Quick fix to add flight stick for Torque

The aim of this article is to show a quick fix to add analog flight stick support for the Torque Game Engine. I call it a quick fix as it's not the cleanest way to do it. Moreover, it works only for Windows as I was not able to do it for Linux & Mac (i do not own a linux box and mac one). If someone has the time to do it for Linux & Mac, it will be very nice.

First, let's take a look at dinput.h (in your dx include path) :

#define DI8DEVTYPE_DEVICE           0x11
#define DI8DEVTYPE_MOUSE            0x12
#define DI8DEVTYPE_KEYBOARD         0x13
#define DI8DEVTYPE_JOYSTICK         0x14
#define DI8DEVTYPE_GAMEPAD          0x15
#define DI8DEVTYPE_DRIVING          0x16
#define DI8DEVTYPE_FLIGHT           0x17
#define DI8DEVTYPE_1STPERSON        0x18
#define DI8DEVTYPE_DEVICECTRL       0x19
#define DI8DEVTYPE_SCREENPOINTER    0x1A
#define DI8DEVTYPE_REMOTE           0x1B
#define DI8DEVTYPE_SUPPLEMENTAL     0x1C

As you can see in DX8, you have different define for joystick, gamepad, driving steer, and flight stick.

If we take a look at winDInputDevice.cc in platformWin32, we have the following :

switch ( GET_DIDEVICE_TYPE( mDeviceInstance.dwDevType ) )
   {
      case DI8DEVTYPE_KEYBOARD:
         mDeviceType = KeyboardDeviceType;
         mDeviceID   = smKeyboardCount++;
         dSprintf( mName, 29, "keyboard%d", mDeviceID );
         break;

      case DI8DEVTYPE_MOUSE:
         mDeviceType = MouseDeviceType;
         mDeviceID   = smMouseCount++;
         dSprintf( mName, 29, "mouse%d", mDeviceID );
         break;

      case DI8DEVTYPE_JOYSTICK:
         mDeviceType = JoystickDeviceType;
         mDeviceID   = smJoystickCount++;
         dSprintf( mName, 29, "joystick%d", mDeviceID );
         break;

      default:
         mDeviceType = UnknownDeviceType;
         mDeviceID   = smUnknownCount++;
         dSprintf( mName, 29, "unknown%d", mDeviceID );
         break;
   }

and in winDirectInput.cc (platformWin32)

void DInputManager::enumerateDevices()
{
   if ( mDInputInterface )
   {
#ifdef LOG_INPUT
      Input::log( "Enumerating input devices...\n" );
#endif

      DInputDevice::init();
      DInputDevice::smDInputInterface = mDInputInterface;
      mDInputInterface->EnumDevices( DI8DEVTYPE_KEYBOARD, EnumDevicesProc, this, DIEDFL_ATTACHEDONLY );
      mDInputInterface->EnumDevices( DI8DEVTYPE_MOUSE, EnumDevicesProc, this, DIEDFL_ATTACHEDONLY );
      mDInputInterface->EnumDevices( DI8DEVTYPE_JOYSTICK, EnumDevicesProc, this, DIEDFL_ATTACHEDONLY );
   }
}

So, the minor fix I propose is the following. Add the line

mDInputInterface->EnumDevices( DI8DEVTYPE_FLIGHT, EnumDevicesProc, this, DIEDFL_ATTACHEDONLY );

just after the last EnumDevice in DInputManager::enumerateDevices() (file platformWin32/winDirectInput.cc)

Then in the file platformWin32/winDInputDevice.cc, add the following line

case DI8DEVTYPE_FLIGHT:

just after the case DI8DEVTYPE_JOYSTICK:

Moreover in order to cope with a 'bug', you need to change the following line of code

bool DInputDevice::processImmediate()
{
   if ( !mDevice )
      return false;

   ....

   // Loop through all of the objects and produce events where
   // the states have changed:
   S32 newData, oldData;
   for ( DWORD i = 0; i < mObjCount; i++ )

with the following code

bool DInputDevice::processImmediate()
{
   if ( !mDevice )
      return false;

   ....

   // Loop through all of the objects and produce events where
   // the states have changed:
   S32 newData, oldData = 0;
   for ( DWORD i = 0; i < mObjCount; i++ )

It will just solve an assert problem with oldData not beeing set properly.

Now, here is a small script code that I'm using in DoP to have a correct analog control of the plane (in file default.bind.cs

// Analog Joystick static variable
$lastYaw=0;
$lastPitch=0;
function getJoystickAdjustAmount(%val,%last)
{
   if( %val > - $pref::Input::DeadZone && %val < $pref::Input::DeadZone ) return 0;
   %offset = %val - %last;
   return(%offset * ($cameraFov / 90) * $pref::Input::Sensitivity);
}

function yaw2(%val)
{
   $mvYaw += getJoystickAdjustAmount(%val,$lastYaw);
   if( %val > - $pref::Input::DeadZone && %val < $pref::Input::DeadZone ) return;
   $lastYaw=%val;
}

function pitch2(%val)
{
  if($pref::Input::InvertMouse)
  {
   $mvPitch -= getJoystickAdjustAmount(%val,$lastPitch);
  }
  else
  {
   $mvPitch += getJoystickAdjustAmount(%val,$lastPitch);
  }
  if( %val > - $pref::Input::DeadZone && %val < $pref::Input::DeadZone ) return;
  $lastPitch=%val;
}

function resetCommand()
{
   $lastYaw=0;
   $lastPitch=0;
}

Then instead using the regular yaw() and pitch() function, you can use these functions to bind the x & y axis of your stick.

moveMap.bind(joystick0, "xaxis", yaw2);
moveMap.bind(joystick0, "yaxis", pitch2);

Do not forget to set the variables $pref::Input::DeadZone & $pref::Input::Sensitivity t o correct values also.

So that's all. All the tests were done on my computer with two different USB flight stick. For the steering wheel, just change the DI8DEVTYPE_FLIGHT with DI8DEVTYPE_DRIVING, it should work (i'm unable to test it as i do not have a steering wheel).

Nota
Why did i say it's a quick fix. I say so, because i think it may be better to add a new control device flightstick, like mouse or keyboard, and then rewrite some part of the torque dinput code with that in mind.
BTW, I'm also working on support for zaxis and POV button. I just need a stick to test it.