Merge pull request #4452 from NaterGator/sdlerr

SDL: warn with SDL error string when joystick feature detection fails

src/Joystick/JoystickManager.cc

@@ -53,7 +53,10 @@ void JoystickManager::setToolbox(QGCToolbox *toolbox)
     _multiVehicleManager = _toolbox->multiVehicleManager();
 
     QQmlEngine::setObjectOwnership(this, QQmlEngine::CppOwnership);
+}
 
+void JoystickManager::discoverJoysticks()
+{
 #ifdef __sdljoystick__
     _name2JoystickMap = JoystickSDL::discover(_multiVehicleManager);
 #elif defined(__android__)

src/Joystick/JoystickManager.h

@@ -48,6 +48,9 @@ public:
     // Override from QGCTool
     virtual void setToolbox(QGCToolbox *toolbox);
 
+public slots:
+    void discoverJoysticks();
+
 signals:
     void activeJoystickChanged(Joystick* joystick);
     void activeJoystickNameChanged(const QString& name);

src/Joystick/JoystickSDL.cc

@@ -15,7 +15,7 @@ JoystickSDL::JoystickSDL(const QString& name, int axisCount, int buttonCount, in
 QMap<QString, Joystick*> JoystickSDL::discover(MultiVehicleManager* _multiVehicleManager) {
     static QMap<QString, Joystick*> ret;
 
-    if (SDL_InitSubSystem(SDL_INIT_GAMECONTROLLER | SDL_INIT_NOPARACHUTE) < 0) {
+    if (SDL_InitSubSystem(SDL_INIT_GAMECONTROLLER | SDL_INIT_JOYSTICK | SDL_INIT_NOPARACHUTE) < 0) {
         qWarning() << "Couldn't initialize SimpleDirectMediaLayer:" << SDL_GetError();
         return ret;
     }
@@ -33,7 +33,7 @@ QMap<QString, Joystick*> JoystickSDL::discover(MultiVehicleManager* _multiVehicl
             int axisCount, buttonCount, hatCount;
             bool isGameController;
 
-            SDL_Joystick* sdlJoystick = SDL_JoystickOpen(i);
+
             if (SDL_IsGameController(i)) {
                 isGameController = true;
                 axisCount = SDL_CONTROLLER_AXIS_MAX;
@@ -41,12 +41,20 @@ QMap<QString, Joystick*> JoystickSDL::discover(MultiVehicleManager* _multiVehicl
                 hatCount = 0;
             } else {
                 isGameController = false;
+                if (SDL_Joystick* sdlJoystick = SDL_JoystickOpen(i)) {
+                    SDL_ClearError();
                     axisCount = SDL_JoystickNumAxes(sdlJoystick);
                     buttonCount = SDL_JoystickNumButtons(sdlJoystick);
                     hatCount = SDL_JoystickNumHats(sdlJoystick);
+                    if (axisCount < 0 || buttonCount < 0 || hatCount < 0) {
+                        qCWarning(JoystickLog) << "\t libsdl error parsing joystick features:" << SDL_GetError();
                     }
-
                     SDL_JoystickClose(sdlJoystick);
+                } else {
+                    qCWarning(JoystickLog) << "\t libsdl failed opening joystick" << qPrintable(name) << "error:" << SDL_GetError();
+                    continue;
+                }
+            }
 
             qCDebug(JoystickLog) << "\t" << name << "axes:" << axisCount << "buttons:" << buttonCount << "hats:" << hatCount << "isGC:" << isGameController;
             ret[name] = new JoystickSDL(name, qMax(0,axisCount), qMax(0,buttonCount), qMax(0,hatCount), i, isGameController, _multiVehicleManager);

src/QGCApplication.cc

@@ -429,6 +429,9 @@ bool QGCApplication::_initForNormalAppBoot(void)
     // Load known link configurations
     toolbox()->linkManager()->loadLinkConfigurationList();
 
+    // Probe for joysticks - TODO: manage on a timer or use events to deal with hotplug
+    toolbox()->joystickManager()->discoverJoysticks();
+
     if (_settingsUpgraded) {
         settings.clear();
         settings.setValue(_settingsVersionKey, QGC_SETTINGS_VERSION);