[SOLVED] how can I get the connected joypad names?

[Rion]

@meleu

I think I will hold off on that until you made some progress on the run command script.

But thank you for pointing it out for me :)

[meleu]

@Zigurana You are amazing!!! :D

You pointed me out that SDL stuff and I did my research on that topic.

I can't play with C++ but I can remember my teenager hacking days with C language!

I wrote this small program to get the joystick names and indexes:

/* jslist.c
 * This little program just list the joysticks connected to the system.
 * The ouput format is "index:JoystickName".
 */

#include <stdio.h>
#include "SDL.h"

int main(void) {
	int num_joy, i;

	SDL_Init(SDL_INIT_JOYSTICK);

	num_joy = SDL_NumJoysticks();

	for(i = 0; i < num_joy; i++)
		printf("%d:%s\n", i, SDL_JoystickNameForIndex(i));

	SDL_Quit();
	return 0;
}

The command to compile this code (as pointed in SDL Wiki):
gcc jslist.c -o jslist $(sdl2-config --cflags --libs)

This was my first step. The jslist needs some little improvements to avoid problems with controllers with the same name. It's easy to solve, but I will work on that later. Now I have to play with my children! :D

[Zigurana]

Good work! interested to see where this ends!
Have fun with the little ones!

[meleu]

This post is deleted!

[meleu]

Hey guys! I think I did it! Or, at least, started it!

Let's talk about it at a proper thread:
https://retropie.org.uk/forum/topic/1167/here-is-a-way-to-select-input-for-retroarch-players-1-4

[BuZz]

from shell

for js in /dev/input/js*; do path=$(udevadm info --name=$js | grep DEVPATH | cut -d= -f2); name=$(</$(dirname sys$path)/name); echo $name; done

[meleu]

@BuZz said in [SOLVED] how can I get the connected joypad names?:

from shell

for js in /dev/input/js*; do path=$(udevadm info --name=$js | grep DEVPATH | cut -d= -f2); name=$(</$(dirname sys$path)/name); echo $name; done

pretty awesome! :)

It perfectly answer the topic question. But another problem arises for my application...

The problem is how to find out the proper SDL2/RetroArch index. The SDL2 gives to my jslist.c the correct index, and it doesn't always happen to be the same number after the /dev/input/js.

Example: I have 3 usb controllers (as js0, js1 and js2) and one bluetooth controller as js3. The js-RetroArch equivalence is:
js0 = 0
js1 = 1
js2 = 2
js3 = 3

Then I unplug the second usb controller. Now the the relation is:
js0 = 0
js2 = 1
js3 = 2

I think it's hard to find the proper index with "pure" shell script.

[BuZz]

thats ok, you just go through them and increment the index in the loop.

[BuZz]

i=0; for dev in $(find /dev/input -name "js*" | sort); do path=$(udevadm info --name=$dev | grep DEVPATH | cut -d= -f2); name=$(</$(dirname sys$path)/name); echo $dev $i $name; ((i++)); done

/dev/input/js0 0 USB,2-axis 8-button gamepad
/dev/input/js1 1 8Bitdo SFC30 GamePad Joystick

then unplugging the USB

/dev/input/js1 0 8Bitdo SFC30 GamePad Joystick

(switched to find to avoid an error if no joysticks connected, but just for this quick one line example)

[meleu]

@BuZz
Initially I was excited with this solution and went for the tests...

Then I realized that the SDL algorithm index assignment isn't that simple...

The scenario: 4 usb joysticks (js0, js1, js2 and js3) and one bluetooth controller (js4). And then I disconnected the 1st and 2nd usb joysticks (js0 and js1), and the bluetooth controller also. Several minutes later I reconnected the bluetooth controller and it took the js0 "slot". Look at the output differences:

[prompt]$ jslist 
0:Twin USB Joystick
1:Twin USB Joystick
2:8Bitdo Zero GamePad
[prompt]$ bash buzz-jslist.sh
/dev/input/js0 0 8Bitdo Zero GamePad
/dev/input/js2 1 Twin USB Joystick
/dev/input/js3 2 Twin USB Joystick

[meleu]

I think my current dilema is: C or Python?

The C solution is great because the SDL2 is installed by default in RetroPie. The only doubt I have is "where to put the binary?". Maybe /opt/retropie/supplementary?

The Python solution requires the installation of python-pygame. It means 15.2 MB of additional disk space just to list the available joysticks.

For the moment I think the C approach is the winner.

[meleu]

Hey @BuZz , I've just realized that your method can be used to let the user choose which controller to use in runcommand.
I saw this line in runcommand.sh and it seems to always get the first /dev/input/js*.
(no need for that sermon about your priorities. :-) It's just an enhancement idea, ok...)

[BuZz]

The smiley doesn't make that line funny.

[meleu]

@BuZz it represents the effect, not the cause