mirrors/SDL
1
0
Fork 0
mirror of https://github.com/libsdl-org/SDL.git synced 2025-09-13 14:58:14 +00:00
Code Issues Packages Projects Releases Wiki Activity

Fixed bug 5161 - Autodetect controller mappings based on the Linux Gamepad Specification

Browse Source 
Jan Bujak

I wrote a new driver for my gamepad on Linux. I'd like SDL to support it out-of-box, as currently it just treats it as a generic joystick instead of a gamepad. From what I can see the only way to do that is to either 1) pick one of the already supported controllers' PID, VID and button layouts and have my driver send that (effectively lying that it's something else), or 2) submit a preconfigured, hardcoded mapping to SDL.

Both of those, in my opinion, are silly when we already have the Linux Gamepad Specification which standarizes this:

https://www.kernel.org/doc/html/v4.15/input/gamepad.html

Unfortunately SDL doesn't make use of it currently. So I've took it upon myself to add it; patch is in the attachments.

Basically what the patch does is that if SDL finds no built-it controller mappings for a given joystick it then asks the joystick backend to autodetect it, and that uses the relevant evdev bits to figure out which button/axis is which. (See the specs for more details.)

With this patch applied my own driver for my controller works out-of-box with SDL with no extra configuration and is correctly recognized as a gamepad; this is also going to be the case for any other driver which follows the Linux Gamepad Specification.
This commit is contained in:
Sam Lantinga
2020-05-29 13:37:21 -07:00
parent e2dbed9cfe
commit 345b4d7e14
18 changed files with 419 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

180
src/joystick/linux/SDL_sysjoystick.c
View File

@@ -656,6 +656,7 @@ ConfigJoystick(SDL_Joystick * joystick, int fd)
printf("Joystick has button: 0x%x\n", i);
#endif
joystick->hwdata->key_map[i] = joystick->nbuttons;
joystick->hwdata->has_key[i] = SDL_TRUE;
++joystick->nbuttons;
}
}
@@ -665,6 +666,7 @@ ConfigJoystick(SDL_Joystick * joystick, int fd)
printf("Joystick has button: 0x%x\n", i);
#endif
joystick->hwdata->key_map[i] = joystick->nbuttons;
joystick->hwdata->has_key[i] = SDL_TRUE;
++joystick->nbuttons;
}
}
@@ -687,6 +689,7 @@ ConfigJoystick(SDL_Joystick * joystick, int fd)
absinfo.fuzz, absinfo.flat);
#endif /* DEBUG_INPUT_EVENTS */
joystick->hwdata->abs_map[i] = joystick->naxes;
joystick->hwdata->has_abs[i] = SDL_TRUE;
if (absinfo.minimum == absinfo.maximum) {
joystick->hwdata->abs_correct[i].used = 0;
} else {
@@ -721,6 +724,7 @@ ConfigJoystick(SDL_Joystick * joystick, int fd)
absinfo.fuzz, absinfo.flat);
#endif /* DEBUG_INPUT_EVENTS */
joystick->hwdata->hats_indices[hat_index] = joystick->nhats++;
joystick->hwdata->has_hat[hat_index] = SDL_TRUE;
}
}
if (test_bit(REL_X, relbit) || test_bit(REL_Y, relbit)) {
@@ -1100,6 +1104,181 @@ LINUX_JoystickQuit(void)
SDL_QuitSteamControllers();
}
/*
This is based on the Linux Gamepad Specification
available at: https://www.kernel.org/doc/html/v4.15/input/gamepad.html
*/
static SDL_bool
LINUX_JoystickGetGamepadMapping(int device_index, SDL_GamepadMapping *out)
{
SDL_Joystick * joystick;
joystick = (SDL_Joystick *) SDL_calloc(sizeof(*joystick), 1);
if (joystick == NULL) {
SDL_OutOfMemory();
return SDL_FALSE;
}
/* We temporarily open the device to check how it's configured. */
if (LINUX_JoystickOpen(joystick, device_index) < 0) {
SDL_free(joystick);
return SDL_FALSE;
}
if (!joystick->hwdata->has_key[BTN_GAMEPAD]) {
/* Not a gamepad according to the specs. */
LINUX_JoystickClose(joystick);
SDL_free(joystick);
return SDL_FALSE;
}
/* We have a gamepad; start filling out the mappings. */
memset(out, 0, sizeof(SDL_GamepadMapping));
if (joystick->hwdata->has_key[BTN_SOUTH]) {
out->a.kind = EMappingKind_Button;
out->a.target = joystick->hwdata->key_map[BTN_SOUTH];
}
if (joystick->hwdata->has_key[BTN_EAST]) {
out->b.kind = EMappingKind_Button;
out->b.target = joystick->hwdata->key_map[BTN_EAST];
}
if (joystick->hwdata->has_key[BTN_NORTH]) {
out->y.kind = EMappingKind_Button;
out->y.target = joystick->hwdata->key_map[BTN_NORTH];
}
if (joystick->hwdata->has_key[BTN_WEST]) {
out->x.kind = EMappingKind_Button;
out->x.target = joystick->hwdata->key_map[BTN_WEST];
}
if (joystick->hwdata->has_key[BTN_SELECT]) {
out->back.kind = EMappingKind_Button;
out->back.target = joystick->hwdata->key_map[BTN_SELECT];
}
if (joystick->hwdata->has_key[BTN_START]) {
out->start.kind = EMappingKind_Button;
out->start.target = joystick->hwdata->key_map[BTN_START];
}
if (joystick->hwdata->has_key[BTN_THUMBL]) {
out->leftstick.kind = EMappingKind_Button;
out->leftstick.target = joystick->hwdata->key_map[BTN_THUMBL];
}
if (joystick->hwdata->has_key[BTN_THUMBR]) {
out->rightstick.kind = EMappingKind_Button;
out->rightstick.target = joystick->hwdata->key_map[BTN_THUMBR];
}
if (joystick->hwdata->has_key[BTN_MODE]) {
out->guide.kind = EMappingKind_Button;
out->guide.target = joystick->hwdata->key_map[BTN_MODE];
}
/*
According to the specs the D-Pad, the shoulder buttons and the triggers
can be digital, or analog, or both at the same time.
*/
/* Prefer digital shoulder buttons, but settle for analog if missing. */
if (joystick->hwdata->has_key[BTN_TL]) {
out->leftshoulder.kind = EMappingKind_Button;
out->leftshoulder.target = joystick->hwdata->key_map[BTN_TL];
}
if (joystick->hwdata->has_key[BTN_TR]) {
out->rightshoulder.kind = EMappingKind_Button;
out->rightshoulder.target = joystick->hwdata->key_map[BTN_TR];
}
if (joystick->hwdata->has_hat[1] && /* Check if ABS_HAT1{X, Y} is available. */
(!joystick->hwdata->has_key[BTN_TL] || !joystick->hwdata->has_key[BTN_TR])) {
int hat = joystick->hwdata->hats_indices[1] << 4;
out->leftshoulder.kind = EMappingKind_Hat;
out->rightshoulder.kind = EMappingKind_Hat;
out->leftshoulder.target = hat | 0x4;
out->rightshoulder.target = hat | 0x2;
}
/* Prefer analog triggers, but settle for digital if missing. */
if (joystick->hwdata->has_hat[2]) { /* Check if ABS_HAT2{X,Y} is available. */
int hat = joystick->hwdata->hats_indices[2] << 4;
out->lefttrigger.kind = EMappingKind_Hat;
out->righttrigger.kind = EMappingKind_Hat;
out->lefttrigger.target = hat | 0x4;
out->righttrigger.target = hat | 0x2;
} else {
if (joystick->hwdata->has_key[BTN_TL2]) {
out->lefttrigger.kind = EMappingKind_Button;
out->lefttrigger.target = joystick->hwdata->key_map[BTN_TL2];
}
if (joystick->hwdata->has_key[BTN_TR2]) {
out->righttrigger.kind = EMappingKind_Button;
out->righttrigger.target = joystick->hwdata->key_map[BTN_TR2];
}
}
/* Prefer digital D-Pad, but settle for analog if missing. */
if (joystick->hwdata->has_key[BTN_DPAD_UP]) {
out->dpup.kind = EMappingKind_Button;
out->dpup.target = joystick->hwdata->key_map[BTN_DPAD_UP];
}
if (joystick->hwdata->has_key[BTN_DPAD_DOWN]) {
out->dpdown.kind = EMappingKind_Button;
out->dpdown.target = joystick->hwdata->key_map[BTN_DPAD_DOWN];
}
if (joystick->hwdata->has_key[BTN_DPAD_LEFT]) {
out->dpleft.kind = EMappingKind_Button;
out->dpleft.target = joystick->hwdata->key_map[BTN_DPAD_LEFT];
}
if (joystick->hwdata->has_key[BTN_DPAD_RIGHT]) {
out->dpright.kind = EMappingKind_Button;
out->dpright.target = joystick->hwdata->key_map[BTN_DPAD_RIGHT];
}
if (joystick->hwdata->has_hat[0] && /* Check if ABS_HAT0{X,Y} is available. */
(!joystick->hwdata->has_key[BTN_DPAD_LEFT] || !joystick->hwdata->has_key[BTN_DPAD_RIGHT] ||
!joystick->hwdata->has_key[BTN_DPAD_UP] || !joystick->hwdata->has_key[BTN_DPAD_DOWN])) {
int hat = joystick->hwdata->hats_indices[0] << 4;
out->dpleft.kind = EMappingKind_Hat;
out->dpright.kind = EMappingKind_Hat;
out->dpup.kind = EMappingKind_Hat;
out->dpdown.kind = EMappingKind_Hat;
out->dpleft.target = hat | 0x8;
out->dpright.target = hat | 0x2;
out->dpup.target = hat | 0x1;
out->dpdown.target = hat | 0x4;
}
if (joystick->hwdata->has_abs[ABS_X] && joystick->hwdata->has_abs[ABS_Y]) {
out->leftx.kind = EMappingKind_Axis;
out->lefty.kind = EMappingKind_Axis;
out->leftx.target = joystick->hwdata->abs_map[ABS_X];
out->lefty.target = joystick->hwdata->abs_map[ABS_Y];
}
if (joystick->hwdata->has_abs[ABS_RX] && joystick->hwdata->has_abs[ABS_RY]) {
out->rightx.kind = EMappingKind_Axis;
out->righty.kind = EMappingKind_Axis;
out->rightx.target = joystick->hwdata->abs_map[ABS_RX];
out->righty.target = joystick->hwdata->abs_map[ABS_RY];
}
LINUX_JoystickClose(joystick);
SDL_free(joystick);
return SDL_TRUE;
}
SDL_JoystickDriver SDL_LINUX_JoystickDriver =
{
LINUX_JoystickInit,
@@ -1115,6 +1294,7 @@ SDL_JoystickDriver SDL_LINUX_JoystickDriver =
LINUX_JoystickUpdate,
LINUX_JoystickClose,
LINUX_JoystickQuit,
LINUX_JoystickGetGamepadMapping
};
#endif /* SDL_JOYSTICK_LINUX */