joycon2cpp

A C++ executable that makes Switch 2 controllers into working PC controllers.

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UI made with ImGui

DISCLAIMER

This project is Windows-only, primarily because the ViGEmBus Driver (used for virtual controller output) is exclusive to Windows.
You're free to make your own macOS/Linux fork if you want.

DEPENDENCIES

• ViGEmBus drivers
• Microsoft Visual C++ Redistributable 2015–2022 (x64)

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Usage Guide

• Download the latest release's .exe file (or, optionally, build from source as detailed below) and open it
• Use the UI to add players, pick their controllers and set everything up (settings are explained in detail below)
• Follow the onscreen pairing instructions and pair the correct controllers for each player
• When completed, you will have WGInput controllers ready for every player to use. (they show up as Sony DualShock4 Gamepad)
• Click the chat button to toggle mouse functions，3 adjustable modes for the mouse pointer.

Note: Bit layouts differ slightly between left and right Joy-Cons, so correct side pairing is important.

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Rumble Instructions

• When picking the motor in your emulator, pick the corresponding side depending on controller. (eg. Motor L for left joycon)
• If playing with Dual Joycons or a ProCon2 controller, all rumble data gets replicated to all motors, so picking any of them works fine.
• Rumble is not supported for the NSOGC Controller
• (pro controller rumble is untested! let me know if it doesnt work!!!)

Building from source

If you want to build the project yourself, follow these instructions (Windows + Visual Studio):

Requirements

Make sure the following are installed via Visual Studio Installer:

Visual Studio 2022 or newer Workload: Desktop development with C++ Component: Windows 10 or 11 SDK Component: MSVC v14.x

(Optional but useful) C++/WinRT

1. Open the x64 Native Tools Command Prompt for VS (whatever your version is)

2. Go into the project's root directory and make a build folder:

   cd (path to the main directory of the project here)
   mkdir build
   cd build
   

3. Generate Visual Studio project files with CMake:

   cmake .. -G "Visual Studio 17 2022" -A x64

4. Build the project in Release mode:

   cmake --build . --config Release

5. The compiled executable will be located in:

   build\Release\testapp.exe
   

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Other

In-App Settings

This section details what each setting does.

CONTROLLER SETTINGS (the settings on each player's controller)

• Side (Single Joycons) Details the side this joycon is. (L/R)

• Orientation (Single Joycons) Details what orientation this joycon is. (Upright/Sideways)

• Gyro Source (Dual Joycons)

Controls what joycon's gyro/accel data to use.

• Gyro Output

This setting controls where gyro/accel data will be fed to.

DS4 Raw: Feeds the data directly into the virtual DS4 controller using DS4 axis conventions.

DS4 Switch Emu: Same as DS4 Raw, but remaps gyro axes to match Switch controller conventions. Use this if motion controls feel wrong or inverted in your emulator.

DSU UDP: Sends gyro/accel data over the DSU protocol to a local DSU client. Uses the standard DSU server address (127.0.0.1, port 26760), compatible with Dolphin, Cemu, and other DSU-supporting emulators.

• Mouse (Singular Joycons) Toggles the mouse input.
• DPAD (Left Joycon) Toggles whether the left joycon's buttons map to DPAD or ABXY.
• Remap (Sideways Singular Joycons) Toggles whether the buttons get rotated 90 degrees for sideways use (e.g X becomes A, Y becomes X)

GLOBAL SETTINGS (found under the Settings dropdown menu)

Swap A/B and X/Y buttons - changes the layout to Nintendo ABXY instead of DualShock4

Joy-Con 2 BLE Notification Layout

This document outlines some findings related to Joy-Con 2 BLE input behavior. If you're developing or reverse-engineering Joy-Con 2, Pro Controller 2, or other supported Nintendo controllers over BLE, this may be useful.

Behavior Quirks

A notable quirk of these controllers is that if you attempt to connect or pair them repeatedly in a short time span, they may stop responding or fail to connect entirely for several minutes. This appears to be a controller-level cooldown behavior rather than an OS/BLE stack issue.

If your controller stops connecting:
Wait a few minutes before trying again. It should recover on its own.

BLE Notification (with IMU enabled, Left Joy-Con)

Here’s an example notification received from a Joy-Con 2 via BLE, with the IMU command sent. (Pro Controller 2 and GC Controller notifications follow similar layouts but may shift certain fields.)

08670000000000e0ff0ffff77f23287a0000000000000000000000000000005f0e007907000000000001ce7b52010500beffb501ee0ffeff04000200000000

Field Breakdown (based on known Joy-Con 2 layout)

huge thanks to @german77 for providing me with the notification layout below!!

Offset	Size	Value	Comment
0x00	0x4	Packet ID	Sequence or timestamp
0x04	0x4	Buttons	Button state bitmap
0x08	0x3	Left Stick	12-bit X/Y packed
0x0B	0x3	Right Stick	12-bit X/Y packed
0x0E	0x2	Mouse X
0x10	0x2	Mouse Y
0x12	0x2	Mouse Unk	Possibly extra motion data
0x14	0x2	Mouse Distance	Distance to IR/motion surface
0x16	0x2	Magnetometer X
0x18	0x2	Magnetometer Y
0x1A	0x2	Magnetometer Z
0x1C	0x2	Battery Voltage	1000 = 1V
0x1E	0x2	Battery Current	100 = 1mA
0x20	0xE	Reserved	Undocumented region
0x2E	0x2	Temperature	25°C + raw / 127
0x30	0x2	Accel X	4096 = 1G
0x32	0x2	Accel Y
0x34	0x2	Accel Z
0x36	0x2	Gyro X	48000 = 360°/s
0x38	0x2	Gyro Y
0x3A	0x2	Gyro Z
0x3C	0x1	Analog Trigger L
0x3D	0x1	Analog Trigger R

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🧪 Field Example Breakdown

Offset	Size	Field	Raw Value	Interpreted
0x00	4	Packet ID	08 67 00 00	0x00006708 → 26376
0x04	4	Buttons	00 00 00 00	No buttons pressed
0x08	3	Left Stick	e0 ff 0f	X = 0x0FF0 = 4080, Y = 0x0FE0 = 4064
0x0B	3	Right Stick	ff f7 7f	Garbage on Left Joy-Con
0x2E	2	Temperature	5f 0e	0x0E5F = 3679 → ~54°C
0x30	2	Accel X	00 79	0x7900 = 30976
0x32	2	Accel Y	07 00	0x0007 = 7
0x34	2	Accel Z	00 00	0
0x36	2	Gyro X	01 ce	0xCE01 = 52737
0x38	2	Gyro Y	7b 52	0x527B = 21115
0x3A	2	Gyro Z	01 05	0x0501 = 1281

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📘 Notes

• Left Joy-Con does not use Right Stick, so data at 0x0B–0x0D is typically junk.
• Stick values use 12-bit X/Y packed across 3 bytes:
  • X = upper 12 bits of first 1.5 bytes
  • Y = lower 12 bits of next 1.5 bytes
• Accel/Gyro fields are signed 16-bit:
  • Accelerometer: 4096 = 1G
  • Gyroscope: 48000 = 360°/s
• Temperature:
  25°C + (raw / 127)
  → 25 + (3679 / 127) ≈ 54°C
• Battery voltage:
  Reported as millivolts. 3000 = 3.0V. If 0x0000, likely unavailable at that time.

Latency Diagnostics

The test app can write an internal latency CSV while you compare update policies:

.\testapp.exe--latency-test --update-policy low --latency-csv low.csv
.\testapp.exe--latency-test --update-policy balanced --latency-csv balanced.csv
.\testapp.exe--latency-test --update-policy legacy --latency-csv legacy.csv

Policies:

• low / LowLatency: send a ViGEm update for each BLE notification.
• balanced / Balanced120Hz: limit output to about 120 Hz.
• legacy / Legacy60Hz: limit output to about 60 Hz for comparison.

The CSV columns are:

mode,controller_type,event_index,ble_delta_ms,buffer_age_left_ms,buffer_age_right_ms,decode_to_vigem_us,total_pipeline_us

For a repeatable manual comparison, run each policy with the same controller, keep it still for 10 seconds, then press one button 30 times at a steady rhythm. Repeat for Single Joy-Con, Dual Joy-Con, and Pro Controller. For perceived end-to-end latency, record the physical controller and gamepad-tester.com or Steam Input at 240 fps, count frames between the visible press and on-screen response, and convert with latency_ms = frames / fps * 1000.