gsdx:ogl: Call swap interval function on rendering thread

The swap interval function must be called on the same thread that
rendering takes place on. This fixes an issue where the turbo speed and
frame limiter hotkeys fail to disable vsync when the OpenGL renderer is
used.

plugins/GSdx/GSWnd.cpp

@@ -199,5 +199,7 @@ void GSWndGL::SetVSync(int vsync)
 	else
 		m_vsync = vsync;
 
-	SetSwapInterval(m_vsync);
+	// The WGL/GLX/EGL swap interval function must be called on the rendering
+	// thread or else the change won't be properly applied.
+	m_vsync_change_requested = true;
 }

plugins/GSdx/GSWnd.h

@@ -60,7 +60,8 @@ class GSWndGL : public GSWnd
 {
 protected:
 	bool m_ctx_attached;
-	int m_vsync;
+	std::atomic<bool> m_vsync_change_requested;
+	std::atomic<int> m_vsync;
 
 	bool IsContextAttached() const { return m_ctx_attached; }
 	void PopulateGlFunction();
@@ -68,11 +69,11 @@ protected:
 	void FullContextInit();
 	virtual void CreateContext(int major, int minor) = 0;
 
-	virtual void SetSwapInterval(int vsync) = 0;
+	virtual void SetSwapInterval() = 0;
 	virtual bool HasLateVsyncSupport() = 0;
 
 public:
-	GSWndGL() : m_ctx_attached(false), m_vsync(0) {};
+	GSWndGL() : m_ctx_attached(false), m_vsync_change_requested(false), m_vsync(0) {};
 	virtual ~GSWndGL() {};
 
 	virtual bool Create(const string& title, int w, int h) = 0;

plugins/GSdx/GSWndEGL.cpp

@@ -235,15 +235,18 @@ GSVector4i GSWndEGL::GetClientRect()
 	return GSVector4i(0, 0, w, h);
 }
 
-void GSWndEGL::SetSwapInterval(int vsync)
+void GSWndEGL::SetSwapInterval()
 {
 	// 0 -> disable vsync
 	// n -> wait n frame
-	eglSwapInterval(m_eglDisplay, vsync);
+	eglSwapInterval(m_eglDisplay, m_vsync);
 }
 
 void GSWndEGL::Flip()
 {
+	if (m_vsync_change_requested.exchange(false))
+		SetSwapInterval();
+
 	eglSwapBuffers(m_eglDisplay, m_eglSurface);
 }
 

plugins/GSdx/GSWndEGL.h

@@ -42,7 +42,7 @@ class GSWndEGL : public GSWndGL
 	void CreateContext(int major, int minor);
 	void BindAPI();
 
-	void SetSwapInterval(int vsync) final;
+	void SetSwapInterval() final;
 	bool HasLateVsyncSupport() final { return false; }
 
 	void OpenEGLDisplay();

plugins/GSdx/GSWndOGL.cpp

@@ -238,18 +238,21 @@ bool GSWndOGL::SetWindowText(const char* title)
 	return true;
 }
 
-void GSWndOGL::SetSwapInterval(int vsync)
+void GSWndOGL::SetSwapInterval()
 {
 	// m_swapinterval uses an integer as parameter
 	// 0 -> disable vsync
 	// n -> wait n frame
-	if      (m_swapinterval_ext)  m_swapinterval_ext(m_NativeDisplay, m_NativeWindow, vsync);
-	else if (m_swapinterval_mesa) m_swapinterval_mesa(vsync);
+	if      (m_swapinterval_ext)  m_swapinterval_ext(m_NativeDisplay, m_NativeWindow, m_vsync);
+	else if (m_swapinterval_mesa) m_swapinterval_mesa(m_vsync);
 	else						 fprintf(stderr, "Failed to set VSync\n");
 }
 
 void GSWndOGL::Flip()
 {
+	if (m_vsync_change_requested.exchange(false))
+		SetSwapInterval();
+
 	glXSwapBuffers(m_NativeDisplay, m_NativeWindow);
 }
 

plugins/GSdx/GSWndOGL.h

@@ -38,7 +38,7 @@ class GSWndOGL final : public GSWndGL
 	void PopulateWndGlFunction();
 	void CreateContext(int major, int minor);
 
-	void SetSwapInterval(int vsync);
+	void SetSwapInterval();
 	bool HasLateVsyncSupport() { return m_has_late_vsync; }
 
 public:

plugins/GSdx/GSWndWGL.cpp

@@ -324,16 +324,19 @@ void* GSWndWGL::GetProcAddress(const char* name, bool opt)
 
 //TODO: check extensions supported or not
 //FIXME : extension allocation
-void GSWndWGL::SetSwapInterval(int vsync)
+void GSWndWGL::SetSwapInterval()
 {
 	// m_swapinterval uses an integer as parameter
 	// 0 -> disable vsync
 	// n -> wait n frame
-	if (m_swapinterval) m_swapinterval(vsync);
+	if (m_swapinterval) m_swapinterval(m_vsync);
 }
 
 void GSWndWGL::Flip()
 {
+	if (m_vsync_change_requested.exchange(false))
+		SetSwapInterval();
+
 	SwapBuffers(m_NativeDisplay);
 }
 

plugins/GSdx/GSWndWGL.h

@@ -38,7 +38,7 @@ class GSWndWGL : public GSWndGL
 	void CloseWGLDisplay();
 	void OpenWGLDisplay();
 
-	void SetSwapInterval(int vsync);
+	void SetSwapInterval();
 	bool HasLateVsyncSupport() { return m_has_late_vsync; }
 
 	static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);