Platform: minor code deduplication, documentation and cleanup.

src/Platform/Sdl2Application.cpp

@@ -111,23 +111,30 @@ bool Sdl2Application::tryCreateContext(const Configuration& configuration) {
 
     /** @todo Remove when Emscripten has proper SDL2 support */
     #ifndef CORRADE_TARGET_EMSCRIPTEN
-
+    /* On OS X we need to create 3.2 context, as the default (2.1) contains
+       compatibility features which are not implemented for newer GL versions
+       in Apple's GL drivers, thus we would be forever stuck on 2.1 without the
+       new features. In practice SDL fails to create 2.1 context on recent OS X
+       versions. */
     #ifdef __APPLE__
-
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
+    #endif
 
     if(!(window = SDL_CreateWindow(configuration.title().data(),
         SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
         configuration.size().x(), configuration.size().y(),
-        SDL_WINDOW_OPENGL|flags))){
-            Error() << "Platform::Sdl2Application::tryCreateContext(): cannot create core window:" << SDL_GetError();
-            return false;
+        SDL_WINDOW_OPENGL|flags)))
+    {
+        Error() << "Platform::Sdl2Application::tryCreateContext(): cannot create window:" << SDL_GetError();
+        return false;
     }
 
+    /* Fall back to GL 2.1, if 3.2 context creation fails on OS X */
+    #ifdef __APPLE__
     if(!(context = SDL_GL_CreateContext(window))){
-        Error() << "Platform::Sdl2Application::tryCreateContext(): cannot create core context:" << SDL_GetError() << " falling back to compatibility context.";
+        Warning() << "Platform::Sdl2Application::tryCreateContext(): cannot create core context:" << SDL_GetError() << "(falling back to compatibility context)";
         SDL_DestroyWindow(window);
 
         SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
@@ -137,9 +144,10 @@ bool Sdl2Application::tryCreateContext(const Configuration& configuration) {
         if(!(window = SDL_CreateWindow(configuration.title().data(),
             SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
             configuration.size().x(), configuration.size().y(),
-            SDL_WINDOW_OPENGL|flags))){
-                Error() << "Platform::Sdl2Application::tryCreateContext(): cannot create window:" << SDL_GetError();
-                return false;
+            SDL_WINDOW_OPENGL|flags)))
+        {
+            Error() << "Platform::Sdl2Application::tryCreateContext(): cannot create window:" << SDL_GetError();
+            return false;
         }
 
         if(!(context = SDL_GL_CreateContext(window))){
@@ -149,16 +157,7 @@ bool Sdl2Application::tryCreateContext(const Configuration& configuration) {
             return false;
         }
     }
-
     #else
-    if(!(window = SDL_CreateWindow(configuration.title().data(),
-            SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
-            configuration.size().x(), configuration.size().y(),
-            SDL_WINDOW_OPENGL|flags))) {
-        Error() << "Platform::Sdl2Application::tryCreateContext(): cannot create window:" << SDL_GetError();
-        return false;
-    }
-
     if(!(context = SDL_GL_CreateContext(window))) {
         Error() << "Platform::Sdl2Application::tryCreateContext(): cannot create context:" << SDL_GetError();
         SDL_DestroyWindow(window);