Fix Joystick/GameController SDL polling loop

Author: bhall-ctre

GameController.cpp

@@ -3,27 +3,22 @@
 /*static*/ std::mutex GameController::s_joyCntLck;
 /*static*/ uint64_t GameController::s_joyCnt{0};
 
-bool GameController::IsConnected() const
+void GameController::Periodic()
 {
-    if (!_joy) {
-        /* no game controller */
-        return false;
-    }
+    SDL_Event event;
+    while (SDL_PollEvent(&event)) {}
 
     /* poll for game controller disconnects */
-    SDL_Event event;
-    while (SDL_PollEvent(&event)) {
-        if (event.type == SDL_QUIT) {
-            /* SDL shut down */
-            return false;
-        }
-        else if (event.cdevice.type == SDL_CONTROLLERDEVICEREMOVED) {
-            /* SDL game controller removed */
-            return false;
-        }
+    if (!IsConnected()) {
+        /* one of the game controllers disconnected, assume it was ours */
+        Close();
     }
 
-    return true;
+    /* game controller may have disconnected, make sure it's still valid */
+    if (!_joy) {
+        /* no game controller, initialize a new one */
+        Init();
+    }
 }
 
 void GameController::ReportMissingGameController()
@@ -39,11 +34,6 @@ void GameController::ReportMissingGameController()
 
 SDL_GameController *GameController::CreateGameController()
 {
-    /* SDL seems somewhat fragile, shut it down and bring it up */
-    SDL_Quit();
-    SDL_SetHint(SDL_HINT_NO_SIGNAL_HANDLERS, "1"); // so Ctrl-C still works
-    SDL_Init(SDL_INIT_GAMECONTROLLER);
-
     /* poll for game controller */
     int res = SDL_NumJoysticks();
     if (res < 0) {

GameController.hpp

@@ -51,7 +51,10 @@ class GameController {
         /* first increment game controller count */
         {
             std::lock_guard lck{s_joyCntLck};
-            ++s_joyCnt;
+            if (s_joyCnt++ == 0) {
+                SDL_SetHint(SDL_HINT_NO_SIGNAL_HANDLERS, "1"); // so Ctrl-C still works
+                SDL_Init(SDL_INIT_GAMECONTROLLER);
+            }
         }
 
         /* then initialize this game controller */
@@ -131,26 +134,16 @@ class GameController {
     /**
      * Returns whether this game controller is currently connected.
      */
-    bool IsConnected() const;
+    bool IsConnected() const
+    {
+        return _joy && SDL_GameControllerGetAttached(_joy);
+    }
 
     /**
      * Periodically manages this game controller, handling disconnect
      * events in the process.
      */
-    void Periodic()
-    {
-        /* poll for game controller disconnects */
-        if (!IsConnected()) {
-            /* one of the game controllers disconnected, assume it was ours */
-            Close();
-        }
-
-        /* game controller may have disconnected, make sure it's still valid */
-        if (!_joy) {
-            /* no game controller, initialize a new one */
-            Init();
-        }
-    }
+    void Periodic();
 
 private:
     static constexpr auto kErrorTimeMs = 3000;

Joystick.cpp

@@ -3,27 +3,22 @@
 /*static*/ std::mutex Joystick::s_joyCntLck;
 /*static*/ uint64_t Joystick::s_joyCnt{0};
 
-bool Joystick::IsConnected() const
+void Joystick::Periodic()
 {
-    if (!_joy) {
-        /* no joystick */
-        return false;
-    }
+    SDL_Event event;
+    while (SDL_PollEvent(&event)) {}
 
     /* poll for joystick disconnects */
-    SDL_Event event;
-    while (SDL_PollEvent(&event)) {
-        if (event.type == SDL_QUIT) {
-            /* SDL shut down */
-            return false;
-        }
-        else if (event.cdevice.type == SDL_JOYDEVICEREMOVED) {
-            /* SDL joystick removed */
-            return false;
-        }
+    if (!IsConnected()) {
+        /* one of the joysticks disconnected, assume it was ours */
+        Close();
     }
 
-    return true;
+    /* joystick may have disconnected, make sure it's still valid */
+    if (!_joy) {
+        /* no joystick, initialize a new one */
+        Init();
+    }
 }
 
 void Joystick::ReportMissingJoystick()
@@ -39,11 +34,6 @@ void Joystick::ReportMissingJoystick()
 
 SDL_Joystick *Joystick::CreateJoystick()
 {
-    /* SDL seems somewhat fragile, shut it down and bring it up */
-    SDL_Quit();
-    SDL_SetHint(SDL_HINT_NO_SIGNAL_HANDLERS, "1"); // so Ctrl-C still works
-    SDL_Init(SDL_INIT_GAMECONTROLLER);
-
     /* poll for joysticks */
     int res = SDL_NumJoysticks();
     if (res < 0) {

Joystick.hpp

@@ -54,7 +54,10 @@ class Joystick {
         /* first increment joystick count */
         {
             std::lock_guard lck{s_joyCntLck};
-            ++s_joyCnt;
+            if (s_joyCnt++ == 0) {
+                SDL_SetHint(SDL_HINT_NO_SIGNAL_HANDLERS, "1"); // so Ctrl-C still works
+                SDL_Init(SDL_INIT_GAMECONTROLLER);
+            }
         }
 
         /* then initialize this joystick */
@@ -170,26 +173,16 @@ class Joystick {
     /**
      * Returns whether this joystick is currently connected.
      */
-    bool IsConnected() const;
+    bool IsConnected() const
+    {
+        return _joy && SDL_JoystickGetAttached(_joy);
+    }
 
     /**
      * Periodically manages this joystick, handling disconnect
      * events in the process.
      */
-    void Periodic()
-    {
-        /* poll for joystick disconnects */
-        if (!IsConnected()) {
-            /* one of the joysticks disconnected, assume it was ours */
-            Close();
-        }
-
-        /* joystick may have disconnected, make sure it's still valid */
-        if (!_joy) {
-            /* no joystick, initialize a new one */
-            Init();
-        }
-    }
+    void Periodic();
 
 private:
     static constexpr auto kErrorTimeMs = 3000;