Platform: moved Sdl2Application event loop into separate function.

Allowing it to be called perodically from some callback.

src/Platform/Sdl2Application.cpp

@@ -127,7 +127,11 @@ Sdl2Application::~Sdl2Application() {
 }
 
 int Sdl2Application::exec() {
-    while(!(flags & Flag::Exit)) {
+    while(!(flags & Flag::Exit)) mainLoop();
+    return 0;
+}
+
+void Sdl2Application::mainLoop() {
     SDL_Event event;
 
     while(SDL_PollEvent(&event)) {
@@ -167,7 +171,7 @@ int Sdl2Application::exec() {
                 break;
             }
 
-                case SDL_QUIT: return 0;
+            case SDL_QUIT: return;
         }
     }
 
@@ -177,9 +181,6 @@ int Sdl2Application::exec() {
     } else Corrade::Utility::sleep(5);
 }
 
-    return 0;
-}
-
 void Sdl2Application::setMouseLocked(bool enabled) {
     SDL_SetWindowGrab(window, enabled ? SDL_TRUE : SDL_FALSE);
     SDL_SetRelativeMouseMode(enabled ? SDL_TRUE : SDL_FALSE);

src/Platform/Sdl2Application.h

@@ -174,6 +174,7 @@ class Sdl2Application {
         CORRADE_ENUMSET_FRIEND_OPERATORS(Flags)
 
         void initialize();
+        void mainLoop();
 
         SDL_Window* window;
         SDL_GLContext context;