Platform: minor code cleanup in Sdl2Application.

* Explicitly set multisample attributes in all cases (so the attributes
   are always properly set when creating another context).
 * Do both assign and test in `if` statement.

src/Platform/Sdl2Application.cpp

@@ -70,15 +70,14 @@ void Sdl2Application::createContext(Configuration* configuration) {
     SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
 
     /* Multisampling */
-    if(configuration->sampleCount()) {
-        SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
-        SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, configuration->sampleCount());
-    }
-
-    window = SDL_CreateWindow(configuration->title().c_str(), SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
-        configuration->size().x(), configuration->size().y(), SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN);
-    if(!window) {
-        Error() << "Cannot create window.";
+    SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, configuration->sampleCount() > 1 ? 1 : 0);
+    SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, configuration->sampleCount());
+
+    if(!(window = SDL_CreateWindow(configuration->title().c_str(),
+            SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
+            configuration->size().x(), configuration->size().y(),
+            SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN))) {
+        Error() << "Platform::Sdl2Application::tryCreateContext(): cannot create window";
         std::exit(2);
     }