[Ohrrpgce] Multiple joysticks, multiplayer, and control remapping

Fri Apr 16 18:09:08 PDT 2021

Nice to hear that! That's a massive break from gamedev. I've been playing
EoG for a bit. I like the ordered dithering aesthetic, although to begin
with I thought the ladders were one-way since at the wrong distance the up
ladders are almost invisible against a stone wall! It's a dungeon crawler
distilled down to basics.
I was going to say that I can't really complete the game without breaking
out pen and paper but I JUST discovered there's a minimap if you press ESC!

Getting back to controllers...

I was initially quite surprised that SDL allows each player to have at most
one joystick, because of things like the Switch Joycon and also flight
simulator controllers (separate joystick and throttle - I actually have
these but haven't used them for 20 years because I don't have a sound card!)
But it turns out that SDL didn't really support Joycons until very recently:
https://discourse.libsdl.org/t/simple-proper-joy-con-support/28567
https://github.com/libsdl-org/SDL/commit/0f57864c9eb60807da20d793290d9f4b1a19d756
It still doesn't merge them into a single controller, that's up to the
application

I wasn't clear, but I was suggesting letting each player have at most one
keyboard, one joystick and one mouse.

For single-player games the one-joystick-per-player is not a limitation
because you can just use the player number to refer to controller number if
necessary, and all the joysticks/keyboard will be coalesced so I think
joycons will just work automatically. Throttles+joysticks however won't
work properly unless you access them separately, because their buttons
(arbitrarily numbered each starting from 0) would get OR'd together to
produce the "player 0" input. I don't think we should care about supporting
these at all, but if we did it would require shifting the button numbering
so they don't overlap.

On Sat, 17 Apr 2021 at 01:49, Simon Bradley <neworiginal at gmail.com> wrote:

> I've been thinking about this sort of stuff in another context recently (I
> just wrote my first hobby game in more than a decade, for a jam on itch.io
> - it's here if you want to take a look:
> https://drnefario.itch.io/eye-of-gath - I'm getting my mojo back after
> working from home for more than a year.)
>
> Most of the time, for a single-player game, you want a coalesced input
> that has maybe been abstracted to an action. You don't care whether it was
> a d-pad up or an arrow-key up, you just want an up. And you also don't want
> to move twice as fast if you press both.
>
> Even if you want to treat controllers as belonging to separate users, you
> quite often want to be able allow a player to have more than one input
> device, such as mouse and keyboard, or controller and touchscreen, or some
> such. It seems to be an Xbox thing to tie user accounts to a specific
> controller, but even there you must be able to add other non-controller
> input sources somehow. The xbox supports usb keyboards, I think.
>
> Note that I did work on an AppleTV project a while ago where we did need
> to be able to treat two controllers as a single user: the Siri Remote is
> treated as a controller, and you have to expect someone to be using the
> remote to launch apps while they use their game controller inside the
> games. It's a bit of a weird edge case, though.
>
> Cheers,
> Simon
>
> On Fri, 16 Apr 2021 at 14:05, Ralph Versteegen <teeemcee at gmail.com> wrote:
>
>> I've been working through (especially in gfx_sdl2) gamepad bugs and
>> unfinished features (none of which made it to github) and now I've only got
>> handling of multiple gamepads left to improve. For better joystick
>> numbering I'm thinking forwards to local multiplayer, remappable controls,
>> ohrkeys joystick support, and even simple remote multiplayer via input
>> forwarding.
>>
>> Currently a number of commands (keyval, keyispressed, keypress,
>> newkeypress, joystickbutton, joystickaxis, getjoystickname,
>> joystickbuttoncount, joystickaxiscount, joystickhatcount) take the joystick
>> number as an extra argument. But there are lots of problems with this:
>> -if there are multiple joysticks on the system you would have to loop
>> through all of them to figure out which one the player is using
>> -I added getnumjoysticks recently but it's undocumented
>> -in gfx_sdl2 and gfx_directx joysticks can get renumbered if any are
>> removed or even added (not possible in gfx_sdl anyway)
>> -the joystick number is currently ignored for control keys like usekey
>> (It's also ignored for keyboard scancodes), instead all inputs joysticks
>> are OR'd
>>
>> But I used rpgbatch to scan the gamelists and there was only a single
>> game that made use of the joystick number arg, Porosis on SS, which
>> erroneously contains "key is pressed(key:A,true)". "joystick axis" wasn't
>> used either (though Blood Ledger and inputtest.rpg now use it.)
>>
>> Further, I want to let people define additional keys to usekey, menukey,
>> etc. (I think we could break convention and export these to the hsi as
>> "shootkey", "runkey",  etc. for a form of consistency, since there will be
>> little difference between builtin and additional controls.) So instead of
>> hardcoding e.g. a charge-up action to the joy:Y button you'd define a
>> "charge key" with some default mappings which can then be changed by either
>> a scripted or future builtin control mapping menu.
>>
>> SDL2 has functions to get/set the player number for each
>> joystick/gamepad. At most one joystick can be assigned to a player, which
>> is a reasonable limitation. On most platforms these functions don't really
>> do anything, but on consoles they report the actual player number and
>> apparently some consoles have coloured LED lights to indicate which
>> controller is each player.
>>
>> So it occurred to me that we should repurpose the 2nd arg to all those
>> commands as the *player number* rather than the joystick number. Each
>> player has at most one joystick and keyboard (and in future mice could also
>> gain a player number arg) but note that a player might have no joystick,
>> just a keyboard. I suggest that players are numbered from 1 up, which is
>> less confusing, and the default player=0 (which is also used by all builtin
>> controls) can just be all input from all control devices OR'd together so
>> if you have multiple gamepads all existing games will just work. There
>> could be a command to instead set a specific player as the default, e.g.
>> for local or remote multiplayer where you want just one player to control
>> the hero/menus.
>>
>> If you want to change which player a device is assigned to that might be
>> tricky if there are no commands to enumerate joysticks, but we could have a
>> command such as "swap player gamepads(player A, player B)"
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