docs: input integration guide (cockpit -> RIOJoy -> game)

Companion to OUTPUT-INTEGRATION.md: the three input surfaces (ViGEm x360
pad, SendInput scancode keyboard/mouse, RioGamepad HID), per-button routing
kinds incl. the fixed 11-button pad order, axis calibration + routing with
the triggers-are-buttons trap and the shipped Descent pattern, per-game
strategy, profile building/triggers workflow, benchless testing, checklist.
Cross-linked from README and the output guide.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -23,7 +23,8 @@ Red Planet — talk to the RIO directly and do not use this app.)
 | [`docs/PLAN.md`](docs/PLAN.md) | Full modernization plan |
 | [`docs/PROTOCOL.md`](docs/PROTOCOL.md) | RIO wire format + `iRIO` input-map reference |
 | [`docs/FEEDBACK.md`](docs/FEEDBACK.md) | Game→cockpit feedback endpoint (lamps + plasma over pipe/UDP, rumble) |
-| [`docs/OUTPUT-INTEGRATION.md`](docs/OUTPUT-INTEGRATION.md) | Integrator's guide: lamp address map, plasma display model, per-game recipes |
+| [`docs/INPUT-INTEGRATION.md`](docs/INPUT-INTEGRATION.md) | Integrator's guide: cockpit→game — routing kinds, pad/axis mapping, profile building |
+| [`docs/OUTPUT-INTEGRATION.md`](docs/OUTPUT-INTEGRATION.md) | Integrator's guide: game→cockpit — lamp address map, plasma display model, recipes |
 | _RIO board hardware & firmware_ | Moved to the [TeslaRel410 `restoration/`](https://gitea.mysticmachines.com/VWE/TeslaRel410/src/branch/main/restoration) archive — board photos, schematics, GAL decode (`restoration/rio-hardware`) and the RIO 4.3 board firmware (`restoration/rio-firmware`) |
 | [`docs/reference/`](docs/reference/) | Cockpit overlay art & the legacy labeling pipeline |
 | [`legacy/`](legacy/) | Original C++/vJoy implementation, kept as reference |

docs/INPUT-INTEGRATION.md

@@ -0,0 +1,161 @@
+# Input integration guide (cockpit → RIOJoy → game)
+
+How a game receives the cockpit's **inputs** — the 72 lighted buttons, two
+16-key keypads, and 5 analog axes — and how to build the profile that maps
+them. This is the mirror of [OUTPUT-INTEGRATION.md](OUTPUT-INTEGRATION.md)
+(game → cockpit); the wire protocol lives in [PROTOCOL.md](PROTOCOL.md), the
+profile/auto-switch model in [PLAN.md](PLAN.md).
+
+## What a game sees
+
+RIOJoy translates cockpit events into ordinary Windows input, per profile,
+through three surfaces (all can be active at once — each button picks its
+route):
+
+| Surface | What the game sees | When |
+|---|---|---|
+| **Virtual Xbox 360 pad** (ViGEm) | a normal XInput controller: 11 buttons, D-pad, 2 sticks, 2 triggers | default on Windows 10/11 when ViGEmBus is installed |
+| **Keyboard / mouse** (`SendInput`) | scancode keystrokes with modifiers; relative mouse moves + clicks | any button routed to a key/mouse action |
+| **RioGamepad HID** | a native 6-axis, 96-button, 1-hat joystick | fallback when ViGEm is absent; the XP flavor |
+
+The sink is chosen at activation: ViGEm → RioGamepad feeder → none (keyboard
+and mouse always work). Most games — XInput and DirectInput alike — see the
+Xbox 360 pad as a standard controller; the practical limit is its **11
+mappable buttons**, so keyboard routing carries everything beyond that.
+
+## The input inventory
+
+- **72 lighted buttons**, RIO addresses `0x00–0x47`, grouped into five MFD
+  clusters and four columns — the physical map is in
+  [OUTPUT-INTEGRATION.md](OUTPUT-INTEGRATION.md#address-map-functional-groups).
+- **Two 4×4 keypads**: internal `0x50–0x5F`, external `0x60–0x6F` (key label →
+  address = base + hex digit; no lamps).
+- **5 analog inputs** — joystick X/Y, throttle, left pedal, right pedal —
+  calibrated into **6 virtual axes** (X, Y, Z, Rx, Ry, Rz), each `0..32766`
+  with center `16383`.
+
+## Per-button routing
+
+Every mapped address carries one action (the `iRIO` word, PROTOCOL.md §5).
+The editor exposes these as the **Action** kinds:
+
+| Kind | What happens on press/release |
+|---|---|
+| **Keyboard** | key down/up by **scancode** (so DOS-era and raw-input games see it), with optional Shift/Ctrl/Alt held around it and the extended-key flag for nav keys |
+| **Joystick** | virtual pad button 1–11 (or 1–96 on the RioGamepad HID) |
+| **Hat** | the POV hat / D-pad direction (up/right/down/left; release = centered) |
+| **Mouse** | relative move in clean 50-px steps (up/right/down/left) or left/right click — the legacy build's mixed-up move deltas are fixed in the port |
+| **RIO command** | internal: axis recalibrations/resets, version/check request, diagnostic toggles — useful on a spare cockpit button so recalibration never needs the desktop |
+| **Lit** flag | lamp follows the button (dim idle, bright pressed). Also marks the lamp as *profile-owned*, which shields it from the feedback endpoint (see OUTPUT-INTEGRATION.md) |
+
+### The Xbox 360 button map
+
+RIO joystick buttons are assigned in this fixed order — pick low numbers for
+the game's most important actions:
+
+| RIO joy button | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 |
+|---|---|---|---|---|---|---|---|---|---|---|---|
+| Pad button | A | B | X | Y | LB | RB | Back | Start | L3 | R3 | Guide |
+
+The hat maps to the D-pad. Buttons past 11 are dropped by the pad — route
+those to the keyboard instead. (On the RioGamepad HID all 96 buttons exist
+natively and no mapping table applies.)
+
+## Axes
+
+### Calibration (per profile)
+
+`Calibration` holds per-axis invert flags and `EnableZR`:
+
+- **Joystick X/Y** auto-range from observed travel with a small deadzone.
+- **Throttle (Z)** is the ratcheted lever; calibrated so the detent rest
+  position reads **0**, full forward `32766` — i.e. it is naturally
+  **unipolar**.
+- **Pedals** feed Rx/Ry directly, or — with `EnableZR` — mix into a single
+  rudder axis: `Rz = 16383 − left/2 + right/2` (Rx/Ry then idle).
+
+### Routing onto the pad (`AxisRouting`, JSON-only)
+
+Each of the six axes picks a `Target` and `Mode`
+(`src/RioJoy.Core/Output/AxisRoutingConfig.cs`; null section = the legacy
+default routing):
+
+| Axis | Default target | Conversion |
+|---|---|---|
+| X | LeftThumbX | Centered |
+| Y | LeftThumbY | Centered |
+| Z | LeftTrigger | trigger byte `value×255/32766` |
+| Rx | RightThumbX | Centered |
+| Ry | RightThumbY | Centered |
+| Rz | RightTrigger | trigger byte |
+
+Modes for thumb targets: **`Centered`** (`(value−16383)×2` → stick range) for
+axes that rest mid-travel, **`UnipolarPositive`** (rest 0 = stick center,
+32766 = stick max — only the upper half is used) for the ratcheted throttle.
+`Target: "None"` suppresses an axis entirely.
+
+**The triggers-are-buttons trap:** many games hard-bind the pad triggers to
+fire/actions. If the throttle rides `LeftTrigger` (the default), advancing the
+throttle *fires*. The shipped Descent profile
+([`profiles/descent-d1x.json`](../profiles/descent-d1x.json)) is the worked
+example: throttle → `RightThumbY` `UnipolarPositive`, rudder mix → 
+`RightThumbX`, pedals `None`, keeping both triggers free for the game.
+
+## Choosing a strategy per game
+
+- **Modern XInput game** — pad buttons + axes for the flight controls, keyboard
+  routing for the long tail (MFD pages, systems). Check the game's own binding
+  UI to see the pad.
+- **DOS / emulated game (DOSBox, source ports)** — mostly keyboard routing (it
+  arrives as scancodes, which DOSBox maps cleanly); axes via the pad if the
+  emulator supports a controller, else map coarse throttle steps to keys.
+- **Legacy DirectInput sim** — the x360 pad appears as a DirectInput device
+  too; if the game needs more than 11 buttons on the *stick itself*, prefer
+  keyboard routing or run the RioGamepad HID (96 native buttons).
+- **Anything with a clickable cockpit** — mouse routing gives you cursor
+  nudges and clicks from cockpit buttons.
+
+## Building the profile
+
+1. **Create/edit** from the tray: *Edit profile*. The editor shows the cockpit
+   panel in its functional groups; click a button, set its label, action,
+   modifiers, and **Lit**, then Apply. Save writes the config.
+2. **Live check**: with the RIO (or vRIO) connected, physical presses light the
+   panel and the axis gauges move — before any game is involved. The "Send
+   button output to the PC" toggle turns real keystroke injection on when you
+   want to test into an editor/notepad.
+3. **Triggers**: comma-separated executable names that auto-activate the
+   profile when their window is foreground (`d1x-rebirth, descent`). Matching
+   is basename, case-insensitive, `.exe` optional. First matching profile
+   wins; DOSBox-hosted games all share the DOSBox exe name (rename per game or
+   switch manually); native games (Firestorm, Red Planet) go in
+   `NativeGameExecutables` instead — RIOJoy releases the ports for them.
+4. **RIO port**: leave `(app default)`, or a COM name, or `pipe:vrio` for the
+   emulator.
+5. **JSON-only settings** (edit `%APPDATA%\RIOJoy\config.json`): `AxisRouting`,
+   `Calibration` fine points, `PlasmaComPort`/`PlasmaGreeting`, and the
+   `Feedback` section (see FEEDBACK.md).
+6. **Legacy import**: `RioJoy.Tray.exe --import-profile <file>` merges a
+   single-profile JSON document; the `Import .ini` menu converts an original
+   `RIO.ini` (buttons, inverts, greeting).
+
+## Testing without hardware or game
+
+- **vRIO** (`pipe:vrio`): click buttons on the emulator's panel and watch them
+  arrive — the editor lights up, the pad reacts.
+- **joy.cpl** (Game Controllers): shows the virtual pad's axes/buttons moving.
+- Keyboard routes: open Notepad, enable the editor's output toggle, press
+  cockpit buttons.
+
+## Checklist for a new game
+
+1. Find the game's real executable name (foreground window process) → Triggers.
+2. Decide the axis story first: does the game hard-use triggers? If yes, route
+   the throttle to a thumb axis `UnipolarPositive` (copy the Descent pattern).
+3. Map the few primary actions to pad buttons 1–11, everything else to
+   keyboard; mark cockpit-lit buttons **Lit**.
+4. Set `EnableZR` if the game wants one rudder axis rather than two pedals.
+5. Live-check in the editor, then in-game; bind a spare cockpit button to
+   *RIO command → recalibrate* for the cabinet.
+6. Add the `Feedback` section if the game will drive lamps/plasma back
+   (OUTPUT-INTEGRATION.md).

docs/OUTPUT-INTEGRATION.md

@@ -5,7 +5,8 @@ through RIOJoy: the lighted buttons (lamps) and the plasma/VFD text display.
 This is the integrator's view — what the hardware can show, which addresses
 mean what, and how to feed them. The exact wire grammar lives in
 [FEEDBACK.md](FEEDBACK.md); the RIO serial protocol in
-[PROTOCOL.md](PROTOCOL.md).
+[PROTOCOL.md](PROTOCOL.md); the mirror direction (cockpit inputs → game) in
+[INPUT-INTEGRATION.md](INPUT-INTEGRATION.md).
 
 ## The four output channels