Force
feedback
| Use
the force! |
|
Force feedback can be a valuable add-on to your sim. Problems
seem to be (in my case):
- Getting DirectInput
running. Look at qdxinput.cpp in the QLib
docs on how to do this for example.
- Sending
force feedback commands to the wheel may be slow.
This is seen for several configurations, but depend on the type of wheel,
the type of connection (USB, serial) etc. I've not noticed it too much yet,
since I can easily do 80 to 100 fps with FF (v0.4.1-PII-400-Geforce2MX), so
it's not a real concern yet. A tip: only send feedback updates every rendered
frame, and certainly not every integration step. You could also define a fixed
frequency, independent of framerate, and send feedbacks based on that (a bit
more accurate).
- Getting multiple
effects running. The MS DirectInput docs are nice, but don't go into
much detail for some things, like how to add friction and inertia force effects.
In a net search I came across Immersion,
which offers great documentation and a free SDK from which you can learn how
to do this. You can also skim the QLib docs
(QDXJoy), on this site.
Also, check out the Game Developer
Magazine's archives. Download the nov97.zip file there. It contains
some neat wrapper code for effects, so you can see how to use them. I got
my friction and inertia code working from it.
(last
updated
June 29, 2009
)