src/app.rs

@@ -23,7 +23,7 @@ use crate::{
     vram::VramProcessor,
     window::{
         AboutWindow, AppWindow, BgMapWindow, CharacterDataWindow, GameWindow, GdbServerWindow,
-        InputWindow, ObjectWindow,
+        InputWindow, ObjectWindow, WorldWindow,
     },
 };
 
@@ -225,6 +225,10 @@ impl ApplicationHandler<UserEvent> for Application {
                 let objects = ObjectWindow::new(sim_id, &self.memory, &mut self.vram);
                 self.open(event_loop, Box::new(objects));
             }
+            UserEvent::OpenWorlds(sim_id) => {
+                let world = WorldWindow::new(sim_id, &self.memory, &mut self.vram);
+                self.open(event_loop, Box::new(world));
+            }
             UserEvent::OpenDebugger(sim_id) => {
                 let debugger =
                     GdbServerWindow::new(sim_id, self.client.clone(), self.proxy.clone());
@@ -486,6 +490,7 @@ pub enum UserEvent {
     OpenCharacterData(SimId),
     OpenBgMap(SimId),
     OpenObjects(SimId),
+    OpenWorlds(SimId),
     OpenDebugger(SimId),
     OpenInput,
     OpenPlayer2,

src/memory.rs

@@ -1,6 +1,7 @@
 use std::{
     collections::HashMap,
     fmt::Debug,
+    iter::FusedIterator,
     sync::{atomic::AtomicU64, Arc, Mutex, RwLock, RwLockReadGuard, TryLockError, Weak},
 };
 
@@ -117,7 +118,6 @@ impl<const N: usize, T: MemoryValue> MemoryValue for [T; N] {
 
 pub struct MemoryIter<'a, T> {
     bytes: &'a [u8],
-    index: usize,
     _phantom: std::marker::PhantomData<T>,
 }
 
@@ -125,7 +125,6 @@ impl<'a, T> MemoryIter<'a, T> {
     fn new(bytes: &'a [u8]) -> Self {
         Self {
             bytes,
-            index: 0,
             _phantom: std::marker::PhantomData,
         }
     }
@@ -136,15 +135,30 @@ impl<T: MemoryValue> Iterator for MemoryIter<'_, T> {
 
     #[inline]
     fn next(&mut self) -> Option<Self::Item> {
-        if self.index >= self.bytes.len() {
-            return None;
-        }
-        let bytes = &self.bytes[self.index..self.index + std::mem::size_of::<T>()];
-        self.index += std::mem::size_of::<T>();
+        let (bytes, rest) = self.bytes.split_at_checked(std::mem::size_of::<T>())?;
+        self.bytes = rest;
+        Some(T::from_bytes(bytes))
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let size = self.bytes.len() / std::mem::size_of::<T>();
+        (size, Some(size))
+    }
+}
+
+impl<T: MemoryValue> DoubleEndedIterator for MemoryIter<'_, T> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        let mid = self.bytes.len().checked_sub(std::mem::size_of::<T>())?;
+        // SAFETY: the checked_sub above is effectively a bounds check
+        let (rest, bytes) = unsafe { self.bytes.split_at_unchecked(mid) };
+        self.bytes = rest;
         Some(T::from_bytes(bytes))
     }
 }
 
+impl<T: MemoryValue> FusedIterator for MemoryIter<'_, T> {}
+
 impl MemoryRef<'_> {
     pub fn read<T: MemoryValue>(&self, index: usize) -> T {
         let from = index * size_of::<T>();

src/vram.rs

@@ -39,6 +39,7 @@ impl VramProcessor {
     pub fn add<const N: usize, R: VramRenderer<N> + 'static>(
         &self,
         renderer: R,
+        params: R::Params,
     ) -> ([VramImageHandle; N], VramParams<R::Params>) {
         let states = renderer.sizes().map(VramRenderImageState::new);
         let handles = states.clone().map(|state| VramImageHandle {
@@ -48,7 +49,7 @@ impl VramProcessor {
         let images = renderer
             .sizes()
             .map(|[width, height]| VramImage::new(width, height));
-        let sink = Arc::new(Mutex::new(R::Params::default()));
+        let sink = Arc::new(Mutex::new(params.clone()));
         let _ = self.sender.send(Box::new(VramRendererWrapper {
             renderer,
             params: Arc::downgrade(&sink),
@@ -56,7 +57,7 @@ impl VramProcessor {
             states,
         }));
         let params = VramParams {
-            value: R::Params::default(),
+            value: params,
             sink,
         };
         (handles, params)
@@ -100,32 +101,32 @@ impl VramProcessorWorker {
 }
 
 pub struct VramImage {
-    size: [usize; 2],
-    shades: Vec<Color32>,
+    pub size: [usize; 2],
+    pub pixels: Vec<Color32>,
 }
 
 impl VramImage {
     pub fn new(width: usize, height: usize) -> Self {
         Self {
             size: [width, height],
-            shades: vec![Color32::BLACK; width * height],
+            pixels: vec![Color32::BLACK; width * height],
         }
     }
 
     pub fn clear(&mut self) {
-        for shade in self.shades.iter_mut() {
-            *shade = Color32::BLACK;
+        for pixel in self.pixels.iter_mut() {
+            *pixel = Color32::BLACK;
         }
     }
 
     pub fn write(&mut self, coords: (usize, usize), pixel: Color32) {
-        self.shades[coords.1 * self.size[0] + coords.0] = pixel;
+        self.pixels[coords.1 * self.size[0] + coords.0] = pixel;
     }
 
     pub fn add(&mut self, coords: (usize, usize), pixel: Color32) {
         let index = coords.1 * self.size[0] + coords.0;
-        let old = self.shades[index];
-        self.shades[index] = Color32::from_rgb(
+        let old = self.pixels[index];
+        self.pixels[index] = Color32::from_rgb(
             old.r() + pixel.r(),
             old.g() + pixel.g(),
             old.b() + pixel.b(),
@@ -133,11 +134,11 @@ impl VramImage {
     }
 
     pub fn changed(&self, image: &ColorImage) -> bool {
-        image.pixels.iter().zip(&self.shades).any(|(a, b)| a != b)
+        image.pixels.iter().zip(&self.pixels).any(|(a, b)| a != b)
     }
 
     pub fn read(&self, image: &mut ColorImage) {
-        image.pixels.copy_from_slice(&self.shades);
+        image.pixels.copy_from_slice(&self.pixels);
     }
 }
 
@@ -176,7 +177,7 @@ impl<T: Clone + Eq> VramParams<T> {
 }
 
 pub trait VramRenderer<const N: usize>: Send {
-    type Params: Clone + Default + Send;
+    type Params: Clone + Send;
     fn sizes(&self) -> [[usize; 2]; N];
     fn render(&mut self, params: &Self::Params, images: &mut [VramImage; N]);
 }

src/window.rs

@@ -3,7 +3,7 @@ use egui::{Context, ViewportBuilder, ViewportId};
 pub use game::GameWindow;
 pub use gdb::GdbServerWindow;
 pub use input::InputWindow;
-pub use vram::{BgMapWindow, CharacterDataWindow, ObjectWindow};
+pub use vram::{BgMapWindow, CharacterDataWindow, ObjectWindow, WorldWindow};
 use winit::event::KeyEvent;
 
 use crate::emulator::SimId;

src/window/game.rs

@@ -150,6 +150,12 @@ impl GameWindow {
                     .unwrap();
                 ui.close_menu();
             }
+            if ui.button("Worlds").clicked() {
+                self.proxy
+                    .send_event(UserEvent::OpenWorlds(self.sim_id))
+                    .unwrap();
+                ui.close_menu();
+            }
         });
         ui.menu_button("Help", |ui| {
             if ui.button("About").clicked() {

src/window/vram.rs

@@ -2,7 +2,9 @@ mod bgmap;
 mod chardata;
 mod object;
 mod utils;
+mod world;
 
 pub use bgmap::*;
 pub use chardata::*;
 pub use object::*;
+pub use world::*;

src/window/vram/bgmap.rs

@@ -33,7 +33,7 @@ pub struct BgMapWindow {
 impl BgMapWindow {
     pub fn new(sim_id: SimId, memory: &Arc<MemoryClient>, vram: &mut VramProcessor) -> Self {
         let renderer = BgMapRenderer::new(sim_id, memory);
-        let ([cell, bgmap], params) = vram.add(renderer);
+        let ([cell, bgmap], params) = vram.add(renderer, BgMapParams::default());
         let loader =
             VramTextureLoader::new([("vram://cell".into(), cell), ("vram://bgmap".into(), bgmap)]);
         Self {
@@ -41,8 +41,8 @@ impl BgMapWindow {
             loader: Arc::new(loader),
             memory: memory.clone(),
             bgmaps: memory.watch(sim_id, 0x00020000, 0x1d800),
-            cell_index: 0,
-            generic_palette: false,
+            cell_index: params.cell_index,
+            generic_palette: params.generic_palette,
             params,
             scale: 1.0,
             show_grid: false,
@@ -243,7 +243,7 @@ impl BgMapRenderer {
         let colors = if generic_palette {
             [utils::generic_palette(Color32::RED); 4]
         } else {
-            [0, 2, 4, 6].map(|i| utils::parse_palette(palettes.read(i), &brts, Color32::RED))
+            [0, 2, 4, 6].map(|i| utils::palette_colors(palettes.read(i), &brts, Color32::RED))
         };
 
         for (i, cell) in bgmaps.range::<u16>(bgmap_index * 4096, 4096).enumerate() {
@@ -286,7 +286,7 @@ impl BgMapRenderer {
         let palette = if generic_palette {
             utils::generic_palette(Color32::RED)
         } else {
-            utils::parse_palette(palettes.read(palette_index * 2), &brts, Color32::RED)
+            utils::palette_colors(palettes.read(palette_index * 2), &brts, Color32::RED)
         };
 
         for row in 0..8 {

src/window/vram/chardata.rs

@@ -94,7 +94,7 @@ pub struct CharacterDataWindow {
 impl CharacterDataWindow {
     pub fn new(sim_id: SimId, memory: &MemoryClient, vram: &mut VramProcessor) -> Self {
         let renderer = CharDataRenderer::new(sim_id, memory);
-        let ([char, chardata], params) = vram.add(renderer);
+        let ([char, chardata], params) = vram.add(renderer, CharDataParams::default());
         let loader = VramTextureLoader::new([
             ("vram://char".into(), char),
             ("vram://chardata".into(), chardata),
@@ -222,7 +222,7 @@ impl CharacterDataWindow {
         let palette = self.palettes.borrow().read(offset);
         let brightnesses = self.brightness.borrow();
         let brts = brightnesses.read(0);
-        utils::parse_palette(palette, &brts, Color32::RED)
+        utils::palette_colors(palette, &brts, Color32::RED)
     }
 
     fn show_chardata(&mut self, ui: &mut Ui) {
@@ -351,6 +351,6 @@ impl CharDataRenderer {
         let palette = self.palettes.borrow().read(offset);
         let brightnesses = self.brightness.borrow();
         let brts = brightnesses.read(0);
-        utils::parse_palette(palette, &brts, Color32::RED)
+        utils::palette_colors(palette, &brts, Color32::RED)
     }
 }

src/window/vram/object.rs

@@ -31,8 +31,14 @@ pub struct ObjectWindow {
 
 impl ObjectWindow {
     pub fn new(sim_id: SimId, memory: &Arc<MemoryClient>, vram: &mut VramProcessor) -> 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),
+        };
         let renderer = ObjectRenderer::new(sim_id, memory);
-        let ([zoom, full], params) = vram.add(renderer);
+        let ([zoom, full], params) = vram.add(renderer, initial_params);
         let loader =
             VramTextureLoader::new([("vram://zoom".into(), zoom), ("vram://full".into(), full)]);
         Self {
@@ -40,8 +46,8 @@ impl ObjectWindow {
             loader: Arc::new(loader),
             memory: memory.clone(),
             objects: memory.watch(sim_id, 0x0003e000, 0x2000),
-            index: 0,
-            generic_palette: false,
+            index: params.index,
+            generic_palette: params.generic_palette,
             params,
             scale: 1.0,
         }
@@ -175,7 +181,7 @@ impl ObjectWindow {
         self.params.write(ObjectParams {
             index: self.index,
             generic_palette: self.generic_palette,
-            ..ObjectParams::default()
+            ..*self.params
         });
     }
 
@@ -233,17 +239,6 @@ struct ObjectParams {
     right_color: Color32,
 }
 
-impl Default for ObjectParams {
-    fn default() -> Self {
-        Self {
-            index: 0,
-            generic_palette: false,
-            left_color: Color32::from_rgb(0xff, 0x00, 0x00),
-            right_color: Color32::from_rgb(0x00, 0xc6, 0xf0),
-        }
-    }
-}
-
 enum Eye {
     Left,
     Right,
@@ -302,7 +297,7 @@ impl ObjectRenderer {
         let palette = if params.generic_palette {
             utils::generic_palette(color)
         } else {
-            utils::parse_palette(palettes.read(8 + obj.data.palette_index * 2), &brts, color)
+            utils::palette_colors(palettes.read(8 + obj.data.palette_index * 2), &brts, color)
         };
 
         for row in 0..8 {

src/window/vram/utils.rs

@@ -10,24 +10,29 @@ pub fn generic_palette(color: Color32) -> [Color32; 4] {
     GENERIC_PALETTE.map(|brt| shade(brt, color))
 }
 
-pub fn parse_palette(palette: u8, brts: &[u8; 8], color: Color32) -> [Color32; 4] {
-    let shades = [
-        Color32::BLACK,
-        shade(brts[0], color),
-        shade(brts[2], color),
-        shade(
-            brts[0].saturating_add(brts[2]).saturating_add(brts[4]),
-            color,
-        ),
-    ];
+pub const fn parse_palette(palette: u8) -> [u8; 4] {
     [
-        Color32::BLACK,
-        shades[(palette >> 2) as usize & 0x03],
-        shades[(palette >> 4) as usize & 0x03],
-        shades[(palette >> 6) as usize & 0x03],
+        0,
+        (palette >> 2) & 0x03,
+        (palette >> 4) & 0x03,
+        (palette >> 6) & 0x03,
     ]
 }
 
+pub const fn parse_shades(brts: &[u8; 8]) -> [u8; 4] {
+    [
+        0,
+        brts[0],
+        brts[2],
+        brts[0].saturating_add(brts[2]).saturating_add(brts[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])
+}
+
 pub struct Object {
     pub x: i16,
     pub lon: bool,

src/window/vram/world.rs

@@ -0,0 +1,409 @@
+use std::{fmt::Display, sync::Arc};
+
+use egui::{
+    CentralPanel, Checkbox, Color32, ComboBox, Context, Image, ScrollArea, Slider, TextureOptions,
+    Ui, ViewportBuilder, ViewportId,
+};
+use egui_extras::{Column, Size, StripBuilder, TableBuilder};
+use num_derive::{FromPrimitive, ToPrimitive};
+use num_traits::FromPrimitive;
+
+use crate::{
+    emulator::SimId,
+    memory::{MemoryClient, MemoryView},
+    vram::{VramImage, VramParams, VramProcessor, VramRenderer, VramTextureLoader},
+    window::{
+        utils::{NumberEdit, UiExt as _},
+        AppWindow,
+    },
+};
+
+use super::utils::{self, shade, Object};
+
+pub struct WorldWindow {
+    sim_id: SimId,
+    loader: Arc<VramTextureLoader>,
+    worlds: MemoryView,
+    index: usize,
+    generic_palette: bool,
+    params: VramParams<WorldParams>,
+    scale: f32,
+}
+
+impl WorldWindow {
+    pub fn new(sim_id: SimId, memory: &MemoryClient, vram: &mut VramProcessor) -> 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),
+        };
+        let renderer = WorldRenderer::new(sim_id, memory);
+        let ([world], params) = vram.add(renderer, initial_params);
+        let loader = VramTextureLoader::new([("vram://world".into(), world)]);
+        Self {
+            sim_id,
+            loader: Arc::new(loader),
+            worlds: memory.watch(sim_id, 0x3d800, 0x400),
+            index: params.index,
+            generic_palette: params.generic_palette,
+            params,
+            scale: 1.0,
+        }
+    }
+
+    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| {
+                            ui.add(NumberEdit::new(&mut self.index).range(0..32));
+                        });
+                    });
+                });
+            let data = {
+                let worlds = self.worlds.borrow();
+                worlds.read(self.index)
+            };
+            let mut world = World::parse(&data);
+            ui.section("Properties", |ui| {
+                TableBuilder::new(ui)
+                    .column(Column::remainder())
+                    .column(Column::remainder())
+                    .body(|mut body| {
+                        body.row(row_height, |mut row| {
+                            row.col(|ui| {
+                                ui.label("Mode");
+                            });
+                            row.col(|ui| {
+                                ComboBox::from_id_salt("mode")
+                                    .selected_text(world.header.mode.to_string())
+                                    .width(ui.available_width())
+                                    .show_ui(ui, |ui| {
+                                        for mode in WorldMode::values() {
+                                            ui.selectable_value(
+                                                &mut world.header.mode,
+                                                mode,
+                                                mode.to_string(),
+                                            );
+                                        }
+                                    });
+                            });
+                        });
+                        body.row(row_height, |mut row| {
+                            row.col(|ui| {
+                                ui.add(Checkbox::new(&mut world.header.lon, "Left"));
+                            });
+                            row.col(|ui| {
+                                ui.add(Checkbox::new(&mut world.header.ron, "Right"));
+                            });
+                        });
+                        body.row(row_height, |mut row| {
+                            row.col(|ui| {
+                                ui.add(Checkbox::new(&mut world.header.end, "End"));
+                            });
+                            row.col(|ui| {
+                                ui.add(Checkbox::new(&mut world.header.over, "Overplane"));
+                            });
+                        });
+                    });
+            });
+            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.generic_palette, "Generic palette");
+            });
+        });
+        self.params.write(WorldParams {
+            index: self.index,
+            generic_palette: self.generic_palette,
+            ..*self.params
+        });
+    }
+
+    fn show_world(&mut self, ui: &mut Ui) {
+        let image = Image::new("vram://world")
+            .fit_to_original_size(self.scale)
+            .texture_options(TextureOptions::NEAREST);
+        ui.add(image);
+    }
+}
+
+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 initial_viewport(&self) -> ViewportBuilder {
+        ViewportBuilder::default()
+            .with_title(format!("Worlds ({})", self.sim_id))
+            .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| {
+            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_world(ui));
+                        });
+                    });
+            });
+        });
+    }
+}
+
+#[derive(Clone, PartialEq, Eq)]
+struct WorldParams {
+    index: usize,
+    generic_palette: bool,
+    left_color: Color32,
+    right_color: Color32,
+}
+
+struct WorldRenderer {
+    chardata: MemoryView,
+    objects: MemoryView,
+    worlds: MemoryView,
+    brightness: MemoryView,
+    palettes: MemoryView,
+    scr: MemoryView,
+    // an object world could update the same pixel more than once,
+    // so we can't add the left/right eye color to the output buffer directly.
+    buffer: Box<[[u8; 2]; 384 * 224]>,
+}
+
+impl WorldRenderer {
+    pub fn new(sim_id: SimId, memory: &MemoryClient) -> Self {
+        Self {
+            chardata: memory.watch(sim_id, 0x00078000, 0x8000),
+            objects: memory.watch(sim_id, 0x0003e000, 0x2000),
+            worlds: memory.watch(sim_id, 0x0003d800, 0x400),
+            brightness: memory.watch(sim_id, 0x0005f824, 8),
+            palettes: memory.watch(sim_id, 0x0005f860, 16),
+            scr: memory.watch(sim_id, 0x0005f848, 8),
+
+            buffer: vec![[0, 0]; 384 * 224]
+                .into_boxed_slice()
+                .try_into()
+                .unwrap(),
+        }
+    }
+
+    fn render_object_world(&mut self, group: usize, params: &WorldParams, image: &mut VramImage) {
+        for cell in self.buffer.iter_mut() {
+            *cell = [0, 0];
+        }
+
+        let palettes = {
+            let palettes = self.palettes.borrow().read::<[u8; 8]>(1);
+            [
+                utils::parse_palette(palettes[0]),
+                utils::parse_palette(palettes[2]),
+                utils::parse_palette(palettes[4]),
+                utils::parse_palette(palettes[6]),
+            ]
+        };
+        let chardata = self.chardata.borrow();
+        let objects = self.objects.borrow();
+
+        let (first_range, second_range) = {
+            let scr = self.scr.borrow();
+            let start = if group == 0 {
+                0
+            } else {
+                scr.read::<u16>(group - 1).wrapping_add(1) as usize & 0x03ff
+            };
+            let end = scr.read::<u16>(group).wrapping_add(1) as usize & 0x03ff;
+            if start > end {
+                ((start, 1024 - start), (end != 0).then_some((0, end)))
+            } else {
+                ((start, end - start), None)
+            }
+        };
+
+        // Fill the buffer
+        for object in std::iter::once(first_range)
+            .chain(second_range)
+            .flat_map(|(start, count)| objects.range(start, count))
+            .rev()
+        {
+            let obj = Object::parse(object);
+            if !obj.lon && !obj.ron {
+                continue;
+            }
+
+            let char = chardata.read::<[u16; 8]>(obj.data.char_index);
+            let palette = &palettes[obj.data.palette_index];
+
+            for row in 0..8 {
+                let y = obj.y + row as i16;
+                if !(0..224).contains(&y) {
+                    continue;
+                }
+                for (col, pixel) in
+                    utils::read_char_row(&char, obj.data.hflip, obj.data.vflip, row).enumerate()
+                {
+                    if pixel == 0 {
+                        // transparent
+                        continue;
+                    }
+                    let lx = obj.x + col as i16 - obj.parallax;
+                    if obj.lon && (0..384).contains(&lx) {
+                        let index = (y as usize) * 384 + lx as usize;
+                        self.buffer[index][0] = palette[pixel as usize];
+                    }
+                    let rx = obj.x + col as i16 + obj.parallax;
+                    if obj.ron & (0..384).contains(&rx) {
+                        let index = (y as usize) * 384 + rx as usize;
+                        self.buffer[index][1] = palette[pixel as usize];
+                    }
+                }
+            }
+        }
+
+        let colors = if params.generic_palette {
+            [
+                utils::generic_palette(params.left_color),
+                utils::generic_palette(params.right_color),
+            ]
+        } else {
+            let brts = self.brightness.borrow().read::<[u8; 8]>(0);
+            let shades = utils::parse_shades(&brts);
+            [
+                shades.map(|s| shade(s, params.left_color)),
+                shades.map(|s| shade(s, params.right_color)),
+            ]
+        };
+
+        for (dst, shades) in image.pixels.iter_mut().zip(self.buffer.iter()) {
+            let left = colors[0][shades[0] as usize];
+            let right = colors[1][shades[1] as usize];
+            *dst = Color32::from_rgb(
+                left.r() + right.r(),
+                left.g() + right.g(),
+                left.b() + right.b(),
+            )
+        }
+    }
+}
+
+impl VramRenderer<1> for WorldRenderer {
+    type Params = WorldParams;
+
+    fn sizes(&self) -> [[usize; 2]; 1] {
+        [[384, 224]]
+    }
+
+    fn render(&mut self, params: &Self::Params, images: &mut [VramImage; 1]) {
+        let image = &mut images[0];
+
+        let worlds = self.worlds.borrow();
+        let header = WorldHeader::parse(worlds.read(params.index * 16));
+        if header.end || (!header.lon && header.ron) {
+            image.clear();
+            return;
+        }
+
+        if header.mode == WorldMode::Object {
+            let mut group = 3usize;
+            for world in params.index + 1..32 {
+                let header = WorldHeader::parse(worlds.read(world * 16));
+                if header.mode == WorldMode::Object && (header.lon || header.ron) {
+                    group = group.checked_sub(1).unwrap_or(3);
+                }
+            }
+            drop(worlds);
+            self.render_object_world(group, params, image);
+        }
+    }
+}
+
+struct World {
+    header: WorldHeader,
+}
+
+impl World {
+    pub fn parse(data: &[u16; 16]) -> Self {
+        Self {
+            header: WorldHeader::parse(data[0]),
+        }
+    }
+}
+
+struct WorldHeader {
+    lon: bool,
+    ron: bool,
+    mode: WorldMode,
+    over: bool,
+    end: bool,
+}
+
+impl WorldHeader {
+    fn parse(data: u16) -> Self {
+        let lon = data & 0x8000 != 0;
+        let ron = data & 0x4000 != 0;
+        let mode = WorldMode::from_u16((data >> 12) & 0x3).unwrap();
+        let over = data & 0x0080 != 0;
+        let end = data & 0x0040 != 0;
+        Self {
+            lon,
+            ron,
+            mode,
+            over,
+            end,
+        }
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, FromPrimitive, ToPrimitive)]
+enum WorldMode {
+    Normal = 0,
+    HBias = 1,
+    Affine = 2,
+    Object = 3,
+}
+
+impl WorldMode {
+    fn values() -> [Self; 4] {
+        [Self::Normal, Self::HBias, Self::Affine, Self::Object]
+    }
+}
+
+impl Display for WorldMode {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            Self::Normal => "Normal",
+            Self::HBias => "H-bias",
+            Self::Affine => "Affine",
+            Self::Object => "Object",
+        })
+    }
+}