Noob: can someone please help me understand input and input devices?

[craigbot]

I think this project is fantastic, and I am just getting to know it. I have scoured the web and the great docs at https://retropie.org.uk/docs, but I'm dense, so I still don't understand various things. If anyone could help me understand input and input devices for RetroPie, I'd be really appreciative. I'm very familiar with Pis, and have this Pi 4 with RetroPie on it set up so that I can ssh into it and edit files if needed. Questions:

• When setting up a controller, does that controller then replace or add to another controller that was previously set up?
  • Is it possible to have different controllers for different games? If so, how?
  • Is it possible to have 2 controllers for a 2 player game? If so, how?
• Is a USB keyboard always recognized, and if it's set up as a controller, is it just for mapping keyboard keys?
• How can I map keyboard keys to a controller for a specific game? (For example, I start a game with K on the keyboard. How do I map the K key to an Xbox controller button for a specific Apple II game?)
• Does the order of USB ports of the Pi matter for input devices?
• How can I get a USB mouse to select? I have Amiberry set up in RetroPie, and when I choose "Start Amiberry from the menu, I get a screen with a lot of configuration options. With a standard 3 button mouse (the wheel in the middle is the 3rd button) I can move the cursor. If I click on a left hand side tab, it's selected. But I can't select anything in the options pane at all--clicking on a down triangle next to an input box does nothing. How can I select and update options?

Many thanks in advance for any help you can give!

[mitu]

@craigbot said in Noob: can someone please help me understand input and input devices?:

When setting up a controller, does that controller then replace or add to another controller that was previously set up?

When you add a new controller (in EmulationStation) it's added, it's not replacing any previous used/added controller. You can add as many controllers as you want.

    Is it possible to have different controllers for different games? If so, how?

Yes, most of the time (i.e. when using RetroArch cores).
Leaving aside the situation when you use just the controller that you want when starting the game, you can re-arrange the controller order so that Player 1 (P1) is assigned to the controller you want. The reordering can be done through the Configuration Editor or with @meleu's Joystick Selection tool.
NB: only the latter allows you to choose for each game the controller, from the runcommand menu.

    Is it possible to have 2 controllers for a 2 player game? If so, how?

Yes. Just connect the controllers and make sure they're configured (once) in EmulationStation. If the controllers are the same make/model, you only need to configure one of them. Start the game and both controllers should be active and acting as P1/P2, just like on a real console.

Is a USB keyboard always recognized, and if it's set up as a controller, is it just for mapping keyboard keys?

Depends on the emulator. RetroArch by default has a keyboard configured, even if not present, for P1. EmulationStation does not have a default input scheme defined for a keyboard, but you can just configure the keyboard just like any other controller, through the input mapping dialog.

How can I map keyboard keys to a controller for a specific game? (For example, I start a game with K on the keyboard. How do I map the K key to an Xbox controller button for a specific Apple II game?)

That depends on the emulator. If the emulator or game doesn't support a gamepad, you can use Xboxdrv to map gamepad inputs to a keyboard input. See here for an overview and examples. In general, try to look the emulator documentation on how to map the gamepad before attempting to use xboxdrv.

Does the order of USB ports of the Pi matter for input devices?

If you have more than one plugged in, yes. Keyboard don't matter, since they're a different input type, they can be plugged in any port, but for controllers the order in which they are enumerated by the operating system also becomes the order of players in emulators, so 1st gamepad becomes P1, etc.

How can I get a USB mouse to select? I have Amiberry set up in RetroPie, and when I choose "Start Amiberry from the menu, I get a screen with a lot of configuration options. With a standard 3 button mouse (the wheel in the middle is the 3rd button) I can move the cursor. If I click on a left hand side tab, it's selected. But I can't select anything in the options pane at all--clicking on a down triangle next to an input box does nothing. How can I select and update options?

That's strange, it should work as a regular mouse. Which screen - specifically - are you talking about ? What are you choosing in the left tree and what are you trying to enable/select on the right dialog side ?

[craigbot]

@mitu You * are * a * godsend 😊 Thank you so much for putting in the time and effort to answer those questions. For the Amiberry config one, it was seeing your reply that got me to where I could work the screen: I tried again with the keyboard, and finally figured out that it was the space key on the keyboard that worked on the down arrow to the right of the input boxes.

I'd really like to get the Xbox controller to function as left arrow, right arrow, space, and K (to start) keyboard keys. Those keyboard keys are working for Apple II Bug Attack. All of the Xbox controller keys make a beep but do nothing else when I'm playing the game. I tried xboxdrv according to the instructions, but it doesn't seem to be there:

pi@retropie:/opt/retropie/configs/amiga $ /opt/retropie/supplementary/xboxdrv/bin/xboxdrv --help-key
-bash: /opt/retropie/supplementary/xboxdrv/bin/xboxdrv: No such file or directory
pi@retropie:/opt/retropie/configs/amiga $ sudo /opt/retropie/supplementary/xboxdrv/bin/xboxdrv --help-key
sudo: /opt/retropie/supplementary/xboxdrv/bin/xboxdrv: command not found
pi@retropie:/opt/retropie/configs/amiga $ which xboxdrv
pi@retropie:/opt/retropie/configs/amiga $

How do I fire it up? I saw in the instructions, but unless I'm mistaken, they're all assuming xboxdrv exists. I can't find it if it does 😊

So many thanks!

[mitu]

@craigbot said in Noob: can someone please help me understand input and input devices?:

I tried xboxdrv according to the instructions, but it doesn't seem to be there:

It's not installed by default, you need to install it first, from the drivers section of the packages.