ogl: fix single core crash

osx is missing, sorry but I'm too stupid for objective-c

Source/Core/DolphinWX/Src/GLInterface/AGL.cpp

@@ -87,6 +87,13 @@ bool cInterfaceAGL::MakeCurrent()
 	return true;
 }
 
+bool cInterfaceAGL::ClearCurrent()
+{
+	// not tested at all
+	//clearCurrentContext();
+	return true;
+}
+
 // Close backend
 void cInterfaceAGL::Shutdown()
 {

Source/Core/DolphinWX/Src/GLInterface/AGL.h

@@ -30,6 +30,7 @@ public:
 	void Swap();
 	bool Create(void *&window_handle);
 	bool MakeCurrent();
+	bool ClearCurrent();
 	void Shutdown();
 	void Update();
 

Source/Core/DolphinWX/Src/GLInterface/GLX.cpp

@@ -141,12 +141,17 @@ bool cInterfaceGLX::MakeCurrent()
 	#endif
 	return glXMakeCurrent(GLWin.dpy, GLWin.win, GLWin.ctx);
 }
+
+bool cInterfaceGLX::ClearCurrent()
+{
+	return glXMakeCurrent(GLWin.dpy, None, NULL);
+}
+
+
 // Close backend
 void cInterfaceGLX::Shutdown()
 {
 	XWindow.DestroyXWindow();
-	if (GLWin.ctx && !glXMakeCurrent(GLWin.dpy, None, NULL))
-		NOTICE_LOG(VIDEO, "Could not release drawing context.");
 	if (GLWin.ctx)
 	{
 		glXDestroyContext(GLWin.dpy, GLWin.ctx);

Source/Core/DolphinWX/Src/GLInterface/GLX.h

@@ -36,6 +36,7 @@ public:
 	void UpdateFPSDisplay(const char *Text);
 	bool Create(void *&window_handle);
 	bool MakeCurrent();
+	bool ClearCurrent();
 	void Shutdown(); 
 };
 #endif

Source/Core/DolphinWX/Src/GLInterface/InterfaceBase.h

@@ -27,6 +27,7 @@ public:
 	virtual void UpdateFPSDisplay(const char *Text) {}
 	virtual bool Create(void *&window_handle) { return true; }
 	virtual bool MakeCurrent() { return true; }
+	virtual bool ClearCurrent() { return true; }
 	virtual void Shutdown() {} 
 
 	virtual void SwapInterval(int Interval) { }

Source/Core/DolphinWX/Src/GLInterface/WGL.cpp

@@ -131,6 +131,11 @@ bool cInterfaceWGL::MakeCurrent()
 	return wglMakeCurrent(hDC, hRC) ? true : false;
 }
 
+bool cInterfaceWGL::ClearCurrent()
+{
+	return wglMakeCurrent(hDC, NULL) ? true : false;
+}
+
 // Update window width, size and etc. Called from Render.cpp
 void cInterfaceWGL::Update()
 {

Source/Core/DolphinWX/Src/GLInterface/WGL.h

@@ -33,6 +33,7 @@ public:
 	void UpdateFPSDisplay(const char *Text);
 	bool Create(void *&window_handle);
 	bool MakeCurrent();
+	bool ClearCurrent();
 	void Shutdown(); 
 
 	void Update();

Source/Plugins/Plugin_VideoOGL/Src/main.cpp

@@ -253,6 +253,7 @@ void VideoBackend::Video_Cleanup() {
 		OpcodeDecoder_Shutdown();
 		delete g_renderer;
 		g_renderer = NULL;
+		GLInterface->ClearCurrent();
 	}
 }