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Add gamepad support to woodeneye-008 #14167

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80 changes: 78 additions & 2 deletions examples/demo/02-woodeneye-008/woodeneye-008.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@
typedef struct {
SDL_MouseID mouse;
SDL_KeyboardID keyboard;
SDL_Gamepad *gamepad;
double pos[3];
double vel[3];
unsigned int yaw;
Expand Down Expand Up @@ -60,6 +61,15 @@ static int whoseKeyboard(SDL_KeyboardID keyboard, const Player players[], int pl
return -1;
}

static int whoseGamepad(SDL_JoystickID gamepad, const Player players[], int players_len)
{
int i;
for (i = 0; i < players_len; i++) {
if (SDL_GetGamepadID(players[i].gamepad) == gamepad) return i;
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@madebr madebr Oct 7, 2025 •
edited
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I think the comment is about not always using curly braces, and indentation.

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@slouken slouken Oct 7, 2025

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Yep, for example, here the code would be:

Suggested change
if (SDL_GetGamepadID(players[i].gamepad) == gamepad) return i;
if (SDL_GetGamepadID(players[i].gamepad) == gamepad) {
return i;
}

}
return -1;
}

static void shoot(int shooter, Player players[], int players_len)
{
int i, j;
Expand Down Expand Up @@ -288,6 +298,7 @@ static void initPlayers(Player *players, int len)
players[i].wasd = 0;
players[i].mouse = 0;
players[i].keyboard = 0;
players[i].gamepad = NULL;
players[i].color[0] = (1 << (i / 2)) & 2 ? 0 : 0xff;
players[i].color[1] = (1 << (i / 2)) & 1 ? 0 : 0xff;
players[i].color[2] = (1 << (i / 2)) & 4 ? 0 : 0xff;
Expand Down Expand Up @@ -344,7 +355,7 @@ SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
*appstate = as;
}

if (!SDL_Init(SDL_INIT_VIDEO)) {
if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_GAMEPAD)) {
return SDL_APP_FAILURE;
}
if (!SDL_CreateWindowAndRenderer("examples/demo/woodeneye-008", 640, 480, 0, &as->window, &as->renderer)) {
Expand Down Expand Up @@ -386,6 +397,25 @@ SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
}
}
break;
case SDL_EVENT_GAMEPAD_REMOVED:
for (i = 0; i < player_count; i++) {
if (players[i].gamepad && (SDL_GetGamepadID(players[i].gamepad) == event->gdevice.which)) {
SDL_CloseGamepad(players[i].gamepad);
players[i].gamepad = NULL;
}
}
break;
case SDL_EVENT_GAMEPAD_ADDED:
for (i = 0; i < player_count; i++) {
if (players[i].gamepad == NULL) {
players[i].gamepad = SDL_OpenGamepad(event->gdevice.which);
if (!players[i].gamepad)
SDL_Log("Failed to open gamepad ID %u: %s", (unsigned int) event->gdevice.which, SDL_GetError());
else
as->player_count = SDL_max(as->player_count, i + 1);
}
}
break;
case SDL_EVENT_MOUSE_MOTION: {
SDL_MouseID id = event->motion.which;
int index = whoseMouse(id, players, player_count);
Expand Down Expand Up @@ -446,6 +476,44 @@ SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
}
break;
}
case SDL_EVENT_GAMEPAD_AXIS_MOTION: {
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@expikr expikr Oct 24, 2025

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If I understand correctly, this event is fired only when the axis value changes. This implementation results in the camera only rotation when you wiggle the thumbstick, instead of the thumbstick controlling the velocity of camera rotation.

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@slouken slouken Oct 24, 2025

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That's correct. If you want to have control based on state you should just query the axis value instead of responding to an axis change event.

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@expikr expikr Oct 24, 2025

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Also I’m pretty sure the convention is to use the right stick for camera controls rather than left. It’d be a little bit awkward having both movement and aim on the left side of the controller.

SDL_JoystickID id = event->gaxis.which;
int index = whoseGamepad(id, players, player_count);
if (index >= 0) {
if (event->gaxis.axis == SDL_GAMEPAD_AXIS_LEFTX)
players[index].yaw -= ((int)event->gaxis.value) * 0x00000800;
if (event->gaxis.axis == SDL_GAMEPAD_AXIS_LEFTY)
players[index].pitch = SDL_max(-0x40000000, SDL_min(0x40000000, players[index].pitch - ((int)event->gaxis.value) * 0x00000800));
}
break;
}
case SDL_EVENT_GAMEPAD_BUTTON_DOWN: {
Uint8 button = event->gbutton.button;
SDL_JoystickID id = event->gbutton.which;
int index = whoseGamepad(id, players, player_count);
if (index >= 0) {
if (button == SDL_GAMEPAD_BUTTON_DPAD_UP) players[index].wasd |= 1;
if (button == SDL_GAMEPAD_BUTTON_DPAD_LEFT) players[index].wasd |= 2;
if (button == SDL_GAMEPAD_BUTTON_DPAD_DOWN) players[index].wasd |= 4;
if (button == SDL_GAMEPAD_BUTTON_DPAD_RIGHT) players[index].wasd |= 8;
if (button == SDL_GAMEPAD_BUTTON_SOUTH) players[index].wasd |= 16;
if (button == SDL_GAMEPAD_BUTTON_EAST) shoot(index, players, player_count);
}
break;
}
case SDL_EVENT_GAMEPAD_BUTTON_UP: {
Uint8 button = event->gbutton.button;
SDL_JoystickID id = event->gbutton.which;
int index = whoseGamepad(id, players, player_count);
if (index >= 0) {
if (button == SDL_GAMEPAD_BUTTON_DPAD_UP) players[index].wasd &= 30;
if (button == SDL_GAMEPAD_BUTTON_DPAD_LEFT) players[index].wasd &= 29;
if (button == SDL_GAMEPAD_BUTTON_DPAD_DOWN) players[index].wasd &= 27;
if (button == SDL_GAMEPAD_BUTTON_DPAD_RIGHT) players[index].wasd &= 23;
if (button == SDL_GAMEPAD_BUTTON_SOUTH) players[index].wasd &= 15;
}
break;
}
}
return SDL_APP_CONTINUE;
}
Expand Down Expand Up @@ -476,5 +544,13 @@ SDL_AppResult SDL_AppIterate(void *appstate)

void SDL_AppQuit(void *appstate, SDL_AppResult result)
{
AppState *as = appstate;
Player *players = as->players;
int player_count = as->player_count;
int i;
for (i = 0; i < player_count; i++) {
if (players[i].gamepad)
SDL_CloseGamepad(players[i].gamepad);
}
SDL_free(appstate); // just free the memory, SDL will clean up the window/renderer for us.
}
}
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