import array
import struct
import time
from fcntl import ioctl
from typing import IO
from platypush.backend import Backend
from platypush.message.event.joystick import JoystickConnectedEvent, JoystickDisconnectedEvent, \
JoystickButtonPressedEvent, JoystickButtonReleasedEvent, JoystickAxisEvent
[docs]class JoystickLinuxBackend(Backend):
"""
This backend intercepts events from joystick devices through the native Linux API implementation.
It is loosely based on https://gist.github.com/rdb/8864666, which itself uses the
`Linux kernel joystick API <https://www.kernel.org/doc/Documentation/input/joystick-api.txt>`_ to interact with
the devices.
Triggers:
* :class:`platypush.message.event.joystick.JoystickConnectedEvent` when the joystick is connected.
* :class:`platypush.message.event.joystick.JoystickDisconnectedEvent` when the joystick is disconnected.
* :class:`platypush.message.event.joystick.JoystickButtonPressedEvent` when a joystick button is pressed.
* :class:`platypush.message.event.joystick.JoystickButtonReleasedEvent` when a joystick button is released.
* :class:`platypush.message.event.joystick.JoystickAxisEvent` when an axis value of the joystick changes.
"""
# These constants were borrowed from linux/input.h
axis_names = {
0x00: 'x',
0x01: 'y',
0x02: 'z',
0x03: 'rx',
0x04: 'ry',
0x05: 'rz',
0x06: 'throttle',
0x07: 'rudder',
0x08: 'wheel',
0x09: 'gas',
0x0a: 'brake',
0x10: 'hat0x',
0x11: 'hat0y',
0x12: 'hat1x',
0x13: 'hat1y',
0x14: 'hat2x',
0x15: 'hat2y',
0x16: 'hat3x',
0x17: 'hat3y',
0x18: 'pressure',
0x19: 'distance',
0x1a: 'tilt_x',
0x1b: 'tilt_y',
0x1c: 'tool_width',
0x20: 'volume',
0x28: 'misc',
}
button_names = {
0x120: 'trigger',
0x121: 'thumb',
0x122: 'thumb2',
0x123: 'top',
0x124: 'top2',
0x125: 'pinkie',
0x126: 'base',
0x127: 'base2',
0x128: 'base3',
0x129: 'base4',
0x12a: 'base5',
0x12b: 'base6',
0x12f: 'dead',
0x130: 'a',
0x131: 'b',
0x132: 'c',
0x133: 'x',
0x134: 'y',
0x135: 'z',
0x136: 'tl',
0x137: 'tr',
0x138: 'tl2',
0x139: 'tr2',
0x13a: 'select',
0x13b: 'start',
0x13c: 'mode',
0x13d: 'thumbl',
0x13e: 'thumbr',
0x220: 'dpad_up',
0x221: 'dpad_down',
0x222: 'dpad_left',
0x223: 'dpad_right',
# XBox 360 controller uses these codes.
0x2c0: 'dpad_left',
0x2c1: 'dpad_right',
0x2c2: 'dpad_up',
0x2c3: 'dpad_down',
}
[docs] def __init__(self, device: str = '/dev/input/js0', *args, **kwargs):
"""
:param device: Joystick device to monitor (default: ``/dev/input/js0``).
"""
super().__init__(*args, **kwargs)
self.device = device
self._axis_states = {}
self._button_states = {}
self._axis_map = []
self._button_map = []
def _init_joystick(self, dev: IO):
# Get the device name.
buf = array.array('B', [0] * 64)
ioctl(dev, 0x80006a13 + (0x10000 * len(buf)), buf) # JSIOCGNAME(len)
js_name = buf.tobytes().rstrip(b'\x00').decode('utf-8')
# Get number of axes and buttons.
buf = array.array('B', [0])
ioctl(dev, 0x80016a11, buf) # JSIOCGAXES
num_axes = buf[0]
buf = array.array('B', [0])
ioctl(dev, 0x80016a12, buf) # JSIOCGBUTTONS
num_buttons = buf[0]
# Get the axis map.
buf = array.array('B', [0] * 0x40)
ioctl(dev, 0x80406a32, buf) # JSIOCGAXMAP
for axis in buf[:num_axes]:
axis_name = self.axis_names.get(axis, 'unknown(0x%02x)' % axis)
self._axis_map.append(axis_name)
self._axis_states[axis_name] = 0.0
# Get the button map.
buf = array.array('H', [0] * 200)
ioctl(dev, 0x80406a34, buf) # JSIOCGBTNMAP
for btn in buf[:num_buttons]:
btn_name = self.button_names.get(btn, 'unknown(0x%03x)' % btn)
self._button_map.append(btn_name)
self._button_states[btn_name] = 0
self.bus.post(JoystickConnectedEvent(device=self.device, name=js_name, axes=self._axis_map,
buttons=self._button_map))
[docs] def run(self):
super().run()
self.logger.info(f'Opening {self.device}...')
while not self.should_stop():
# Open the joystick device.
try:
jsdev = open(self.device, 'rb')
self._init_joystick(jsdev)
except Exception as e:
self.logger.debug(f'Joystick device on {self.device} not available: {e}')
time.sleep(5)
continue
# Joystick event loop
while not self.should_stop():
try:
evbuf = jsdev.read(8)
if evbuf:
_, value, evt_type, number = struct.unpack('IhBB', evbuf)
if evt_type & 0x80: # Initial state notification
continue
if evt_type & 0x01:
button = self._button_map[number]
if button:
self._button_states[button] = value
evt_class = JoystickButtonPressedEvent if value else JoystickButtonReleasedEvent
# noinspection PyTypeChecker
self.bus.post(evt_class(device=self.device, button=button))
if evt_type & 0x02:
axis = self._axis_map[number]
if axis:
fvalue = value / 32767.0
self._axis_states[axis] = fvalue
# noinspection PyTypeChecker
self.bus.post(JoystickAxisEvent(device=self.device, axis=axis, value=fvalue))
except OSError as e:
self.logger.warning(f'Connection to {self.device} lost: {e}')
self.bus.post(JoystickDisconnectedEvent(device=self.device))
break
