SDL_GameController is for game controllers aka gamepads, which tend to be
similar to the xbox360 or PS2/3/4 pad (one DPAD on the left, two analog
sticks, 4 buttons for the right thumb, 2 shoulder buttons on each side that
may be trigger axes and those “back” and “start” buttons in the middle, maybe
even an “xbox” button or similar).
I think the main purposes are
- making it easy(er) to port XInput code to SDL, esp. for Linux/Mac
- allowing game developers to set default bindings for gamepads that make
sense with most gamepads.
Okay, so this basically provides a way for a game using SDL to turn every
device into an ABXY input device, hide the details from the user and have
them plug it in and figure out on their own which controls act like “A”,
“RT”, “RS”, etc. That’s certainly useful.
Usually you use SDL_GameController with the corresponding events
(SDL_CONTROLLER*), I think, but you can also use it to set the displayed
names etc of normal SDL_Joystick buttons, if the joystick happens to be a
known game controller.
SDL_IsGameController(joystick) tells you if a joystick is a know game
controller, SDL_GameControllerGetBindForAxis() and
SDL_GameControllerGetBindForButton() tell you how things are mapped.
(I’ve used it that way so I don’t have to handle game controller events
separately, but still get the mapping)
That’s useful too. I’m porting some code that has it’s own "action"
mapping system that maps the SDL joystick number (v1.2) + control changes
(button 0 down, axis 0 right, hat left) to game actions… so to work with
this I need to still use the SDL_Joystickxxxx() calls but I’m trying to
take advantage of the knowledge available in the SDL_GameController
mappings to respond to “button A down” instead of “button n down” (where X
varies depending on device). Also, when setting up the mappings, if I
have a game controller mapping in SDL, I’d like to display “button A” in
the mapping GUI instead of “button 0”, at least for XINPUT devices. I’m
thinking that, for DINPUT devices, showing the game controller mapped
names will just add to the confusion for non-XINPUT devices that might
have a button named X on them, but it’s not anywhere near where the X
button is on an XBox gamepad.
Regarding Steam: The documentation is referring to the gamepad configuration
in the Steam (Linux?) Big Picture settings, that lets you create a mapping
from your gamepad’s buttons/axes to the xbox controller model. I think Steam
then sets the SDL_GAMECONTROLLERCONFIG environment variable with the mapping
string, which SDL2 then uses for games that use SDL2 and are launched from
Yeah, I’m a bit confused regarding the BPM controller mapping GUI. With a
Steam Controller, it seems to allow me to remap things even for a game
that has no Steam game “action map” file published. For other
controllers, on SteamOS, it seems to not let me do ANY remapping for even,
say, a Wireless XB360 controller. This weirdness makes it difficult to
test, and makes me feel like I’m missing something basic.
That aside, the environment variable mapping string… doesn’t it include
mappings for ALL the game controllers that have configs for the game? Or
does it include all connected game controllers that have configs for the
game? If I don’t have my controller plugged in, and I fire up the game
and connect my controller, will there be a config for it, or will the user
have to restart the game?
So “mapping” refers to “Button 3 corresponds to SDL_CONTROLLER_BUTTON_A,
Axis 2 corresponds to SDL_CONTROLLER_AXIS_RIGHTX” and so on, not to
standard actions. No idea if standard action mappings are available on
Steam/Linux, but if they are that’s something provided by Steamworks
SDK, not by SDL2.
Steam configuration of a controller allows the user to map “actions” (the
things in the actions file like “strafe left”, “fire missle”, “toggle
shield mode”, etc.) to controls on their device. The game sees no input
controls… only triggered actions and readings from axis/mouse
inputs/trackpad inputs. However, for games without an “actions” file, I’m
not sure what it’s supposed to do… the Steam Controller is obviously
special, it can be set up like an XBox gamepad with or without a mouse
control via the right trackpad and DPAD control via the left trackpad,
etc. It doesn’t seem to let me do this kind of thing for any other type
of device tho’.
So, the fact that the BPM controller config stuff can’t deal with ALL
devices leads me to needing to keep my game’s controller mapping GUI, and
try to at least make things work automatically as best as possible for
XBox Gamepad-like devices (or those with SDL mappings to make it seem like
an XBox Gamepad), and let them “deep dive” and customize mappings if they
Players these days will connect a device and start pressing buttons,
expecting it to work just like the game they were just playing, even if
that makes no logical sense.
is an interesting read about how handling joysticks and similar input devices
sucks (only difference is that now with SDL2 it’s a a bit better for
YES! That is a complete hoot to read! I’ve been dealing with all of that
kind of stuff for years, and the guy is right, most of it has never made
a lick of sense.
Ed Phillips <@Ed_Phillips> University of Delaware (302) 831-6082
Systems Programmer IV, Network and Systems ServicesOn Thu, 1 Dec 2016, Daniel Gibson wrote: