- changed order of SwapBuffers and glFinish call. The new order with glFinish coming last is recommended by OpenGL and it fixes a stalling problem with portals and camera textures visible at the same time.

- check and use WGL_EXT_swap_control_tear extension. The above change makes the system always wait for a full vsync with a wglSwapInterval of 1, so it now uses the official extension that enables adaptive vsync. Hopefully this also works on the cards where the old setup did not.

src/gl/system/gl_framebuffer.cpp

@@ -209,13 +209,13 @@ void OpenGLFrameBuffer::Swap()
 {
 	Finish.Reset();
 	Finish.Clock();
-	glFinish();
 	if (needsetgamma) 
 	{
 		//DoSetGamma();
 		needsetgamma = false;
 	}
 	SwapBuffers();
+	glFinish();
 	Finish.Unclock();
 	swapped = true;
 	FHardwareTexture::UnbindAll();