Fg-Haptic

Force feedback (haptic) support for Flight Gear flight simulator

Version 0.6

Copyright (C) Lauri Peltonen, 2011, 2020

This program is released under GPLv2 or later.

Description

This force feedback support consists of 4 components:

• fg-haptic or fg-haptic.exe
• force-feedback.xml
• force_feedback.nas
• ff-protocol.xml

fg-haptic or fg-haptic.exe is the main program, which supports force feedback devices through SDL 2 library.

force-feedback.xml is a configuration dialog which resides inside Flight Gear's data directory.

force_feedback.nas is a wrapper between different flight dynamics models etc. and the force feedback effects.

ff-protocol.xml is a generic IO protocol which fg-haptic uses to communicate with flight Gear.

This program has been tested with following devices:

• Saitek Cyborg Evo Force (Linux)

  • All effects supported
  • Needs special kernel patch

• Saitek Cyborg Evo Force (Windows 10, 64 bit)

  • Joystick driver does not work properly. Even Saitek's own force tester in configuration crashes.

• Gametech "Twin USB Joystick" gamepad with rumble effect (Linux)

  • Supports only stick shaker, if gain & strength are around 1.0
  • Does not have axis (so 1?) but claims to have 2

• Logitech Driving Force GT wheel (Linux)

  • Supports only constant forces
  • Really has 1 axis only, but claims to have 2

• Logitech Wingman Force 3D (Linux)

  • Supports only constant forces

• Microsoft Sidewinder Force Feedback 2 (Linux)

  • Supports numerous modes including constant force and stick shaker

Building

Required libraries:

• libsdl2-dev
• libsdl2-net-dev

fg-haptic should build by running:

make fg-haptic

For windows, you might need to set EXE=.exe also, i.e.:

make fg-haptic EXE=.exe

Installation

fg-haptic(.exe) can reside anywhere on your system.

Linux: Install libsdl2 and libsdl2-net.

Windows: Install SDL2 runtime and SDL2_net runtime dlls to the same directory as fg-haptic.exe.

force-feedback.xml must be copied into gui/dialogs/ directory inside Flight Gear's data directory.

force_feedback.nas must be copied into Nasal/ directory inside Flight Gear's data directory.

ff-protocol.xml must be copied into Protocol/ directory inside Flight Gear's data directory.

Running

Launch flightgear with at least the following options:

fgfs --telnet=5401 --generic=socket,out,20,localhost,5402,udp,ff-protocol

Then run fg-haptic(.exe).

You can also launch them in different order (fg-haptic first). Also you can replace localhost with any other address, fg-haptic tries to determine the FlightGear's address from the first received packet.

fg-haptic expects telnet to be at port 5401 and receives generic IO on port 5402. These are currently hard coded. Note that compared to previous versions, fg-haptic now uses UDP so fg-haptic can be launched/restarted while Flight Gear is running.

If FlightGear's menu is not visible, press F10 to display it. In the Help menu you can find Force feedback options. Tune them to your liking and fly!

To test force feedback effects, run

fg-haptic --test or fg-haptic -t

which tests all effects on all connected joysticks. There is also a simple test implemented in the dialog inside Flight Gear.

Effects

There are currently following effects implemented:

• Pilot forces. Any force (acceleration) on the pilot can be transferred to the force feedback device.'
• Stick forces. Basic effect is speed dependent stiffening of the joystick. Other effects include stick shaker when the aircraft is about to stall and stick pusher if aircraft AoA is too high.
• Ground rumble. A periodic "click" when speeding up on a runway.
• Force feedback trim, which changes the center location of the joystick depending on the trim value.