Debug options screen (F3+F6): choose what the F3 overlay shows

Ports DebugOptionsScreen, DebugScreenEntries and DebugScreenEntryList
from 26.3: every entry can be off, in the overlay or always shown, the
default and performance profiles, debug-profile.json beside options.txt.
The overlay, F3+B, F3+G and the 3D crosshair follow the entries, and the
screen's GUI Scale button edits debugGuiScale.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

.gitignore

@@ -21,6 +21,7 @@
 .DS_Store
 # What the client writes to its working directory when run from the repo root.
 /options.txt
+/debug-profile.json
 /horizon.txt
 /horizon-graphics.txt
 /horizon-controller.txt

crates/horizon-client/src/debug_entries.rs

@@ -0,0 +1,430 @@
+//! The debug screen's entries (26.3 `DebugScreenEntries`, `DebugScreenEntryList`):
+//! what each F3 line block and debug renderer is, whether it shows always,
+//! only in the overlay or never, the two built-in profiles, and
+//! `debug-profile.json` beside `options.txt`, which keeps them.
+use std::collections::BTreeMap;
+use std::path::{Path, PathBuf};
+
+/// `DebugScreenEntryStatus`.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Status {
+    AlwaysOn,
+    InOverlay,
+    Never,
+}
+
+impl Status {
+    /// `getSerializedName`.
+    pub fn name(self) -> &'static str {
+        match self {
+            Status::AlwaysOn => "alwaysOn",
+            Status::InOverlay => "inOverlay",
+            Status::Never => "never",
+        }
+    }
+    fn parse(name: &str) -> Option<Self> {
+        [Status::AlwaysOn, Status::InOverlay, Status::Never]
+            .into_iter()
+            .find(|s| s.name() == name)
+    }
+}
+
+/// `DebugScreenProfile`.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Profile {
+    Default,
+    Performance,
+}
+
+impl Profile {
+    pub fn name(self) -> &'static str {
+        match self {
+            Profile::Default => "default",
+            Profile::Performance => "performance",
+        }
+    }
+    pub fn translation_key(self) -> &'static str {
+        match self {
+            Profile::Default => "debug.options.profile.default",
+            Profile::Performance => "debug.options.profile.performance",
+        }
+    }
+    fn parse(name: &str) -> Option<Self> {
+        [Profile::Default, Profile::Performance]
+            .into_iter()
+            .find(|p| p.name() == name)
+    }
+    /// `DebugScreenEntries.PROFILES`.
+    fn statuses(self) -> &'static [(&'static str, Status)] {
+        use Status::*;
+        match self {
+            Profile::Default => &[
+                ("3d_crosshair", InOverlay),
+                ("game_version", InOverlay),
+                ("tps", InOverlay),
+                ("fps", InOverlay),
+                ("memory", InOverlay),
+                ("system_specs", InOverlay),
+                ("player_position", InOverlay),
+                ("player_section_position", InOverlay),
+                ("simple_performance_impactors", InOverlay),
+            ],
+            Profile::Performance => &[
+                ("tps", InOverlay),
+                ("fps", AlwaysOn),
+                ("gpu_utilization", InOverlay),
+                ("memory", InOverlay),
+                ("simple_performance_impactors", InOverlay),
+            ],
+        }
+    }
+}
+
+/// `DebugEntryCategory`: the screen's two sections, by `sortKey`.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub enum Category {
+    /// `SCREEN_TEXT`, `debug.options.category.text`.
+    Text,
+    /// `RENDERER` (`DebugEntryNoop`), `debug.options.category.renderer`.
+    Renderer,
+}
+
+impl Category {
+    pub fn translation_key(self) -> &'static str {
+        match self {
+            Category::Text => "debug.options.category.text",
+            Category::Renderer => "debug.options.category.renderer",
+        }
+    }
+}
+
+/// One registered entry: its path in the `minecraft` namespace, its section,
+/// and whether it shows while debug info is reduced (`isAllowed(true)`).
+#[derive(Clone, Copy, Debug)]
+pub struct Entry {
+    pub path: &'static str,
+    pub category: Category,
+    pub reduced: bool,
+}
+
+const fn text(path: &'static str, reduced: bool) -> Entry {
+    Entry {
+        path,
+        category: Category::Text,
+        reduced,
+    }
+}
+const fn renderer(path: &'static str) -> Entry {
+    Entry {
+        path,
+        category: Category::Renderer,
+        reduced: false,
+    }
+}
+
+/// `DebugScreenEntries`' registrations, in their order.
+pub const ENTRIES: [Entry; 46] = [
+    text("game_version", true),
+    text("fps", true),
+    text("tps", true),
+    text("memory", true),
+    text("detailed_memory", true),
+    text("system_specs", true),
+    text("looking_at_block_state", false),
+    text("looking_at_block_tags", false),
+    text("looking_at_fluid_state", false),
+    text("looking_at_fluid_tags", false),
+    text("looking_at_entity", false),
+    text("looking_at_entity_tags", false),
+    text("chunk_render_stats", true),
+    text("chunk_generation_stats", false),
+    text("entity_render_stats", true),
+    text("particle_render_stats", false),
+    text("chunk_source_stats", true),
+    text("player_position", false),
+    text("player_section_position", true),
+    text("player_speed", false),
+    text("light_levels", false),
+    text("heightmap", false),
+    text("biome", false),
+    text("local_difficulty", false),
+    text("day_count", false),
+    text("entity_spawn_counts", false),
+    text("sound_mood", false),
+    text("sound_cache", true),
+    text("post_effects", false),
+    renderer("entity_hitboxes"),
+    renderer("chunk_borders"),
+    renderer("3d_crosshair"),
+    renderer("chunk_section_paths"),
+    text("gpu_utilization", true),
+    text("simple_performance_impactors", true),
+    renderer("chunk_section_octree"),
+    renderer("visualize_water_levels"),
+    renderer("visualize_heightmap"),
+    renderer("visualize_collision_boxes"),
+    renderer("visualize_entity_supporting_blocks"),
+    renderer("visualize_block_light_levels"),
+    renderer("visualize_sky_light_levels"),
+    renderer("visualize_solid_faces"),
+    renderer("visualize_chunks_on_server"),
+    renderer("visualize_sky_light_sections"),
+    renderer("chunk_section_visibility"),
+];
+
+/// `DebugScreenEntries.getEntry` by path.
+pub fn entry(path: &str) -> Option<&'static Entry> {
+    ENTRIES.iter().find(|e| e.path == path)
+}
+
+/// `DebugOptionsScreen.OptionList.updateSearch`: the entries whose path
+/// contains `search`, by category then identifier.
+pub fn search(search: &str) -> Vec<&'static Entry> {
+    let mut all: Vec<&Entry> = ENTRIES.iter().filter(|e| e.path.contains(search)).collect();
+    all.sort_by(|a, b| a.category.cmp(&b.category).then(a.path.cmp(b.path)));
+    all
+}
+
+/// `DebugScreenEntryList`: every entry's status (by full identifier, as the
+/// file keeps them) and the profile they came from if unchanged. Whether the
+/// F3 overlay is open (`isOverlayVisible`) is the game's `debug`.
+#[derive(Clone, Debug)]
+pub struct DebugEntries {
+    statuses: BTreeMap<String, Status>,
+    profile: Option<Profile>,
+    file: Option<PathBuf>,
+}
+
+impl Default for DebugEntries {
+    fn default() -> Self {
+        let mut entries = Self {
+            statuses: BTreeMap::new(),
+            profile: None,
+            file: None,
+        };
+        entries.reset_to_profile(Profile::Default);
+        entries
+    }
+}
+
+fn identifier(path: &str) -> String {
+    format!("minecraft:{path}")
+}
+
+impl DebugEntries {
+    /// `DebugScreenEntryList.load` from `debug-profile.json` in `dir`: the
+    /// default profile without a file; a file that does not parse is reset
+    /// to it and saved again.
+    pub fn load(dir: &Path) -> Self {
+        let file = dir.join("debug-profile.json");
+        let mut entries = Self {
+            file: Some(file.clone()),
+            ..Self::default()
+        };
+        let Ok(text) = std::fs::read_to_string(&file) else {
+            return entries;
+        };
+        match Self::parse(&text) {
+            Some((Some(profile), _)) => entries.reset_to_profile(profile),
+            Some((None, custom)) => {
+                entries.statuses = custom;
+                entries.profile = None;
+            }
+            None => {
+                log::error!(
+                    "Couldn't read debug profile file {}, resetting to default",
+                    file.display()
+                );
+                entries.save();
+            }
+        }
+        entries
+    }
+    /// `SerializedOptions.CODEC`: an optional `profile` name and an optional
+    /// `custom` map of identifiers to statuses.
+    fn parse(text: &str) -> Option<(Option<Profile>, BTreeMap<String, Status>)> {
+        let json: serde_json::Value = serde_json::from_str(text).ok()?;
+        let object = json.as_object()?;
+        let profile = match object.get("profile") {
+            Some(name) => Some(Profile::parse(name.as_str()?)?),
+            None => None,
+        };
+        let mut custom = BTreeMap::new();
+        if let Some(map) = object.get("custom") {
+            for (key, status) in map.as_object()? {
+                // Identifier.CODEC: a bare path is in the minecraft namespace.
+                let key = if key.contains(':') {
+                    key.clone()
+                } else {
+                    identifier(key)
+                };
+                custom.insert(key, Status::parse(status.as_str()?)?);
+            }
+        }
+        Some((profile, custom))
+    }
+    /// `DebugScreenEntryList.save`: the profile's name while it is unchanged,
+    /// else every status, with the data version the codec wraps it in.
+    pub fn save(&self) {
+        let Some(file) = &self.file else {
+            return;
+        };
+        let mut json = serde_json::Map::new();
+        json.insert(
+            "DataVersion".into(),
+            horizon_core::version::DATA_VERSION.into(),
+        );
+        match self.profile {
+            Some(profile) => {
+                json.insert("profile".into(), profile.name().into());
+            }
+            None => {
+                let custom: serde_json::Map<String, serde_json::Value> = self
+                    .statuses
+                    .iter()
+                    .map(|(k, s)| (k.clone(), s.name().into()))
+                    .collect();
+                json.insert("custom".into(), custom.into());
+            }
+        }
+        if let Err(e) = std::fs::write(file, serde_json::Value::Object(json).to_string()) {
+            log::error!("Failed to save debug profile file {}: {e}", file.display());
+        }
+    }
+    fn reset_to_profile(&mut self, profile: Profile) {
+        self.profile = Some(profile);
+        self.statuses = profile
+            .statuses()
+            .iter()
+            .map(|(path, status)| (identifier(path), *status))
+            .collect();
+    }
+    /// `loadProfile` then `save` (the screen's profile buttons).
+    pub fn load_profile(&mut self, profile: Profile) {
+        self.reset_to_profile(profile);
+        self.save();
+    }
+    pub fn is_using_profile(&self, profile: Profile) -> bool {
+        self.profile == Some(profile)
+    }
+    /// `getStatus`: never for an entry the statuses leave out.
+    pub fn status(&self, path: &str) -> Status {
+        self.statuses
+            .get(&identifier(path))
+            .copied()
+            .unwrap_or(Status::Never)
+    }
+    /// `setStatus`: the statuses are custom from now on, and saved.
+    pub fn set_status(&mut self, path: &str, status: Status) {
+        self.profile = None;
+        self.statuses.insert(identifier(path), status);
+        self.save();
+    }
+    /// `toggleStatus` (F3+B, F3+G) with the overlay open or not: whether the
+    /// entry is on afterwards.
+    pub fn toggle_status(&mut self, path: &str, overlay: bool) -> bool {
+        let (status, on) = match self.statuses.get(&identifier(path)) {
+            Some(Status::AlwaysOn) => (Status::Never, false),
+            Some(Status::InOverlay) if overlay => (Status::Never, false),
+            Some(Status::Never) if overlay => (Status::InOverlay, true),
+            _ => (Status::AlwaysOn, true),
+        };
+        self.set_status(path, status);
+        on
+    }
+    /// `isCurrentlyEnabled` (`rebuildCurrentList`): on always, or in the
+    /// `overlay` while it is open, and allowed with the debug info `reduced`.
+    pub fn enabled(&self, path: &str, overlay: bool, reduced: bool) -> bool {
+        let shown = match self.status(path) {
+            Status::AlwaysOn => true,
+            Status::InOverlay => overlay,
+            Status::Never => false,
+        };
+        shown && entry(path).is_some_and(|e| e.reduced || !reduced)
+    }
+    /// `getCurrentlyEnabled().isEmpty()` negated: something to draw.
+    pub fn any_enabled(&self, overlay: bool, reduced: bool) -> bool {
+        ENTRIES
+            .iter()
+            .any(|e| self.enabled(e.path, overlay, reduced))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn toggling_follows_the_overlay() {
+        let mut e = DebugEntries::default();
+        // Not in the default profile: on always while F3 is closed.
+        assert!(e.toggle_status("entity_hitboxes", false));
+        assert_eq!(e.status("entity_hitboxes"), Status::AlwaysOn);
+        assert!(!e.toggle_status("entity_hitboxes", false));
+        assert_eq!(e.status("entity_hitboxes"), Status::Never);
+        // With F3 open, a hidden entry goes in the overlay only.
+        assert!(e.toggle_status("chunk_borders", true));
+        assert_eq!(e.status("chunk_borders"), Status::AlwaysOn);
+        assert!(!e.toggle_status("chunk_borders", true));
+        assert_eq!(e.status("chunk_borders"), Status::Never);
+        assert!(e.toggle_status("chunk_borders", true));
+        assert_eq!(e.status("chunk_borders"), Status::InOverlay);
+        assert!(!e.toggle_status("chunk_borders", true));
+        assert!(!e.is_using_profile(Profile::Default));
+    }
+
+    #[test]
+    fn enabled_needs_the_overlay_and_full_debug_info() {
+        let mut e = DebugEntries::default();
+        assert!(!e.any_enabled(false, false));
+        assert!(e.enabled("player_position", true, false));
+        // Reduced debug info hides the position, not the section.
+        assert!(!e.enabled("player_position", true, true));
+        assert!(e.enabled("player_section_position", true, true));
+        e.load_profile(Profile::Performance);
+        assert!(e.enabled("fps", false, false));
+        assert!(!e.enabled("memory", false, false));
+    }
+
+    #[test]
+    fn the_file_keeps_a_profile_or_the_statuses() {
+        let dir =
+            std::env::temp_dir().join(format!("horizon-debug-profile-{}", std::process::id()));
+        std::fs::create_dir_all(&dir).unwrap();
+        let mut e = DebugEntries::load(&dir);
+        assert!(e.is_using_profile(Profile::Default));
+        e.load_profile(Profile::Performance);
+        let saved: serde_json::Value =
+            serde_json::from_str(&std::fs::read_to_string(dir.join("debug-profile.json")).unwrap())
+                .unwrap();
+        assert_eq!(saved["profile"], "performance");
+        assert!(DebugEntries::load(&dir).is_using_profile(Profile::Performance));
+        e.set_status("biome", Status::AlwaysOn);
+        let loaded = DebugEntries::load(&dir);
+        assert_eq!(loaded.status("biome"), Status::AlwaysOn);
+        assert_eq!(loaded.status("fps"), Status::AlwaysOn);
+        assert!(!loaded.is_using_profile(Profile::Performance));
+        // A broken file is reset to the default profile.
+        std::fs::write(dir.join("debug-profile.json"), "{\"profile\":\"nope\"}").unwrap();
+        assert!(DebugEntries::load(&dir).is_using_profile(Profile::Default));
+        std::fs::remove_dir_all(&dir).unwrap();
+    }
+
+    #[test]
+    fn the_list_sorts_text_before_renderers() {
+        let all = search("");
+        assert_eq!(all.len(), 46);
+        assert_eq!(all[0].path, "biome");
+        let first_renderer = all
+            .iter()
+            .position(|e| e.category == Category::Renderer)
+            .unwrap();
+        assert_eq!(all[first_renderer].path, "3d_crosshair");
+        assert!(
+            all[first_renderer..]
+                .iter()
+                .all(|e| e.category == Category::Renderer)
+        );
+        assert_eq!(search("chunk_b").len(), 1);
+    }
+}

crates/horizon-client/src/game.rs

@@ -87,6 +87,7 @@ mod creatures;
 mod crossbow;
 pub(crate) mod cushions;
 mod debug_keys;
+mod debug_options;
 mod debug_stick;
 mod decorated_pot;
 mod dedicated;
@@ -703,6 +704,8 @@ enum Screen {
     DialogWarning,
     /// WinScreen: the end poem and the credits (game/win.rs).
     Win,
+    /// DebugOptionsScreen, F3+F6 (game/debug_options.rs).
+    DebugOptions,
 }
 struct Mining {
     pos: [i32; 3],
@@ -2284,8 +2287,11 @@ struct Game<'a> {
     debug_keys: horizon_client::debug_keys::DebugKeys,
     /// The F3 overlay's charts (F3+2, F3+3).
     debug_charts: horizon_client::debug_chart::DebugCharts,
-    show_hitboxes: bool,
-    show_chunk_borders: bool,
+    /// `Minecraft.debugEntries`: what the overlay and the debug renderers
+    /// show (`debug-profile.json`, F3+F6).
+    debug_entries: horizon_client::debug_entries::DebugEntries,
+    /// `DebugOptionsScreen` while it is open (game/debug_options.rs).
+    debug_options: Option<debug_options::DebugOptionsUi>,
     /// PauseScreen.showPauseMenu (false after F3+Escape).
     pause_menu: bool,
     /// MultiPlayerGameMode.previousLocalPlayerMode (F3+N goes back to it).
@@ -6707,6 +6713,7 @@ impl Game<'_> {
                     | Screen::ConfirmLink
                     | Screen::DialogWarning
                     | Screen::CommandBlock
+                    | Screen::DebugOptions
             ) || self.book.is_some()
                 || self.win_screen_pauses())
     }
@@ -7363,6 +7370,7 @@ impl Game<'_> {
             Screen::DialogWarning => self.draw_dialog_warning(&mut batch),
             Screen::CommandBlock => self.draw_command_block(&mut batch),
             Screen::BlockEditor => self.draw_block_editor(&mut batch),
+            Screen::DebugOptions => self.draw_debug_options(&mut batch),
             Screen::Inventory => {
                 self.draw_inventory(&mut batch);
                 self.draw_mod_browser(&mut batch);
@@ -13870,6 +13878,7 @@ impl Game<'_> {
                 Screen::BlockEditor => self.close_block_editor(),
                 Screen::Chat => self.close_chat(chat::ChatExit::Intentional),
                 Screen::Win => self.close_win_screen()?,
+                Screen::DebugOptions => self.close_debug_options(),
             },
             KeyCode::Digit1
             | KeyCode::Digit2
@@ -14743,6 +14752,9 @@ impl ApplicationHandler for Game<'_> {
                     if self.screen == Screen::ServerLinks && d != 0.0 {
                         self.server_links_scroll(d);
                     }
+                    if self.screen == Screen::DebugOptions && d != 0.0 {
+                        self.debug_options_scroll(d);
+                    }
                     if self.screen == Screen::Advancements {
                         self.advancements_scroll(scaled(raw_x) as f32, d);
                     }
@@ -14940,6 +14952,9 @@ impl ApplicationHandler for Game<'_> {
                         Screen::ServerLinks if pressed && button == MouseButton::Left => {
                             self.server_links_click()?
                         }
+                        Screen::DebugOptions if pressed && button == MouseButton::Left => {
+                            self.debug_options_click()
+                        }
                         Screen::ConfirmLink if pressed && button == MouseButton::Left => {
                             self.confirm_link_click()
                         }
@@ -15110,6 +15125,9 @@ impl ApplicationHandler for Game<'_> {
                 WindowEvent::KeyboardInput { event, .. } if self.screen == Screen::CommandBlock => {
                     self.command_block_key(&event)
                 }
+                WindowEvent::KeyboardInput { event, .. } if self.screen == Screen::DebugOptions => {
+                    self.debug_options_key(&event)
+                }
                 WindowEvent::KeyboardInput { event, .. } if self.screen == Screen::BlockEditor => {
                     self.block_editor_key(&event)
                 }
@@ -15937,8 +15955,10 @@ impl<'a> Game<'a> {
             friends: None,
             debug_keys: Default::default(),
             debug_charts: Default::default(),
-            show_hitboxes: false,
-            show_chunk_borders: false,
+            debug_entries: horizon_client::debug_entries::DebugEntries::load(
+                &std::env::current_dir().unwrap_or_default(),
+            ),
+            debug_options: None,
             pause_menu: true,
             previous_mode: None,
             gamemode_switcher: None,

crates/horizon-client/src/game/agent.rs

@@ -424,6 +424,7 @@ impl Game<'_> {
             Screen::CommandBlock => "command-block",
             Screen::BlockEditor => "block-editor",
             Screen::Win => "win",
+            Screen::DebugOptions => "debug-options",
         }
     }
     pub(super) fn inventory_counts(&self) -> BTreeMap<String, i64> {

crates/horizon-client/src/game/control.rs

@@ -630,6 +630,7 @@ impl Game<'_> {
                     Screen::Chat => self.chat_type(text),
                     Screen::CommandBlock => self.command_block_type(text),
                     Screen::BlockEditor => self.block_editor_type(text),
+                    Screen::DebugOptions => self.debug_options_type(text),
                     Screen::Options => self.ui.options.type_text(&self.gui.atlas, text),
                     // The port, or the game rules' search and number boxes.
                     Screen::WorldOptions if text == "\\b" => self.world_options_text(None),
@@ -909,6 +910,7 @@ impl Game<'_> {
             Screen::CommandBlock => "command-block",
             Screen::BlockEditor => "block-editor",
             Screen::Win => "win",
+            Screen::DebugOptions => "debug-options",
         }
     }
 
@@ -1040,8 +1042,8 @@ impl Game<'_> {
             "screen": self.screen_name(),
             "debug": {
                 "overlay": self.debug,
-                "hitboxes": self.show_hitboxes,
-                "chunk_borders": self.show_chunk_borders,
+                "hitboxes": self.debug_entry("entity_hitboxes"),
+                "chunk_borders": self.debug_entry("chunk_borders"),
                 "pause_menu": self.pause_menu,
                 "advanced_tooltips": self.settings.file.bool("advancedItemTooltips"),
                 "pause_on_lost_focus": self.settings.file.bool("pauseOnLostFocus"),

crates/horizon-client/src/game/debug_keys.rs

@@ -278,14 +278,26 @@ impl Game<'_> {
             format!("To edit: press {}", key("key.debug.debugOptions")),
         ]
     }
-    /// `DebugScreenOverlay.extractRenderState` with the default profile's
-    /// entries, over everything the frame drew (menus too), at the debug GUI
-    /// scale. F1 hides it unless a screen is open.
+    /// `Gui.extractRenderState`'s debug overlay, over everything the frame
+    /// drew (menus too); the debug options screen draws it under itself.
     pub(super) fn draw_debug_overlay(&self, batch: &mut HudBatch, size: [u32; 2]) {
+        if self.screen != Screen::DebugOptions {
+            self.draw_debug_overlay_under(batch, size);
+        }
+    }
+    /// `DebugScreenOverlay.extractRenderState`: the enabled entries' lines
+    /// (`debug-profile.json`), at the debug GUI scale, and the charts while
+    /// the overlay is open. F1 hides it unless a screen is open.
+    pub(super) fn draw_debug_overlay_under(&self, batch: &mut HudBatch, size: [u32; 2]) {
         let screen_open = self.screen != Screen::Playing;
-        if self.title.is_some() || !self.debug || (self.ui.hide_gui && !screen_open) {
+        let reduced = self.reduced_debug_info();
+        if self.title.is_some()
+            || !self.debug_entries.any_enabled(self.debug, reduced)
+            || (self.ui.hide_gui && !screen_open)
+        {
             return;
         }
+        let on = |path: &str| self.debug_entries.enabled(path, self.debug, reduced);
         let framebuffer = size.map(|v| v as i32);
         let (scale, [width, height]) = debug_overlay::scale(
             framebuffer,
@@ -296,6 +308,83 @@ impl Game<'_> {
         );
         let mut d = debug_overlay::Displayer::default();
         // fps: DebugEntryFps.
+        if on("fps") {
+            self.debug_fps_line(&mut d);
+        }
+        // game_version: DebugEntryVersion (the launched version and brand).
+        if on("game_version") {
+            d.priority(format!("Minecraft {VERSION_NAME} ({VERSION_NAME}/horizon)"));
+        }
+        // player_position, player_section_position.
+        if let Some(p) = self.player.as_ref() {
+            let mut lines = debug_overlay::position(
+                [p.position.x, p.position.y, p.position.z],
+                self.yaw,
+                self.pitch,
+                self.dim.id(),
+                self.streaming.forced.len(),
+            );
+            let section = lines.pop().unwrap_or_default();
+            if on("player_position") {
+                d.group("position", lines);
+            }
+            if on("player_section_position") {
+                d.group("position", [section]);
+            }
+        }
+        if on("simple_performance_impactors") {
+            self.debug_performance_lines(&mut d);
+        }
+        if on("system_specs") {
+            self.debug_system_lines(&mut d, framebuffer);
+        }
+        // Horizon's own: the shader pack's GPU time per pass (an empty group would move others).
+        let pass_lines = self.renderer.as_ref().map_or_else(Vec::new, |r| {
+            debug_overlay::shader_pass_lines(&r.shader_pass_times())
+        });
+        if self.debug && !pass_lines.is_empty() {
+            d.group("shader pack", pass_lines);
+        }
+        if on("tps") {
+            self.debug_tps_line(&mut d);
+        }
+        // The chart keys and the charts only while the overlay is open.
+        let footer = if self.debug {
+            self.debug_chart_lines().to_vec()
+        } else {
+            Vec::new()
+        };
+        let (left, right) = d.columns(&footer);
+        let atlas = &self.gui.atlas;
+        let mut draws = debug_overlay::draw(&atlas.font, [&left, &right], scale, width);
+        if self.debug {
+            let charts = self.debug_charts.draw(
+                &atlas.font,
+                width,
+                height,
+                self.settings.max_fps,
+                1000.0 / self.clock.rate(),
+                !self.has_singleplayer_server(),
+            );
+            draws.push(hud_layout::GuiDraw::Push(vec![hud_layout::PoseOp::Scale(
+                scale, scale,
+            )]));
+            draws.extend(charts);
+            if self.debug_charts.lightmap
+                && let Some(r) = &self.renderer
+            {
+                draws.extend(horizon_client::debug_chart::lightmap(
+                    &r.lightmap_pixels,
+                    width,
+                    height,
+                ));
+            }
+            draws.push(hud_layout::GuiDraw::Pop);
+        }
+        hud_layout::paint(batch, atlas, &draws);
+    }
+    /// `DebugEntryFps`.
+    fn debug_fps_line(&self, d: &mut debug_overlay::Displayer) {
         let limit = self.framerate_limit();
         let present = self
             .renderer
@@ -324,24 +413,9 @@ impl Game<'_> {
                 limit.to_string()
             },
         ));
-        // game_version: DebugEntryVersion (the launched version and brand).
-        d.priority(format!("Minecraft {VERSION_NAME} ({VERSION_NAME}/horizon)"));
-        // player_position, player_section_position.
-        if let Some(p) = self.player.as_ref() {
-            let mut lines = debug_overlay::position(
-                [p.position.x, p.position.y, p.position.z],
-                self.yaw,
-                self.pitch,
-                self.dim.id(),
-                self.streaming.forced.len(),
-            );
-            let section = lines.pop().unwrap_or_default();
-            if !self.reduced_debug_info() {
-                d.group("position", lines);
     }
-            d.group("position", [section]);
-        }
-        // simple_performance_impactors.
+    /// `DebugEntrySimplePerformanceImpactors`.
+    fn debug_performance_lines(&self, d: &mut debug_overlay::Displayer) {
         let s = &self.settings;
         d.line(format!(
             "{}{}B: {}",
@@ -366,7 +440,9 @@ impl Game<'_> {
                 "naive"
             }
         ));
-        // system_specs (no Java line: Horizon has no JVM).
+    }
+    /// `DebugEntrySystemSpecs` (no Java line: Horizon has no JVM).
+    fn debug_system_lines(&self, d: &mut debug_overlay::Displayer, framebuffer: [i32; 2]) {
         if let Some(r) = self.renderer.as_ref() {
             static CPU: std::sync::OnceLock<String> = std::sync::OnceLock::new();
             d.group(
@@ -432,14 +508,9 @@ impl Game<'_> {
         {
             d.group("system", [r.hdr_line()]);
         }
-        // Horizon's own: the shader pack's GPU time per pass (an empty group would move others).
-        let pass_lines = self.renderer.as_ref().map_or_else(Vec::new, |r| {
-            debug_overlay::shader_pass_lines(&r.shader_pass_times())
-        });
-        if !pass_lines.is_empty() {
-            d.group("shader pack", pass_lines);
     }
-        // tps: DebugEntryTps for local and remote connections.
+    /// `DebugEntryTps` for local and remote connections.
+    fn debug_tps_line(&self, d: &mut debug_overlay::Displayer) {
         if self.player.is_some() {
             let [tx, rx] = self.debug_charts.packet_rates.map(|n| n.round() as i64);
             let (target, status) = if self.clock.sprinting() {
@@ -471,32 +542,6 @@ impl Game<'_> {
                 ));
             }
         }
-        let (left, right) = d.columns(&self.debug_chart_lines());
-        let atlas = &self.gui.atlas;
-        let mut draws = debug_overlay::draw(&atlas.font, [&left, &right], scale, width);
-        let charts = self.debug_charts.draw(
-            &atlas.font,
-            width,
-            height,
-            self.settings.max_fps,
-            1000.0 / self.clock.rate(),
-            !self.has_singleplayer_server(),
-        );
-        draws.push(hud_layout::GuiDraw::Push(vec![hud_layout::PoseOp::Scale(
-            scale, scale,
-        )]));
-        draws.extend(charts);
-        if self.debug_charts.lightmap
-            && let Some(r) = &self.renderer
-        {
-            draws.extend(horizon_client::debug_chart::lightmap(
-                &r.lightmap_pixels,
-                width,
-                height,
-            ));
-        }
-        draws.push(hud_layout::GuiDraw::Pop);
-        hud_layout::paint(batch, atlas, &draws);
     }
     /// `KeyMapping.getTranslatedKeyMessage`.
     fn key_text(&self, mapping: &str) -> Text {
@@ -525,13 +570,17 @@ impl Game<'_> {
         self.debug_feedback(Text::translate(key, &[]));
     }
     /// `LocalPlayer.isReducedDebugInfo`: the server's rule or the option.
-    fn reduced_debug_info(&self) -> bool {
+    pub(super) fn reduced_debug_info(&self) -> bool {
         self.settings.reduced_debug_info || self.ui.rules.bool("reduced_debug_info")
     }
-    /// The default profile's `3d_crosshair` entry: on while the overlay is
-    /// open, unless debug info is reduced.
+    /// `DebugScreenEntryList.isCurrentlyEnabled` for an entry's path.
+    pub(super) fn debug_entry(&self, path: &str) -> bool {
+        self.debug_entries
+            .enabled(path, self.debug, self.reduced_debug_info())
+    }
+    /// The `3d_crosshair` entry.
     pub(super) fn debug_crosshair(&self) -> bool {
-        self.debug && !self.reduced_debug_info()
+        self.debug_entry("3d_crosshair")
     }
     /// `Permissions.COMMANDS_GAMEMASTER` (`GameModeCommand.PERMISSION_CHECK`).
     pub(super) fn gamemaster(&self) -> bool {
@@ -555,8 +604,10 @@ impl Game<'_> {
                 true
             }
             DebugAction::ShowHitboxes if player => {
-                self.show_hitboxes = !self.show_hitboxes;
-                self.debug_translated(if self.show_hitboxes {
+                let on = self
+                    .debug_entries
+                    .toggle_status("entity_hitboxes", self.debug);
+                self.debug_translated(if on {
                     "debug.show_hitboxes.on"
                 } else {
                     "debug.show_hitboxes.off"
@@ -569,8 +620,10 @@ impl Game<'_> {
                 true
             }
             DebugAction::ShowChunkBorders if player => {
-                self.show_chunk_borders = !self.show_chunk_borders;
-                self.debug_translated(if self.show_chunk_borders {
+                let on = self
+                    .debug_entries
+                    .toggle_status("chunk_borders", self.debug);
+                self.debug_translated(if on {
                     "debug.chunk_boundaries.on"
                 } else {
                     "debug.chunk_boundaries.off"
@@ -674,11 +727,13 @@ impl Game<'_> {
                 self.debug_charts.toggle_lightmap(&mut self.debug);
                 true
             }
-            // Screens and overlays Horizon does not draw yet (the debug
-            // options screen, the profiler and its chart, the texture dump):
-            // the keys are used up as in vanilla.
-            DebugAction::DebugOptions
-            | DebugAction::DumpDynamicTextures
+            DebugAction::DebugOptions => {
+                self.toggle_debug_options();
+                true
+            }
+            // Screens and overlays Horizon does not draw yet (the profiler and
+            // its chart, the texture dump): the keys are used up as in vanilla.
+            DebugAction::DumpDynamicTextures
             | DebugAction::Profiling
             | DebugAction::ProfilingChart => true,
             DebugAction::ShowHitboxes
@@ -859,7 +914,7 @@ impl Game<'_> {
     pub(super) fn debug_gizmos(&self, alpha: f32, camera: [f64; 3]) -> Gizmos {
         let mut g = Gizmos::default();
         self.bounding_box_gizmos(camera, &mut g);
-        if self.show_chunk_borders
+        if self.debug_entry("chunk_borders")
             && let Some(p) = &self.player
         {
             let block = [
@@ -870,7 +925,7 @@ impl Game<'_> {
             let min_y = self.world.bottom_y();
             g.chunk_borders(block, min_y, min_y + self.world.layout().height() - 1);
         }
-        if !self.show_hitboxes {
+        if !self.debug_entry("entity_hitboxes") {
             return g;
         }
         let lerp = |a: f64, b: f64| a + f64::from(alpha) * (b - a);

crates/horizon-client/src/game/debug_options.rs

@@ -0,0 +1,466 @@
+//! `DebugOptionsScreen` (F3+F6): every debug entry with Off / In Overlay /
+//! Always buttons, a search box over them, the two built-in profiles and the
+//! debug overlay's GUI scale. The statuses live in `debug-profile.json`
+//! (`horizon_client::debug_entries`).
+//! https://mcsrc.dev/2/26.3/net/minecraft/client/gui/screens/debug/DebugOptionsScreen
+use super::{Game, Screen};
+use horizon_client::{
+    debug_entries::{Category, Entry, Profile, Status, search},
+    hud::HudBatch,
+    options_file::V,
+    text::Text,
+    ui::{self, EditBox, Scroll},
+};
+use winit::event::{ElementState, KeyEvent};
+use winit::keyboard::{KeyCode, PhysicalKey};
+
+/// `HeaderAndFooterLayout(this, 61, 33)`.
+const HEADER: f32 = 61.0;
+const FOOTER: f32 = 33.0;
+/// `OptionList.getRowWidth` and `ITEM_HEIGHT`.
+const ROW_WIDTH: f32 = 350.0;
+const ITEM: f32 = 20.0;
+/// `OptionEntry.BUTTON_WIDTH`, at the CycleButtons' 16 pixels high.
+const BUTTON: f32 = 60.0;
+/// The footer: two profile buttons, the GUI scale and Done, 4 pixels apart.
+const FOOTER_BUTTONS: [f32; 4] = [120.0, 120.0, 110.0, 60.0];
+/// `debug.options.warning`'s colour (-2142128) and the buttons' text colours.
+const WARNING: u32 = 0xDF_5050;
+const UNSELECTED: u32 = 0xBA_BABA;
+const OVERLAY: u32 = 0xFF_FF55;
+const NOT_ALLOWED: u32 = 0x80_8080;
+/// `EditBox.SEARCH_HINT_STYLE`: `ChatFormatting.GRAY`.
+const HINT: u32 = 0xAA_AAAA;
+
+/// The open screen: its search box and the list's scroll.
+pub(super) struct DebugOptionsUi {
+    search: EditBox,
+    scroll: Scroll,
+}
+
+impl DebugOptionsUi {
+    pub(super) fn search_focused(&self) -> bool {
+        self.search.focused
+    }
+}
+
+/// One list row (`AbstractOptionEntry`).
+enum Row {
+    Category(Category),
+    Option(&'static Entry),
+}
+
+/// `OptionList.updateSearch`: a category row before each category's entries.
+fn rows(value: &str) -> Vec<Row> {
+    let mut rows = Vec::new();
+    let mut current = None;
+    for entry in search(value) {
+        if current != Some(entry.category) {
+            rows.push(Row::Category(entry.category));
+            current = Some(entry.category);
+        }
+        rows.push(Row::Option(entry));
+    }
+    rows
+}
+
+/// `AbstractSelectionList.contentHeight`.
+fn content_height(n: usize) -> f32 {
+    n as f32 * ITEM + 4.0
+}
+/// `getRowLeft`: the list spans the screen, its rows centred.
+fn row_left(w: f32) -> f32 {
+    (w / 2.0).floor() - ROW_WIDTH / 2.0
+}
+/// The three buttons' left edges (Off, In Overlay, Always) for a row whose
+/// content starts at `x` (`extractContent`).
+fn button_xs(content_x: f32) -> [f32; 3] {
+    let start = content_x + ROW_WIDTH - 4.0 - 3.0 * BUTTON;
+    [start, start + BUTTON, start + 2.0 * BUTTON]
+}
+/// The footer buttons' left edges and their row's top.
+fn footer(w: f32, h: f32) -> ([f32; 4], f32) {
+    let total: f32 = FOOTER_BUTTONS.iter().sum::<f32>() + 3.0 * 4.0;
+    let mut x = ((w - total) / 2.0).floor();
+    let mut xs = [0.0; 4];
+    for (slot, width) in xs.iter_mut().zip(FOOTER_BUTTONS) {
+        *slot = x;
+        x += width + 4.0;
+    }
+    (xs, h - FOOTER + ((FOOTER - 20.0) / 2.0).floor())
+}
+/// The three buttons' statuses and texts, in their order on the row.
+const BUTTONS: [(Status, &str, u32); 3] = [
+    (Status::Never, "options.off", 0xFF_FFFF),
+    (Status::InOverlay, "debug.entry.overlay", OVERLAY),
+    (Status::AlwaysOn, "debug.entry.always", WARNING),
+];
+
+impl Game<'_> {
+    /// `KeyboardHandler`'s F3+F6: closes the screen if it is open, else opens
+    /// it over the game or the pause menu (`canInterruptScreen`).
+    pub(super) fn toggle_debug_options(&mut self) {
+        match self.screen {
+            Screen::DebugOptions => self.close_debug_options(),
+            Screen::Playing | Screen::Paused if !self.screen_over_playing() => {
+                let mut search = EditBox::new(0.0, 0.0, (ROW_WIDTH / 3.0).floor(), 20.0);
+                search.max_length = 32;
+                self.debug_options = Some(DebugOptionsUi {
+                    search,
+                    scroll: Scroll::default(),
+                });
+                self.screen = Screen::DebugOptions;
+                self.pause_menu = true;
+                self.capture(false);
+                self.mining = None;
+            }
+            _ => {}
+        }
+    }
+    /// `Screen.onClose`: back to the game.
+    pub(super) fn close_debug_options(&mut self) {
+        self.debug_options = None;
+        self.screen = Screen::Playing;
+        self.capture(true);
+    }
+    /// The header's title row and warning (`init`'s vertical layout,
+    /// centred in the header): the title's x, the row's top, the warning's
+    /// lines with their y.
+    fn debug_options_header(&self, w: f32) -> (f32, f32, Vec<(Text, f32)>) {
+        let font = &self.gui.atlas.font;
+        let title = Text::translate("debug.options.title", &[]);
+        let warning = Text::translate("debug.options.warning", &[]).with_color(WARNING);
+        let lines = font.split(&warning, ROW_WIDTH);
+        let height = 20.0 + 8.0 + lines.len() as f32 * 9.0;
+        let top = ((HEADER - height) / 2.0).floor();
+        let third = (ROW_WIDTH / 3.0).floor();
+        let tw = font.width_text(&title);
+        let row = third + 8.0 + tw + 8.0 + third;
+        let title_x = ((w - row) / 2.0).floor() + third + 8.0;
+        let lines = lines
+            .into_iter()
+            .enumerate()
+            .map(|(i, line)| (line, top + 28.0 + i as f32 * 9.0))
+            .collect();
+        (title_x, top, lines)
+    }
+    /// `debugGuiScale`'s button: `GUI Scale: Unchanged`, `Auto` or the scale.
+    fn debug_gui_scale_label(&self) -> Text {
+        let value = match self.settings.file.int("debugGuiScale") {
+            -1 => Text::translate("options.debugGuiScale.unchanged", &[]),
+            0 => Text::translate("options.guiScale.auto", &[]),
+            n => Text::literal(n.to_string()),
+        };
+        Text::translate(
+            "options.generic_value",
+            &[Text::translate("options.guiScale", &[]), value],
+        )
+    }
+    /// `ClampingLazyMaxIntRange(-1, window.calculateScale(0, unicode))` as a
+    /// CycleButton: the next value, or the previous one with Shift.
+    fn cycle_debug_gui_scale(&mut self, back: bool) {
+        let size = self.renderer.as_ref().map_or([1280, 720], |r| {
+            [r.config.width as i32, r.config.height as i32]
+        });
+        let max = horizon_client::window::calculate_scale(size, 0, self.settings.force_unicode);
+        let current = self.settings.file.int("debugGuiScale").clamp(-1, max);
+        let next = match (back, current) {
+            (false, c) if c >= max => -1,
+            (false, c) => c + 1,
+            (true, -1) => max,
+            (true, c) => c - 1,
+        };
+        self.settings.file.set("debugGuiScale", V::Int(next));
+        self.settings.save(&Self::options_path());
+    }
+    pub(super) fn draw_debug_options(&mut self, batch: &mut HudBatch) {
+        let Some(mut s) = self.debug_options.take() else {
+            return;
+        };
+        let (w, h) = (batch.width, batch.height);
+        // extractBlurredBackground: the debug overlay goes under the screen.
+        let size = self
+            .renderer
+            .as_ref()
+            .map_or([w as u32, h as u32], |r| [r.config.width, r.config.height]);
+        self.draw_debug_overlay_under(batch, size);
+        let atlas = &self.gui.atlas;
+        ui::menu_background(batch, atlas, 0.0, 0.0, w, h, true);
+        let reduced = self.reduced_debug_info();
+        let rows = rows(&s.search.value);
+        let (top, bottom) = (HEADER, h - FOOTER);
+        let content = content_height(rows.len());
+        s.scroll.clamp(top, bottom, content);
+        // The list: background, rows clipped to it, separators, scrollbar.
+        ui::list_background(batch, atlas, top, bottom, true);
+        let first = batch.vertices.len();
+        let left = row_left(w);
+        let inside = self.cursor.1 >= top && self.cursor.1 < bottom;
+        let mut tooltip = None;
+        for (i, row) in rows.iter().enumerate() {
+            let y = top + 2.0 - s.scroll.amount.trunc() + i as f32 * ITEM;
+            if y + ITEM < top || y > bottom {
+                continue;
+            }
+            let (cx, cy) = (left + 2.0, y + 2.0);
+            match row {
+                Row::Category(category) => {
+                    let label = Text::translate(category.translation_key(), &[])
+                        .bold()
+                        .underlined();
+                    let lw = atlas.font.width_text(&label);
+                    let lx = (cx + (ROW_WIDTH - 4.0) / 2.0 - (lw + 8.0) / 2.0).floor() + 4.0;
+                    batch.text_styled(atlas, &label, lx, cy + 4.0, u32::MAX, true);
+                }
+                Row::Option(entry) => {
+                    let allowed = entry.reduced || !reduced;
+                    let name = if allowed {
+                        Text::literal(entry.path)
+                    } else {
+                        Text::literal(entry.path).italic().with_color(NOT_ALLOWED)
+                    };
+                    batch.text_styled(atlas, &name, cx, cy + 5.0, u32::MAX, true);
+                    let xs = button_xs(cx);
+                    let status = self.debug_entries.status(entry.path);
+                    for ((status_of, key, color), x) in BUTTONS.into_iter().zip(xs) {
+                        let selected = status == status_of;
+                        let label = Text::translate(key, &[]).with_color(if selected {
+                            color
+                        } else {
+                            UNSELECTED
+                        });
+                        let hover = inside && ui::hovered(self.cursor, x, cy, BUTTON, 16.0);
+                        ui::button(batch, atlas, x, cy, BUTTON, 16.0, &label, !selected, hover);
+                    }
+                    if !allowed && inside && ui::hovered(self.cursor, cx, y, xs[0] - cx, ITEM) {
+                        tooltip = Some(Text::translate("debug.options.notAllowed.tooltip", &[]));
+                    }
+                }
+            }
+        }
+        batch.clip_since(first, 0.0, top, w, bottom);
+        ui::separators(batch, atlas, top, bottom, true);
+        ui::scrollbar(
+            batch,
+            atlas,
+            left + ROW_WIDTH + 8.0,
+            top,
+            bottom,
+            content,
+            s.scroll.amount.trunc(),
+        );
+        // The header: title, search box, warning.
+        let (title_x, header_top, lines) = self.debug_options_header(w);
+        let title = Text::translate("debug.options.title", &[]);
+        batch.text_styled(atlas, &title, title_x, header_top + 5.0, u32::MAX, true);
+        s.search.x = title_x + atlas.font.width_text(&title) + 8.0;
+        s.search.y = header_top;
+        s.search.draw(batch, atlas, None);
+        if s.search.value.is_empty() {
+            let hint = Text::translate("debug.options.search", &[])
+                .with_color(HINT)
+                .italic();
+            batch.text_styled(
+                atlas,
+                &hint,
+                s.search.text_x(),
+                s.search.text_y(),
+                u32::MAX,
+                true,
+            );
+        }
+        for (line, y) in &lines {
+            let lw = atlas.font.width_text(line);
+            batch.text_styled(atlas, line, ((w - lw) / 2.0).floor(), *y, u32::MAX, true);
+        }
+        // The footer.
+        let (xs, fy) = footer(w, h);
+        let labels = [
+            Text::translate(Profile::Default.translation_key(), &[]),
+            Text::translate(Profile::Performance.translation_key(), &[]),
+            self.debug_gui_scale_label(),
+            Text::translate("gui.done", &[]),
+        ];
+        let active = [
+            !self.debug_entries.is_using_profile(Profile::Default),
+            !self.debug_entries.is_using_profile(Profile::Performance),
+            true,
+            true,
+        ];
+        for (i, label) in labels.iter().enumerate() {
+            let hover = ui::hovered(self.cursor, xs[i], fy, FOOTER_BUTTONS[i], 20.0);
+            ui::button(
+                batch,
+                atlas,
+                xs[i],
+                fy,
+                FOOTER_BUTTONS[i],
+                20.0,
+                label,
+                active[i],
+                hover,
+            );
+            if i == 2 && hover {
+                tooltip = Some(Text::translate("options.debugGuiScale.tooltip", &[]));
+            }
+        }
+        if let Some(tooltip) = tooltip {
+            let lines = atlas.font.split(&tooltip, 200.0);
+            ui::tooltip(batch, atlas, &lines, self.cursor);
+        }
+        self.debug_options = Some(s);
+    }
+    /// A left click: a status button, the search box, a footer button.
+    pub(super) fn debug_options_click(&mut self) {
+        let Some(mut s) = self.debug_options.take() else {
+            return;
+        };
+        let (w, h) = self.gui_size();
+        let (top, bottom) = (HEADER, h - FOOTER);
+        let shift =
+            self.keys.contains(&KeyCode::ShiftLeft) || self.keys.contains(&KeyCode::ShiftRight);
+        s.search.focused = ui::hovered(
+            self.cursor,
+            s.search.x,
+            s.search.y,
+            s.search.width,
+            s.search.height,
+        );
+        if s.search.focused {
+            s.search.click(&self.gui.atlas, self.cursor.0, shift, false);
+        }
+        let inside = self.cursor.1 >= top && self.cursor.1 < bottom;
+        let rows = rows(&s.search.value);
+        let left = row_left(w);
+        let mut clicked = None;
+        if inside {
+            for (i, row) in rows.iter().enumerate() {
+                let Row::Option(entry) = row else { continue };
+                let cy = top + 2.0 - s.scroll.amount.trunc() + i as f32 * ITEM + 2.0;
+                let status = self.debug_entries.status(entry.path);
+                for ((status_of, _, _), x) in BUTTONS.into_iter().zip(button_xs(left + 2.0)) {
+                    if status != status_of && ui::hovered(self.cursor, x, cy, BUTTON, 16.0) {
+                        clicked = Some((entry.path, status_of));
+                    }
+                }
+            }
+        }
+        self.debug_options = Some(s);
+        if let Some((path, status)) = clicked {
+            // OptionEntry.setValue.
+            self.audio.play_button_click();
+            self.debug_entries.set_status(path, status);
+            return;
+        }
+        let (xs, fy) = footer(w, h);
+        let Some(i) =
+            (0..4).find(|&i| ui::hovered(self.cursor, xs[i], fy, FOOTER_BUTTONS[i], 20.0))
+        else {
+            return;
+        };
+        match i {
+            0 | 1 => {
+                let profile = if i == 0 {
+                    Profile::Default
+                } else {
+                    Profile::Performance
+                };
+                if self.debug_entries.is_using_profile(profile) {
+                    return;
+                }
+                self.audio.play_button_click();
+                self.debug_entries.load_profile(profile);
+            }
+            2 => {
+                self.audio.play_button_click();
+                self.cycle_debug_gui_scale(shift);
+            }
+            _ => {
+                self.audio.play_button_click();
+                self.close_debug_options();
+            }
+        }
+    }
+    /// The mouse wheel over the list (`scrollRate`: half a row).
+    pub(super) fn debug_options_scroll(&mut self, delta: f32) {
+        let (_, h) = self.gui_size();
+        if let Some(s) = &mut self.debug_options {
+            let content = content_height(rows(&s.search.value).len());
+            s.scroll
+                .wheel(delta, ITEM / 2.0, HEADER, h - FOOTER, content);
+        }
+    }
+    /// A key the debug keys left: Escape closes, the rest edits the search.
+    pub(super) fn debug_options_key(&mut self, event: &KeyEvent) {
+        if event.state != ElementState::Pressed {
+            return;
+        }
+        let PhysicalKey::Code(key) = event.physical_key else {
+            return;
+        };
+        if key == KeyCode::Escape {
+            self.close_debug_options();
+            return;
+        }
+        let shortcut = self.edit_shortcut(event);
+        let ctrl = self.keys.contains(&KeyCode::ControlLeft);
+        let shift = self.keys.contains(&KeyCode::ShiftLeft);
+        let types_text = self.types_text();
+        let Some(s) = &mut self.debug_options else {
+            return;
+        };
+        if !s.search.focused {
+            return;
+        }
+        if let Some(shortcut) = shortcut {
+            s.search.shortcut(shortcut, &mut self.clipboard);
+        } else if !s.search.key(key, ctrl, shift)
+            && types_text
+            && let Some(text) = event.text.as_deref()
+        {
+            self.debug_options_type(text);
+        }
+    }
+    /// Characters typed into the search box (`EditBox.charTyped`).
+    pub(super) fn debug_options_type(&mut self, typed: &str) {
+        let allowed: String = typed
+            .chars()
+            .filter(|&c| c != '\u{a7}' && c >= ' ' && c != '\u{7f}')
+            .collect();
+        if let Some(s) = &mut self.debug_options
+            && s.search.focused
+            && !allowed.is_empty()
+        {
+            s.search.insert_text(&allowed);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn rows_put_a_category_before_each_section() {
+        let all = rows("");
+        assert_eq!(all.len(), 48);
+        assert!(matches!(all[0], Row::Category(Category::Text)));
+        let renderer = all
+            .iter()
+            .position(|r| matches!(r, Row::Category(Category::Renderer)))
+            .unwrap();
+        assert!(matches!(all[renderer + 1], Row::Option(e) if e.path == "3d_crosshair"));
+        // A search inside one section shows only its heading.
+        let hitboxes = rows("hitbox");
+        assert_eq!(hitboxes.len(), 2);
+        assert!(matches!(hitboxes[0], Row::Category(Category::Renderer)));
+    }
+
+    #[test]
+    fn the_layout_matches_vanilla_at_854_by_480() {
+        // 854x480 at GUI scale 2 is 427x240.
+        assert_eq!(row_left(427.0), 38.0);
+        assert_eq!(button_xs(40.0), [206.0, 266.0, 326.0]);
+        assert_eq!(footer(427.0, 240.0), ([2.0, 126.0, 250.0, 364.0], 213.0));
+    }
+}

crates/horizon-client/src/game/ime.rs

@@ -22,6 +22,10 @@ impl Game<'_> {
         }
         match self.screen {
             Screen::Chat | Screen::CommandBlock => true,
+            Screen::DebugOptions => self
+                .debug_options
+                .as_ref()
+                .is_some_and(|s| s.search_focused()),
             Screen::WorldOptions => self.world_options_typing(),
             Screen::Creative => self.creative_screen.tab().search,
             Screen::Inventory => {
@@ -106,6 +110,7 @@ impl Game<'_> {
             match self.screen {
                 Screen::Chat => self.chat_type(&text),
                 Screen::CommandBlock => self.command_block_type(&text),
+                Screen::DebugOptions => self.debug_options_type(&text),
                 Screen::WorldOptions => self.world_options_text(Some(&text)),
                 Screen::Creative => self.creative_search_edit(Some(&text)),
                 Screen::Inventory if self.mod_browser_typing() => {

crates/horizon-client/src/game/screens.rs

@@ -22,7 +22,8 @@ impl Screen {
             | Self::Friends
             | Self::ServerLinks
             | Self::ConfirmLink
-            | Self::DialogWarning => true,
+            | Self::DialogWarning
+            | Self::DebugOptions => true,
             Self::Playing
             | Self::GameModeSwitcher
             | Self::Chat

crates/horizon-client/src/lib.rs

@@ -42,6 +42,7 @@ pub mod creative;
 pub mod cushion;
 pub mod data_cmd;
 pub mod debug_chart;
+pub mod debug_entries;
 pub mod debug_keys;
 pub mod debug_overlay;
 pub mod dialog;