private void PollJoystick(LinuxJoystickDetails js)
{
unsafe
{
const int EventCount = 32;
InputEvent *events = stackalloc InputEvent[EventCount];
long length = 0;
while (true)
{
length = (long)Libc.read(js.FileDescriptor, (void *)events, (UIntPtr)(sizeof(InputEvent) * EventCount));
if (length <= 0)
{
break;
}
// Only mark the joystick as connected when we actually start receiving events.
// Otherwise, the Xbox wireless receiver will register 4 joysticks even if no
// actual joystick is connected to the receiver.
js.Caps.SetIsConnected(true);
js.State.SetIsConnected(true);
length /= sizeof(InputEvent);
for (int i = 0; i < length; i++)
{
InputEvent *e = events + i;
switch (e->Type)
{
case EvdevType.ABS:
{
AxisInfo axis;
if (js.AxisMap.TryGetValue((EvdevAxis)e->Code, out axis))
{
if (axis.Info.Maximum > axis.Info.Minimum)
{
if (e->Code >= (int)EvdevAxis.HAT0X && e->Code <= (int)EvdevAxis.HAT3Y)
{
// We currently treat analogue hats as digital hats
// to maintain compatibility with SDL2. We can do
// better than this, however.
int hat = (e->Code - (int)EvdevAxis.HAT0X) / 2;
int xy_axis = (int)axis.Axis & 0x1;
int value = e->Value.CompareTo(0) + 1;
switch (xy_axis)
{
case 0:
// X-axis
js.hatStates[hat, 1] = value;
break;
case 1:
// Y-axis
js.hatStates[hat, 0] = value;
break;
}
js.State.SetHat((JoystickHat)hat, TranslateHat(js.hatStates[hat, 0], js.hatStates[hat, 1]));
}
else
{
// This axis represents a regular axis or trigger
js.State.SetAxis(
axis.Axis,
(short)Common.HidHelper.ScaleValue(e->Value,
axis.Info.Minimum, axis.Info.Maximum,
short.MinValue, short.MaxValue));
}
}
}
break;
}
case EvdevType.KEY:
{
int button;
if (js.ButtonMap.TryGetValue((EvdevButton)e->Code, out button))
{
js.State.SetButton(button, e->Value != 0);
}
break;
}
}
// Create a serial number (total seconds in 24.8 fixed point format)
int sec = (int)((long)e->Time.Seconds & 0xffffffff);
int msec = (int)e->Time.MicroSeconds / 1000;
int packet =
((sec & 0x00ffffff) << 24) |
Common.HidHelper.ScaleValue(msec, 0, 1000, 0, 255);
js.State.SetPacketNumber(packet);
}
}
}
}
private LinuxJoystickDetails OpenJoystick(string path)
{
LinuxJoystickDetails stick = null;
int number = GetJoystickNumber(Path.GetFileName(path));
if (number >= 0)
{
int fd = -1;
try
{
fd = Libc.open(path, OpenFlags.NonBlock);
if (fd == -1)
{
return(null);
}
unsafe
{
const int evsize = Evdev.EventCount / 8;
const int axissize = Evdev.AxisCount / 8;
const int keysize = Evdev.KeyCount / 8;
byte * evbit = stackalloc byte[evsize];
byte * axisbit = stackalloc byte[axissize];
byte * keybit = stackalloc byte[keysize];
string name;
EvdevInputId id;
// Ensure this is a joystick device
bool is_valid = true;
is_valid &= Evdev.GetBit(fd, 0, evsize, new IntPtr(evbit)) >= 0;
is_valid &= Evdev.GetBit(fd, EvdevType.ABS, axissize, new IntPtr(axisbit)) >= 0;
is_valid &= Evdev.GetBit(fd, EvdevType.KEY, keysize, new IntPtr(keybit)) >= 0;
is_valid &= TestBit(evbit, (int)EvdevType.KEY);
is_valid &= TestBit(evbit, (int)EvdevType.ABS);
is_valid &= TestBit(axisbit, (int)EvdevAxis.X);
is_valid &= TestBit(axisbit, (int)EvdevAxis.Y);
is_valid &= Evdev.GetName(fd, out name) >= 0;
is_valid &= Evdev.GetId(fd, out id) >= 0;
if (is_valid)
{
stick = new LinuxJoystickDetails
{
FileDescriptor = fd,
PathIndex = number,
State = new JoystickState(),
Name = name,
Guid = CreateGuid(id, name),
};
int axes, buttons, hats;
QueryCapabilities(stick, axisbit, axissize, keybit, keysize,
out axes, out buttons, out hats);
stick.Caps = new JoystickCapabilities(axes, buttons, hats, false);
// Poll the joystick once, to initialize its state
PollJoystick(stick);
}
}
Debug.Print("Found joystick on path {0}", path);
}
catch (Exception e)
{
Debug.Print("Error opening joystick: {0}", e.ToString());
}
finally
{
if (stick == null && fd != -1)
{
// Not a joystick
Libc.close(fd);
}
}
}
return(stick);
}