title: How Do I Blur a Scene in SpriteKit?
body: <p>How would I add a gaussian blur to all nodes (there's no fixed number of nodes) in an SKScene in SpriteKit?  A label will be added on top of the scene later, this will be my pause menu.
  Almost anything would help!</p>
  
  <p>Something like this is what I'm going for:
  <img src="https://3.bp.blogspot.com/-Gp50obMJTDg/Uj73AfCsy9I/AAAAAAAABLM/XabQjJV9mW4/s1600/blur.png" alt="Gaussian pause menu"></p>