New implementation for reading/showing vram

src/app.rs

@@ -18,8 +18,12 @@ use crate::{
     controller::ControllerManager,
     emulator::{EmulatorClient, EmulatorCommand, SimId},
     input::MappingProvider,
+    memory::MemoryMonitor,
     persistence::Persistence,
-    window::{AboutWindow, AppWindow, GameWindow, GdbServerWindow, InputWindow},
+    window::{
+        AboutWindow, AppWindow, BgMapWindow, CharacterDataWindow, GameWindow, GdbServerWindow,
+        InputWindow,
+    },
 };
 
 fn load_icon() -> anyhow::Result<IconData> {
@@ -39,6 +43,7 @@ pub struct Application {
     proxy: EventLoopProxy<UserEvent>,
     mappings: MappingProvider,
     controllers: ControllerManager,
+    memory: MemoryMonitor,
     persistence: Persistence,
     viewports: HashMap<ViewportId, Viewport>,
     focused: Option<ViewportId>,
@@ -55,6 +60,7 @@ impl Application {
         let persistence = Persistence::new();
         let mappings = MappingProvider::new(persistence.clone());
         let controllers = ControllerManager::new(client.clone(), &mappings);
+        let memory = MemoryMonitor::new(client.clone());
         {
             let mappings = mappings.clone();
             let proxy = proxy.clone();
@@ -65,6 +71,7 @@ impl Application {
             client,
             proxy,
             mappings,
+            memory,
             controllers,
             persistence,
             viewports: HashMap::new(),
@@ -194,6 +201,14 @@ impl ApplicationHandler<UserEvent> for Application {
                 let about = AboutWindow;
                 self.open(event_loop, Box::new(about));
             }
+            UserEvent::OpenCharacterData(sim_id) => {
+                let vram = CharacterDataWindow::new(sim_id, &mut self.memory);
+                self.open(event_loop, Box::new(vram));
+            }
+            UserEvent::OpenBgMap(sim_id) => {
+                let bgmap = BgMapWindow::new(sim_id, &mut self.memory);
+                self.open(event_loop, Box::new(bgmap));
+            }
             UserEvent::OpenDebugger(sim_id) => {
                 let debugger =
                     GdbServerWindow::new(sim_id, self.client.clone(), self.proxy.clone());
@@ -300,7 +315,7 @@ impl Viewport {
         let (window, state) = create_window_and_state(&ctx, event_loop, &builder, &mut painter);
         egui_winit::update_viewport_info(&mut info, &ctx, &window, true);
 
-        app.on_init(painter.render_state().as_ref().unwrap());
+        app.on_init(&ctx, painter.render_state().as_ref().unwrap());
         Self {
             painter,
             ctx,
@@ -403,6 +418,8 @@ impl Drop for Viewport {
 pub enum UserEvent {
     GamepadEvent(gilrs::Event),
     OpenAbout,
+    OpenCharacterData(SimId),
+    OpenBgMap(SimId),
     OpenDebugger(SimId),
     OpenInput,
     OpenPlayer2,

src/main.rs

@@ -19,7 +19,9 @@ mod emulator;
 mod gdbserver;
 mod graphics;
 mod input;
+mod memory;
 mod persistence;
+mod vram;
 mod window;
 
 #[derive(Parser)]

src/memory.rs

@@ -0,0 +1,88 @@
+use std::{
+    collections::HashMap,
+    sync::{Arc, Mutex, MutexGuard},
+};
+
+use bytemuck::BoxBytes;
+
+use crate::emulator::{EmulatorClient, EmulatorCommand, SimId};
+
+pub struct MemoryMonitor {
+    client: EmulatorClient,
+    regions: HashMap<MemoryRegion, Arc<Mutex<BoxBytes>>>,
+}
+
+impl MemoryMonitor {
+    pub fn new(client: EmulatorClient) -> Self {
+        Self {
+            client,
+            regions: HashMap::new(),
+        }
+    }
+
+    pub fn view(&mut self, sim: SimId, start: u32, length: usize) -> MemoryView {
+        let region = MemoryRegion { sim, start, length };
+        let memory = self.regions.entry(region).or_insert_with(|| {
+            let mut buf = aligned_memory(start, length);
+            let (tx, rx) = oneshot::channel();
+            self.client
+                .send_command(EmulatorCommand::ReadMemory(sim, start, length, vec![], tx));
+            let bytes = pollster::block_on(rx).unwrap();
+            buf.copy_from_slice(&bytes);
+            #[expect(clippy::arc_with_non_send_sync)] // TODO: remove after bytemuck upgrade
+            Arc::new(Mutex::new(buf))
+        });
+        MemoryView {
+            memory: memory.clone(),
+        }
+    }
+}
+
+fn aligned_memory(start: u32, length: usize) -> BoxBytes {
+    if start % 4 == 0 && length % 4 == 0 {
+        let memory = vec![0u32; length / 4].into_boxed_slice();
+        return bytemuck::box_bytes_of(memory);
+    }
+    if start % 2 == 0 && length % 2 == 0 {
+        let memory = vec![0u16; length / 2].into_boxed_slice();
+        return bytemuck::box_bytes_of(memory);
+    }
+    let memory = vec![0u8; length].into_boxed_slice();
+    bytemuck::box_bytes_of(memory)
+}
+
+pub struct MemoryView {
+    memory: Arc<Mutex<BoxBytes>>,
+}
+// SAFETY: BoxBytes is supposed to be Send+Sync, will be in a new version
+unsafe impl Send for MemoryView {}
+
+impl MemoryView {
+    pub fn borrow(&self) -> MemoryRef<'_> {
+        MemoryRef {
+            inner: self.memory.lock().unwrap(),
+        }
+    }
+}
+
+pub struct MemoryRef<'a> {
+    inner: MutexGuard<'a, BoxBytes>,
+}
+
+impl MemoryRef<'_> {
+    pub fn read(&self, index: usize) -> u8 {
+        self.inner[index]
+    }
+    pub fn range<T: bytemuck::AnyBitPattern>(&self, start: usize, count: usize) -> &[T] {
+        let from = start * size_of::<T>();
+        let to = from + (count * size_of::<T>());
+        bytemuck::cast_slice(&self.inner[from..to])
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
+struct MemoryRegion {
+    sim: SimId,
+    start: u32,
+    length: usize,
+}

src/vram.rs

@@ -0,0 +1,121 @@
+use std::{
+    collections::{hash_map::Entry, HashMap},
+    hash::Hash,
+    sync::Mutex,
+};
+
+use egui::{
+    epaint::ImageDelta,
+    load::{LoadError, SizedTexture, TextureLoader, TexturePoll},
+    ColorImage, Context, TextureHandle, TextureOptions,
+};
+use serde::{Deserialize, Serialize};
+
+pub trait VramResource: Sized + PartialEq + Eq + Hash {
+    fn to_uri(&self) -> String;
+    fn from_uri(uri: &str) -> Option<Self>;
+}
+
+impl<T: Serialize + for<'a> Deserialize<'a> + PartialEq + Eq + Hash> VramResource for T {
+    fn to_uri(&self) -> String {
+        format!("vram://{}", serde_json::to_string(self).unwrap())
+    }
+
+    fn from_uri(uri: &str) -> Option<Self> {
+        let content = uri.strip_prefix("vram://")?;
+        serde_json::from_str(content).ok()
+    }
+}
+
+pub trait VramImageLoader {
+    type Resource: VramResource;
+
+    fn id(&self) -> &str;
+    fn add(&self, resource: &Self::Resource) -> Option<ColorImage>;
+    fn update<'a>(
+        &'a self,
+        resources: impl Iterator<Item = &'a Self::Resource>,
+    ) -> Vec<(&'a Self::Resource, ColorImage)>;
+}
+
+pub struct VramTextureLoader<T: VramImageLoader> {
+    id: String,
+    loader: Mutex<T>,
+    cache: Mutex<HashMap<T::Resource, TextureHandle>>,
+}
+
+impl<T: VramImageLoader> VramTextureLoader<T> {
+    pub fn new(loader: T) -> Self {
+        Self {
+            id: loader.id().to_string(),
+            loader: Mutex::new(loader),
+            cache: Mutex::new(HashMap::new()),
+        }
+    }
+}
+
+impl<T: VramImageLoader> TextureLoader for VramTextureLoader<T> {
+    fn id(&self) -> &str {
+        &self.id
+    }
+
+    fn load(
+        &self,
+        ctx: &Context,
+        uri: &str,
+        texture_options: TextureOptions,
+        _size_hint: egui::SizeHint,
+    ) -> Result<TexturePoll, LoadError> {
+        let Some(resource) = T::Resource::from_uri(uri) else {
+            return Err(LoadError::NotSupported);
+        };
+        if texture_options != TextureOptions::NEAREST {
+            return Err(LoadError::Loading(
+                "Only TextureOptions::NEAREST are supported".into(),
+            ));
+        }
+        let loader = self.loader.lock().unwrap();
+        let mut cache = self.cache.lock().unwrap();
+        for (resource, updated_image) in loader.update(cache.keys()) {
+            if let Some(handle) = cache.get(resource) {
+                let delta = ImageDelta::full(updated_image, TextureOptions::NEAREST);
+                ctx.tex_manager().write().set(handle.id(), delta);
+            }
+        }
+        match cache.entry(resource) {
+            Entry::Occupied(entry) => {
+                let texture = SizedTexture::from_handle(entry.get());
+                Ok(TexturePoll::Ready { texture })
+            }
+            Entry::Vacant(entry) => {
+                if let Some(image) = loader.add(entry.key()) {
+                    let handle =
+                        entry.insert(ctx.load_texture(uri, image, TextureOptions::NEAREST));
+                    let texture = SizedTexture::from_handle(handle);
+                    Ok(TexturePoll::Ready { texture })
+                } else {
+                    Err(LoadError::Loading("could not load texture".into()))
+                }
+            }
+        }
+    }
+
+    fn forget(&self, uri: &str) {
+        if let Some(resource) = T::Resource::from_uri(uri) {
+            self.cache.lock().unwrap().remove(&resource);
+        }
+    }
+
+    fn forget_all(&self) {
+        self.cache.lock().unwrap().clear();
+    }
+
+    fn byte_size(&self) -> usize {
+        self.cache
+            .lock()
+            .unwrap()
+            .values()
+            .map(|h| h.byte_size())
+            .sum()
+    }
+}

src/window.rs

@@ -3,6 +3,7 @@ use egui::{Context, ViewportBuilder, ViewportId};
 pub use game::GameWindow;
 pub use gdb::GdbServerWindow;
 pub use input::InputWindow;
+pub use vram::{BgMapWindow, CharacterDataWindow};
 use winit::event::KeyEvent;
 
 use crate::emulator::SimId;
@@ -12,6 +13,7 @@ mod game;
 mod game_screen;
 mod gdb;
 mod input;
+mod vram;
 
 pub trait AppWindow {
     fn viewport_id(&self) -> ViewportId;
@@ -20,7 +22,8 @@ pub trait AppWindow {
     }
     fn initial_viewport(&self) -> ViewportBuilder;
     fn show(&mut self, ctx: &Context);
-    fn on_init(&mut self, render_state: &egui_wgpu::RenderState) {
+    fn on_init(&mut self, ctx: &Context, render_state: &egui_wgpu::RenderState) {
+        let _ = ctx;
         let _ = render_state;
     }
     fn on_destroy(&mut self) {}

src/window/game.rs

@@ -132,6 +132,18 @@ impl GameWindow {
                     .unwrap();
                 ui.close_menu();
             }
+            if ui.button("Character Data").clicked() {
+                self.proxy
+                    .send_event(UserEvent::OpenCharacterData(self.sim_id))
+                    .unwrap();
+                ui.close_menu();
+            }
+            if ui.button("Background Maps").clicked() {
+                self.proxy
+                    .send_event(UserEvent::OpenBgMap(self.sim_id))
+                    .unwrap();
+                ui.close_menu();
+            }
         });
         ui.menu_button("About", |ui| {
             self.proxy.send_event(UserEvent::OpenAbout).unwrap();
@@ -369,7 +381,7 @@ impl AppWindow for GameWindow {
         toasts.show(ctx);
     }
 
-    fn on_init(&mut self, render_state: &egui_wgpu::RenderState) {
+    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(

src/window/vram.rs

@@ -0,0 +1,6 @@
+mod bgmap;
+mod chardata;
+mod utils;
+
+pub use bgmap::*;
+pub use chardata::*;

src/window/vram/bgmap.rs

@@ -0,0 +1,151 @@
+use std::sync::Arc;
+
+use egui::{CentralPanel, ColorImage, Context, Image, TextureOptions, ViewportBuilder, ViewportId};
+use serde::{Deserialize, Serialize};
+
+use crate::{
+    emulator::SimId,
+    memory::{MemoryMonitor, MemoryView},
+    vram::{VramImageLoader, VramResource as _, VramTextureLoader},
+    window::AppWindow,
+};
+
+use super::utils::parse_palette;
+
+pub struct BgMapWindow {
+    sim_id: SimId,
+    loader: Option<BgMapLoader>,
+}
+
+impl BgMapWindow {
+    pub fn new(sim_id: SimId, memory: &mut MemoryMonitor) -> Self {
+        Self {
+            sim_id,
+            loader: Some(BgMapLoader::new(sim_id, memory)),
+        }
+    }
+}
+
+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 initial_viewport(&self) -> ViewportBuilder {
+        ViewportBuilder::default()
+            .with_title(format!("BG Map Data ({})", self.sim_id))
+            .with_inner_size((640.0, 480.0))
+    }
+
+    fn on_init(&mut self, ctx: &Context, _render_state: &egui_wgpu::RenderState) {
+        let loader = self.loader.take().unwrap();
+        ctx.add_texture_loader(Arc::new(VramTextureLoader::new(loader)));
+    }
+
+    fn show(&mut self, ctx: &Context) {
+        CentralPanel::default().show(ctx, |ui| {
+            let resource = BgMapResource { index: 0 };
+            let image = Image::new(resource.to_uri()).texture_options(TextureOptions::NEAREST);
+            ui.add(image);
+        });
+    }
+}
+
+#[derive(Serialize, Deserialize, PartialEq, Eq, Hash)]
+struct BgMapResource {
+    index: usize,
+}
+
+struct BgMapLoader {
+    chardata: MemoryView,
+    bgmaps: MemoryView,
+    brightness: MemoryView,
+    palettes: MemoryView,
+}
+
+impl BgMapLoader {
+    pub fn new(sim_id: SimId, memory: &mut MemoryMonitor) -> Self {
+        Self {
+            chardata: memory.view(sim_id, 0x00078000, 0x8000),
+            bgmaps: memory.view(sim_id, 0x00020000, 0x1d800),
+            brightness: memory.view(sim_id, 0x0005f824, 8),
+            palettes: memory.view(sim_id, 0x0005f860, 16),
+        }
+    }
+
+    fn load_bgmap(&self, index: usize) -> Option<ColorImage> {
+        let chardata = self.chardata.borrow();
+        let bgmaps = self.bgmaps.borrow();
+        let brightness = self.brightness.borrow();
+        let palettes = self.palettes.borrow();
+
+        let brts = brightness.range::<u8>(0, 8);
+        let colors = [
+            parse_palette(palettes.read(0), brts),
+            parse_palette(palettes.read(2), brts),
+            parse_palette(palettes.read(4), brts),
+            parse_palette(palettes.read(6), brts),
+        ];
+
+        let mut data = vec![0u8; 512 * 512];
+        for (i, cell) in bgmaps.range::<u16>(index * 4096, 4096).iter().enumerate() {
+            let char_index = (cell & 0x7ff) as usize;
+            let char = chardata.range::<u16>(char_index * 8, 8);
+            let vflip = cell & 0x1000 != 0;
+            let hflip = cell & 0x2000 != 0;
+            let palette_index = (cell >> 14) as usize;
+            let palette = &colors[palette_index];
+
+            let mut target_idx = (i % 64) * 8 + (i / 64) * 8 * 512;
+            for row in 0..8 {
+                let dests = &mut data[target_idx..target_idx + 8];
+                let pixels = self.read_char_row(char, hflip, vflip, row);
+                for (dest, pixel) in dests.iter_mut().zip(pixels) {
+                    *dest = palette[pixel as usize];
+                }
+                target_idx += 512;
+            }
+        }
+
+        Some(ColorImage::from_gray([512, 512], &data))
+    }
+
+    fn read_char_row(
+        &self,
+        char: &[u16],
+        hflip: bool,
+        vflip: bool,
+        row: usize,
+    ) -> impl Iterator<Item = u8> {
+        let pixels = if vflip { char[7 - row] } else { char[row] };
+        (0..16).step_by(2).map(move |i| {
+            let pixel = if hflip { 14 - i } else { i };
+            ((pixels >> pixel) & 0x3) as u8
+        })
+    }
+}
+
+impl VramImageLoader for BgMapLoader {
+    type Resource = BgMapResource;
+
+    fn id(&self) -> &str {
+        concat!(module_path!(), "::BgMapLoader")
+    }
+
+    fn add(&self, resource: &Self::Resource) -> Option<ColorImage> {
+        let BgMapResource { index } = resource;
+        self.load_bgmap(*index)
+    }
+
+    fn update<'a>(
+        &'a self,
+        resources: impl Iterator<Item = &'a Self::Resource>,
+    ) -> Vec<(&'a Self::Resource, ColorImage)> {
+        let _ = resources;
+        vec![]
+    }
+}

src/window/vram/chardata.rs

@@ -0,0 +1,433 @@
+use std::{fmt::Display, sync::Arc};
+
+use egui::{
+    Align, CentralPanel, Color32, ColorImage, ComboBox, Context, Frame, Image, RichText,
+    ScrollArea, Sense, Slider, TextEdit, TextureOptions, Ui, UiBuilder, Vec2, ViewportBuilder,
+    ViewportId,
+};
+use egui_extras::{Column, Size, StripBuilder, TableBuilder};
+use serde::{Deserialize, Serialize};
+
+use crate::{
+    emulator::SimId,
+    memory::{MemoryMonitor, MemoryView},
+    vram::{VramImageLoader, VramResource as _, VramTextureLoader},
+    window::AppWindow,
+};
+
+use super::utils;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
+pub enum VramPalette {
+    Generic,
+    Bg0,
+    Bg1,
+    Bg2,
+    Bg3,
+    Obj0,
+    Obj1,
+    Obj2,
+    Obj3,
+}
+
+impl VramPalette {
+    pub const fn values() -> [VramPalette; 9] {
+        [
+            Self::Generic,
+            Self::Bg0,
+            Self::Bg1,
+            Self::Bg2,
+            Self::Bg3,
+            Self::Obj0,
+            Self::Obj1,
+            Self::Obj2,
+            Self::Obj3,
+        ]
+    }
+
+    pub const fn offset(self) -> Option<usize> {
+        match self {
+            Self::Generic => None,
+            Self::Bg0 => Some(0),
+            Self::Bg1 => Some(2),
+            Self::Bg2 => Some(4),
+            Self::Bg3 => Some(6),
+            Self::Obj0 => Some(8),
+            Self::Obj1 => Some(10),
+            Self::Obj2 => Some(12),
+            Self::Obj3 => Some(14),
+        }
+    }
+}
+
+impl Display for VramPalette {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Generic => f.write_str("Generic"),
+            Self::Bg0 => f.write_str("BG 0"),
+            Self::Bg1 => f.write_str("BG 1"),
+            Self::Bg2 => f.write_str("BG 2"),
+            Self::Bg3 => f.write_str("BG 3"),
+            Self::Obj0 => f.write_str("OBJ 0"),
+            Self::Obj1 => f.write_str("OBJ 1"),
+            Self::Obj2 => f.write_str("OBJ 2"),
+            Self::Obj3 => f.write_str("OBJ 3"),
+        }
+    }
+}
+
+pub struct CharacterDataWindow {
+    sim_id: SimId,
+    loader: Option<CharDataLoader>,
+    brightness: MemoryView,
+    palettes: MemoryView,
+    palette: VramPalette,
+    index: usize,
+    index_str: String,
+    scale: f32,
+    show_grid: bool,
+}
+
+impl CharacterDataWindow {
+    pub fn new(sim_id: SimId, memory: &mut MemoryMonitor) -> Self {
+        Self {
+            sim_id,
+            loader: Some(CharDataLoader::new(sim_id, memory)),
+            brightness: memory.view(sim_id, 0x0005f824, 8),
+            palettes: memory.view(sim_id, 0x0005f860, 16),
+            palette: VramPalette::Generic,
+            index: 0,
+            index_str: "0".into(),
+            scale: 4.0,
+            show_grid: true,
+        }
+    }
+
+    fn show_form(&mut self, ui: &mut Ui) {
+        let row_height = ui.spacing().interact_size.y;
+        ui.vertical(|ui| {
+            TableBuilder::new(ui)
+                .column(Column::auto())
+                .column(Column::remainder())
+                .body(|mut body| {
+                    body.row(row_height, |mut row| {
+                        row.col(|ui| {
+                            ui.label("Index");
+                        });
+                        row.col(|ui| {
+                            let res = ui.add(
+                                TextEdit::singleline(&mut self.index_str)
+                                    .horizontal_align(Align::Max),
+                            );
+                            if res.changed() {
+                                if let Some(index) =
+                                    self.index_str.parse().ok().filter(|id| *id < 2048)
+                                {
+                                    self.index = index;
+                                }
+                            }
+                        });
+                    });
+                    body.row(row_height, |mut row| {
+                        row.col(|ui| {
+                            ui.label("Address");
+                        });
+                        row.col(|ui| {
+                            let address = match self.index {
+                                0x000..0x200 => 0x00060000 + self.index,
+                                0x200..0x400 => 0x000e0000 + (self.index - 0x200),
+                                0x400..0x600 => 0x00160000 + (self.index - 0x400),
+                                0x600..0x800 => 0x001e0000 + (self.index - 0x600),
+                                _ => unreachable!("can't happen"),
+                            };
+                            let mut address_str = format!("{address:08x}");
+                            ui.add_enabled(
+                                false,
+                                TextEdit::singleline(&mut address_str).horizontal_align(Align::Max),
+                            );
+                        });
+                    });
+                    body.row(row_height, |mut row| {
+                        row.col(|ui| {
+                            ui.label("Mirror");
+                        });
+                        row.col(|ui| {
+                            let mirror = 0x00078000 + (self.index * 16);
+                            let mut mirror_str = format!("{mirror:08x}");
+                            ui.add_enabled(
+                                false,
+                                TextEdit::singleline(&mut mirror_str).horizontal_align(Align::Max),
+                            );
+                        });
+                    });
+                });
+            let resource = CharDataResource::Character {
+                palette: self.palette,
+                index: self.index,
+            };
+            let image = Image::new(resource.to_uri())
+                .maintain_aspect_ratio(true)
+                .tint(Color32::RED)
+                .texture_options(TextureOptions::NEAREST);
+            ui.add(image);
+            ui.section("Colors", |ui| {
+                ui.horizontal(|ui| {
+                    ui.label("Palette");
+                    ComboBox::from_id_salt("palette")
+                        .selected_text(self.palette.to_string())
+                        .width(ui.available_width())
+                        .show_ui(ui, |ui| {
+                            for palette in VramPalette::values() {
+                                ui.selectable_value(
+                                    &mut self.palette,
+                                    palette,
+                                    palette.to_string(),
+                                );
+                            }
+                        });
+                });
+                TableBuilder::new(ui)
+                    .columns(Column::remainder(), 4)
+                    .body(|mut body| {
+                        let palette = self.load_palette_colors();
+                        body.row(30.0, |mut row| {
+                            for color in palette {
+                                row.col(|ui| {
+                                    let rect = ui.available_rect_before_wrap();
+                                    let scale = rect.height() / rect.width();
+                                    let rect = rect.scale_from_center2(Vec2::new(scale, 1.0));
+                                    ui.painter().rect_filled(
+                                        rect,
+                                        0.0,
+                                        Color32::RED * Color32::from_gray(color),
+                                    );
+                                });
+                            }
+                        });
+                    });
+            });
+            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)
+                        .step_by(1.0)
+                        .show_value(false);
+                    ui.add(slider);
+                });
+                ui.checkbox(&mut self.show_grid, "Show grid");
+            });
+        });
+    }
+
+    fn load_palette_colors(&self) -> [u8; 4] {
+        let Some(offset) = self.palette.offset() else {
+            return utils::GENERIC_PALETTE;
+        };
+        let palette = self.palettes.borrow().read(offset);
+        let brightnesses = self.brightness.borrow();
+        let brts = brightnesses.range(0, 8);
+        utils::parse_palette(palette, brts)
+    }
+
+    fn show_chardata(&mut self, ui: &mut Ui) {
+        let start_pos = ui.cursor().min;
+        let resource = CharDataResource::CharacterData {
+            palette: self.palette,
+        };
+        let image = Image::new(resource.to_uri())
+            .fit_to_original_size(self.scale)
+            .tint(Color32::RED)
+            .texture_options(TextureOptions::NEAREST)
+            .sense(Sense::click());
+        let res = ui.add(image);
+        if res.clicked() {
+            if let Some(click_pos) = res.interact_pointer_pos() {
+                let fixed_pos = (click_pos - start_pos) / self.scale;
+                let x = (fixed_pos.x / 8.0) as usize;
+                let y = (fixed_pos.y / 8.0) as usize;
+                self.index = (y * 16) + x;
+                self.index_str = self.index.to_string();
+            }
+        }
+        let painter = ui.painter_at(res.rect);
+        if self.show_grid {
+            let stroke = ui.style().visuals.widgets.noninteractive.fg_stroke;
+            for x in (1..16).map(|i| (i as f32) * 8.0 * self.scale) {
+                let p1 = res.rect.min + (x, 0.0).into();
+                let p2 = res.rect.min + (x, 128.0 * 8.0 * self.scale).into();
+                painter.line(vec![p1, p2], stroke);
+            }
+            for y in (1..128).map(|i| (i as f32) * 8.0 * self.scale) {
+                let p1 = res.rect.min + (0.0, y).into();
+                let p2 = res.rect.min + (16.0 * 8.0 * self.scale, y).into();
+                painter.line(vec![p1, p2], stroke);
+            }
+        }
+        // draw box around selected
+        let x1 = (self.index % 16) as f32 * 8.0 * self.scale;
+        let x2 = x1 + (8.0 * self.scale);
+        let y1 = (self.index / 16) as f32 * 8.0 * self.scale;
+        let y2 = y1 + (8.0 * self.scale);
+        painter.line(
+            vec![
+                (res.rect.min + (x1, y1).into()),
+                (res.rect.min + (x2, y1).into()),
+                (res.rect.min + (x2, y2).into()),
+                (res.rect.min + (x1, y2).into()),
+                (res.rect.min + (x1, y1).into()),
+            ],
+            ui.style().visuals.widgets.active.fg_stroke,
+        );
+    }
+}
+
+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 initial_viewport(&self) -> ViewportBuilder {
+        ViewportBuilder::default()
+            .with_title(format!("Character Data ({})", self.sim_id))
+            .with_inner_size((640.0, 480.0))
+    }
+
+    fn on_init(&mut self, ctx: &Context, _render_state: &egui_wgpu::RenderState) {
+        let loader = self.loader.take().unwrap();
+        ctx.add_texture_loader(Arc::new(VramTextureLoader::new(loader)));
+    }
+
+    fn show(&mut self, ctx: &Context) {
+        CentralPanel::default().show(ctx, |ui| {
+            ui.horizontal_top(|ui| {
+                StripBuilder::new(ui)
+                    .size(Size::relative(0.3))
+                    .size(Size::remainder())
+                    .horizontal(|mut strip| {
+                        strip.cell(|ui| {
+                            ScrollArea::vertical().show(ui, |ui| self.show_form(ui));
+                        });
+                        strip.cell(|ui| {
+                            ScrollArea::both().show(ui, |ui| self.show_chardata(ui));
+                        });
+                    });
+            });
+        });
+    }
+}
+
+#[derive(Serialize, Deserialize, PartialEq, Eq, Hash)]
+enum CharDataResource {
+    Character { palette: VramPalette, index: usize },
+    CharacterData { palette: VramPalette },
+}
+
+struct CharDataLoader {
+    chardata: MemoryView,
+    brightness: MemoryView,
+    palettes: MemoryView,
+}
+
+impl CharDataLoader {
+    pub fn new(sim_id: SimId, memory: &mut MemoryMonitor) -> Self {
+        Self {
+            chardata: memory.view(sim_id, 0x00078000, 0x8000),
+            brightness: memory.view(sim_id, 0x0005f824, 8),
+            palettes: memory.view(sim_id, 0x0005f860, 16),
+        }
+    }
+
+    fn load_character(&self, palette: VramPalette, index: usize) -> Option<ColorImage> {
+        if index >= 2048 {
+            return None;
+        }
+        let palette = self.load_palette(palette);
+        let chardata = self.chardata.borrow();
+        let character = chardata.range::<u16>(index * 8, 8);
+        let mut buffer = Vec::with_capacity(8 * 8);
+        for row in character {
+            for offset in (0..16).step_by(2) {
+                let char = (row >> offset) & 0x3;
+                buffer.push(palette[char as usize]);
+            }
+        }
+        Some(ColorImage::from_gray([8, 8], &buffer))
+    }
+
+    fn load_character_data(&self, palette: VramPalette) -> Option<ColorImage> {
+        let palette = self.load_palette(palette);
+        let chardata = self.chardata.borrow();
+        let mut buffer = vec![0; 8 * 8 * 2048];
+        for (i, row) in chardata.range::<u16>(0, 2048).iter().enumerate() {
+            let bytes =
+                [0, 2, 4, 6, 8, 10, 12, 14].map(|off| palette[(*row as usize >> off) & 0x3]);
+            let char_index = i / 8;
+            let row_index = i % 8;
+            let x = (char_index % 16) * 8;
+            let y = (char_index / 16) * 8 + row_index;
+            let write_index = (y * 16 * 8) + x;
+            buffer[write_index..write_index + 8].copy_from_slice(&bytes);
+        }
+        Some(ColorImage::from_gray([8 * 16, 8 * 128], &buffer))
+    }
+
+    fn load_palette(&self, palette: VramPalette) -> [u8; 4] {
+        let Some(offset) = palette.offset() else {
+            return utils::GENERIC_PALETTE;
+        };
+        let palette = self.palettes.borrow().read(offset);
+        let brightnesses = self.brightness.borrow();
+        let brts = brightnesses.range(0, 8);
+        utils::parse_palette(palette, brts)
+    }
+}
+
+impl VramImageLoader for CharDataLoader {
+    type Resource = CharDataResource;
+
+    fn id(&self) -> &str {
+        concat!(module_path!(), "::CharDataLoader")
+    }
+
+    fn add(&self, resource: &Self::Resource) -> Option<ColorImage> {
+        match resource {
+            CharDataResource::Character { palette, index } => self.load_character(*palette, *index),
+            CharDataResource::CharacterData { palette } => self.load_character_data(*palette),
+        }
+    }
+
+    fn update<'a>(
+        &'a self,
+        resources: impl Iterator<Item = &'a Self::Resource>,
+    ) -> Vec<(&'a Self::Resource, ColorImage)> {
+        let _ = resources;
+        vec![]
+    }
+}
+
+trait UiExt {
+    fn section(&mut self, title: impl Into<String>, add_contents: impl FnOnce(&mut Ui));
+}
+
+impl UiExt for Ui {
+    fn section(&mut self, title: impl Into<String>, add_contents: impl FnOnce(&mut Ui)) {
+        let mut frame = Frame::group(self.style());
+        frame.outer_margin.top += 10.0;
+        frame.inner_margin.top += 2.0;
+        let res = frame.show(self, add_contents);
+        let text = RichText::new(title).background_color(self.style().visuals.panel_fill);
+        let old_rect = res.response.rect;
+        let mut text_rect = old_rect;
+        text_rect.min.x += 6.0;
+        let new_rect = self
+            .allocate_new_ui(UiBuilder::new().max_rect(text_rect), |ui| ui.label(text))
+            .response
+            .rect;
+        self.allocate_space((old_rect.max - new_rect.max) - (old_rect.min - new_rect.min));
+    }
+}

src/window/vram/utils.rs

@@ -0,0 +1,16 @@
+pub const GENERIC_PALETTE: [u8; 4] = [0, 64, 128, 255];
+
+pub fn parse_palette(palette: u8, brts: &[u8]) -> [u8; 4] {
+    let shades = [
+        0,
+        brts[0],
+        brts[2],
+        brts[0].saturating_add(brts[2]).saturating_add(brts[4]),
+    ];
+    [
+        0,
+        shades[(palette >> 2) as usize & 0x03],
+        shades[(palette >> 4) as usize & 0x03],
+        shades[(palette >> 6) as usize & 0x03],
+    ]
+}