add general async swap

src/app.cpp

@@ -17,7 +17,7 @@ void android_async_unlock(struct engine* engine);
 #elif _WIN32
 bool async_lock_try();
 void async_lock();
-void async_swap();
+void win32_async_swap();
 void async_unlock();
 void destroy_window();
 #endif
@@ -521,6 +521,19 @@ void App::async_end()
 #endif
 }
 
+void App::async_swap()
+{
+#if __OSX__
+    [osx_view async_swap];
+#elif __IOS__
+    [ios_view async_swap];
+#elif __ANDROID__
+    android_async_swap(and_engine);
+#elif _WIN32
+    win32_async_swap();
+#endif
+}
+
 bool App::update_ui_observer(Node *n)
 {
     if (n && n->m_display)
@@ -1039,7 +1052,7 @@ void App::render_thread_main()
         // execute the tasks
         if (!working_list.empty())
         {
-            async_lock();
+            async_start();
             while (!working_list.empty())
             {
                 //LOG("render task %d", count);
@@ -1047,7 +1060,7 @@ void App::render_thread_main()
                 working_list.front()();
                 working_list.pop_front();
             }
-            async_unlock();
+            async_end();
         }
     }
 }