Linux force feedback with SDL 1.3

[dubigrasu]

Hello everyone.
(hope this is the right section to post this...)
First of all I want to thank the devs for this little gem which is the Dolphin emulator.

Before boring everyone to death with I've done and what not, I have a small (big) question.
Is my understanding that Dolphin can provide force feedback in Linux if compiled with SDL 1.3. It is however not clear to me if someone (devs or users) actually managed to see this in action.

I've searched the forum and Dolphin's page on code.google with no success.
I managed to compile a working version of Dolphin with SDL 1.3 from source (actually several of them) but unfortunately force feedback is still elusive.

So, the question: Is Dolphin in its current state able to provide force feedback in Linux or just provides a support for future (SDL 1.3.) releases?
I see in the source code a SDL 1.3 folder but I'm not skilled enough to figure out if it has a present purpose or is there for future releases.
I know that SDL 1.3 (stable) isn't out there yet so maybe it isn't suppose to work yet.

Some things to mention:
The emulator is working fine, the joystick is recognized and working properly.
The force feedback is working on my gamepad (Logitech Rumblepad 2), tested with several games through Wine and even with a (native Linux) PS1 emulator.

Thanks for you attention and have a nice day!

[dubigrasu]

Think I have my answer.

Comment 10 by project member smelenchuk,Today (5 hours ago) regarding issue 3338: http://code.google.com/p/dolphin-emu/issues/detail?id=3338

Quote:The fixes suggested above were committed in r7199; I can now get force feedback with the controller that I have here (it's not a 360 gamepad, but it does have force feedback support). Further issues are probably related to your controller drivers and/or SDL itself.

Unfortunately for me they are the same fixes I used to compile Dolphin with SDL1.3 in the first place, and as suggested, the problem then lies somewhere else.

[dubigrasu]

Searched a little deeper...asked the SDL guys about force feedback and what can I do to establish if my gamepad is working or not with SDL 1.3 on Linux.
They mentioned to me 2 tests from within their source code that I can use to verify the issue, testhaptic and testjoystick.

I compiled them and went on with the tests. it turns out that my gamepad is supported/recognized and currently can reproduce three specific effects: Sine, Square and Triangle.
(I have in fact two Logitech Rumblepad, one wired/one cordless, and both of them are working with the above mentioned tests)
However, the working effects still don't show up in the Dolphin's configuration panel.

So SDL 1.3 does support force feedback for my gamepads, and Dolphin supports my gamepads but something could be broken or not complete in between.

I have no idea what to do next

[Billiard26]

Dolphin only supports "Constant" and "Ramp" effects through SDL currently.

[dubigrasu]

(02-22-2011, 06:46 AM)Billiard26 Wrote: Dolphin only supports "Constant" and "Ramp" effects through SDL currently.

Ah, thank you, this definitely cleared things up and answered my issue. Although is more like:
"Nurse, the medical analysis on patient XXX was a triumph and a total success!"
"And the patient?"
"The patient died, but now we know why."

It is kinda bummer because now I have nothing to go on with.
By chance, are there any remotely future plans to include those missing effects (sine/square/triangle) in Dolphin's capabilities?

Or is there any chance (for me) to alter the source code (SDL's or Doplhin's) to work with those effects that I do have?
(I'm thinking something like somehow simply replacing one effect that doesn't work with my game-pad with one that does.)
I had some feeble attempts to butcher the source code for this purpose (basically I replaced Constant with Sine and Ramp with Triangle), and so far I only succeeded to get the effects showing up in Dolphin's control panel, but not actually working though...

Thing is that I don't know if it is possible (or how) and if I'm just wasting my time (and others).


Eventually, I'm willing to buy another game-pad (good gosh, I have already four!) , but how would I know if the new one will work?
I thought at first to buy a Xbox360 one, but I see in the source code that it doesn't work with SDL, and SDL 1.3 is the only way to get force feedback in Linux.

It would be great if someone (with a force feedback working controller in Dolphin/Linux) can point me to such elusive device and end my misery

Thanks!

[Billiard26]

It would be possible to add the additional effect types.
I have no interest in doing it myself. I can answer any questions you have though.

[dubigrasu]

(02-23-2011, 07:56 PM)Billiard26 Wrote: It would be possible to add the additional effect types.
I have no interest in doing it myself. I can answer any questions you have though.

Thanks for the info, is good to know that hope still exists. Maybe someone, someday...
I'm grateful for your offer to help but from your words I draw the conclusion that is not quite an easy thing to do...it must be something way over my head.
Other than playing (unsuccessfully) with SDL.cpp and SDL.h from "Source/Core/InputCommon/Src/ControllerInterface/SDL" I have no idea where/what/how to do it.
It is not quite the same thing as replicate another existing effect's section and giving it another name as I hoped.
Sine, Square and Triangle belong all together to Periodic effects and each have more and different values to enter (magnitude, period, offset and...something) than Constant and Ramp which seem much simpler.
I studied SDL_haptic.h from SDL source code (which seem to explain almost everything) to get an idea, but in the end I'm no developer and as I said, is way over my head.

Time to draw the line and give it up.
Thanks for your assistance.

[dubigrasu]

So... since playing with the source code is out of my league, I just bought another gamepad in the hope that the new one will work.
So, what gamepad to buy? Since no one here or elsewhere was able to name one of those magical/elusive/fantastic gamepads that DO work in Dolphin/Linux with FF, I decided to took a gamble and buy one of the most common (good) joysticks out there, namely the Xbox 360 controller.

Seemed a good choice at the time, is even listed as one of the few gamepads working with FF in Linux: http://freegamedev.net/wiki/Force_Feedback
Listed there are i-Force devices (unfortunately I don't know what the heck are those), the ThrustMaster Firestorm Dual Power 3 (I have one yes, and of course is working beautifully with FF in Linux but not on Dolphin)...and the above mentioned Xbox.

OK, so Dolphin on Linux is able to work only with Constant and Ramp through SDL 1.3.

And what SDL 1.3's own force feedback test is saying about my brand new Xbox360 controller?

Quote:[root@test SDL]# ./testhaptic
1 Haptic devices detected.
Device: Xbox Gamepad (userspace driver) - 1
Supported effects [16 effects, 16 playing]:
constant
sine
square
triangle
sawtoothup
sawtoothdown
ramp
custom
Supported capabilities:
gain

Constant and Ramp are there, so is gotta work! Yupeee!

Well...the hell yupeee......even with Constant and Ramp clearly supported, Dolphin gives me nothing.
Back to testing with other apps and games...yes the gamepad is working with the above mentioned force feedback effects, still Dolphin refuse to do the same.
(The gamepad itself as a controller is working OK).

Any ideas folks?...any one here able to tell me what to do, or at least to tell me one single gamepad that DOES work?

Thank you in advance.