Update the docs and add AGENTS.md

README.md

@@ -6,6 +6,17 @@ An open source project to play the classic 1994 System Shock on a VR
 headset, built on top of [Shockolate](https://github.com/Interrupt/systemshock),
 a cross-platform port of the original game.
 
+The game is played on a virtual screen: the engine renders its usual flat 2D
+frame, and Questshock shows it as a large screen floating in front of you in
+VR. It is not a stereoscopic 3D conversion; you sit or stand in front of the
+screen the way you would in front of a monitor or a cinema screen. The
+screen's width and distance can be set separately for the menus/intro and for
+gameplay. Both controllers act as laser pointers for the game's mouse-driven
+interface and for a VR menu and on-screen keyboard, and every controller
+button, stick direction and game hotkey can be assigned to a game action.
+Questshock runs entirely on the headset (tested on a Meta Quest 2) as a
+sideloaded Android app, and needs your own copy of the game data.
+
 ## 1. Design principles
 
 - **Standalone-headset-only.** The game must run entirely on the headset
@@ -31,6 +42,10 @@ a cross-platform port of the original game.
   "3. Game assets" below); `res/assets/extract_assets.sh` extracts it into
   `ss_ee/`.
 - `res/run.sh` - the launcher script, copied into `dist/` on build.
+- `res/questshock.config.default.json` - the bundled default configuration
+  (see [CONFIG.md](CONFIG.md)); `res/controller_profiles/` - the per-controller
+  illustrations and labels shown in the Controller Options tab (see
+  [CONFIG.md](CONFIG.md)). Both are copied into the APK.
 - `Makefile` - targets:
   - `all` (default) - alias for `dist`.
   - `build-image` - builds the Docker build-image (`./build-image.sh`).
@@ -105,6 +120,10 @@ Enhanced Edition one and `extract_assets.sh` pulls them out of it too,
 entirely optionally - it still runs fine with just the Enhanced Edition
 installer.
 
+The intro cutscene follows the selected language too, when the matching
+voice-over file (`svfrintr.res`/`svgeintr.res` under `res/data/`) is present;
+otherwise the English intro plays.
+
 ## 4. Desktop build
 
 Builds and runs Questshock natively on the desktop (your dev machine, or
@@ -218,18 +237,17 @@ driven by a laser-pointer-style aim ray from each hand
 interact with it, same as the game's own Bluetooth mouse/keyboard input
 otherwise works unchanged.
 
-The menu launcher (`MenuOverlay.java` - just a "Keyboard" button so far)
-and the keyboard (`KeyboardOverlay.java`) are two fully independent quads,
-each its own `XrOverlay` instance (`android/app/src/main/cpp/xr_overlay.c`
-- a generic "off-screen Android View rendered into an OpenXR quad,
-hit-tested via a laser pointer" module shared by both, and by whatever
-similar panel comes next) with its own swapchain, visibility, and
-position, so they can be shown/hidden/moved independently - a design
-specifically meant to let the keyboard stay open while also picking
-something from the (still-to-be-built-out) menu. The controller's menu
-button only ever opens/closes the launcher; clicking its "Keyboard" button
-only opens the keyboard (never touching the launcher's own visibility) -
-the keyboard's own title bar holds the only way to close it again.
+The menu (`MenuOverlay.java`, described in "5.1.1. Menu, controls and
+cheats" below) and the keyboard (`KeyboardOverlay.java`) are two fully
+independent quads, each its own `XrOverlay` instance
+(`android/app/src/main/cpp/xr_overlay.c` - a generic "off-screen Android View
+rendered into an OpenXR quad, hit-tested via a laser pointer" module shared by
+both) with its own swapchain, visibility, and position, so they can be
+shown/hidden/moved independently - the keyboard can stay open while also
+picking something from the menu. The controller's menu button only ever
+opens/closes the menu; the menu's "Keyboard" button only opens the keyboard
+(never touching the menu's own visibility) - the keyboard's own title bar
+holds the only way to close it again.
 
 The keyboard is a hand-built, full US-layout key grid (there's no system
 IME to borrow once immersive) that forwards each key press straight to the
@@ -288,7 +306,50 @@ debugging enabled.)
 `/sdcard/questshock/` also holds an optional persistent settings file,
 `questshock.config.json`, loaded automatically at startup and saved/loaded
 from the in-headset menu - see [CONFIG.md](CONFIG.md) for the documented
-options.
+options. Every launch also refreshes `questshock.config.default.json` (the
+bundled defaults, used when there is no `questshock.config.json`) and
+`controller_profiles/` (controller illustrations for the Controller Options
+tab) there; your own saved config and any extra profiles you add are left
+alone.
+
+#### 5.1.1. Menu, controls and cheats
+
+The controller's menu button (left controller) opens and closes the menu. It
+can't be reassigned. Opening it pauses a running game; closing it resumes the
+game, unless it was already paused. Aim with either hand's ray and pull the
+trigger to press buttons. The menu has four tabs:
+
+- **Main Menu** - Keyboard, Save/Load Configuration, Reset Position and the
+  language.
+- **Video Options** - renderer, resolution, and the width and distance of the
+  virtual screen for the initial screen (splash, intro, main menu) and the game
+  screen.
+- **Controller Options** - shows the active controller with labelled inputs,
+  and one button per action to assign it to a controller input (tap the
+  button, then press the input). Assigning an input that another action
+  already uses unbinds that other action. **Reset to Defaults** restores the
+  default bindings.
+- **Cheats** - the engine's cheats as buttons (give all items and weapons,
+  toggle physics, next and previous level) and four independent switches for
+  unlimited health, energy, ammo and items. The switches last until the app
+  restarts and are not saved. They only work while a game is running.
+
+Default controls (all assignable, see [CONFIG.md](CONFIG.md)):
+
+| Input | On foot | In cyberspace |
+|---|---|---|
+| Left stick | Move forward/back, strafe | Pitch up/down, bank left/right |
+| Right stick left/right | Turn | Roll |
+| Right stick up | Stand | Thrust |
+| Right stick down | Prone | - |
+| Left stick click | Jump | - |
+| Right stick click | Automap | - |
+| Right A / B | Click / double-click | Click / double-click |
+| Right trigger | Fire weapon | Fire weapon |
+| Left grip (hold) | Free view with the left stick | Free view with the left stick |
+
+Every game hotkey (weapon select, MFD panels, save/load, ...) can also be
+assigned to a controller input; they are unbound by default.
 
 ### 5.2. Building natively in Android Studio
 
@@ -533,6 +594,23 @@ each one does:
   `qs_config_load_startup()` in `Shock.c`'s `main()`, right after
   `LoadPrefs()`, and one check in `sdl_events.c`'s `pump_events()` to drain
   the custom SDL events the menu's Save/Load Configuration buttons enqueue.
+- **`22-android-screen-profile.patch`** - `mainloop.c` reports every
+  loop-mode change to `qs_screen_profile_notify_loop_mode()`, which picks
+  between the initial-screen and game-screen virtual-screen presets (see
+  [CONFIG.md](CONFIG.md)) and tells the menu whether a game is running.
+- **`23-android-intro-language.patch`** - `cutsloop.c` opens the intro
+  cutscene file for the current language (`svgaintr.res`/`svfrintr.res`/
+  `svgeintr.res`), falling back to English when it isn't installed.
+- **`24-android-cyberspace-query.patch`** - adds `qs_in_cyberspace()` to
+  `mouselook.c`, which `xr_input.c` uses to switch between the on-foot and
+  cyberspace controller actions.
+- **`25-android-cyberspace-analog-scale.patch`** - `movekeys.c` scales the
+  cyberspace pitch and bank strength by `qs_cyber_pitch_scale`/
+  `qs_cyber_bank_scale`, which `xr_input.c` sets from the thumbstick
+  deflection each frame (1.0 for keys and buttons).
+- **`26-android-cheat-refill.patch`** - adds `qs_cheat_refill()` to
+  `hkeyfunc.c`, which tops up health, energy, ammo and items (grenades and
+  drugs the player already holds) for the Cheats tab's unlimited switches.
 
 `android/gl4es-patches/`: