error}"),
+                        );
+                    }
+                }
+            }
             EmulatorCommand::StartSecondSim(path) => {
                 if let Err(error) = self.start_second_sim(path) {
                     self.report_error(
@@ -714,9 +823,8 @@ impl Emulator {
                 };
                 sim.watch_stdout(true);
             }
-            EmulatorCommand::SetAudioEnabled(p1, p2) => {
-                self.audio_on[SimId::Player1.to_index()].store(p1, Ordering::Release);
-                self.audio_on[SimId::Player2.to_index()].store(p2, Ordering::Release);
+            EmulatorCommand::SetAudioEnabled(sim_id, enabled) => {
+                self.audio_on[sim_id.to_index()].store(enabled, Ordering::Release);
             }
             EmulatorCommand::Link => {
                 self.link_sims();
@@ -725,9 +833,7 @@ impl Emulator {
                 self.unlink_sims();
             }
             EmulatorCommand::Reset(sim_id) => {
-                if let Err(error) = self.reset_sim(sim_id, None) {
-                    self.report_error(sim_id, format!("Error resetting sim: {error}"));
-                }
+                self.reset_sim(sim_id, None);
             }
             EmulatorCommand::SetKeys(sim_id, keys) => {
                 if let Some(sim) = self.sims.get_mut(sim_id.to_index()) {
@@ -769,6 +875,9 @@ impl Emulator {
 pub enum EmulatorCommand {
     ConnectToSim(SimId, TextureSink, mpsc::Sender<Toast>),
     LoadGame(SimId, PathBuf),
+    ReloadRom(SimId),
+    WatchRom(SimId, bool),
+    SetSaveDataLocation(SaveDataLocation),
     StartSecondSim(Option<PathBuf>),
     StopSecondSim,
     Pause,
@@ -791,7 +900,7 @@ pub enum EmulatorCommand {
     AddWatchpoint(SimId, u32, usize, VBWatchpointType),
     RemoveWatchpoint(SimId, u32, usize, VBWatchpointType),
     WatchStdout(SimId, mpsc::Sender<String>),
-    SetAudioEnabled(bool, bool),
+    SetAudioEnabled(SimId, bool),
     Link,
     Unlink,
     Reset(SimId),
@@ -857,23 +966,30 @@ pub struct EmulatorClient {
     queue: mpsc::Sender<EmulatorCommand>,
     sim_state: Arc<[Atomic<SimState>; 2]>,
     state: Arc<Atomic<EmulatorState>>,
-    audio_on: Arc<[AtomicBool; 2]>,
     linked: Arc<AtomicBool>,
+    save_data_location: Arc<Atomic<SaveDataLocation>>,
+    watch_rom: Arc<[AtomicBool; 2]>,
 }
 
 impl EmulatorClient {
+    pub fn has_player_2(&self) -> bool {
+        self.sim_state(SimId::Player2) != SimState::Uninitialized
+    }
     pub fn sim_state(&self, sim_id: SimId) -> SimState {
         self.sim_state[sim_id.to_index()].load(Ordering::Acquire)
     }
     pub fn emulator_state(&self) -> EmulatorState {
         self.state.load(Ordering::Acquire)
     }
-    pub fn is_audio_enabled(&self, sim_id: SimId) -> bool {
-        self.audio_on[sim_id.to_index()].load(Ordering::Acquire)
-    }
     pub fn are_sims_linked(&self) -> bool {
         self.linked.load(Ordering::Acquire)
     }
+    pub fn save_data_location(&self) -> SaveDataLocation {
+        self.save_data_location.load(Ordering::Acquire)
+    }
+    pub fn is_rom_watched(&self, sim_id: SimId) -> bool {
+        self.watch_rom[sim_id.to_index()].load(Ordering::Acquire)
+    }
     pub fn send_command(&self, command: EmulatorCommand) -> bool {
         match self.queue.send(command) {
             Ok(()) => true,

src/emulator/cart.rs

@@ -1,34 +1,45 @@
 use anyhow::Result;
-use rand::Rng;
+use notify::Watcher;
+use rand::RngExt;
 use std::{
     fs::{self, File},
     io::{Read, Seek as _, SeekFrom, Write as _},
     path::{Path, PathBuf},
-    sync::Arc,
+    sync::{Arc, atomic::AtomicBool},
 };
 
-use crate::emulator::{SimId, game_info::GameInfo};
+use crate::{
+    config::SaveDataLocation,
+    emulator::{SimId, game_info::GameInfo, shrooms_vb_util::rom_from_isx},
+    filesystem,
+};
 
 pub struct Cart {
     pub file_path: PathBuf,
+    sim_id: SimId,
     pub rom: Vec<u8>,
     sram_file: File,
     pub sram: Vec<u8>,
     pub info: Arc<GameInfo>,
+    watcher: Option<notify::RecommendedWatcher>,
+    changed: Arc<AtomicBool>,
 }
 
 impl Cart {
-    pub fn load(file_path: &Path, sim_id: SimId) -> Result<Self> {
-        let rom = fs::read(file_path)?;
-        let (rom, info) =
-            try_parse_elf(file_path, &rom).unwrap_or_else(|| (rom, GameInfo::empty(file_path)));
+    pub fn load(
+        file_path: &Path,
+        sim_id: SimId,
+        save_data_location: SaveDataLocation,
+        watch: bool,
+    ) -> Result<Self> {
+        let (rom, info) = Self::read_rom(file_path)?;
 
         let mut sram_file = File::options()
             .read(true)
             .write(true)
             .create(true)
             .truncate(false)
-            .open(sram_path(file_path, sim_id))?;
+            .open(sram_path(file_path, sim_id, save_data_location))?;
 
         let sram = if sram_file.metadata()?.len() == 0 {
             // new SRAM file, randomize the contents
@@ -44,20 +55,111 @@ impl Cart {
             sram
         };
 
+        let changed = Arc::new(AtomicBool::new(false));
+        let watcher = if watch {
+            build_watcher(file_path, changed.clone())
+        } else {
+            None
+        };
+
         Ok(Cart {
             file_path: file_path.to_path_buf(),
+            sim_id,
             rom,
             sram_file,
             sram,
             info: Arc::new(info),
+            watcher,
+            changed,
         })
     }
 
+    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 change_save_data_location(
+        &mut self,
+        save_data_location: SaveDataLocation,
+    ) -> Result<()> {
+        self.sram_file = File::options()
+            .read(true)
+            .write(true)
+            .create(true)
+            .truncate(false)
+            .open(sram_path(&self.file_path, self.sim_id, save_data_location))?;
+        self.save_sram()
+    }
+
     pub fn save_sram(&mut self) -> Result<()> {
         self.sram_file.seek(SeekFrom::Start(0))?;
         self.sram_file.write_all(&self.sram)?;
         Ok(())
     }
+
+    pub fn changed(&self) -> bool {
+        self.changed.load(std::sync::atomic::Ordering::Relaxed)
+    }
+
+    pub fn is_watching(&self) -> bool {
+        self.watcher.is_some()
+    }
+
+    pub fn restart_watching(&mut self) {
+        self.changed = Arc::new(AtomicBool::new(false));
+        if let Some(mut watcher) = self.watcher.take() {
+            let _ = watcher.unwatch(&self.file_path);
+        };
+        self.watcher = build_watcher(&self.file_path, self.changed.clone());
+    }
+
+    pub fn stop_watching(&mut self) {
+        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> {
+    let file_path = file_path.to_path_buf();
+    let mut watcher =
+        notify::recommended_watcher(move |event: Result<notify::Event, notify::Error>| {
+            let Ok(e) = event else {
+                return;
+            };
+            let modified = !matches!(
+                e.kind,
+                notify::EventKind::Access(_)
+                    | notify::EventKind::Modify(notify::event::ModifyKind::Metadata(_))
+            );
+            if modified {
+                changed.store(true, std::sync::atomic::Ordering::Relaxed);
+            }
+        })
+        .ok()?;
+    watcher
+        .watch(&file_path, notify::RecursiveMode::NonRecursive)
+        .ok()?;
+    Some(watcher)
+}
+
+fn try_parse_isx(file_path: &Path, data: &[u8]) -> Option<(Vec<u8>, GameInfo)> {
+    let rom = rom_from_isx(data)?;
+    let info = GameInfo::from_isx(file_path, data);
+    Some((rom, info))
 }
 
 fn try_parse_elf(file_path: &Path, data: &[u8]) -> Option<(Vec<u8>, GameInfo)> {
@@ -73,7 +175,7 @@ fn try_parse_elf(file_path: &Path, data: &[u8]) -> Option<(Vec<u8>, GameInfo)> {
         }
         _ => return None,
     };
-    let info = GameInfo::new(file_path, data).unwrap_or_else(|_| GameInfo::empty(file_path));
+    let info = GameInfo::from_elf(file_path, data).unwrap_or_else(|_| GameInfo::empty(file_path));
     Some((program, info))
 }
 
@@ -86,21 +188,30 @@ fn parse_elf_program<Elf: object::read::elf::FileHeader<Endian = object::Endiann
     let mut bytes = vec![];
     let mut pstart = None;
     for phdr in header.program_headers(endian, data).ok()? {
-        if phdr.p_filesz(endian).into() == 0 {
+        let pma = phdr.p_paddr(endian).into();
+        if pma < 0x07000000 || phdr.p_filesz(endian).into() == 0 {
             continue;
         }
-        let start = pstart.unwrap_or(phdr.p_paddr(endian).into());
+        let start = pstart.unwrap_or(pma);
         pstart = Some(start);
-        bytes.resize((phdr.p_paddr(endian).into() - start) as usize, 0);
+        bytes.resize((pma - start) as usize, 0);
         let data = phdr.data(endian, data).ok()?;
         bytes.extend_from_slice(data);
     }
     Some(bytes)
 }
 
-fn sram_path(file_path: &Path, sim_id: SimId) -> PathBuf {
-    match sim_id {
-        SimId::Player1 => file_path.with_extension("p1.sram"),
-        SimId::Player2 => file_path.with_extension("p2.sram"),
+fn sram_path(file_path: &Path, sim_id: SimId, save_data_location: SaveDataLocation) -> PathBuf {
+    let extension = match sim_id {
+        SimId::Player1 => "p1.sram",
+        SimId::Player2 => "p2.sram",
+    };
+    if let SaveDataLocation::DataDirectory = save_data_location
+        && let Some(data_dir) = filesystem::init_data_dir()
+        && let Some(rom_name) = file_path.file_name()
+    {
+        data_dir.join(rom_name).with_extension(extension)
+    } else {
+        file_path.with_extension(extension)
     }
 }

src/emulator/game_info.rs

@@ -14,7 +14,7 @@ pub struct GameInfo {
 }
 
 impl GameInfo {
-    pub fn new(file_path: &Path, input: &[u8]) -> Result<Self> {
+    pub fn from_elf(file_path: &Path, input: &[u8]) -> Result<Self> {
         let file = object::File::parse(input)?;
 
         let (name, path) = name_and_path(file_path);
@@ -52,6 +52,26 @@ impl GameInfo {
         })
     }
 
+    pub fn from_isx(file_path: &Path, input: &[u8]) -> Self {
+        let (name, path) = name_and_path(file_path);
+        let symbols = extract_isx_symbols(input);
+        let library_info = LibraryInfo {
+            name: name.clone(),
+            debug_name: name,
+            path: path.clone(),
+            debug_path: path,
+            debug_id: DebugId::default(),
+            code_id: None,
+            arch: None,
+            symbol_table: symbols.map(|syms| Arc::new(SymbolTable::new(syms))),
+        };
+        let inline_stack_map = InlineStackMap::empty();
+        Self {
+            library_info,
+            inline_stack_map,
+        }
+    }
+
     pub fn empty(file_path: &Path) -> Self {
         let (name, path) = name_and_path(file_path);
         let library_info = LibraryInfo {
@@ -115,6 +135,66 @@ fn build_inline_stack_map(file: object::File) -> Result<InlineStackMap> {
     Ok(frames.build())
 }
 
+fn extract_isx_symbols(input: &[u8]) -> Option<Vec<Symbol>> {
+    let mut syms = vec![];
+    let (_, mut buf) = input.split_at_checked(32)?;
+    while !buf.is_empty() {
+        let typ;
+        (typ, buf) = buf.split_first()?;
+        match typ {
+            0x11 => {
+                // Code (Virtual Boy)
+                (_, buf) = buf.split_at_checked(4)?;
+                let len_bytes;
+                (len_bytes, buf) = buf.split_first_chunk()?;
+                let len = u32::from_le_bytes(*len_bytes);
+                (_, buf) = buf.split_at_checked(len as usize)?;
+            }
+            0x13 => {
+                // Range (Virtual Boy)
+                let count_bytes;
+                (count_bytes, buf) = buf.split_first_chunk()?;
+                let count = u16::from_le_bytes(*count_bytes);
+                (_, buf) = buf.split_at_checked(count as usize * 9)?;
+            }
+            0x14 => {
+                // Symbol (Virtual Boy)
+                let count_bytes;
+                (count_bytes, buf) = buf.split_first_chunk()?;
+                let count = u16::from_le_bytes(*count_bytes);
+                for _ in 0..count {
+                    let name_len;
+                    (name_len, buf) = buf.split_first()?;
+                    let name_bytes;
+                    (name_bytes, buf) = buf.split_at_checked(*name_len as usize)?;
+                    (_, buf) = buf.split_at_checked(2)?;
+                    let address_bytes;
+                    (address_bytes, buf) = buf.split_first_chunk()?;
+
+                    let name_str = String::from_utf8_lossy(name_bytes);
+                    let address = u32::from_le_bytes(*address_bytes);
+                    syms.push(Symbol {
+                        address: address & 0x07ffffff,
+                        size: Some(4),
+                        name: demangle_any(&name_str),
+                    });
+                }
+            }
+            0x20..=0x22 => {
+                // System (undocumented)
+                let length_bytes;
+                (length_bytes, buf) = buf.split_first_chunk()?;
+                let length = u32::from_le_bytes(*length_bytes);
+                (_, buf) = buf.split_at_checked(length as usize)?;
+            }
+            _ => {
+                return None;
+            }
+        }
+    }
+    Some(syms)
+}
+
 type Reader<'a> = gimli::EndianSlice<'a, gimli::RunTimeEndian>;
 
 struct ParseContext<'a> {
@@ -165,16 +245,19 @@ impl ParseContext<'_> {
     }
 }
 
-fn parse_inline(ctx: &mut ParseContext, node: gimli::EntriesTreeNode<Reader>) -> Result<()> {
+fn parse_inline<'a>(
+    ctx: &mut ParseContext<'a>,
+    node: gimli::EntriesTreeNode<'a, '_, Reader<'a>>,
+) -> Result<()> {
     if node.entry().tag() == gimli::DW_TAG_inlined_subroutine
-        && let Some(attr) = node.entry().attr_value(gimli::DW_AT_abstract_origin)?
+        && let Some(attr) = node.entry().attr_value(gimli::DW_AT_abstract_origin)
         && let Some(name) = ctx.name_attr(attr)?
     {
         let name = Arc::new(name);
         let mut ranges = ctx.dorf.die_ranges(ctx.unit, node.entry())?;
         while let Some(range) = ranges.next()? {
-            let start = range.begin as u32;
-            let end = range.end as u32;
+            let start = range.begin as u32 & 0x07ffffff;
+            let end = range.end as u32 & 0x07ffffff;
             ctx.frames.add(start, end, name.clone());
         }
     }

src/emulator/shrooms_vb_core.rs

@@ -261,7 +261,7 @@ extern "C" fn on_exception(sim: *mut VB, cause: *mut u16) -> c_int {
     };
     data.monitor.event = data.monitor.queued_event.take();
     data.monitor.new_inline_stack = data.monitor.detect_new_inline_stack(pc);
-    data.monitor.queued_event = Some(SimEvent::Interrupt(cause, pc));
+    data.monitor.queued_event = Some(SimEvent::Interrupt(cause, pc & 0x07ffffff));
     unsafe { vb_set_exception_callback(sim, None) };
     if data.monitor.event.is_some() || data.monitor.new_inline_stack.is_some() {
         1
@@ -439,7 +439,9 @@ impl EventMonitor {
                 // JAL .+4 is how programs get r31 to a known value for indirect calls
                 // (which we detect later.)
                 // Any other JAL is a function call.
-                return Some(SimEvent::Call(address.wrapping_add_signed(disp)));
+                return Some(SimEvent::Call(
+                    address.wrapping_add_signed(disp) & 0x07ffffff,
+                ));
             }
         }
 
@@ -453,7 +455,7 @@ impl EventMonitor {
             if r31 as u32 == address.wrapping_add(2) {
                 // JMP anywhere else, if r31 points to after the JMP, is an indirect call
                 let target = unsafe { vb_get_program_register(sim, jmp_reg as u32) };
-                return Some(SimEvent::Call(target as u32));
+                return Some(SimEvent::Call(target as u32 & 0x07ffffff));
             }
         }
 

src/emulator/shrooms_vb_util.rs

@@ -0,0 +1,31 @@
+use std::ffi::c_void;
+
+#[unsafe(no_mangle)]
+unsafe fn vbu_realloc_shim(ptr: *mut c_void, new_size: usize) -> *mut c_void {
+    if !ptr.is_null() {
+        // not supporting proper realloc because it needs bookkeeping and it's unnecessary
+        return std::ptr::null_mut();
+    }
+    let allocation = vec![0u8; new_size].into_boxed_slice();
+    Box::into_raw(allocation).cast()
+}
+
+#[link(name = "vb")]
+unsafe extern "C" {
+    #[link_name = "vbuFromISX"]
+    fn vbu_from_isx(bytes: *const c_void, length: usize, rom_length: *mut usize) -> *mut c_void;
+}
+
+pub fn rom_from_isx(bytes: &[u8]) -> Option<Vec<u8>> {
+    if !bytes.starts_with(b"ISX") {
+        return None;
+    }
+    let mut rom_length = 0;
+    let raw_rom = unsafe { vbu_from_isx(bytes.as_ptr().cast(), bytes.len(), &mut rom_length) };
+    if raw_rom.is_null() {
+        return None;
+    }
+    // SAFETY: the rom was allocated by vbu_realloc_shim, which created it from a Vec<u8>.
+    let rom = unsafe { Vec::from_raw_parts(raw_rom.cast(), rom_length, rom_length) };
+    Some(rom)
+}

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/filesystem.rs

@@ -0,0 +1,52 @@
+use std::{fs, path::PathBuf};
+
+use anyhow::{Result, bail};
+use directories::ProjectDirs;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone)]
+pub struct Persistence {
+    config_dir: Option<PathBuf>,
+}
+
+impl Persistence {
+    pub fn new() -> Self {
+        Self {
+            config_dir: init_config_dir(),
+        }
+    }
+
+    pub fn save_config<T: Serialize>(&self, file: &str, data: &T) -> Result<()> {
+        if let Some(config_dir) = self.config_dir.as_ref() {
+            let bytes = serde_json::to_vec_pretty(data)?;
+            let filename = config_dir.join(file).with_extension("json");
+            fs::write(&filename, bytes)?;
+        }
+        Ok(())
+    }
+
+    pub fn load_config<T: for<'a> Deserialize<'a>>(&self, file: &str) -> Result<T> {
+        let Some(config_dir) = self.config_dir.as_ref() else {
+            bail!("config directory not found");
+        };
+        let filename = config_dir.join(file).with_extension("json");
+        let bytes = fs::read(filename)?;
+        Ok(serde_json::from_slice(&bytes)?)
+    }
+}
+
+fn init_config_dir() -> Option<PathBuf> {
+    let config_dir = project_dirs()?.config_dir().to_path_buf();
+    fs::create_dir_all(&config_dir).ok()?;
+    Some(config_dir)
+}
+
+pub fn init_data_dir() -> Option<PathBuf> {
+    let data_dir = project_dirs()?.data_dir().to_path_buf();
+    fs::create_dir_all(&data_dir).ok()?;
+    Some(data_dir)
+}
+
+fn project_dirs() -> Option<ProjectDirs> {
+    ProjectDirs::from("com", "virtual-boy", "Lemur")
+}

src/images.rs

@@ -1,5 +1,5 @@
 use std::{
-    collections::HashMap,
+    collections::{HashMap, hash_map::Entry},
     ops::Deref,
     sync::{Arc, Mutex, Weak},
     thread,
@@ -7,17 +7,21 @@ use std::{
 };
 
 use egui::{
-    Color32, ColorImage, TextureHandle, TextureOptions,
+    Color32, ColorImage, TextureHandle,
     epaint::ImageDelta,
+    generate_loader_id,
     load::{LoadError, SizedTexture, TextureLoader, TexturePoll},
 };
 use tokio::{sync::mpsc, time::timeout};
 
-pub struct ImageProcessor {
+use crate::emulator::SimId;
+
+pub struct ImageTextureLoader {
+    cache: Mutex<HashMap<String, ImageEntry>>,
     sender: mpsc::UnboundedSender<Box<dyn ImageRendererImpl>>,
 }
 
-impl ImageProcessor {
+impl ImageTextureLoader {
     pub fn new() -> Self {
         let (sender, receiver) = mpsc::unbounded_channel();
         thread::spawn(move || {
@@ -26,29 +30,52 @@ impl ImageProcessor {
                 .build()
                 .unwrap()
                 .block_on(async move {
-                    let mut worker = ImageProcessorWorker {
+                    let mut worker = ImageTextureLoaderWorker {
                         receiver,
                         renderers: vec![],
                     };
                     worker.run().await
                 })
         });
-        Self { sender }
+        Self {
+            cache: Mutex::new(HashMap::new()),
+            sender,
+        }
     }
 
     pub fn add<const N: usize, R: ImageRenderer<N> + 'static>(
         &self,
+        sim_id: SimId,
         renderer: R,
         params: R::Params,
-    ) -> ([ImageHandle; N], ImageParams<R::Params>) {
+    ) -> ImageParams<R::Params> {
         let states = renderer.sizes().map(ImageState::new);
-        let handles = states.clone().map(|state| ImageHandle {
-            size: state.size.map(|i| i as f32),
-            data: state.sink,
-        });
         let images = renderer
             .sizes()
             .map(|[width, height]| ImageBuffer::new(width, height));
+        {
+            let mut cache = self.cache.lock().unwrap();
+            for (name, state) in renderer.names().into_iter().zip(&states) {
+                let url = format!("vip://{sim_id}/{name}");
+                let entry = ImageEntry {
+                    size: state.size.map(|i| i as f32),
+                    data: Arc::downgrade(&state.sink),
+                    texture: None,
+                };
+                match cache.entry(url) {
+                    Entry::Vacant(e) => {
+                        e.insert(entry);
+                    }
+                    Entry::Occupied(mut e) => {
+                        // Only overwrite an old entry if that entry is dead.
+                        // Otherwise, we clear out the reference to a texture actually in use.
+                        if e.get().data.strong_count() == 0 {
+                            e.insert(entry);
+                        }
+                    }
+                }
+            }
+        }
         let sink = Arc::new(Mutex::new(params.clone()));
         let _ = self.sender.send(Box::new(ImageRendererWrapper {
             renderer,
@@ -56,20 +83,87 @@ impl ImageProcessor {
             images,
             states,
         }));
-        let params = ImageParams {
+        ImageParams {
             value: params,
             sink,
-        };
-        (handles, params)
+        }
     }
 }
 
-struct ImageProcessorWorker {
+impl TextureLoader for ImageTextureLoader {
+    fn id(&self) -> &str {
+        generate_loader_id!(ImageTextureLoader2)
+    }
+
+    fn load(
+        &self,
+        ctx: &egui::Context,
+        uri: &str,
+        texture_options: egui::TextureOptions,
+        _size_hint: egui::SizeHint,
+    ) -> Result<TexturePoll, LoadError> {
+        let mut cache = self.cache.lock().unwrap();
+        let Some(entry) = cache.get_mut(uri) else {
+            return Err(LoadError::NotSupported);
+        };
+        if texture_options != egui::TextureOptions::NEAREST {
+            return Err(LoadError::Loading(
+                "Only TextureOptions::NEAREST are supported".into(),
+            ));
+        }
+        let Some(data) = entry.data.upgrade() else {
+            cache.remove(uri);
+            return Err(LoadError::Loading("Backing loader no longer exists".into()));
+        };
+        match (data.lock().unwrap().take(), entry.texture.as_ref()) {
+            (Some(update), Some(handle)) => {
+                let delta = ImageDelta::full(update, texture_options);
+                ctx.tex_manager().write().set(handle.id(), delta);
+                let texture = SizedTexture::new(handle, entry.size);
+                Ok(TexturePoll::Ready { texture })
+            }
+            (Some(update), None) => {
+                let handle = ctx.load_texture(uri, update, texture_options);
+                let texture = SizedTexture::new(&handle, entry.size);
+                entry.texture.replace(handle);
+                Ok(TexturePoll::Ready { texture })
+            }
+            (None, Some(handle)) => {
+                let texture = SizedTexture::new(handle, entry.size);
+                Ok(TexturePoll::Ready { texture })
+            }
+            (None, None) => {
+                let size = entry.size.into();
+                Ok(TexturePoll::Pending { size: Some(size) })
+            }
+        }
+    }
+
+    fn forget(&self, uri: &str) {
+        let _ = uri;
+    }
+
+    fn forget_all(&self) {}
+
+    fn byte_size(&self) -> usize {
+        self.cache
+            .lock()
+            .unwrap()
+            .values()
+            .map(|entry| {
+                let [width, height] = entry.size;
+                width as usize * height as usize * 4
+            })
+            .sum()
+    }
+}
+
+struct ImageTextureLoaderWorker {
     receiver: mpsc::UnboundedReceiver<Box<dyn ImageRendererImpl>>,
     renderers: Vec<Box<dyn ImageRendererImpl>>,
 }
 
-impl ImageProcessorWorker {
+impl ImageTextureLoaderWorker {
     async fn run(&mut self) {
         loop {
             if self.renderers.is_empty() {
@@ -142,16 +236,10 @@ impl ImageBuffer {
     }
 }
 
-#[derive(Clone)]
-pub struct ImageHandle {
+struct ImageEntry {
     size: [f32; 2],
-    data: Arc<Mutex<Option<Arc<ColorImage>>>>,
-}
-
-impl ImageHandle {
-    fn pull(&mut self) -> Option<Arc<ColorImage>> {
-        self.data.lock().unwrap().take()
-    }
+    data: Weak<Mutex<Option<Arc<ColorImage>>>>,
+    texture: Option<TextureHandle>,
 }
 
 pub struct ImageParams<T> {
@@ -178,6 +266,7 @@ impl<T: Clone + Eq> ImageParams<T> {
 
 pub trait ImageRenderer<const N: usize>: Send {
     type Params: Clone + Send;
+    fn names(&self) -> [&str; N];
     fn sizes(&self) -> [[usize; 2]; N];
     fn render(&mut self, params: &Self::Params, images: &mut [ImageBuffer; N]);
 }
@@ -246,83 +335,3 @@ impl<const N: usize, R: ImageRenderer<N> + Send> ImageRendererImpl for ImageRend
         Ok(())
     }
 }
-
-pub struct ImageTextureLoader {
-    cache: Mutex<HashMap<String, (ImageHandle, Option<TextureHandle>)>>,
-}
-
-impl ImageTextureLoader {
-    pub fn new(renderers: impl IntoIterator<Item = (String, ImageHandle)>) -> Self {
-        let mut cache = HashMap::new();
-        for (key, image) in renderers {
-            cache.insert(key, (image, None));
-        }
-        Self {
-            cache: Mutex::new(cache),
-        }
-    }
-}
-
-impl TextureLoader for ImageTextureLoader {
-    fn id(&self) -> &str {
-        concat!(module_path!(), "ImageTextureLoader")
-    }
-
-    fn load(
-        &self,
-        ctx: &egui::Context,
-        uri: &str,
-        texture_options: TextureOptions,
-        _size_hint: egui::SizeHint,
-    ) -> Result<TexturePoll, LoadError> {
-        let mut cache = self.cache.lock().unwrap();
-        let Some((image, maybe_handle)) = cache.get_mut(uri) else {
-            return Err(LoadError::NotSupported);
-        };
-        if texture_options != TextureOptions::NEAREST {
-            return Err(LoadError::Loading(
-                "Only TextureOptions::NEAREST are supported".into(),
-            ));
-        }
-        match (image.pull(), maybe_handle.as_ref()) {
-            (Some(update), Some(handle)) => {
-                let delta = ImageDelta::full(update, texture_options);
-                ctx.tex_manager().write().set(handle.id(), delta);
-                let texture = SizedTexture::new(handle, image.size);
-                Ok(TexturePoll::Ready { texture })
-            }
-            (Some(update), None) => {
-                let handle = ctx.load_texture(uri, update, texture_options);
-                let texture = SizedTexture::new(&handle, image.size);
-                maybe_handle.replace(handle);
-                Ok(TexturePoll::Ready { texture })
-            }
-            (None, Some(handle)) => {
-                let texture = SizedTexture::new(handle, image.size);
-                Ok(TexturePoll::Ready { texture })
-            }
-            (None, None) => {
-                let size = image.size.into();
-                Ok(TexturePoll::Pending { size: Some(size) })
-            }
-        }
-    }
-
-    fn forget(&self, uri: &str) {
-        let _ = uri;
-    }
-
-    fn forget_all(&self) {}
-
-    fn byte_size(&self) -> usize {
-        self.cache
-            .lock()
-            .unwrap()
-            .values()
-            .map(|(image, _)| {
-                let [width, height] = image.size;
-                width as usize * height as usize * 4
-            })
-            .sum()
-    }
-}

src/input.rs

@@ -14,7 +14,7 @@ use winit::keyboard::{KeyCode, PhysicalKey};
 
 use crate::{
     emulator::{SimId, VBKey},
-    persistence::Persistence,
+    filesystem::Persistence,
 };
 
 #[derive(Clone, PartialEq, Eq, Hash)]
@@ -52,12 +52,28 @@ pub trait Mappings {
     fn use_default_mappings(&mut self);
 }
 
+#[derive(Clone, Copy, Serialize, Deserialize)]
+pub struct AxisMapping {
+    pub neg: VBKey,
+    pub pos: VBKey,
+    pub pair: Option<Code>,
+}
+impl Default for AxisMapping {
+    fn default() -> Self {
+        Self {
+            neg: VBKey::empty(),
+            pos: VBKey::empty(),
+            pair: None,
+        }
+    }
+}
+
 #[derive(Serialize, Deserialize)]
 pub struct GamepadMapping {
     buttons: HashMap<Code, VBKey>,
-    axes: HashMap<Code, (VBKey, VBKey)>,
+    axes: HashMap<Code, AxisMapping>,
     default_buttons: HashMap<Code, VBKey>,
-    default_axes: HashMap<Code, (VBKey, VBKey)>,
+    default_axes: HashMap<Code, AxisMapping>,
 }
 
 impl GamepadMapping {
@@ -78,7 +94,8 @@ impl GamepadMapping {
         let mut default_axes = HashMap::new();
         let mut default_axis = |axis: Axis, neg: VBKey, pos: VBKey| {
             if let Some(code) = gamepad.axis_code(axis) {
-                default_axes.insert(code, (neg, pos));
+                let pair = axis.second_axis().and_then(|a| gamepad.axis_code(a));
+                default_axes.insert(code, AxisMapping { neg, pos, pair });
             }
         };
         default_axis(Axis::LeftStickX, VBKey::LL, VBKey::LR);
@@ -102,19 +119,13 @@ impl GamepadMapping {
     }
 
     pub fn add_axis_neg_mapping(&mut self, key: VBKey, code: Code) {
-        let entry = self
-            .axes
-            .entry(code)
-            .or_insert((VBKey::empty(), VBKey::empty()));
-        entry.0 = entry.0.union(key);
+        let entry = self.axes.entry(code).or_default();
+        entry.neg = entry.neg.union(key);
     }
 
     pub fn add_axis_pos_mapping(&mut self, key: VBKey, code: Code) {
-        let entry = self
-            .axes
-            .entry(code)
-            .or_insert((VBKey::empty(), VBKey::empty()));
-        entry.1 = entry.1.union(key);
+        let entry = self.axes.entry(code).or_default();
+        entry.pos = entry.pos.union(key);
     }
 
     fn save_mappings(&self) -> PersistedGamepadMapping {
@@ -145,11 +156,11 @@ impl GamepadMapping {
 impl Mappings for GamepadMapping {
     fn mapping_names(&self) -> HashMap<VBKey, Vec<String>> {
         let mut results: HashMap<VBKey, Vec<String>> = HashMap::new();
-        for (axis, (left_keys, right_keys)) in &self.axes {
-            for key in left_keys.iter() {
+        for (axis, mapping) in &self.axes {
+            for key in mapping.neg.iter() {
                 results.entry(key).or_default().push(format!("-{axis}"));
             }
-            for key in right_keys.iter() {
+            for key in mapping.pos.iter() {
                 results.entry(key).or_default().push(format!("+{axis}"));
             }
         }
@@ -162,10 +173,10 @@ impl Mappings for GamepadMapping {
     }
 
     fn clear_mappings(&mut self, key: VBKey) {
-        self.axes.retain(|_, (left, right)| {
-            *left = left.difference(key);
-            *right = right.difference(key);
-            !(left.is_empty() && right.is_empty())
+        self.axes.retain(|_, mapping| {
+            mapping.neg = mapping.neg.difference(key);
+            mapping.pos = mapping.pos.difference(key);
+            !(mapping.neg.is_empty() && mapping.pos.is_empty())
         });
         self.buttons.retain(|_, keys| {
             *keys = keys.difference(key);
@@ -200,7 +211,7 @@ impl InputMapping {
         mappings.buttons.get(code).copied()
     }
 
-    pub fn map_axis(&self, id: &GamepadId, code: &Code) -> Option<(VBKey, VBKey)> {
+    pub fn map_axis(&self, id: &GamepadId, code: &Code) -> Option<AxisMapping> {
         let mappings = self.gamepads.get(id)?.read().unwrap();
         mappings.axes.get(code).copied()
     }
@@ -272,13 +283,14 @@ impl Mappings for InputMapping {
 #[derive(Clone)]
 pub struct MappingProvider {
     persistence: Persistence,
+    first_gamepad_is_p2: bool,
     device_mappings: Arc<RwLock<HashMap<DeviceId, Arc<RwLock<GamepadMapping>>>>>,
     sim_mappings: HashMap<SimId, Arc<RwLock<InputMapping>>>,
     gamepad_info: Arc<RwLock<HashMap<GamepadId, GamepadInfo>>>,
 }
 
 impl MappingProvider {
-    pub fn new(persistence: Persistence) -> Self {
+    pub fn new(persistence: Persistence, first_gamepad_is_p2: bool) -> Self {
         let mut sim_mappings = HashMap::new();
         let mut device_mappings = HashMap::new();
 
@@ -307,6 +319,7 @@ impl MappingProvider {
             device_mappings: Arc::new(RwLock::new(device_mappings)),
             gamepad_info: Arc::new(RwLock::new(HashMap::new())),
             sim_mappings,
+            first_gamepad_is_p2,
         }
     }
 
@@ -338,7 +351,12 @@ impl MappingProvider {
         .clone();
         drop(lock);
         let mut lock = self.gamepad_info.write().unwrap();
-        let bound_to = SimId::values()
+        let players = if self.first_gamepad_is_p2 {
+            vec![SimId::Player2, SimId::Player1]
+        } else {
+            vec![SimId::Player1, SimId::Player2]
+        };
+        let bound_to = players
             .into_iter()
             .find(|sim_id| lock.values().all(|info| info.bound_to != Some(*sim_id)));
         if let Entry::Vacant(entry) = lock.entry(gamepad.id()) {
@@ -452,20 +470,15 @@ struct PersistedKeyboardMapping {
 #[derive(Serialize, Deserialize)]
 struct PersistedGamepadMapping {
     buttons: Vec<(Code, VBKey)>,
-    axes: Vec<(Code, (VBKey, VBKey))>,
+    axes: Vec<(Code, AxisMapping)>,
     default_buttons: Vec<(Code, VBKey)>,
-    default_axes: Vec<(Code, (VBKey, VBKey))>,
-}
-
-#[derive(Serialize, Deserialize)]
-pub struct Shortcut {
-    pub shortcut: KeyboardShortcut,
-    pub command: Command,
+    default_axes: Vec<(Code, AxisMapping)>,
 }
 
 #[derive(Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Hash)]
 pub enum Command {
     OpenRom,
+    ReloadRom,
     Quit,
     FrameAdvance,
     FastForward(u32),
@@ -476,9 +489,10 @@ pub enum Command {
 }
 
 impl Command {
-    pub fn all() -> [Self; 7] {
+    pub fn all() -> [Self; 8] {
         [
             Self::OpenRom,
+            Self::ReloadRom,
             Self::Quit,
             Self::PauseResume,
             Self::Reset,
@@ -491,6 +505,7 @@ impl Command {
     pub fn name(self) -> &'static str {
         match self {
             Self::OpenRom => "Open ROM",
+            Self::ReloadRom => "Reload ROM",
             Self::Quit => "Exit",
             Self::PauseResume => "Pause/Resume",
             Self::Reset => "Reset",
@@ -522,6 +537,10 @@ impl Default for Shortcuts {
             Command::OpenRom,
             KeyboardShortcut::new(Modifiers::COMMAND, Key::O),
         );
+        shortcuts.set(
+            Command::ReloadRom,
+            KeyboardShortcut::new(Modifiers::COMMAND | Modifiers::SHIFT, Key::F5),
+        );
         shortcuts.set(
             Command::Quit,
             KeyboardShortcut::new(Modifiers::COMMAND, Key::Q),
@@ -682,7 +701,7 @@ impl ShortcutProvider {
                 else {
                     return true;
                 };
-                if shortcut.logical_key != *key || !shortcut.modifiers.contains(*modifiers) {
+                if *key != shortcut.logical_key || !modifiers.contains(shortcut.modifiers) {
                     return true;
                 }
                 if matches!(command, Command::FastForward(_)) {

src/main.rs

@@ -1,7 +1,7 @@
 // hide console in release mode
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
 
-use std::{path::PathBuf, process, time::SystemTime};
+use std::{process, time::SystemTime};
 
 use anyhow::{Result, bail};
 use app::Application;
@@ -12,31 +12,27 @@ use tracing::error;
 use tracing_subscriber::{EnvFilter, Layer, layer::SubscriberExt, util::SubscriberInitExt};
 use winit::event_loop::{ControlFlow, EventLoop};
 
+use crate::{
+    config::{AppConfig, CliArgs, SimConfig},
+    emulator::SimId,
+    filesystem::Persistence,
+};
+
 mod app;
 mod audio;
+mod config;
 mod controller;
 mod emulator;
+mod filepicker;
+mod filesystem;
 mod gdbserver;
 mod graphics;
 mod images;
 mod input;
 mod memory;
-mod persistence;
 mod profiler;
 mod window;
 
-#[derive(Parser)]
-struct Args {
-    /// The path to a virtual boy ROM to run.
-    rom: Option<PathBuf>,
-    /// Start a GDB/LLDB debug server on this port.
-    #[arg(short, long)]
-    debug_port: Option<u16>,
-    /// Enable profiling a game
-    #[arg(short, long)]
-    profile: bool,
-}
-
 fn init_logger() {
     let directives = std::env::var("RUST_LOG").unwrap_or("error,lemur=info".into());
     let filter = EnvFilter::builder().parse_lossy(directives);
@@ -64,14 +60,9 @@ fn set_panic_handler() {
 
         eprint!("{message}");
 
-        let Some(project_dirs) = directories::ProjectDirs::from("com", "virtual-boy", "Lemur")
-        else {
+        let Some(data_dir) = filesystem::init_data_dir() else {
             return;
         };
-        let data_dir = project_dirs.data_dir();
-        if std::fs::create_dir_all(data_dir).is_err() {
-            return;
-        }
         let timestamp = SystemTime::now()
             .duration_since(SystemTime::UNIX_EPOCH)
             .unwrap()
@@ -98,9 +89,18 @@ fn main() -> Result<()> {
     #[cfg(windows)]
     set_process_priority_to_high()?;
 
-    let args = Args::parse();
+    let args = CliArgs::parse();
 
-    let (mut builder, client) = EmulatorBuilder::new();
+    let persistence = Persistence::new();
+
+    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);
+
+    let (mut builder, client) = EmulatorBuilder::new(config.save_data_location);
     if let Some(path) = &args.rom {
         builder = builder.with_rom(path);
     }
@@ -114,6 +114,12 @@ fn main() -> Result<()> {
         builder = builder.start_paused(true)
     }
 
+    let watch = args.watch;
+
+    builder = builder
+        .with_audio_on(p1.audio_enabled, p2.audio_enabled)
+        .with_watch_rom(watch, watch);
+
     ThreadBuilder::default()
         .name("Emulator".to_owned())
         .priority(ThreadPriority::Max)
@@ -131,11 +137,14 @@ 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();
+    let handle = event_loop.owned_display_handle();
     event_loop.run_app(&mut Application::new(
         client,
         proxy,
-        args.debug_port,
-        args.profile,
+        handle,
+        persistence,
+        args,
+        config,
     ))?;
     Ok(())
 }

src/memory.rs

@@ -50,11 +50,11 @@ impl MemoryClient {
 }
 
 fn aligned_memory(start: u32, length: usize) -> BoxBytes {
-    if start % 4 == 0 && length % 4 == 0 {
+    if start.is_multiple_of(4) && length.is_multiple_of(4) {
         let memory = vec![0u32; length / 4].into_boxed_slice();
         return bytemuck::box_bytes_of(memory);
     }
-    if start % 2 == 0 && length % 2 == 0 {
+    if start.is_multiple_of(2) && length.is_multiple_of(2) {
         let memory = vec![0u16; length / 2].into_boxed_slice();
         return bytemuck::box_bytes_of(memory);
     }

src/persistence.rs

@@ -1,46 +0,0 @@
-use std::{fs, path::PathBuf};
-
-use anyhow::{Result, bail};
-use directories::ProjectDirs;
-use serde::{Deserialize, Serialize};
-
-#[derive(Clone)]
-pub struct Persistence {
-    dirs: Option<Dirs>,
-}
-
-impl Persistence {
-    pub fn new() -> Self {
-        Self { dirs: init_dirs() }
-    }
-
-    pub fn save_config<T: Serialize>(&self, file: &str, data: &T) -> Result<()> {
-        if let Some(dirs) = self.dirs.as_ref() {
-            let bytes = serde_json::to_vec_pretty(data)?;
-            let filename = dirs.config_dir.join(file).with_extension("json");
-            fs::write(&filename, bytes)?;
-        }
-        Ok(())
-    }
-
-    pub fn load_config<T: for<'a> Deserialize<'a>>(&self, file: &str) -> Result<T> {
-        let Some(dirs) = self.dirs.as_ref() else {
-            bail!("config directory not found");
-        };
-        let filename = dirs.config_dir.join(file).with_extension("json");
-        let bytes = fs::read(filename)?;
-        Ok(serde_json::from_slice(&bytes)?)
-    }
-}
-
-#[derive(Clone)]
-struct Dirs {
-    config_dir: PathBuf,
-}
-
-fn init_dirs() -> Option<Dirs> {
-    let dirs = ProjectDirs::from("com", "virtual-boy", "Lemur")?;
-    let config_dir = dirs.config_dir().to_path_buf();
-    fs::create_dir_all(&config_dir).ok()?;
-    Some(Dirs { config_dir })
-}

src/profiler/state.rs

@@ -60,6 +60,11 @@ impl ProgramState {
         let Some(stack) = self.call_stacks.get_mut(code) else {
             bail!("missing stack {code:04x}");
         };
+        // just popping the inline frames first
+        while stack
+            .pop_if(|f| matches!(f, StackFrame::Label(_)))
+            .is_some()
+        {}
         if stack.pop().is_none() {
             bail!("returned from {code:04x} but stack was empty");
         }

src/window.rs

@@ -1,6 +1,9 @@
+use std::{path::PathBuf, sync::Arc};
+
 pub use about::AboutWindow;
-use egui::{Context, ViewportBuilder, ViewportId};
-pub use game::GameWindow;
+use egui::{Ui, ViewportBuilder};
+pub use game::{ChildWindow, GameWindow};
+pub use game_screen::{DisplayMode, GameScreen};
 pub use gdb::GdbServerWindow;
 pub use hotkeys::HotkeysWindow;
 pub use input::InputWindow;
@@ -9,7 +12,7 @@ pub use terminal::TerminalWindow;
 pub use vip::{
     BgMapWindow, CharacterDataWindow, FrameBufferWindow, ObjectWindow, RegisterWindow, WorldWindow,
 };
-use winit::event::KeyEvent;
+use winit::{event::KeyEvent, window::Window};
 
 use crate::emulator::SimId;
 
@@ -25,17 +28,17 @@ mod utils;
 mod vip;
 
 pub trait AppWindow {
-    fn viewport_id(&self) -> ViewportId;
-    fn sim_id(&self) -> SimId {
-        SimId::Player1
+    fn sim_id(&self) -> Option<SimId> {
+        None
+    }
+    fn image_url(&self, name: &str) -> String {
+        format!("vip://{}/{name}", self.sim_id().unwrap_or(SimId::Player1))
     }
     fn initial_viewport(&self) -> ViewportBuilder;
-    fn show(&mut self, ctx: &Context);
-    fn on_init(&mut self, ctx: &Context, render_state: &egui_wgpu::RenderState) {
-        let _ = ctx;
-        let _ = render_state;
+    fn show(&mut self, ui: &mut Ui);
+    fn on_init(&mut self, args: InitArgs) {
+        let _ = args;
     }
-    fn on_destroy(&mut self) {}
     fn handle_key_event(&mut self, event: &KeyEvent) -> bool {
         let _ = event;
         false
@@ -44,4 +47,13 @@ pub trait AppWindow {
         let _ = event;
         false
     }
+    fn handle_dropped_file(&mut self, path: PathBuf) -> bool {
+        let _ = path;
+        false
+    }
+}
+
+pub struct InitArgs<'a> {
+    pub window: &'a Arc<Window>,
+    pub render_state: &'a egui_wgpu::RenderState,
 }

src/window/about.rs

@@ -1,22 +1,18 @@
-use egui::{CentralPanel, Context, Image, ViewportBuilder, ViewportId};
+use egui::{CentralPanel, Image, Ui, ViewportBuilder};
 
 use super::AppWindow;
 
 pub struct AboutWindow;
 
 impl AppWindow for AboutWindow {
-    fn viewport_id(&self) -> ViewportId {
-        ViewportId::from_hash_of("About")
-    }
-
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
             .with_title("About Lemur")
             .with_inner_size((300.0, 200.0))
     }
 
-    fn show(&mut self, ctx: &Context) {
-        CentralPanel::default().show(ctx, |ui| {
+    fn show(&mut self, ui: &mut Ui) {
+        CentralPanel::default().show(ui, |ui| {
             ui.vertical_centered(|ui| {
                 ui.label("Lemur Virtual Boy Emulator");
                 ui.label(format!("Version {}", env!("CARGO_PKG_VERSION")));

src/window/game.rs

@@ -1,19 +1,33 @@
-use std::{sync::mpsc, time::Duration};
+use std::{
+    ops::{Deref, DerefMut},
+    path::PathBuf,
+    sync::{Arc, Mutex, atomic::AtomicBool, mpsc},
+    time::Duration,
+};
 
 use crate::{
     app::UserEvent,
+    config::{AppConfig, COLOR_PRESETS, SaveDataLocation, SimConfig},
     emulator::{EmulatorClient, EmulatorCommand, EmulatorState, SimId, SimState},
-    input::{Command, ShortcutProvider},
-    persistence::Persistence,
+    filepicker::FilePicker,
+    filesystem::Persistence,
+    images::ImageTextureLoader,
+    input::{Command, MappingProvider, ShortcutProvider},
+    memory::MemoryClient,
+    window::{
+        AboutWindow, BgMapWindow, CharacterDataWindow, FrameBufferWindow, GdbServerWindow,
+        HotkeysWindow, InitArgs, InputWindow, ObjectWindow, ProfileWindow, RegisterWindow,
+        TerminalWindow, WorldWindow, utils::UiData,
+    },
 };
 use anyhow::Context as _;
 use egui::{
-    Align2, Button, CentralPanel, Color32, Context, Frame, MenuBar, TopBottomPanel, Ui, Vec2,
-    ViewportBuilder, ViewportCommand, ViewportId, Window,
+    Align2, Button, CentralPanel, Color32, Context, Frame, MenuBar, Panel, Pos2, Ui, Vec2,
+    ViewportBuilder, ViewportCommand, ViewportId, ViewportIdMap, Window,
 };
 use egui_notify::{Anchor, Toast, Toasts};
 use serde::{Deserialize, Serialize};
-use winit::event_loop::EventLoopProxy;
+use winit::{event::KeyEvent, event_loop::EventLoopProxy};
 
 use super::{
     AppWindow,
@@ -21,48 +35,52 @@ use super::{
     utils::UiExt as _,
 };
 
-const COLOR_PRESETS: [[Color32; 2]; 3] = [
-    [
-        Color32::from_rgb(0xff, 0x00, 0x00),
-        Color32::from_rgb(0x00, 0xc6, 0xf0),
-    ],
-    [
-        Color32::from_rgb(0x00, 0xb4, 0x00),
-        Color32::from_rgb(0xc8, 0x00, 0xff),
-    ],
-    [
-        Color32::from_rgb(0xb4, 0x9b, 0x00),
-        Color32::from_rgb(0x00, 0x00, 0xff),
-    ],
-];
-
 pub struct GameWindow {
+    viewport_id: ViewportId,
     client: EmulatorClient,
     proxy: EventLoopProxy<UserEvent>,
     persistence: Persistence,
     shortcuts: ShortcutProvider,
     sim_id: SimId,
-    config: GameConfig,
+    config: SimConfig,
     toasts: Toasts,
     screen: Option<GameScreen>,
-    messages: Option<mpsc::Receiver<Toast>>,
+    messages: mpsc::Receiver<Toast>,
+    message_sink: mpsc::Sender<Toast>,
     color_picker: Option<ColorPickerState>,
+    file_picker: FilePicker,
+    memory: Arc<MemoryClient>,
+    images: Arc<ImageTextureLoader>,
+    mappings: MappingProvider,
+    children: ViewportIdMap<ChildWindowWrapper>,
+    child_states: UiData<ViewportIdMap<ChildState>>,
+    queued_children: Vec<ChildWindow>,
+    show_player_name: bool,
 }
 
 impl GameWindow {
+    #[expect(clippy::too_many_arguments)]
     pub fn new(
+        viewport_id: ViewportId,
         client: EmulatorClient,
         proxy: EventLoopProxy<UserEvent>,
         persistence: Persistence,
         shortcuts: ShortcutProvider,
+        memory: &Arc<MemoryClient>,
+        images: &Arc<ImageTextureLoader>,
+        mappings: MappingProvider,
         sim_id: SimId,
     ) -> Self {
-        let config = load_config(&persistence, sim_id);
+        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())
             .reverse(true);
+        let (message_sink, messages) = mpsc::channel();
         Self {
+            viewport_id,
             client,
             proxy,
             persistence,
@@ -71,12 +89,165 @@ impl GameWindow {
             config,
             toasts,
             screen: None,
-            messages: None,
+            messages,
+            message_sink,
             color_picker: None,
+            file_picker: FilePicker::new(),
+            memory: memory.clone(),
+            images: images.clone(),
+            mappings: mappings.clone(),
+            children: ViewportIdMap::default(),
+            child_states: UiData::new(),
+            queued_children: vec![],
+            show_player_name: false,
         }
     }
 
-    fn show_menu(&mut self, ctx: &Context, ui: &mut Ui) {
+    pub fn open(&mut self, window: ChildWindow) {
+        // queue opening this child until our next render call,
+        // so that we get a chance to look up its size
+        self.queued_children.push(window);
+    }
+
+    pub fn close(&mut self, window: ChildWindow) {
+        let id = window.viewport_id(self.sim_id);
+        self.children.remove(&id);
+    }
+
+    fn do_open(&mut self, window: ChildWindow) {
+        let viewport_id = window.viewport_id(self.sim_id);
+        if self.children.contains_key(&viewport_id) {
+            return;
+        }
+        let child = match window {
+            ChildWindow::About => AppWrapper::of_dyn(AboutWindow),
+            ChildWindow::CharacterData => AppWrapper::of_dyn(CharacterDataWindow::new(
+                self.sim_id,
+                &self.memory,
+                &self.images,
+            )),
+            ChildWindow::BgMap => {
+                AppWrapper::of_dyn(BgMapWindow::new(self.sim_id, &self.memory, &self.images))
+            }
+            ChildWindow::Objects => {
+                AppWrapper::of_dyn(ObjectWindow::new(self.sim_id, &self.memory, &self.images))
+            }
+            ChildWindow::Worlds => {
+                AppWrapper::of_dyn(WorldWindow::new(self.sim_id, &self.memory, &self.images))
+            }
+            ChildWindow::FrameBuffers => AppWrapper::of_dyn(FrameBufferWindow::new(
+                self.sim_id,
+                &self.memory,
+                &self.images,
+            )),
+            ChildWindow::Registers => {
+                AppWrapper::of_dyn(RegisterWindow::new(self.sim_id, &self.memory))
+            }
+            ChildWindow::Terminal => {
+                AppWrapper::of_dyn(TerminalWindow::new(self.sim_id, &self.client))
+            }
+            ChildWindow::Profiler { launch } => {
+                let mut profile = ProfileWindow::new(self.sim_id, self.client.clone());
+                if launch {
+                    profile.launch();
+                }
+                AppWrapper::of_dyn(profile)
+            }
+            ChildWindow::Debugger { port } => {
+                let mut debugger =
+                    GdbServerWindow::new(self.sim_id, self.client.clone(), self.proxy.clone());
+                if let Some(port) = port {
+                    debugger.launch(port);
+                }
+                AppWrapper::of_dyn(debugger)
+            }
+            ChildWindow::Input => AppWrapper::of_dyn(InputWindow::new(self.mappings.clone())),
+            ChildWindow::Hotkeys => AppWrapper::of_dyn(HotkeysWindow::new(self.shortcuts.clone())),
+            ChildWindow::Player2 => {
+                if self.sim_id == SimId::Player2 {
+                    return;
+                }
+                AppWrapper::of_game(GameWindow::new(
+                    viewport_id,
+                    self.client.clone(),
+                    self.proxy.clone(),
+                    self.persistence.clone(),
+                    self.shortcuts.clone(),
+                    &self.memory,
+                    &self.images,
+                    self.mappings.clone(),
+                    SimId::Player2,
+                ))
+            }
+        };
+
+        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);
+        }
+        self.children.insert(
+            viewport_id,
+            ChildWindowWrapper {
+                app: Arc::new(Mutex::new(child)),
+                title,
+                sim_id,
+                updates: Some(viewport),
+                close_requested: Arc::new(AtomicBool::new(false)),
+            },
+        );
+    }
+
+    pub fn handle_init(&mut self, viewport_id: ViewportId, args: InitArgs) {
+        self.handle_event(viewport_id, |window| window.on_init(args))
+    }
+
+    pub fn handle_key_event(&mut self, viewport_id: ViewportId, event: &KeyEvent) -> bool {
+        self.handle_event(viewport_id, |window| window.handle_key_event(event))
+    }
+
+    pub fn handle_gamepad_event(&mut self, viewport_id: ViewportId, event: &gilrs::Event) -> bool {
+        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,
+        R: Default,
+    {
+        let p2_viewport_id = ChildWindow::Player2.viewport_id(SimId::Player1);
+
+        if self.viewport_id == viewport_id {
+            cb(self)
+        } else if let Some(child) = self.children.get_mut(&viewport_id) {
+            cb(child.app.lock().unwrap().deref_mut().deref_mut())
+        } else if let Some(mut p2) = self
+            .children
+            .get_mut(&p2_viewport_id)
+            .map(|w| w.app.lock().unwrap())
+        {
+            if let AppWrapper::Game(g) = p2.deref_mut() {
+                g.handle_event(viewport_id, cb)
+            } else {
+                R::default()
+            }
+        } else {
+            R::default()
+        }
+    }
+
+    fn show_menu(&mut self, ui: &mut Ui) {
         let state = self.client.emulator_state();
         let is_ready = self.client.sim_state(self.sim_id) == SimState::Ready;
         let can_pause = is_ready && state == EmulatorState::Running;
@@ -86,14 +257,20 @@ impl GameWindow {
         for command in ui.input_mut(|input| self.shortcuts.consume_all(input)) {
             match command {
                 Command::OpenRom => {
-                    let rom = rfd::FileDialog::new()
-                        .add_filter("Virtual Boy ROMs", &["vb", "vbrom"])
-                        .pick_file();
+                    let rom = self
+                        .file_picker
+                        .pick_file_dialog()
+                        .add_filter("Virtual Boy ROMs", &["vb", "vbrom", "elf", "isx"])
+                        .open();
                     if let Some(path) = rom {
                         self.client
                             .send_command(EmulatorCommand::LoadGame(self.sim_id, path));
                     }
                 }
+                Command::ReloadRom => {
+                    self.client
+                        .send_command(EmulatorCommand::ReloadRom(self.sim_id));
+                }
                 Command::Quit => {
                     let _ = self.proxy.send_event(UserEvent::Quit(self.sim_id));
                 }
@@ -138,14 +315,29 @@ impl GameWindow {
                 .add(self.button_for(ui.ctx(), "Open ROM", Command::OpenRom))
                 .clicked()
             {
-                let rom = rfd::FileDialog::new()
-                    .add_filter("Virtual Boy ROMs", &["vb", "vbrom"])
-                    .pick_file();
+                let rom = self
+                    .file_picker
+                    .pick_file_dialog()
+                    .add_filter("Virtual Boy ROMs", &["vb", "vbrom", "elf", "isx"])
+                    .open();
                 if let Some(path) = rom {
                     self.client
                         .send_command(EmulatorCommand::LoadGame(self.sim_id, path));
                 }
             }
+            if ui
+                .add(self.button_for(ui.ctx(), "Reload ROM", Command::ReloadRom))
+                .clicked()
+            {
+                self.client
+                    .send_command(EmulatorCommand::ReloadRom(self.sim_id));
+            }
+            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));
+            }
             if ui
                 .add(self.button_for(ui.ctx(), "Quit", Command::Quit))
                 .clicked()
@@ -200,17 +392,25 @@ 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(ctx, ui));
+        ui.menu_button("Options", |ui| self.show_options_menu(ui));
         ui.menu_button("Multiplayer", |ui| {
-            let has_player_2 = self.client.sim_state(SimId::Player2) != SimState::Uninitialized;
+            let has_player_2 = self.client.has_player_2();
             if self.sim_id == SimId::Player1
                 && !has_player_2
                 && ui.button("Open Player 2").clicked()
             {
                 self.client
                     .send_command(EmulatorCommand::StartSecondSim(None));
-                self.proxy.send_event(UserEvent::OpenPlayer2).unwrap();
+                self.open(ChildWindow::Player2);
             }
             if has_player_2 {
                 let linked = self.client.are_sims_linked();
@@ -224,55 +424,37 @@ impl GameWindow {
         });
         ui.menu_button("Tools", |ui| {
             if ui.button("Terminal").clicked() {
-                self.proxy
-                    .send_event(UserEvent::OpenTerminal(self.sim_id))
-                    .unwrap();
+                self.open(ChildWindow::Terminal);
             }
             if ui.button("Profiler").clicked() {
-                self.proxy
-                    .send_event(UserEvent::OpenProfiler(self.sim_id))
-                    .unwrap();
+                self.open(ChildWindow::Profiler { launch: false });
             }
             if ui.button("GDB Server").clicked() {
-                self.proxy
-                    .send_event(UserEvent::OpenDebugger(self.sim_id))
-                    .unwrap();
+                self.open(ChildWindow::Debugger { port: None });
             }
             ui.separator();
             if ui.button("Character Data").clicked() {
-                self.proxy
-                    .send_event(UserEvent::OpenCharacterData(self.sim_id))
-                    .unwrap();
+                self.open(ChildWindow::CharacterData);
             }
             if ui.button("Background Maps").clicked() {
-                self.proxy
-                    .send_event(UserEvent::OpenBgMap(self.sim_id))
-                    .unwrap();
+                self.open(ChildWindow::BgMap);
             }
             if ui.button("Objects").clicked() {
-                self.proxy
-                    .send_event(UserEvent::OpenObjects(self.sim_id))
-                    .unwrap();
+                self.open(ChildWindow::Objects);
             }
             if ui.button("Worlds").clicked() {
-                self.proxy
-                    .send_event(UserEvent::OpenWorlds(self.sim_id))
-                    .unwrap();
+                self.open(ChildWindow::Worlds);
             }
             if ui.button("Frame Buffers").clicked() {
-                self.proxy
-                    .send_event(UserEvent::OpenFrameBuffers(self.sim_id))
-                    .unwrap();
+                self.open(ChildWindow::FrameBuffers);
             }
             if ui.button("Registers").clicked() {
-                self.proxy
-                    .send_event(UserEvent::OpenRegisters(self.sim_id))
-                    .unwrap();
+                self.open(ChildWindow::Registers);
             }
         });
         ui.menu_button("Help", |ui| {
             if ui.button("About").clicked() {
-                self.proxy.send_event(UserEvent::OpenAbout).unwrap();
+                self.open(ChildWindow::About);
             }
         });
     }
@@ -298,10 +480,12 @@ impl GameWindow {
         self.client
             .send_command(EmulatorCommand::Screenshot(self.sim_id, tx));
         let bytes = rx.await.context("Could not take screenshot")?;
-        let file = rfd::FileDialog::new()
+        let file = self
+            .file_picker
+            .save_file_dialog()
             .add_filter("PNG images", &["png"])
             .set_file_name("screenshot.png")
-            .save_file();
+            .open();
         let Some(path) = file else {
             return Ok(None);
         };
@@ -318,7 +502,7 @@ impl GameWindow {
         Ok(Some(path.display().to_string()))
     }
 
-    fn show_options_menu(&mut self, ctx: &Context, ui: &mut Ui) {
+    fn show_options_menu(&mut self, ui: &mut Ui) {
         ui.menu_button("Video", |ui| {
             ui.menu_button("Screen Size", |ui| {
                 let current_dims = self.config.dimensions;
@@ -334,7 +518,7 @@ impl GameWindow {
                         .selectable_button((current_dims - dims).length() < 1.0, label)
                         .clicked()
                     {
-                        ctx.send_viewport_cmd(ViewportCommand::InnerSize(dims));
+                        ui.send_viewport_cmd(ViewportCommand::InnerSize(dims));
                     }
                 }
             });
@@ -364,7 +548,7 @@ impl GameWindow {
                 let new_proportions = display_mode.proportions();
                 let scale = new_proportions / old_proportions;
                 if scale != Vec2::new(1.0, 1.0) {
-                    ctx.send_viewport_cmd(ViewportCommand::InnerSize(current_dims * scale));
+                    ui.send_viewport_cmd(ViewportCommand::InnerSize(current_dims * scale));
                 }
 
                 self.update_config(|c| {
@@ -401,25 +585,56 @@ impl GameWindow {
             });
         });
         ui.menu_button("Audio", |ui| {
-            let p1_enabled = self.client.is_audio_enabled(SimId::Player1);
-            let p2_enabled = self.client.is_audio_enabled(SimId::Player2);
-            if ui.selectable_button(p1_enabled, "Player 1").clicked() {
-                self.client
-                    .send_command(EmulatorCommand::SetAudioEnabled(!p1_enabled, p2_enabled));
-            }
-            if ui.selectable_button(p2_enabled, "Player 2").clicked() {
-                self.client
-                    .send_command(EmulatorCommand::SetAudioEnabled(p1_enabled, !p2_enabled));
+            if ui
+                .selectable_button(self.config.audio_enabled, "Enabled")
+                .clicked()
+            {
+                self.update_config(|c| c.audio_enabled = !c.audio_enabled);
+                self.client.send_command(EmulatorCommand::SetAudioEnabled(
+                    self.sim_id,
+                    self.config.audio_enabled,
+                ));
             }
         });
         ui.menu_button("Input", |ui| {
             if ui.button("Bind Inputs").clicked() {
-                self.proxy.send_event(UserEvent::OpenInput).unwrap();
+                self.open(ChildWindow::Input);
             }
         });
         if ui.button("Hotkeys").clicked() {
-            self.proxy.send_event(UserEvent::OpenHotkeys).unwrap();
+            self.open(ChildWindow::Hotkeys);
         }
+        ui.menu_button("Save Data Location", |ui| {
+            let save_data_location = self.client.save_data_location();
+            let update_save_data_location = |new_location: SaveDataLocation| {
+                if new_location == save_data_location {
+                    return;
+                };
+                let mut app_config = AppConfig::load(&self.persistence);
+                app_config.save_data_location = new_location;
+                let _ = app_config.save(&self.persistence);
+                self.client
+                    .send_command(EmulatorCommand::SetSaveDataLocation(new_location));
+            };
+            if ui
+                .selectable_button(
+                    save_data_location == SaveDataLocation::RomDirectory,
+                    "Same Directory as ROM",
+                )
+                .clicked()
+            {
+                update_save_data_location(SaveDataLocation::RomDirectory);
+            }
+            if ui
+                .selectable_button(
+                    save_data_location == SaveDataLocation::DataDirectory,
+                    "App Data Directory",
+                )
+                .clicked()
+            {
+                update_save_data_location(SaveDataLocation::DataDirectory);
+            }
+        });
     }
 
     fn show_color_picker(&mut self, ui: &mut Ui) {
@@ -451,13 +666,11 @@ impl GameWindow {
         }
     }
 
-    fn update_config(&mut self, update: impl FnOnce(&mut GameConfig)) {
+    fn update_config(&mut self, update: impl FnOnce(&mut SimConfig)) {
         let mut new_config = self.config.clone();
         update(&mut new_config);
         if self.config != new_config {
-            let _ = self
-                .persistence
-                .save_config(config_filename(self.sim_id), &new_config);
+            let _ = new_config.save(&self.persistence, self.sim_id);
         }
         self.config = new_config;
     }
@@ -471,93 +684,142 @@ impl GameWindow {
     }
 }
 
-fn config_filename(sim_id: SimId) -> &'static str {
-    match sim_id {
-        SimId::Player1 => "config_p1",
-        SimId::Player2 => "config_p2",
-    }
-}
-
-fn load_config(persistence: &Persistence, sim_id: SimId) -> GameConfig {
-    if let Ok(config) = persistence.load_config(config_filename(sim_id)) {
-        return config;
-    }
-    GameConfig {
-        display_mode: DisplayMode::Anaglyph,
-        colors: COLOR_PRESETS[0],
-        dimensions: DisplayMode::Anaglyph.proportions() + Vec2::new(0.0, 22.0),
-    }
-}
-
 impl AppWindow for GameWindow {
-    fn viewport_id(&self) -> ViewportId {
-        match self.sim_id {
-            SimId::Player1 => ViewportId::ROOT,
-            SimId::Player2 => ViewportId::from_hash_of("Player2"),
-        }
-    }
-
-    fn sim_id(&self) -> SimId {
-        self.sim_id
+    fn sim_id(&self) -> Option<SimId> {
+        Some(self.sim_id)
     }
 
     fn initial_viewport(&self) -> ViewportBuilder {
-        ViewportBuilder::default()
+        let builder = ViewportBuilder::default()
             .with_title("Lemur")
-            .with_inner_size(self.config.dimensions)
+            .with_inner_size(self.config.dimensions);
+        if let Some(position) = self.config.position {
+            builder.with_position(position)
+        } else {
+            builder
+        }
     }
 
-    fn show(&mut self, ctx: &Context) {
+    fn show(&mut self, ui: &mut Ui) {
+        let has_player_2 = self.client.has_player_2();
+        if !self.show_player_name && has_player_2 {
+            ui.send_viewport_cmd(ViewportCommand::Title(format!("Lemur ({})", self.sim_id)));
+            for (viewport_id, child) in &self.children {
+                if let Some(sim_id) = child.sim_id {
+                    ui.send_viewport_cmd_to(
+                        *viewport_id,
+                        ViewportCommand::Title(format!("{} ({sim_id})", child.title)),
+                    );
+                }
+            }
+            self.show_player_name = true;
+        } else if self.show_player_name && !has_player_2 {
+            ui.send_viewport_cmd(ViewportCommand::Title("Lemur".to_string()));
+            for (viewport_id, child) in &self.children {
+                if child.sim_id.is_some() {
+                    ui.send_viewport_cmd_to(
+                        *viewport_id,
+                        ViewportCommand::Title(child.title.clone()),
+                    );
+                }
+            }
+            self.show_player_name = false;
+        }
+        self.child_states.load(ui);
         let dimensions = {
-            let bounds = ctx.available_rect();
+            let bounds = ui.content_rect();
             bounds.max - bounds.min
         };
-        self.update_config(|c| c.dimensions = dimensions);
+        let position = ui.input(|i| i.viewport().outer_rect.map(|r| r.min));
+        self.update_config(|c| {
+            c.dimensions = dimensions;
+            c.position = position;
+        });
 
-        if let Some(messages) = self.messages.as_mut() {
-            while let Ok(toast) = messages.try_recv() {
-                self.toasts.add(toast);
-            }
+        while let Ok(toast) = self.messages.try_recv() {
+            self.toasts.add(toast);
         }
-        TopBottomPanel::top("menubar")
-            .exact_height(22.0)
-            .show(ctx, |ui| {
-                MenuBar::new().ui(ui, |ui| {
-                    self.show_menu(ctx, ui);
-                });
+        Panel::top("menubar").exact_size(22.0).show(ui, |ui| {
+            MenuBar::new().ui(ui, |ui| {
+                self.show_menu(ui);
             });
+        });
         if self.color_picker.is_some() {
             Window::new("Color Picker")
                 .title_bar(false)
                 .resizable(false)
                 .anchor(Align2::CENTER_CENTER, Vec2::ZERO)
-                .show(ctx, |ui| {
+                .show(ui, |ui| {
                     self.show_color_picker(ui);
                 });
         }
-        let frame = Frame::central_panel(&ctx.style()).fill(Color32::BLACK);
-        CentralPanel::default().frame(frame).show(ctx, |ui| {
+        let frame = Frame::central_panel(ui.style()).fill(Color32::BLACK);
+        CentralPanel::default().frame(frame).show(ui, |ui| {
             if let Some(screen) = self.screen.as_mut() {
                 screen.update(self.config.display_mode, self.config.colors);
                 ui.add(screen);
             }
         });
-        self.toasts.show(ctx);
+        self.toasts.show(ui);
+        for window in std::mem::take(&mut self.queued_children) {
+            self.do_open(window);
+        }
+        self.children.retain(|id, child| {
+            if child
+                .close_requested
+                .load(std::sync::atomic::Ordering::Relaxed)
+            {
+                return false;
+            }
+            let app = child.app.clone();
+            let viewport_builder = child.updates.take().unwrap_or_default();
+            let close_requested = child.close_requested.clone();
+            if let (Some(outer), Some(inner)) = ui.input_for(*id, |inp| {
+                let viewport = inp.viewport();
+                (viewport.outer_rect, viewport.inner_rect)
+            }) {
+                self.child_states.insert(
+                    *id,
+                    ChildState {
+                        position: outer.min,
+                        size: inner.size(),
+                    },
+                );
+            }
+            ui.show_viewport_deferred(*id, viewport_builder, move |ui, _| {
+                app.lock().unwrap().show(ui);
+                if ui.input(|s| s.viewport().close_requested()) {
+                    close_requested.store(true, std::sync::atomic::Ordering::Relaxed);
+                }
+            });
+            true
+        });
+        self.child_states.save(ui);
+        ui.request_repaint_after(Duration::from_millis(10));
     }
 
-    fn on_init(&mut self, _ctx: &Context, render_state: &egui_wgpu::RenderState) {
-        let (screen, sink) = GameScreen::init(render_state);
-        let (message_sink, message_source) = mpsc::channel();
-        self.client.send_command(EmulatorCommand::ConnectToSim(
-            self.sim_id,
-            sink,
-            message_sink,
-        ));
-        self.screen = Some(screen);
-        self.messages = Some(message_source);
+    fn on_init(&mut self, args: InitArgs) {
+        if self.screen.is_none() {
+            let (screen, sink) = GameScreen::init(args.render_state);
+            self.client.send_command(EmulatorCommand::ConnectToSim(
+                self.sim_id,
+                sink,
+                self.message_sink.clone(),
+            ));
+            self.screen = Some(screen);
+        }
+        self.file_picker.set_window(args.window);
     }
 
-    fn on_destroy(&mut self) {
+    fn handle_dropped_file(&mut self, path: PathBuf) -> bool {
+        self.client
+            .send_command(EmulatorCommand::LoadGame(self.sim_id, path));
+        true
+    }
+}
+
+impl Drop for GameWindow {
+    fn drop(&mut self) {
         if self.sim_id == SimId::Player2 {
             self.client.send_command(EmulatorCommand::StopSecondSim);
         }
@@ -571,9 +833,84 @@ struct ColorPickerState {
     unpause_on_close: bool,
 }
 
-#[derive(Serialize, Deserialize, Clone, PartialEq, Eq)]
-struct GameConfig {
-    display_mode: DisplayMode,
-    colors: [Color32; 2],
-    dimensions: Vec2,
+struct ChildWindowWrapper {
+    app: Arc<Mutex<AppWrapper>>,
+    title: String,
+    sim_id: Option<SimId>,
+    updates: Option<ViewportBuilder>,
+    close_requested: Arc<AtomicBool>,
+}
+enum AppWrapper {
+    Game(Box<GameWindow>),
+    Dyn(Box<dyn AppWindow + Send + 'static>),
+}
+impl AppWrapper {
+    fn of_game(game: GameWindow) -> Self {
+        Self::Game(Box::new(game))
+    }
+    fn of_dyn<T: AppWindow + Send + 'static>(inner: T) -> Self {
+        Self::Dyn(Box::new(inner))
+    }
+}
+impl Deref for AppWrapper {
+    type Target = dyn AppWindow + Send + 'static;
+    fn deref(&self) -> &Self::Target {
+        match self {
+            Self::Dyn(inner) => inner.as_ref(),
+            Self::Game(inner) => inner.as_ref(),
+        }
+    }
+}
+impl DerefMut for AppWrapper {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        match self {
+            Self::Dyn(inner) => inner.as_mut(),
+            Self::Game(inner) => inner.as_mut(),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum ChildWindow {
+    About,
+    CharacterData,
+    BgMap,
+    Objects,
+    Worlds,
+    FrameBuffers,
+    Registers,
+    Terminal,
+    Profiler { launch: bool },
+    Debugger { port: Option<u16> },
+    Input,
+    Hotkeys,
+    Player2,
+}
+impl ChildWindow {
+    fn viewport_id(&self, sim_id: SimId) -> ViewportId {
+        ViewportId::from_hash_of(format!("{sim_id:?}{}", self.name()))
+    }
+    fn name(&self) -> &'static str {
+        match self {
+            Self::About => "About",
+            Self::CharacterData => "CharacterData",
+            Self::BgMap => "BgMap",
+            Self::Objects => "Objects",
+            Self::Worlds => "Worlds",
+            Self::FrameBuffers => "FrameBuffers",
+            Self::Registers => "Registers",
+            Self::Terminal => "Terminal",
+            Self::Profiler { .. } => "Profiler",
+            Self::Debugger { .. } => "Debugger",
+            Self::Input => "Input",
+            Self::Hotkeys => "Hotkeys",
+            Self::Player2 => "Player2",
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+struct ChildState {
+    position: Pos2,
+    size: Vec2,
 }

src/window/game_screen.rs

@@ -14,7 +14,7 @@ pub struct GameScreen {
 }
 
 impl GameScreen {
-    fn init_pipeline(render_state: &egui_wgpu::RenderState) {
+    pub fn init_pipeline(render_state: &egui_wgpu::RenderState) {
         let device = &render_state.device;
 
         let bind_group_layout = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
@@ -53,8 +53,8 @@ impl GameScreen {
         let render_pipeline_layout =
             device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
                 label: Some("render pipeline layout"),
-                bind_group_layouts: &[&bind_group_layout],
-                push_constant_ranges: &[],
+                bind_group_layouts: &[Some(&bind_group_layout)],
+                immediate_size: 0,
             });
 
         let create_render_pipeline = |entry_point: &str| {
@@ -92,7 +92,7 @@ impl GameScreen {
                     mask: !0,
                     alpha_to_coverage_enabled: false,
                 },
-                multiview: None,
+                multiview_mask: None,
                 cache: None,
             })
         };
@@ -117,8 +117,6 @@ impl GameScreen {
     }
 
     pub fn init(render_state: &egui_wgpu::RenderState) -> (Self, TextureSink) {
-        Self::init_pipeline(render_state);
-
         let device = &render_state.device;
         let queue = &render_state.queue;
 

src/window/gdb.rs

@@ -1,4 +1,4 @@
-use egui::{Button, CentralPanel, TextEdit, ViewportBuilder, ViewportId};
+use egui::{Button, CentralPanel, TextEdit, ViewportBuilder};
 use winit::event_loop::EventLoopProxy;
 
 use crate::{
@@ -42,24 +42,20 @@ impl GdbServerWindow {
 }
 
 impl AppWindow for GdbServerWindow {
-    fn viewport_id(&self) -> ViewportId {
-        ViewportId::from_hash_of(format!("Debugger-{}", self.sim_id))
-    }
-
-    fn sim_id(&self) -> SimId {
-        self.sim_id
+    fn sim_id(&self) -> Option<SimId> {
+        Some(self.sim_id)
     }
 
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
-            .with_title(format!("GDB Server ({})", self.sim_id))
+            .with_title("GDB Server")
             .with_inner_size((300.0, 200.0))
     }
 
-    fn show(&mut self, ctx: &egui::Context) {
+    fn show(&mut self, ui: &mut egui::Ui) {
         let port_num: Option<u16> = self.port_str.parse().ok();
         let status = self.server.status();
-        CentralPanel::default().show(ctx, |ui| {
+        CentralPanel::default().show(ui, |ui| {
             ui.horizontal(|ui| {
                 if port_num.is_none() {
                     let style = ui.style_mut();

src/window/hotkeys.rs

@@ -1,6 +1,5 @@
 use egui::{
-    Button, CentralPanel, Context, Event, KeyboardShortcut, Label, Layout, Slider, Ui,
-    ViewportBuilder, ViewportId,
+    Button, CentralPanel, Event, KeyboardShortcut, Label, Layout, Slider, Ui, ViewportBuilder,
 };
 use egui_extras::{Column, TableBuilder};
 
@@ -125,18 +124,14 @@ impl HotkeysWindow {
 }
 
 impl AppWindow for HotkeysWindow {
-    fn viewport_id(&self) -> ViewportId {
-        ViewportId::from_hash_of("shortcuts")
-    }
-
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
             .with_title("Keyboard Shortcuts")
             .with_inner_size((400.0, 400.0))
     }
 
-    fn show(&mut self, ctx: &Context) {
-        CentralPanel::default().show(ctx, |ui| {
+    fn show(&mut self, ui: &mut Ui) {
+        CentralPanel::default().show(ui, |ui| {
             ui.horizontal(|ui| {
                 if ui.button("Use defaults").clicked() {
                     self.shortcuts.reset();

src/window/input.rs

@@ -1,6 +1,4 @@
-use egui::{
-    Button, CentralPanel, Context, Label, Layout, TopBottomPanel, Ui, ViewportBuilder, ViewportId,
-};
+use egui::{Button, CentralPanel, Label, Layout, Panel, Ui, ViewportBuilder};
 use egui_extras::{Column, TableBuilder};
 use gilrs::{EventType, GamepadId};
 use std::sync::RwLock;
@@ -72,7 +70,7 @@ impl InputWindow {
             .column(Column::remainder())
             .cell_layout(Layout::left_to_right(egui::Align::Center))
             .body(|mut body| {
-                for keys in KEY_NAMES.chunks_exact(2) {
+                for keys in KEY_NAMES.as_chunks::<2>().0 {
                     body.row(20.0, |mut row| {
                         for (key, name) in keys {
                             let binding = names.remove(key).map(|mut s| {
@@ -162,18 +160,14 @@ impl InputWindow {
 }
 
 impl AppWindow for InputWindow {
-    fn viewport_id(&self) -> ViewportId {
-        ViewportId::from_hash_of("input")
-    }
-
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
             .with_title("Bind Inputs")
             .with_inner_size((600.0, 400.0))
     }
 
-    fn show(&mut self, ctx: &Context) {
-        TopBottomPanel::top("options").show(ctx, |ui| {
+    fn show(&mut self, ui: &mut Ui) {
+        Panel::top("options").show(ui, |ui| {
             ui.horizontal(|ui| {
                 let old_active_tab = self.active_tab;
                 ui.selectable_value(&mut self.active_tab, InputTab::Player1, "Player 1");
@@ -188,7 +182,7 @@ impl AppWindow for InputWindow {
                 }
             });
         });
-        CentralPanel::default().show(ctx, |ui| {
+        CentralPanel::default().show(ui, |ui| {
             match self.active_tab {
                 InputTab::Player1 => self.show_key_bindings(ui, SimId::Player1),
                 InputTab::Player2 => self.show_key_bindings(ui, SimId::Player2),

src/window/profile.rs

@@ -1,13 +1,14 @@
 use std::{fs, time::Duration};
 
 use anyhow::Result;
-use egui::{Button, CentralPanel, Checkbox, Label, ViewportBuilder, ViewportId};
+use egui::{Button, CentralPanel, Checkbox, Label, ViewportBuilder};
 use egui_notify::{Anchor, Toast, Toasts};
 
 use crate::{
     emulator::{EmulatorClient, EmulatorCommand, EmulatorState, SimId},
+    filepicker::FilePicker,
     profiler::{Profiler, ProfilerStatus},
-    window::AppWindow,
+    window::{AppWindow, InitArgs},
 };
 
 pub struct ProfileWindow {
@@ -15,6 +16,7 @@ pub struct ProfileWindow {
     client: EmulatorClient,
     profiler: Profiler,
     toasts: Toasts,
+    file_picker: FilePicker,
 }
 
 impl ProfileWindow {
@@ -27,6 +29,7 @@ impl ProfileWindow {
                 .with_anchor(Anchor::BottomLeft)
                 .with_margin((10.0, 10.0).into())
                 .reverse(true),
+            file_picker: FilePicker::new(),
         }
     }
 
@@ -59,12 +62,15 @@ impl ProfileWindow {
 
     fn try_finish_recording(&mut self) -> Result<Option<String>> {
         let bytes_receiver = self.profiler.finish_recording();
-        let file = rfd::FileDialog::new()
+        let file = self
+            .file_picker
+            .save_file_dialog()
             .add_filter("Profiler files", &["json"])
             .set_file_name("profile.json")
-            .save_file();
+            .open();
         if let Some(path) = file {
             let bytes = pollster::block_on(bytes_receiver)?;
+            let _ = fs::remove_file(&path);
             fs::write(&path, bytes)?;
             Ok(Some(path.display().to_string()))
         } else {
@@ -75,24 +81,20 @@ impl ProfileWindow {
 }
 
 impl AppWindow for ProfileWindow {
-    fn viewport_id(&self) -> ViewportId {
-        ViewportId::from_hash_of(format!("Profile-{}", self.sim_id))
-    }
-
-    fn sim_id(&self) -> SimId {
-        self.sim_id
+    fn sim_id(&self) -> Option<SimId> {
+        Some(self.sim_id)
     }
 
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
-            .with_title(format!("Profiler ({})", self.sim_id))
+            .with_title("Profiler")
             .with_inner_size((300.0, 200.0))
     }
 
-    fn show(&mut self, ctx: &egui::Context) {
+    fn show(&mut self, ui: &mut egui::Ui) {
         let status = self.profiler.status();
         let recording = matches!(status, ProfilerStatus::Recording);
-        CentralPanel::default().show(ctx, |ui| {
+        CentralPanel::default().show(ui, |ui| {
             ui.horizontal_wrapped(|ui| {
                 ui.spacing_mut().item_spacing.x = 0.0;
                 ui.add(
@@ -157,6 +159,10 @@ impl AppWindow for ProfileWindow {
                 _ => {}
             }
         });
-        self.toasts.show(ctx);
+        self.toasts.show(ui);
+    }
+
+    fn on_init(&mut self, args: InitArgs) {
+        self.file_picker.set_window(args.window);
     }
 }

src/window/terminal.rs

@@ -1,9 +1,6 @@
 use std::{collections::VecDeque, sync::mpsc};
 
-use egui::{
-    Align, CentralPanel, Context, FontFamily, Label, RichText, ScrollArea, ViewportBuilder,
-    ViewportId,
-};
+use egui::{Align, CentralPanel, FontFamily, Label, RichText, ScrollArea, Ui, ViewportBuilder};
 
 use crate::emulator::{EmulatorClient, EmulatorCommand, SimId};
 
@@ -32,21 +29,17 @@ impl TerminalWindow {
 }
 
 impl AppWindow for TerminalWindow {
-    fn viewport_id(&self) -> ViewportId {
-        ViewportId::from_hash_of(format!("terminal-{}", self.sim_id))
-    }
-
-    fn sim_id(&self) -> SimId {
-        self.sim_id
+    fn sim_id(&self) -> Option<SimId> {
+        Some(self.sim_id)
     }
 
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
-            .with_title(format!("Terminal ({})", self.sim_id))
+            .with_title("Terminal")
             .with_inner_size((640.0, 480.0))
     }
 
-    fn show(&mut self, ctx: &Context) {
+    fn show(&mut self, ui: &mut Ui) {
         if let Ok(text) = self.receiver.try_recv() {
             let mut rest = text.as_str();
             while let Some(index) = rest.find('\n') {
@@ -61,7 +54,7 @@ impl AppWindow for TerminalWindow {
             }
             self.lines.back_mut().unwrap().push_str(rest);
         }
-        CentralPanel::default().show(ctx, |ui| {
+        CentralPanel::default().show(ui, |ui| {
             ScrollArea::vertical()
                 .stick_to_bottom(true)
                 .auto_shrink([false, false])

src/window/utils.rs

@@ -1,6 +1,6 @@
 use std::{
     fmt::{Display, UpperHex},
-    ops::{Bound, RangeBounds},
+    ops::{AddAssign, Bound, Deref, DerefMut, MulAssign, RangeBounds},
     str::FromStr,
 };
 
@@ -8,9 +8,9 @@ use atoi::FromRadix16;
 use egui::{
     Align, Color32, CornerRadius, CursorIcon, Event, Frame, Key, Layout, Margin, Rect, Response,
     RichText, Sense, Shape, Stroke, StrokeKind, TextEdit, Ui, UiBuilder, Vec2, Widget, WidgetText,
-    ecolor::HexColor,
+    ecolor::HexColor, util::id_type_map::SerializableAny,
 };
-use num_traits::{CheckedAdd, CheckedSub, One};
+use num_traits::{CheckedAdd, CheckedSub, One, Zero};
 
 pub trait UiExt {
     fn section(&mut self, title: impl Into<String>, add_contents: impl FnOnce(&mut Ui));
@@ -105,14 +105,16 @@ enum Direction {
 
 pub trait Number:
     Copy
+    + Zero
     + One
+    + AddAssign
+    + MulAssign
     + CheckedAdd
     + CheckedSub
     + Eq
     + Ord
     + Display
     + FromStr
-    + FromRadix16
     + UpperHex
     + Send
     + Sync
@@ -121,14 +123,16 @@ pub trait Number:
 }
 impl<
     T: Copy
+        + Zero
         + One
+        + AddAssign
+        + MulAssign
         + CheckedAdd
         + CheckedSub
         + Eq
         + Ord
         + Display
         + FromStr
-        + FromRadix16
         + UpperHex
         + Send
         + Sync
@@ -209,8 +213,8 @@ impl<T: Number> Widget for NumberEdit<'_, T> {
         let from_string = |val: &str| {
             if self.hex {
                 let bytes = val.as_bytes();
-                let (result, consumed) = T::from_radix_16(bytes);
-                (consumed == bytes.len()).then_some(result)
+                let (result, consumed) = atoi::Integer::<T>::from_radix_16(bytes);
+                (consumed == bytes.len()).then_some(result.0)
             } else {
                 val.parse::<T>().ok()
             }
@@ -409,3 +413,51 @@ impl ResponseExt for Response {
         self.clicked() || self.dragged()
     }
 }
+
+pub struct UiData<T> {
+    current: T,
+    prev: T,
+    loaded: bool,
+}
+
+impl<T> UiData<T>
+where
+    T: Default + PartialEq + SerializableAny,
+{
+    pub fn new() -> Self {
+        Self {
+            current: T::default(),
+            prev: T::default(),
+            loaded: false,
+        }
+    }
+
+    pub fn load(&mut self, ui: &Ui) {
+        if !self.loaded {
+            self.current = ui
+                .data_mut(|d| d.get_persisted(ui.id()))
+                .unwrap_or_default();
+            self.loaded = true;
+        }
+    }
+
+    pub fn save(&mut self, ui: &Ui) {
+        if self.current != self.prev {
+            ui.data_mut(|d| d.insert_persisted(ui.id(), self.current.clone()));
+            self.prev = self.current.clone();
+        }
+    }
+}
+
+impl<T> Deref for UiData<T> {
+    type Target = T;
+    fn deref(&self) -> &Self::Target {
+        &self.current
+    }
+}
+
+impl<T> DerefMut for UiData<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.current
+    }
+}

src/window/vip/bgmap.rs

@@ -1,53 +1,70 @@
 use std::sync::Arc;
 
 use egui::{
-    Align, CentralPanel, Checkbox, Color32, ComboBox, Context, Image, ScrollArea, Slider, TextEdit,
-    TextureOptions, Ui, ViewportBuilder, ViewportId,
+    Align, CentralPanel, Checkbox, Color32, ComboBox, Image, ScrollArea, Slider, TextEdit,
+    TextureOptions, Ui, ViewportBuilder,
 };
 use egui_extras::{Column, Size, StripBuilder, TableBuilder};
+use serde::{Deserialize, Serialize};
 
 use crate::{
     emulator::SimId,
-    images::{ImageBuffer, ImageParams, ImageProcessor, ImageRenderer, ImageTextureLoader},
+    images::{ImageBuffer, ImageParams, ImageRenderer, ImageTextureLoader},
     memory::{MemoryClient, MemoryView},
     window::{
         AppWindow,
-        utils::{NumberEdit, UiExt},
+        utils::{NumberEdit, UiData, UiExt},
     },
 };
 
 use super::utils::{self, CellData, CharacterGrid};
 
-pub struct BgMapWindow {
-    sim_id: SimId,
-    loader: Arc<ImageTextureLoader>,
-    memory: Arc<MemoryClient>,
-    bgmaps: MemoryView,
+#[derive(Clone, PartialEq, Serialize, Deserialize)]
+struct State {
     cell_index: usize,
     generic_palette: bool,
-    params: ImageParams<BgMapParams>,
     scale: f32,
     show_grid: bool,
 }
-
-impl BgMapWindow {
-    pub fn new(sim_id: SimId, memory: &Arc<MemoryClient>, images: &mut ImageProcessor) -> Self {
-        let renderer = BgMapRenderer::new(sim_id, memory);
-        let ([cell, bgmap], params) = images.add(renderer, BgMapParams::default());
-        let loader =
-            ImageTextureLoader::new([("vip://cell".into(), cell), ("vip://bgmap".into(), bgmap)]);
+impl Default for State {
+    fn default() -> Self {
         Self {
-            sim_id,
-            loader: Arc::new(loader),
-            memory: memory.clone(),
-            bgmaps: memory.watch(sim_id, 0x00020000, 0x20000),
-            cell_index: params.cell_index,
-            generic_palette: params.generic_palette,
-            params,
+            cell_index: 0,
+            generic_palette: false,
             scale: 1.0,
             show_grid: false,
         }
     }
+}
+
+pub struct BgMapWindow {
+    sim_id: SimId,
+    memory: Arc<MemoryClient>,
+    bgmaps: MemoryView,
+    params: ImageParams<BgMapParams>,
+    state: UiData<State>,
+}
+
+impl BgMapWindow {
+    pub fn new(sim_id: SimId, memory: &Arc<MemoryClient>, images: &ImageTextureLoader) -> Self {
+        let state: UiData<State> = UiData::new();
+        let renderer = BgMapRenderer::new(sim_id, memory);
+        let params = images.add(
+            sim_id,
+            renderer,
+            BgMapParams {
+                cell_index: state.cell_index,
+                generic_palette: state.generic_palette,
+            },
+        );
+        Self {
+            sim_id,
+            memory: memory.clone(),
+            bgmaps: memory.watch(sim_id, 0x00020000, 0x20000),
+            params,
+            state,
+        }
+    }
 
     fn show_form(&mut self, ui: &mut Ui) {
         let row_height = ui.spacing().interact_size.y;
@@ -61,10 +78,11 @@ impl BgMapWindow {
                             ui.label("Map");
                         });
                         row.col(|ui| {
-                            let mut bgmap_index = self.cell_index / 4096;
+                            let mut bgmap_index = self.state.cell_index / 4096;
                             ui.add(NumberEdit::new(&mut bgmap_index).range(0..16));
-                            if bgmap_index != self.cell_index / 4096 {
-                                self.cell_index = (bgmap_index * 4096) + (self.cell_index % 4096);
+                            if bgmap_index != self.state.cell_index / 4096 {
+                                self.state.cell_index =
+                                    (bgmap_index * 4096) + (self.state.cell_index % 4096);
                             }
                         });
                     });
@@ -73,7 +91,7 @@ impl BgMapWindow {
                             ui.label("Cell");
                         });
                         row.col(|ui| {
-                            ui.add(NumberEdit::new(&mut self.cell_index).range(0..16 * 4096));
+                            ui.add(NumberEdit::new(&mut self.state.cell_index).range(0..16 * 4096));
                         });
                     });
                     body.row(row_height, |mut row| {
@@ -81,7 +99,7 @@ impl BgMapWindow {
                             ui.label("Address");
                         });
                         row.col(|ui| {
-                            let address = 0x00020000 + (self.cell_index * 2);
+                            let address = 0x00020000 + (self.state.cell_index * 2);
                             let mut address_str = format!("{address:08x}");
                             ui.add_enabled(
                                 false,
@@ -90,12 +108,12 @@ impl BgMapWindow {
                         });
                     });
                 });
-            let image = Image::new("vip://cell")
+            let image = Image::new(self.image_url("bgmap-cell"))
                 .maintain_aspect_ratio(true)
                 .texture_options(TextureOptions::NEAREST);
             ui.add(image);
             ui.section("Cell", |ui| {
-                let mut data = self.bgmaps.borrow().read::<u16>(self.cell_index);
+                let mut data = self.bgmaps.borrow().read::<u16>(self.state.cell_index);
                 let mut cell = CellData::parse(data);
                 TableBuilder::new(ui)
                     .column(Column::remainder())
@@ -138,7 +156,7 @@ impl BgMapWindow {
                         });
                     });
                 if cell.update(&mut data) {
-                    let address = 0x00020000 + (self.cell_index * 2);
+                    let address = 0x00020000 + (self.state.cell_index * 2);
                     self.memory.write(self.sim_id, address as u32, &data);
                 }
             });
@@ -146,53 +164,46 @@ impl BgMapWindow {
                 ui.horizontal(|ui| {
                     ui.label("Scale");
                     ui.spacing_mut().slider_width = ui.available_width();
-                    let slider = Slider::new(&mut self.scale, 1.0..=10.0)
+                    let slider = Slider::new(&mut self.state.scale, 1.0..=10.0)
                         .step_by(1.0)
                         .show_value(false);
                     ui.add(slider);
                 });
-                ui.checkbox(&mut self.show_grid, "Show grid");
-                ui.checkbox(&mut self.generic_palette, "Generic palette");
+                ui.checkbox(&mut self.state.show_grid, "Show grid");
+                ui.checkbox(&mut self.state.generic_palette, "Generic palette");
             });
         });
         self.params.write(BgMapParams {
-            cell_index: self.cell_index,
-            generic_palette: self.generic_palette,
+            cell_index: self.state.cell_index,
+            generic_palette: self.state.generic_palette,
         });
     }
 
     fn show_bgmap(&mut self, ui: &mut Ui) {
-        let grid = CharacterGrid::new("vip://bgmap")
-            .with_scale(self.scale)
-            .with_grid(self.show_grid)
-            .with_selected(self.cell_index % 4096);
+        let grid = CharacterGrid::new(self.image_url("bgmap"))
+            .with_scale(self.state.scale)
+            .with_grid(self.state.show_grid)
+            .with_selected(self.state.cell_index % 4096);
         if let Some(selected) = grid.show(ui) {
-            self.cell_index = (self.cell_index / 4096 * 4096) + selected;
+            self.state.cell_index = (self.state.cell_index / 4096 * 4096) + selected;
         }
     }
 }
 
 impl AppWindow for BgMapWindow {
-    fn viewport_id(&self) -> ViewportId {
-        ViewportId::from_hash_of(format!("bgmap-{}", self.sim_id))
-    }
-
-    fn sim_id(&self) -> SimId {
-        self.sim_id
+    fn sim_id(&self) -> Option<SimId> {
+        Some(self.sim_id)
     }
 
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
-            .with_title(format!("BG Map Data ({})", self.sim_id))
+            .with_title("BG Map Data")
             .with_inner_size((640.0, 480.0))
     }
 
-    fn on_init(&mut self, ctx: &Context, _render_state: &egui_wgpu::RenderState) {
-        ctx.add_texture_loader(self.loader.clone());
-    }
-
-    fn show(&mut self, ctx: &Context) {
-        CentralPanel::default().show(ctx, |ui| {
+    fn show(&mut self, ui: &mut Ui) {
+        self.state.load(ui);
+        CentralPanel::default().show(ui, |ui| {
             ui.horizontal_top(|ui| {
                 StripBuilder::new(ui)
                     .size(Size::relative(0.3).at_most(200.0))
@@ -207,6 +218,7 @@ impl AppWindow for BgMapWindow {
                     })
             });
         });
+        self.state.save(ui);
     }
 }
 
@@ -300,6 +312,10 @@ impl BgMapRenderer {
 impl ImageRenderer<2> for BgMapRenderer {
     type Params = BgMapParams;
 
+    fn names(&self) -> [&str; 2] {
+        ["bgmap-cell", "bgmap"]
+    }
+
     fn sizes(&self) -> [[usize; 2]; 2] {
         [[8, 8], [8 * 64, 8 * 64]]
     }

src/window/vip/chardata.rs

@@ -1,19 +1,19 @@
-use std::{fmt::Display, sync::Arc};
+use std::fmt::Display;
 
 use egui::{
-    Align, CentralPanel, Color32, ComboBox, Context, Image, ScrollArea, Slider, TextEdit,
-    TextureOptions, Ui, Vec2, ViewportBuilder, ViewportId,
+    Align, CentralPanel, Color32, ComboBox, Image, ScrollArea, Slider, TextEdit, TextureOptions,
+    Ui, Vec2, ViewportBuilder,
 };
 use egui_extras::{Column, Size, StripBuilder, TableBuilder};
 use serde::{Deserialize, Serialize};
 
 use crate::{
     emulator::SimId,
-    images::{ImageBuffer, ImageParams, ImageProcessor, ImageRenderer, ImageTextureLoader},
+    images::{ImageBuffer, ImageParams, ImageRenderer, ImageTextureLoader},
     memory::{MemoryClient, MemoryView},
     window::{
         AppWindow,
-        utils::{NumberEdit, UiExt as _},
+        utils::{NumberEdit, UiData, UiExt as _},
     },
 };
 
@@ -79,38 +79,52 @@ impl Display for Palette {
     }
 }
 
-pub struct CharacterDataWindow {
-    sim_id: SimId,
-    loader: Arc<ImageTextureLoader>,
-    brightness: MemoryView,
-    palettes: MemoryView,
+#[derive(Clone, PartialEq, Serialize, Deserialize)]
+struct State {
     palette: Palette,
     index: usize,
-    params: ImageParams<CharDataParams>,
     scale: f32,
     show_grid: bool,
 }
-
-impl CharacterDataWindow {
-    pub fn new(sim_id: SimId, memory: &MemoryClient, images: &mut ImageProcessor) -> Self {
-        let renderer = CharDataRenderer::new(sim_id, memory);
-        let ([char, chardata], params) = images.add(renderer, CharDataParams::default());
-        let loader = ImageTextureLoader::new([
-            ("vip://char".into(), char),
-            ("vip://chardata".into(), chardata),
-        ]);
+impl Default for State {
+    fn default() -> Self {
         Self {
-            sim_id,
-            loader: Arc::new(loader),
-            brightness: memory.watch(sim_id, 0x0005f824, 8),
-            palettes: memory.watch(sim_id, 0x0005f860, 16),
-            palette: params.palette,
-            index: params.index,
-            params,
+            palette: Palette::default(),
+            index: 0,
             scale: 4.0,
             show_grid: true,
         }
     }
+}
+
+pub struct CharacterDataWindow {
+    sim_id: SimId,
+    brightness: MemoryView,
+    palettes: MemoryView,
+    params: ImageParams<CharDataParams>,
+    state: UiData<State>,
+}
+
+impl CharacterDataWindow {
+    pub fn new(sim_id: SimId, memory: &MemoryClient, images: &ImageTextureLoader) -> Self {
+        let state: UiData<State> = UiData::new();
+        let renderer = CharDataRenderer::new(sim_id, memory);
+        let params = images.add(
+            sim_id,
+            renderer,
+            CharDataParams {
+                palette: state.palette,
+                index: state.index,
+            },
+        );
+        Self {
+            sim_id,
+            brightness: memory.watch(sim_id, 0x0005f824, 8),
+            palettes: memory.watch(sim_id, 0x0005f860, 16),
+            params,
+            state,
+        }
+    }
 
     fn show_form(&mut self, ui: &mut Ui) {
         let row_height = ui.spacing().interact_size.y;
@@ -124,7 +138,7 @@ impl CharacterDataWindow {
                             ui.label("Index");
                         });
                         row.col(|ui| {
-                            ui.add(NumberEdit::new(&mut self.index).range(0..2048));
+                            ui.add(NumberEdit::new(&mut self.state.index).range(0..2048));
                         });
                     });
                     body.row(row_height, |mut row| {
@@ -132,11 +146,11 @@ impl CharacterDataWindow {
                             ui.label("Address");
                         });
                         row.col(|ui| {
-                            let address = match self.index {
-                                0x000..0x200 => 0x00060000 + self.index * 16,
-                                0x200..0x400 => 0x000e0000 + (self.index - 0x200) * 16,
-                                0x400..0x600 => 0x00160000 + (self.index - 0x400) * 16,
-                                0x600..0x800 => 0x001e0000 + (self.index - 0x600) * 16,
+                            let address = match self.state.index {
+                                0x000..0x200 => 0x00060000 + self.state.index * 16,
+                                0x200..0x400 => 0x000e0000 + (self.state.index - 0x200) * 16,
+                                0x400..0x600 => 0x00160000 + (self.state.index - 0x400) * 16,
+                                0x600..0x800 => 0x001e0000 + (self.state.index - 0x600) * 16,
                                 _ => unreachable!("can't happen"),
                             };
                             let mut address_str = format!("{address:08x}");
@@ -151,7 +165,7 @@ impl CharacterDataWindow {
                             ui.label("Mirror");
                         });
                         row.col(|ui| {
-                            let mirror = 0x00078000 + (self.index * 16);
+                            let mirror = 0x00078000 + (self.state.index * 16);
                             let mut mirror_str = format!("{mirror:08x}");
                             ui.add_enabled(
                                 false,
@@ -160,7 +174,7 @@ impl CharacterDataWindow {
                         });
                     });
                 });
-            let image = Image::new("vip://char")
+            let image = Image::new(self.image_url("chardata-char"))
                 .maintain_aspect_ratio(true)
                 .texture_options(TextureOptions::NEAREST);
             ui.add(image);
@@ -168,12 +182,12 @@ impl CharacterDataWindow {
                 ui.horizontal(|ui| {
                     ui.label("Palette");
                     ComboBox::from_id_salt("palette")
-                        .selected_text(self.palette.to_string())
+                        .selected_text(self.state.palette.to_string())
                         .width(ui.available_width())
                         .show_ui(ui, |ui| {
                             for palette in Palette::values() {
                                 ui.selectable_value(
-                                    &mut self.palette,
+                                    &mut self.state.palette,
                                     palette,
                                     palette.to_string(),
                                 );
@@ -200,23 +214,23 @@ impl CharacterDataWindow {
                 ui.horizontal(|ui| {
                     ui.label("Scale");
                     ui.spacing_mut().slider_width = ui.available_width();
-                    let slider = Slider::new(&mut self.scale, 1.0..=10.0)
+                    let slider = Slider::new(&mut self.state.scale, 1.0..=10.0)
                         .step_by(1.0)
                         .show_value(false);
                     ui.add(slider);
                 });
-                ui.checkbox(&mut self.show_grid, "Show grid");
+                ui.checkbox(&mut self.state.show_grid, "Show grid");
             });
         });
 
         self.params.write(CharDataParams {
-            palette: self.palette,
-            index: self.index,
+            palette: self.state.palette,
+            index: self.state.index,
         });
     }
 
     fn load_palette_colors(&self) -> [Color32; 4] {
-        let Some(offset) = self.palette.offset() else {
+        let Some(offset) = self.state.palette.offset() else {
             return utils::generic_palette(Color32::RED);
         };
         let palette = self.palettes.borrow().read(offset);
@@ -226,37 +240,30 @@ impl CharacterDataWindow {
     }
 
     fn show_chardata(&mut self, ui: &mut Ui) {
-        let grid = CharacterGrid::new("vip://chardata")
-            .with_scale(self.scale)
-            .with_grid(self.show_grid)
-            .with_selected(self.index);
+        let grid = CharacterGrid::new(self.image_url("chardata"))
+            .with_scale(self.state.scale)
+            .with_grid(self.state.show_grid)
+            .with_selected(self.state.index);
         if let Some(selected) = grid.show(ui) {
-            self.index = selected;
+            self.state.index = selected;
         }
     }
 }
 
 impl AppWindow for CharacterDataWindow {
-    fn viewport_id(&self) -> ViewportId {
-        ViewportId::from_hash_of(format!("chardata-{}", self.sim_id))
-    }
-
-    fn sim_id(&self) -> SimId {
-        self.sim_id
+    fn sim_id(&self) -> Option<SimId> {
+        Some(self.sim_id)
     }
 
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
-            .with_title(format!("Character Data ({})", self.sim_id))
+            .with_title("Character Data")
             .with_inner_size((640.0, 480.0))
     }
 
-    fn on_init(&mut self, ctx: &Context, _render_state: &egui_wgpu::RenderState) {
-        ctx.add_texture_loader(self.loader.clone());
-    }
-
-    fn show(&mut self, ctx: &Context) {
-        CentralPanel::default().show(ctx, |ui| {
+    fn show(&mut self, ui: &mut Ui) {
+        self.state.load(ui);
+        CentralPanel::default().show(ui, |ui| {
             ui.horizontal_top(|ui| {
                 StripBuilder::new(ui)
                     .size(Size::relative(0.3).at_most(200.0))
@@ -271,16 +278,11 @@ impl AppWindow for CharacterDataWindow {
                     });
             });
         });
+        self.state.save(ui);
     }
 }
 
-#[derive(Serialize, Deserialize, Clone, PartialEq, Eq, Hash)]
-enum CharDataResource {
-    Character { palette: Palette, index: usize },
-    CharacterData { palette: Palette },
-}
-
-#[derive(Clone, Default, PartialEq, Eq)]
+#[derive(Clone, PartialEq, Eq)]
 struct CharDataParams {
     palette: Palette,
     index: usize,
@@ -295,6 +297,10 @@ struct CharDataRenderer {
 impl ImageRenderer<2> for CharDataRenderer {
     type Params = CharDataParams;
 
+    fn names(&self) -> [&str; 2] {
+        ["chardata-char", "chardata"]
+    }
+
     fn sizes(&self) -> [[usize; 2]; 2] {
         [[8, 8], [16 * 8, 128 * 8]]
     }

src/window/vip/framebuffer.rs

@@ -1,56 +1,68 @@
-use std::sync::Arc;
-
 use egui::{
-    Align, CentralPanel, Color32, Context, Image, ScrollArea, Slider, TextEdit, TextureOptions, Ui,
-    ViewportBuilder, ViewportId,
+    Align, CentralPanel, Color32, Image, ScrollArea, Slider, TextEdit, TextureOptions, Ui,
+    ViewportBuilder,
 };
 use egui_extras::{Column, Size, StripBuilder, TableBuilder};
+use serde::{Deserialize, Serialize};
 
 use crate::{
     emulator::SimId,
-    images::{ImageBuffer, ImageParams, ImageProcessor, ImageRenderer, ImageTextureLoader},
+    images::{ImageBuffer, ImageParams, ImageRenderer, ImageTextureLoader},
     memory::{MemoryClient, MemoryView},
     window::{
         AppWindow,
-        utils::{NumberEdit, UiExt as _},
+        utils::{NumberEdit, UiData, UiExt as _},
     },
 };
 
 use super::utils;
 
-pub struct FrameBufferWindow {
-    sim_id: SimId,
-    loader: Arc<ImageTextureLoader>,
+#[derive(Clone, PartialEq, Serialize, Deserialize)]
+struct State {
     index: usize,
     left: bool,
     right: bool,
     generic_palette: bool,
-    params: ImageParams<FrameBufferParams>,
     scale: f32,
 }
-
-impl FrameBufferWindow {
-    pub fn new(sim_id: SimId, memory: &MemoryClient, images: &mut ImageProcessor) -> Self {
-        let initial_params = FrameBufferParams {
+impl Default for State {
+    fn default() -> Self {
+        Self {
             index: 0,
             left: true,
             right: true,
             generic_palette: false,
-            left_color: Color32::from_rgb(0xff, 0x00, 0x00),
-            right_color: Color32::from_rgb(0x00, 0xc6, 0xf0),
-        };
+            scale: 2.0,
+        }
+    }
+}
+
+pub struct FrameBufferWindow {
+    sim_id: SimId,
+    params: ImageParams<FrameBufferParams>,
+    state: UiData<State>,
+}
+
+impl FrameBufferWindow {
+    pub fn new(sim_id: SimId, memory: &MemoryClient, images: &ImageTextureLoader) -> Self {
+        let state: UiData<State> = UiData::new();
         let renderer = FrameBufferRenderer::new(sim_id, memory);
-        let ([buffer], params) = images.add(renderer, initial_params);
-        let loader = ImageTextureLoader::new([("vip://buffer".into(), buffer)]);
+        let params = images.add(
+            sim_id,
+            renderer,
+            FrameBufferParams {
+                index: state.index,
+                left: state.left,
+                right: state.right,
+                generic_palette: state.generic_palette,
+                left_color: Color32::from_rgb(0xff, 0x00, 0x00),
+                right_color: Color32::from_rgb(0x00, 0xc6, 0xf0),
+            },
+        );
         Self {
             sim_id,
-            loader: Arc::new(loader),
-            index: params.index,
-            left: params.left,
-            right: params.right,
-            generic_palette: params.generic_palette,
             params,
-            scale: 2.0,
+            state,
         }
     }
 
@@ -66,7 +78,7 @@ impl FrameBufferWindow {
                             ui.label("Index");
                         });
                         row.col(|ui| {
-                            ui.add(NumberEdit::new(&mut self.index).range(0..2));
+                            ui.add(NumberEdit::new(&mut self.state.index).range(0..2));
                         });
                     });
                     body.row(row_height, |mut row| {
@@ -74,7 +86,7 @@ impl FrameBufferWindow {
                             ui.label("Left");
                         });
                         row.col(|ui| {
-                            let address = self.index * 0x00008000;
+                            let address = self.state.index * 0x00008000;
                             let mut address_str = format!("{address:08x}");
                             ui.add_enabled(
                                 false,
@@ -87,7 +99,7 @@ impl FrameBufferWindow {
                             ui.label("Right");
                         });
                         row.col(|ui| {
-                            let address = self.index * 0x00008000 + 0x00010000;
+                            let address = self.state.index * 0x00008000 + 0x00010000;
                             let mut address_str = format!("{address:08x}");
                             ui.add_enabled(
                                 false,
@@ -100,7 +112,7 @@ impl FrameBufferWindow {
                 ui.horizontal(|ui| {
                     ui.label("Scale");
                     ui.spacing_mut().slider_width = ui.available_width();
-                    let slider = Slider::new(&mut self.scale, 1.0..=10.0)
+                    let slider = Slider::new(&mut self.state.scale, 1.0..=10.0)
                         .step_by(1.0)
                         .show_value(false);
                     ui.add(slider);
@@ -110,55 +122,48 @@ impl FrameBufferWindow {
                     .body(|mut body| {
                         body.row(row_height, |mut row| {
                             row.col(|ui| {
-                                ui.checkbox(&mut self.left, "Left");
+                                ui.checkbox(&mut self.state.left, "Left");
                             });
                             row.col(|ui| {
-                                ui.checkbox(&mut self.right, "Right");
+                                ui.checkbox(&mut self.state.right, "Right");
                             });
                         });
                     });
-                ui.checkbox(&mut self.generic_palette, "Generic colors");
+                ui.checkbox(&mut self.state.generic_palette, "Generic colors");
             });
         });
 
         self.params.write(FrameBufferParams {
-            index: self.index,
-            left: self.left,
-            right: self.right,
-            generic_palette: self.generic_palette,
+            index: self.state.index,
+            left: self.state.left,
+            right: self.state.right,
+            generic_palette: self.state.generic_palette,
             ..*self.params
         });
     }
 
     fn show_buffers(&mut self, ui: &mut Ui) {
-        let image = Image::new("vip://buffer")
-            .fit_to_original_size(self.scale)
+        let image = Image::new(self.image_url("buffer"))
+            .fit_to_original_size(self.state.scale)
             .texture_options(TextureOptions::NEAREST);
         ui.add(image);
     }
 }
 
 impl AppWindow for FrameBufferWindow {
-    fn viewport_id(&self) -> ViewportId {
-        ViewportId::from_hash_of(format!("framebuffer-{}", self.sim_id))
-    }
-
-    fn sim_id(&self) -> SimId {
-        self.sim_id
+    fn sim_id(&self) -> Option<SimId> {
+        Some(self.sim_id)
     }
 
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
-            .with_title(format!("Frame Buffers ({})", self.sim_id))
+            .with_title("Frame Buffers")
             .with_inner_size((640.0, 480.0))
     }
 
-    fn on_init(&mut self, ctx: &Context, _render_state: &egui_wgpu::RenderState) {
-        ctx.add_texture_loader(self.loader.clone());
-    }
-
-    fn show(&mut self, ctx: &Context) {
-        CentralPanel::default().show(ctx, |ui| {
+    fn show(&mut self, ui: &mut Ui) {
+        self.state.load(ui);
+        CentralPanel::default().show(ui, |ui| {
             ui.horizontal_top(|ui| {
                 StripBuilder::new(ui)
                     .size(Size::relative(0.3).at_most(200.0))
@@ -173,6 +178,7 @@ impl AppWindow for FrameBufferWindow {
                     });
             });
         });
+        self.state.save(ui);
     }
 }
 
@@ -208,6 +214,10 @@ impl FrameBufferRenderer {
 impl ImageRenderer<1> for FrameBufferRenderer {
     type Params = FrameBufferParams;
 
+    fn names(&self) -> [&str; 1] {
+        ["buffer"]
+    }
+
     fn sizes(&self) -> [[usize; 2]; 1] {
         [[384, 224]]
     }

src/window/vip/object.rs

@@ -1,55 +1,68 @@
 use std::sync::Arc;
 
 use egui::{
-    Align, CentralPanel, Checkbox, Color32, ComboBox, Context, Image, ScrollArea, Slider, TextEdit,
-    TextureOptions, Ui, ViewportBuilder, ViewportId,
+    Align, CentralPanel, Checkbox, Color32, ComboBox, Image, ScrollArea, Slider, TextEdit,
+    TextureOptions, Ui, ViewportBuilder,
 };
 use egui_extras::{Column, Size, StripBuilder, TableBuilder};
+use serde::{Deserialize, Serialize};
 
 use crate::{
     emulator::SimId,
-    images::{ImageBuffer, ImageParams, ImageProcessor, ImageRenderer, ImageTextureLoader},
+    images::{ImageBuffer, ImageParams, ImageRenderer, ImageTextureLoader},
     memory::{MemoryClient, MemoryView},
     window::{
         AppWindow,
-        utils::{NumberEdit, UiExt as _},
+        utils::{NumberEdit, UiData, UiExt as _},
     },
 };
 
 use super::utils::{self, Object};
 
-pub struct ObjectWindow {
-    sim_id: SimId,
-    loader: Arc<ImageTextureLoader>,
-    memory: Arc<MemoryClient>,
-    objects: MemoryView,
+#[derive(Clone, PartialEq, Serialize, Deserialize)]
+struct State {
     index: usize,
     generic_palette: bool,
-    params: ImageParams<ObjectParams>,
     scale: f32,
 }
+impl Default for State {
+    fn default() -> Self {
+        Self {
+            index: 0,
+            generic_palette: false,
+            scale: 1.0,
+        }
+    }
+}
+
+pub struct ObjectWindow {
+    sim_id: SimId,
+    memory: Arc<MemoryClient>,
+    objects: MemoryView,
+    params: ImageParams<ObjectParams>,
+    state: UiData<State>,
+}
 
 impl ObjectWindow {
-    pub fn new(sim_id: SimId, memory: &Arc<MemoryClient>, images: &mut ImageProcessor) -> Self {
-        let initial_params = ObjectParams {
-            index: 0,
-            generic_palette: false,
-            left_color: Color32::from_rgb(0xff, 0x00, 0x00),
-            right_color: Color32::from_rgb(0x00, 0xc6, 0xf0),
-        };
+    pub fn new(sim_id: SimId, memory: &Arc<MemoryClient>, images: &ImageTextureLoader) -> Self {
+        let state: UiData<State> = UiData::new();
         let renderer = ObjectRenderer::new(sim_id, memory);
-        let ([zoom, full], params) = images.add(renderer, initial_params);
-        let loader =
-            ImageTextureLoader::new([("vip://zoom".into(), zoom), ("vip://full".into(), full)]);
+        let params = images.add(
+            sim_id,
+            renderer,
+            ObjectParams {
+                index: state.index,
+                generic_palette: state.generic_palette,
+                left_color: Color32::from_rgb(0xff, 0x00, 0x00),
+                right_color: Color32::from_rgb(0x00, 0xc6, 0xf0),
+            },
+        );
         Self {
             sim_id,
-            loader: Arc::new(loader),
             memory: memory.clone(),
             objects: memory.watch(sim_id, 0x0003e000, 0x2000),
-            index: params.index,
-            generic_palette: params.generic_palette,
             params,
-            scale: 1.0,
+            state,
         }
     }
 
@@ -65,7 +78,7 @@ impl ObjectWindow {
                             ui.label("Index");
                         });
                         row.col(|ui| {
-                            ui.add(NumberEdit::new(&mut self.index).range(0..1024));
+                            ui.add(NumberEdit::new(&mut self.state.index).range(0..1024));
                         });
                     });
                     body.row(row_height, |mut row| {
@@ -73,7 +86,7 @@ impl ObjectWindow {
                             ui.label("Address");
                         });
                         row.col(|ui| {
-                            let address = 0x3e000 + self.index * 8;
+                            let address = 0x3e000 + self.state.index * 8;
                             let mut address_str = format!("{address:08x}");
                             ui.add_enabled(
                                 false,
@@ -82,12 +95,12 @@ impl ObjectWindow {
                         });
                     });
                 });
-            let image = Image::new("vip://zoom")
+            let image = Image::new(self.image_url("object-zoom"))
                 .maintain_aspect_ratio(true)
                 .texture_options(TextureOptions::NEAREST);
             ui.add(image);
             ui.section("Properties", |ui| {
-                let mut object = self.objects.borrow().read::<[u16; 4]>(self.index);
+                let mut object = self.objects.borrow().read::<[u16; 4]>(self.state.index);
                 let mut obj = Object::parse(object);
                 TableBuilder::new(ui)
                     .column(Column::remainder())
@@ -162,7 +175,7 @@ impl ObjectWindow {
                         });
                     });
                 if obj.update(&mut object) {
-                    let address = 0x3e000 + self.index * 8;
+                    let address = 0x3e000 + self.state.index * 8;
                     self.memory.write(self.sim_id, address as u32, &object);
                 }
             });
@@ -170,50 +183,43 @@ impl ObjectWindow {
                 ui.horizontal(|ui| {
                     ui.label("Scale");
                     ui.spacing_mut().slider_width = ui.available_width();
-                    let slider = Slider::new(&mut self.scale, 1.0..=10.0)
+                    let slider = Slider::new(&mut self.state.scale, 1.0..=10.0)
                         .step_by(1.0)
                         .show_value(false);
                     ui.add(slider);
                 });
-                ui.checkbox(&mut self.generic_palette, "Generic palette");
+                ui.checkbox(&mut self.state.generic_palette, "Generic palette");
             });
         });
         self.params.write(ObjectParams {
-            index: self.index,
-            generic_palette: self.generic_palette,
+            index: self.state.index,
+            generic_palette: self.state.generic_palette,
             ..*self.params
         });
     }
 
     fn show_object(&mut self, ui: &mut Ui) {
-        let image = Image::new("vip://full")
-            .fit_to_original_size(self.scale)
+        let image = Image::new(self.image_url("object-full"))
+            .fit_to_original_size(self.state.scale)
             .texture_options(TextureOptions::NEAREST);
         ui.add(image);
     }
 }
 
 impl AppWindow for ObjectWindow {
-    fn viewport_id(&self) -> egui::ViewportId {
-        ViewportId::from_hash_of(format!("object-{}", self.sim_id))
-    }
-
-    fn sim_id(&self) -> SimId {
-        self.sim_id
+    fn sim_id(&self) -> Option<SimId> {
+        Some(self.sim_id)
     }
 
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
-            .with_title(format!("Object Data ({})", self.sim_id))
+            .with_title("Object Data")
             .with_inner_size((640.0, 500.0))
     }
 
-    fn on_init(&mut self, ctx: &Context, _render_state: &egui_wgpu::RenderState) {
-        ctx.add_texture_loader(self.loader.clone());
-    }
-
-    fn show(&mut self, ctx: &Context) {
-        CentralPanel::default().show(ctx, |ui| {
+    fn show(&mut self, ui: &mut Ui) {
+        self.state.load(ui);
+        CentralPanel::default().show(ui, |ui| {
             ui.horizontal_top(|ui| {
                 StripBuilder::new(ui)
                     .size(Size::relative(0.3).at_most(200.0))
@@ -228,6 +234,7 @@ impl AppWindow for ObjectWindow {
                     });
             });
         });
+        self.state.save(ui);
     }
 }
 
@@ -327,6 +334,10 @@ impl ObjectRenderer {
 impl ImageRenderer<2> for ObjectRenderer {
     type Params = ObjectParams;
 
+    fn names(&self) -> [&str; 2] {
+        ["object-zoom", "object-full"]
+    }
+
     fn sizes(&self) -> [[usize; 2]; 2] {
         [[8, 8], [384, 224]]
     }

src/window/vip/registers.rs

@@ -1,8 +1,8 @@
 use std::sync::Arc;
 
 use egui::{
-    Align, Button, CentralPanel, Checkbox, Color32, Context, Direction, Label, Layout, ScrollArea,
-    TextEdit, Ui, ViewportBuilder, ViewportId,
+    Align, Button, CentralPanel, Checkbox, Color32, Direction, Label, Layout, ScrollArea, TextEdit,
+    Ui, ViewportBuilder,
 };
 use egui_extras::{Column, Size, StripBuilder, TableBuilder};
 
@@ -630,22 +630,18 @@ fn read_address<T: MemoryValue>(registers: &MemoryRef, address: usize) -> T {
 }
 
 impl AppWindow for RegisterWindow {
-    fn viewport_id(&self) -> ViewportId {
-        ViewportId::from_hash_of(format!("registers-{}", self.sim_id))
-    }
-
-    fn sim_id(&self) -> SimId {
-        self.sim_id
+    fn sim_id(&self) -> Option<SimId> {
+        Some(self.sim_id)
     }
 
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
-            .with_title(format!("Registers ({})", self.sim_id))
+            .with_title("Registers")
             .with_inner_size((800.0, 480.0))
     }
 
-    fn show(&mut self, ctx: &Context) {
-        CentralPanel::default().show(ctx, |ui| {
+    fn show(&mut self, ui: &mut Ui) {
+        CentralPanel::default().show(ui, |ui| {
             ScrollArea::vertical().show(ui, |ui| {
                 ui.horizontal_top(|ui| {
                     let width = ui.available_width();

src/window/vip/utils.rs

@@ -1,6 +1,7 @@
 use egui::{Color32, Image, ImageSource, Response, Sense, TextureOptions, Ui, Widget};
 
 pub const GENERIC_PALETTE: [u8; 4] = [0, 32, 64, 128];
+const COLOR_TRANSPARENT: Color32 = Color32::from_rgb(0x25, 0x25, 0x25);
 
 pub fn shade(brt: u8, color: Color32) -> Color32 {
     let corrected = if brt > 132 {
@@ -44,7 +45,9 @@ pub fn parse_brts(brts: &[u16; 3], color: Color32) -> [Color32; 4] {
 
 pub fn palette_colors(palette: u8, brts: &[u8; 8], color: Color32) -> [Color32; 4] {
     let colors = parse_shades(brts).map(|s| shade(s, color));
-    parse_palette(palette).map(|p| colors[p as usize])
+    let mut palette_colors = parse_palette(palette).map(|p| colors[p as usize]);
+    palette_colors[0] = COLOR_TRANSPARENT;
+    palette_colors
 }
 
 pub struct Object {

src/window/vip/world.rs

@@ -1,8 +1,8 @@
 use std::{fmt::Display, sync::Arc};
 
 use egui::{
-    Align, CentralPanel, Checkbox, Color32, ComboBox, Context, Image, ScrollArea, Slider, TextEdit,
-    TextureOptions, Ui, ViewportBuilder, ViewportId,
+    Align, CentralPanel, Checkbox, Color32, ComboBox, Image, ScrollArea, Slider, TextEdit,
+    TextureOptions, Ui, ViewportBuilder,
 };
 use egui_extras::{Column, Size, StripBuilder, TableBuilder};
 use fixed::{
@@ -11,56 +11,70 @@ use fixed::{
 };
 use num_derive::{FromPrimitive, ToPrimitive};
 use num_traits::{FromPrimitive, ToPrimitive};
+use serde::{Deserialize, Serialize};
 
 use crate::{
     emulator::SimId,
-    images::{ImageBuffer, ImageParams, ImageProcessor, ImageRenderer, ImageTextureLoader},
+    images::{ImageBuffer, ImageParams, ImageRenderer, ImageTextureLoader},
     memory::{MemoryClient, MemoryRef, MemoryView},
     window::{
         AppWindow,
-        utils::{NumberEdit, UiExt as _},
+        utils::{NumberEdit, UiData, UiExt as _},
     },
 };
 
 use super::utils::{self, CellData, Object, shade};
 
-pub struct WorldWindow {
-    sim_id: SimId,
-    loader: Arc<ImageTextureLoader>,
-    memory: Arc<MemoryClient>,
-    worlds: MemoryView,
-    bgmaps: MemoryView,
+#[derive(Clone, PartialEq, Serialize, Deserialize)]
+struct State {
     index: usize,
     param_index: usize,
     generic_palette: bool,
     show_extents: bool,
-    params: ImageParams<WorldParams>,
     scale: f32,
 }
+impl Default for State {
+    fn default() -> Self {
+        Self {
+            index: 31,
+            param_index: 0,
+            generic_palette: false,
+            show_extents: false,
+            scale: 1.0,
+        }
+    }
+}
+
+pub struct WorldWindow {
+    sim_id: SimId,
+    memory: Arc<MemoryClient>,
+    worlds: MemoryView,
+    bgmaps: MemoryView,
+    params: ImageParams<WorldParams>,
+    state: UiData<State>,
+}
 
 impl WorldWindow {
-    pub fn new(sim_id: SimId, memory: &Arc<MemoryClient>, images: &mut ImageProcessor) -> Self {
-        let initial_params = WorldParams {
-            index: 31,
-            generic_palette: false,
-            left_color: Color32::from_rgb(0xff, 0x00, 0x00),
-            right_color: Color32::from_rgb(0x00, 0xc6, 0xf0),
-        };
+    pub fn new(sim_id: SimId, memory: &Arc<MemoryClient>, images: &ImageTextureLoader) -> Self {
+        let state: UiData<State> = UiData::new();
         let renderer = WorldRenderer::new(sim_id, memory);
-        let ([world], params) = images.add(renderer, initial_params);
-        let loader = ImageTextureLoader::new([("vip://world".into(), world)]);
+        let params = images.add(
+            sim_id,
+            renderer,
+            WorldParams {
+                index: state.index,
+                generic_palette: state.generic_palette,
+                left_color: Color32::from_rgb(0xff, 0x00, 0x00),
+                right_color: Color32::from_rgb(0x00, 0xc6, 0xf0),
+            },
+        );
         Self {
             sim_id,
-            loader: Arc::new(loader),
             memory: memory.clone(),
             worlds: memory.watch(sim_id, 0x0003d800, 0x400),
             bgmaps: memory.watch(sim_id, 0x00020000, 0x20000),
-            index: params.index,
-            param_index: 0,
-            generic_palette: params.generic_palette,
-            show_extents: false,
             params,
-            scale: 1.0,
+            state,
         }
     }
 
@@ -76,7 +90,7 @@ impl WorldWindow {
                             ui.label("Index");
                         });
                         row.col(|ui| {
-                            ui.add(NumberEdit::new(&mut self.index).range(0..32));
+                            ui.add(NumberEdit::new(&mut self.state.index).range(0..32));
                         });
                     });
                     body.row(row_height, |mut row| {
@@ -84,7 +98,7 @@ impl WorldWindow {
                             ui.label("Address");
                         });
                         row.col(|ui| {
-                            let address = 0x0003d800 + self.index * 32;
+                            let address = 0x0003d800 + self.state.index * 32;
                             let mut address_str = format!("{address:08x}");
                             ui.add_enabled(
                                 false,
@@ -95,7 +109,7 @@ impl WorldWindow {
                 });
             let mut data = {
                 let worlds = self.worlds.borrow();
-                worlds.read(self.index)
+                worlds.read(self.state.index)
             };
             let mut world = World::parse(&data);
             ui.section("Properties", |ui| {
@@ -275,7 +289,7 @@ impl WorldWindow {
                     });
             });
             if world.update(&mut data) {
-                let address = 0x0003d800 + self.index * 32;
+                let address = 0x0003d800 + self.state.index * 32;
                 self.memory.write(self.sim_id, address as u32, &data);
             }
             if world.header.mode == WorldMode::HBias {
@@ -290,10 +304,12 @@ impl WorldWindow {
                                 });
                                 row.col(|ui| {
                                     let max = world.height.max(8) as usize;
-                                    ui.add(NumberEdit::new(&mut self.param_index).range(0..max));
+                                    ui.add(
+                                        NumberEdit::new(&mut self.state.param_index).range(0..max),
+                                    );
                                 });
                             });
-                            let base = (world.param_base + self.param_index * 2) & 0x1ffff;
+                            let base = (world.param_base + self.state.param_index * 2) & 0x1ffff;
                             let mut param = HBiasParam::load(&self.bgmaps.borrow(), base);
                             body.row(row_height, |mut row| {
                                 row.col(|ui| {
@@ -340,10 +356,12 @@ impl WorldWindow {
                                 });
                                 row.col(|ui| {
                                     let max = world.height.max(1) as usize;
-                                    ui.add(NumberEdit::new(&mut self.param_index).range(0..max));
+                                    ui.add(
+                                        NumberEdit::new(&mut self.state.param_index).range(0..max),
+                                    );
                                 });
                             });
-                            let base = (world.param_base + self.param_index * 8) & 0x1ffff;
+                            let base = (world.param_base + self.state.param_index * 8) & 0x1ffff;
                             let mut param = AffineParam::load(&self.bgmaps.borrow(), base);
                             body.row(row_height, |mut row| {
                                 row.col(|ui| {
@@ -403,49 +421,49 @@ impl WorldWindow {
                         });
                 });
             } else {
-                self.param_index = 0;
+                self.state.param_index = 0;
             }
             ui.section("Display", |ui| {
                 ui.horizontal(|ui| {
                     ui.label("Scale");
                     ui.spacing_mut().slider_width = ui.available_width();
-                    let slider = Slider::new(&mut self.scale, 1.0..=10.0)
+                    let slider = Slider::new(&mut self.state.scale, 1.0..=10.0)
                         .step_by(1.0)
                         .show_value(false);
                     ui.add(slider);
                 });
-                ui.checkbox(&mut self.generic_palette, "Generic palette");
-                ui.checkbox(&mut self.show_extents, "Show extents");
+                ui.checkbox(&mut self.state.generic_palette, "Generic palette");
+                ui.checkbox(&mut self.state.show_extents, "Show extents");
             });
         });
         self.params.write(WorldParams {
-            index: self.index,
-            generic_palette: self.generic_palette,
+            index: self.state.index,
+            generic_palette: self.state.generic_palette,
             ..*self.params
         });
     }
 
     fn show_world(&mut self, ui: &mut Ui) {
-        let image = Image::new("vip://world")
-            .fit_to_original_size(self.scale)
+        let image = Image::new(self.image_url("world"))
+            .fit_to_original_size(self.state.scale)
             .texture_options(TextureOptions::NEAREST);
         let res = ui.add(image);
-        if self.show_extents {
+        if self.state.show_extents {
             let world = {
                 let worlds = self.worlds.borrow();
-                let data = worlds.read(self.index);
+                let data = worlds.read(self.state.index);
                 World::parse(&data)
             };
             if world.header.mode == WorldMode::Object {
                 return;
             }
 
-            let lx1 = (world.dst_x - world.dst_parallax) as f32 * self.scale;
-            let lx2 = lx1 + world.width as f32 * self.scale;
-            let rx1 = (world.dst_x + world.dst_parallax) as f32 * self.scale;
-            let rx2 = rx1 + world.width as f32 * self.scale;
-            let y1 = world.dst_y as f32 * self.scale;
-            let y2 = y1 + world.height as f32 * self.scale;
+            let lx1 = (world.dst_x - world.dst_parallax) as f32 * self.state.scale;
+            let lx2 = lx1 + world.width as f32 * self.state.scale;
+            let rx1 = (world.dst_x + world.dst_parallax) as f32 * self.state.scale;
+            let rx2 = rx1 + world.width as f32 * self.state.scale;
+            let y1 = world.dst_y as f32 * self.state.scale;
+            let y2 = y1 + world.height as f32 * self.state.scale;
 
             let left_color = self.params.left_color;
             let right_color = self.params.right_color;
@@ -509,26 +527,19 @@ impl WorldWindow {
 }
 
 impl AppWindow for WorldWindow {
-    fn viewport_id(&self) -> ViewportId {
-        ViewportId::from_hash_of(format!("world-{}", self.sim_id))
-    }
-
-    fn sim_id(&self) -> SimId {
-        self.sim_id
+    fn sim_id(&self) -> Option<SimId> {
+        Some(self.sim_id)
     }
 
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
-            .with_title(format!("Worlds ({})", self.sim_id))
+            .with_title("Worlds")
             .with_inner_size((640.0, 520.0))
     }
 
-    fn on_init(&mut self, ctx: &Context, _render_state: &egui_wgpu::RenderState) {
-        ctx.add_texture_loader(self.loader.clone());
-    }
-
-    fn show(&mut self, ctx: &Context) {
-        CentralPanel::default().show(ctx, |ui| {
+    fn show(&mut self, ui: &mut Ui) {
+        self.state.load(ui);
+        CentralPanel::default().show(ui, |ui| {
             ui.horizontal_top(|ui| {
                 StripBuilder::new(ui)
                     .size(Size::relative(0.3).at_most(200.0))
@@ -543,6 +554,7 @@ impl AppWindow for WorldWindow {
                     });
             });
         });
+        self.state.save(ui);
     }
 }
 
@@ -779,6 +791,10 @@ impl WorldRenderer {
 impl ImageRenderer<1> for WorldRenderer {
     type Params = WorldParams;
 
+    fn names(&self) -> [&str; 1] {
+        ["world"]
+    }
+
     fn sizes(&self) -> [[usize; 2]; 1] {
         [[384, 224]]
     }
@@ -1065,8 +1081,8 @@ impl<'a> SourceCoordCalculator<'a> {
                 (sx, sy)
             }
             SourceParam::Affine(affine) => {
-                let sx = affine_coord(affine.src_x, x, affine.dx, affine.src_parallax.min(0));
-                let sy = affine_coord(affine.src_y, x, affine.dy, affine.src_parallax.min(0));
+                let sx = affine_coord(affine.src_x, x, affine.dx, -(affine.src_parallax.min(0)));
+                let sy = affine_coord(affine.src_y, x, affine.dy, -(affine.src_parallax.min(0)));
                 (sx, sy)
             }
         }