use the message queue for GL context init/deinit

src/frontend/qt_sdl/EmuThread.cpp

@@ -443,22 +443,6 @@ void EmuThread::run()
             {
                 emuInstance->drawScreenGL();
             }
-
-            ContextRequestKind contextRequest = ContextRequest;
-            if (contextRequest == contextRequest_InitGL)
-            {
-                emuInstance->initOpenGL();
-
-                useOpenGL = true;
-                ContextRequest = contextRequest_None;
-            }
-            else if (contextRequest == contextRequest_DeInitGL)
-            {
-                emuInstance->deinitOpenGL();
-
-                useOpenGL = false;
-                ContextRequest = contextRequest_None;
-            }
         }
 
         handleMessages();
@@ -510,6 +494,16 @@ void EmuThread::handleMessages()
             emuInstance->audioDisable();
             emit windowEmuStop();
             break;
+
+        case msg_InitGL:
+            emuInstance->initOpenGL();
+            useOpenGL = true;
+            break;
+
+        case msg_DeInitGL:
+            emuInstance->deinitOpenGL();
+            useOpenGL = false;
+            break;
         }
 
         msgSemaphore.release();
@@ -535,14 +529,14 @@ void EmuThread::emuRun()
 
 void EmuThread::initContext()
 {
-    ContextRequest = contextRequest_InitGL;
+    sendMessage(msg_InitGL);
-    while (ContextRequest != contextRequest_None);
+    waitMessage();
 }
 
 void EmuThread::deinitContext()
 {
-    ContextRequest = contextRequest_DeInitGL;
+    sendMessage(msg_DeInitGL);
-    while (ContextRequest != contextRequest_None);
+    waitMessage();
 }
 
 void EmuThread::emuPause()

src/frontend/qt_sdl/EmuThread.h

@@ -58,6 +58,9 @@ public:
     enum MessageType
     {
         msg_EmuStop,
+
+        msg_InitGL,
+        msg_DeInitGL,
     };
 
     struct Message
@@ -146,14 +149,6 @@ private:
     QSemaphore msgSemaphore;
     QQueue<Message> msgQueue;
 
-    enum ContextRequestKind
-    {
-        contextRequest_None = 0,
-        contextRequest_InitGL,
-        contextRequest_DeInitGL
-    };
-    std::atomic<ContextRequestKind> ContextRequest = contextRequest_None;
-
     EmuInstance* emuInstance;
 
     int autoScreenSizing;