# 🎮 Gamepad Controllers

<video autoplay="" muted="" loop="" playsinline="" controls="" src="../_static/gamepad.webm"></video>

Don't you want to use a video game controller to control your trained policy? Genesis Forge currently integrates with the Logitech [F310](https://www.logitechg.com/en-us/shop/p/f310-gamepad.940-000110?sp=1&searchclick=Logitech%20G) and [F710](https://www.logitechg.com/en-us/shop/p/f710-wireless-gamepad) controllers.

```{figure} _images/f710.webp
:alt: F10 controller
:width: 350
:align: center
:class: dark-light
The Logitech F710 gamepad controller
```

# Installation

To use these controllers, you need to install [HIDAPI](https://github.com/libusb/hidapi) on your computer:

## Mac

With [Homebrew](https://brew.sh/)

```shell
brew install hidapi
```

## Windows

Download the windows files from [here](https://github.com/libusb/hidapi/releases) and then place them in `Windows/System32`.

## Linux

Use your package manager to install `libhidapi-dev`, for example:

```shell
sudo apt install libhidapi-dev
```

You'll likely also need to add udev rules for the controllers. Create the file: `/etc/udev/rules.d/100-hidapi.rules`

```{code-block}
:caption: /etc/udev/rules.d/100-hidapi.rules
SUBSYSTEM=="usb", ATTR{idVendor}=="046d", ATTR{idProduct}=="c216", MODE="0660", GROUP="plugdev", TAG+="uaccess", TAG+="udev-acl", SYMLINK+="logitech_f310%n"
KERNEL=="hidraw*", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c216", MODE="0660", GROUP="plugdev", TAG+="uaccess", TAG+="udev-acl"
SUBSYSTEM=="usb", ATTR{idVendor}=="046d", ATTR{idProduct}=="c219", MODE="0660", GROUP="plugdev", TAG+="uaccess", TAG+="udev-acl", SYMLINK+="logitech_f710%n"
KERNEL=="hidraw*", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c219", MODE="0660", GROUP="plugdev", TAG+="uaccess", TAG+="udev-acl"
```

Then

```bash
sudo chmod 644 /etc/udev/rules.d/00-hidapi.rules
sudo udevadm control --reload-rules
```

## Usage

If you have one or more [command managers](./managers//command) defined in your environment, you can easily connect the gamepad to them in your eval program.

For example, let's say you have both a velocity command and a target height command defined in your environment:

```{code-block} python
:caption: environment.py

self.velocity_command = VelocityCommandManager(
    self,
    range={
        "lin_vel_x": [-1.0, 1.0],
        "lin_vel_y": [-1.0, 1.0],
        "ang_vel_z": [-1.0, 1.0],
    },
)
self.height_command = CommandManager(self, range=(0.2, 0.4))
```

Now let's create an eval script that uses the gamepad controller to set these values:

```{code-block} python
:caption: eval.py

# This is where the trained policy was saved
EXPERIMENT_DIR = "./logs/experiment"
TRAINED_MODEL = f"{EXPERIMENT_DIR}/model_100.pt"
[cfg] = pickle.load(open(f"{EXPERIMENT_DIR}/cfgs.pkl", "rb"))

# Initialize the genesis simulator
gs.init(logging_level="warning", backend=gs.gpu)

# Setup the environment
env = MyEnv(num_envs=1, headless=False)
env.build()

# Connect the gamepad
gamepad = Gamepad()
env.velocity_command.use_gamepad(
    gamepad, lin_vel_y_axis=0, lin_vel_x_axis=1, ang_vel_z_axis=2
)
env.height_command.use_gamepad(gamepad, range_axis=3)

# Setup policy runner
env = RslRlWrapper(env)
runner = OnPolicyRunner(env, cfg, EXPERIMENT_DIR, device=gs.device)
runner.load(TRAINED_MODEL)
policy = runner.get_inference_policy(device=gs.device)

obs, _ = env.reset()
with torch.no_grad():
    while True:
        actions = policy(obs)
        obs, _rews, _dones, _infos = env.step(actions)
```

This maps joystick axis 0 and 1 (left joystick) to the robot's Y and X movements, and axis 2 and 3 (right joystick) to rotation and height.