Skip to content

make gamepad work on sdl backends #190

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
Eliandro4 wants to merge 2 commits into
base: main
Choose a base branch
from
Open

make gamepad work on sdl backends #190

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
677eb49
sdl1 gamepad
Eliandro4 Jun 4, 2026
76635f3
sdl2 gamepad
Eliandro4 Jun 5, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 7 additions & 7 deletions CMakeLists.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -238,13 +238,6 @@ if(PLATFORM STREQUAL "desktop")
target_link_directories(butterscotch PRIVATE ${GLFW3_LIBRARY_DIRS})
set(BACKEND_LIBRARIES ${GLFW3_LIBRARIES})
endif()

#gamecontrollerdb
add_custom_command(TARGET butterscotch POST_BUILD
COMMAND ${CMAKE_COMMAND} -E copy_if_different
${CMAKE_SOURCE_DIR}/vendor/gamecontrollerdb.txt
$<TARGET_FILE_DIR:butterscotch>/gamecontrollerdb.txt
)
elseif(DESKTOP_BACKEND STREQUAL "glfw2")
add_compile_definitions(USE_GLFW2)

Expand Down Expand Up @@ -282,6 +275,13 @@ if(PLATFORM STREQUAL "desktop")
target_compile_options(butterscotch PRIVATE -fsanitize=address -fno-omit-frame-pointer)
target_link_options(butterscotch PRIVATE -fsanitize=address)
endif()

#gamecontrollerdb
add_custom_command(TARGET butterscotch POST_BUILD
COMMAND ${CMAKE_COMMAND} -E copy_if_different
${CMAKE_SOURCE_DIR}/vendor/gamecontrollerdb.txt
$<TARGET_FILE_DIR:butterscotch>/gamecontrollerdb.txt
)
elseif(PLATFORM STREQUAL "web")
if (NOT ENABLE_MODERN_GL)
message(FATAL_ERROR "Web requires modern gl!")
Expand Down
322 changes: 321 additions & 1 deletion src/desktop/backends/sdl1.c
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,7 @@
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>

#include <SDL/SDL_events.h>
#include <SDL/SDL.h>
Expand All @@ -12,7 +14,185 @@
static Runner *g_runner;
static int32_t fbWidth, fbHeight;
static SDL_Surface* scr;
static SDL_Joystick* openJoysticks[MAX_GAMEPADS];

typedef struct {
bool valid;
int max_button;
int max_axis;
int max_hat;

int button_map[GP_BUTTON_COUNT];
int axis_map[GP_AXIS_COUNT];
int hat_map[GP_BUTTON_COUNT];
int hat_mask[GP_BUTTON_COUNT];
int axis_button_map[GP_BUTTON_COUNT];
float axis_button_sign[GP_BUTTON_COUNT];
} GamepadMapping;

static GamepadMapping joystickMappings[MAX_GAMEPADS];

static void parseMappingField(GamepadMapping* mapping, const char* key, const char* val) {
int gml_btn = -1;
int gml_axis = -1;

if (strcmp(key, "a") == 0) gml_btn = 0;
else if (strcmp(key, "b") == 0) gml_btn = 1;
else if (strcmp(key, "x") == 0) gml_btn = 2;
else if (strcmp(key, "y") == 0) gml_btn = 3;
else if (strcmp(key, "leftshoulder") == 0) gml_btn = 4;
else if (strcmp(key, "rightshoulder") == 0) gml_btn = 5;
else if (strcmp(key, "lefttrigger") == 0) gml_btn = 6;
else if (strcmp(key, "righttrigger") == 0) gml_btn = 7;
else if (strcmp(key, "back") == 0) gml_btn = 8;
else if (strcmp(key, "start") == 0) gml_btn = 9;
else if (strcmp(key, "leftstick") == 0) gml_btn = 10;
else if (strcmp(key, "rightstick") == 0) gml_btn = 11;
else if (strcmp(key, "dpup") == 0) gml_btn = 12;
else if (strcmp(key, "dpdown") == 0) gml_btn = 13;
else if (strcmp(key, "dpleft") == 0) gml_btn = 14;
else if (strcmp(key, "dpright") == 0) gml_btn = 15;
else if (strcmp(key, "guide") == 0) gml_btn = 16;
else if (strcmp(key, "leftx") == 0) gml_axis = 0;
else if (strcmp(key, "lefty") == 0) gml_axis = 1;
else if (strcmp(key, "rightx") == 0) gml_axis = 2;
else if (strcmp(key, "righty") == 0) gml_axis = 3;

if (gml_btn == -1 && gml_axis == -1) return;

if (val[0] == 'b') {
int b = atoi(val + 1);
if (gml_btn != -1) {
mapping->button_map[gml_btn] = b;
if (b > mapping->max_button) mapping->max_button = b;
}
} else if (val[0] == 'a') {
int a = atoi(val + 1);
if (gml_axis != -1) {
mapping->axis_map[gml_axis] = a;
if (a > mapping->max_axis) mapping->max_axis = a;
} else if (gml_btn != -1) {
mapping->axis_button_map[gml_btn] = a;
mapping->axis_button_sign[gml_btn] = 1.0f;
if (a > mapping->max_axis) mapping->max_axis = a;
}
} else if (val[0] == '+' && val[1] == 'a') {
int a = atoi(val + 2);
if (gml_btn != -1) {
mapping->axis_button_map[gml_btn] = a;
mapping->axis_button_sign[gml_btn] = 1.0f;
if (a > mapping->max_axis) mapping->max_axis = a;
} else if (gml_axis != -1) {
mapping->axis_map[gml_axis] = a;
if (a > mapping->max_axis) mapping->max_axis = a;
}
} else if (val[0] == '-' && val[1] == 'a') {
int a = atoi(val + 2);
if (gml_btn != -1) {
mapping->axis_button_map[gml_btn] = a;
mapping->axis_button_sign[gml_btn] = -1.0f;
if (a > mapping->max_axis) mapping->max_axis = a;
} else if (gml_axis != -1) {
mapping->axis_map[gml_axis] = a;
if (a > mapping->max_axis) mapping->max_axis = a;
}
} else if (val[0] == 'h') {
int h = atoi(val + 1);
const char* dot = strchr(val, '.');
if (dot && gml_btn != -1) {
int dir = atoi(dot + 1);
mapping->hat_map[gml_btn] = h;
mapping->hat_mask[gml_btn] = dir;
if (h > mapping->max_hat) mapping->max_hat = h;
}
}
}

#if defined(_WIN32) || defined(__WIN32__) || defined(__WINDOWS__)
#define MAPPING_PLATFORM_STR "platform:Windows"
#elif defined(__APPLE__)
#include <TargetConditionals.h>
#if TARGET_OS_IPHONE || TARGET_IPHONE_SIMULATOR
#define MAPPING_PLATFORM_STR "platform:iOS"
#else
#define MAPPING_PLATFORM_STR "platform:Mac OS X"
#endif
#elif defined(__ANDROID__)
#define MAPPING_PLATFORM_STR "platform:Android"
#elif defined(__linux__) || defined(__gnu_linux__)
#define MAPPING_PLATFORM_STR "platform:Linux"
#else
#define MAPPING_PLATFORM_STR "platform:Unknown" //Gamepad wont work at all here
#endif

static void loadGamepadMappings(void) {
const char* dbPath = "gamecontrollerdb.txt";
FILE* f = fopen(dbPath, "r");
if (!f) {
fprintf(stderr, "Gamepad: SDL gamecontrollerdb.txt not found at %s, ignoring mappings\n", dbPath);
return;
}

char line[1024];
while (fgets(line, sizeof(line), f)) {
size_t len = strlen(line);
while (len > 0 && (line[len-1] == '\n' || line[len-1] == '\r')) {
line[--len] = '\0';
}
if (len == 0 || line[0] == '#') continue;

char* guid = line;
char* name = strchr(guid, ',');
if (!name) continue;
*name++ = '\0';

char* mapping_str = strchr(name, ',');
if (!mapping_str) continue;
*mapping_str++ = '\0';

if (strstr(mapping_str, "platform:") != NULL && strstr(mapping_str, MAPPING_PLATFORM_STR) == NULL) {
continue;
}

GamepadMapping temp;
temp.valid = true;
temp.max_button = -1;
temp.max_axis = -1;
temp.max_hat = -1;
for (int i = 0; i < GP_BUTTON_COUNT; i++) {
temp.button_map[i] = -1;
temp.hat_map[i] = -1;
temp.hat_mask[i] = -1;
temp.axis_button_map[i] = -1;
temp.axis_button_sign[i] = 1.0f;
}
for (int i = 0; i < GP_AXIS_COUNT; i++) {
temp.axis_map[i] = -1;
}

char* token = strtok(mapping_str, ",");
while (token) {
char* colon = strchr(token, ':');
if (colon) {
*colon = '\0';
parseMappingField(&temp, token, colon + 1);
}
token = strtok(NULL, ",");
}

for (int i = 0; i < MAX_GAMEPADS; i++) {
SDL_Joystick* joy = openJoysticks[i];
if (joy && !joystickMappings[i].valid) {
const char* jname = SDL_JoystickName(i);
if (jname && strcasecmp(jname, name) == 0) {
joystickMappings[i] = temp;
fprintf(stderr, "Gamepad: Mapped '%s' (slot %d)\n", jname, i);
}
}
}
}
fclose(f);
}
void platformSetWindowTitle(const char* title) {
char windowTitle[256];
snprintf(windowTitle, sizeof(windowTitle), "Butterscotch - %s", title);
Expand Down Expand Up @@ -57,11 +237,25 @@ bool platformInit(int32_t reqW, int32_t reqH, const char *title, bool headless)
}

// Init SDL
if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER)) {
if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER|SDL_INIT_JOYSTICK)) {
fprintf(stderr, "Failed to initialize SDL\n");
return false;
}

SDL_JoystickEventState(SDL_IGNORE);
int numJoysticks = SDL_NumJoysticks();
for (int i = 0; i < MAX_GAMEPADS; i++) {
memset(&joystickMappings[i], 0, sizeof(GamepadMapping));
joystickMappings[i].valid = false;

if (i < numJoysticks) {
openJoysticks[i] = SDL_JoystickOpen(i);
} else {
openJoysticks[i] = NULL;
}
}
loadGamepadMappings();

fbWidth = reqW;
fbHeight = reqH;
if(!headless) {
Expand Down Expand Up @@ -90,6 +284,12 @@ bool platformInit(int32_t reqW, int32_t reqH, const char *title, bool headless)
}

void platformExit(void) {
for (int i = 0; i < MAX_GAMEPADS; i++) {
if (openJoysticks[i]) {
SDL_JoystickClose(openJoysticks[i]);
openJoysticks[i] = NULL;
}
}
SDL_Quit();
}

Expand Down Expand Up @@ -203,6 +403,126 @@ static int32_t SDLMouseButtonToGml(int sdlButton) {
}

bool platformHandleEvents(void) {
static double lastJoyCheck = 0;
if (platformGetTime() - lastJoyCheck > 2.0) {
lastJoyCheck = platformGetTime();

char oldNames[MAX_GAMEPADS][256] = {0};
for (int i = 0; i < MAX_GAMEPADS; i++) {
if (openJoysticks[i]) {
const char* name = SDL_JoystickName(i);
if (name) {
strncpy(oldNames[i], name, sizeof(oldNames[i]) - 1);
}
SDL_JoystickClose(openJoysticks[i]);
openJoysticks[i] = NULL;
}
}

SDL_QuitSubSystem(SDL_INIT_JOYSTICK);
SDL_InitSubSystem(SDL_INIT_JOYSTICK);
SDL_JoystickEventState(SDL_IGNORE);

int numJoysticks = SDL_NumJoysticks();
bool needsRemap = false;
for (int i = 0; i < numJoysticks && i < MAX_GAMEPADS; i++) {
openJoysticks[i] = SDL_JoystickOpen(i);
const char* newName = SDL_JoystickName(i);
if (!newName) newName = "";
if (strcmp(oldNames[i], newName) != 0) {
joystickMappings[i].valid = false;
needsRemap = true;
}
}

for (int i = numJoysticks; i < MAX_GAMEPADS; i++) {
joystickMappings[i].valid = false;
}

if (needsRemap) {
loadGamepadMappings();
}
}

SDL_JoystickUpdate();

g_runner->gamepads->connectedCount = 0;
for (int slotIdx = 0; slotIdx < MAX_GAMEPADS; slotIdx++) {
GamepadSlot* slot = g_runner->gamepads->slots + slotIdx;
SDL_Joystick* joy = openJoysticks[slotIdx];

memcpy(slot->buttonDownPrev, slot->buttonDown, sizeof(slot->buttonDown));
memset(slot->buttonDown, 0, sizeof(slot->buttonDown));
memset(slot->buttonPressed, 0, sizeof(slot->buttonPressed));
memset(slot->buttonReleased, 0, sizeof(slot->buttonReleased));
memset(slot->buttonValue, 0, sizeof(slot->buttonValue));
memset(slot->axisValue, 0, sizeof(slot->axisValue));

if (joy != NULL) {
slot->connected = true;
slot->jid = slotIdx;

const char* name = SDL_JoystickName(slotIdx);
if (name != NULL) {
strncpy(slot->description, name, sizeof(slot->description) - 1);
slot->description[sizeof(slot->description) - 1] = '\0';
} else {
slot->description[0] = '\0';
}

slot->guid[0] = '\0';

GamepadMapping* map = &joystickMappings[slotIdx];

if (map->valid) {
for (int btn = 0; btn < GP_BUTTON_COUNT; btn++) {
if (map->button_map[btn] != -1) {
if (SDL_JoystickGetButton(joy, map->button_map[btn])) {
slot->buttonDown[btn] = true;
slot->buttonValue[btn] = 1.0f;
}
}
if (map->hat_map[btn] != -1) {
Uint8 hat = SDL_JoystickGetHat(joy, map->hat_map[btn]);
if (hat & map->hat_mask[btn]) {
slot->buttonDown[btn] = true;
slot->buttonValue[btn] = 1.0f;
}
}
if (map->axis_button_map[btn] != -1) {
Sint16 val = SDL_JoystickGetAxis(joy, map->axis_button_map[btn]);
float norm = val / 32767.0f;
if (map->axis_button_sign[btn] < 0) norm = -norm;
if (norm < 0.0f) norm = 0.0f;

if (norm > slot->buttonValue[btn]) {
slot->buttonValue[btn] = norm;
}
if (slot->buttonValue[btn] >= slot->triggerThreshold) {
slot->buttonDown[btn] = true;
}
}
}

for (int a = 0; a < GP_AXIS_COUNT; a++) {
if (map->axis_map[a] != -1) {
Sint16 val = SDL_JoystickGetAxis(joy, map->axis_map[a]);
slot->axisValue[a] = val / 32767.0f;
}
}
}

for (int btn = 0; GP_BUTTON_COUNT > btn; btn++) {
bool wasDown = slot->buttonDownPrev[btn];
if (slot->buttonDown[btn] && !wasDown) slot->buttonPressed[btn] = true;
if (!slot->buttonDown[btn] && wasDown) slot->buttonReleased[btn] = true;
}
g_runner->gamepads->connectedCount++;
} else {
slot->connected = false;
}
}

SDL_Event e;
while (SDL_PollEvent(&e)) {
switch(e.type) {
Expand Down
Loading
Loading