Don't do anything in SwapBuffers if no GL context is active

renderdoc/driver/gl/gl_common.h

@@ -38,6 +38,8 @@
 
 struct GLWindowingData
 {
+	GLWindowingData() { DC = NULL; ctx = NULL; wnd = NULL; }
+
 	void SetCtx(void *c) { ctx = (HGLRC)c; }
 	HDC DC;
 	HGLRC ctx;
@@ -54,6 +56,8 @@ struct GLWindowingData
 
 struct GLWindowingData
 {
+	GLWindowingData() { dpy = NULL; ctx = NULL; wnd = NULL; }
+
 	void SetCtx(void *c) { ctx = (GLXContext)c; }
 	Display *dpy;
 	GLXContext ctx;

renderdoc/driver/gl/gl_driver.cpp

@@ -1967,6 +1967,10 @@ void WrappedOpenGL::SwapBuffers(void *windowHandle)
 {
 	if(m_State == WRITING_IDLE)
 		RenderDoc::Inst().Tick();
+
+	// don't do anything if no context is active.
+	if(GetCtx() == NULL)
+		return;
 	
 	m_FrameCounter++; // first present becomes frame #1, this function is at the end of the frame