title: How to get common area of two nodes in SpriteKit?
body: <p>First of all, what I want to achieve is a shape node filled with two different, distinct colors (not blended), e.g. top part of a circle is white, bottom is black.</p>
  
  <p>From what I've found, my only option is to <a href="https://stackoverflow.com/questions/19100888/draw-rectangle-circle-and-triangle-in-spritekit-with-two-colors">manually create</a> paths and color them. That's fine with me, but I first need to know the exact paths.</p>
  
  <p>I'm trying to avoid complex calculations, so my question is - is there any way to get a path describing a common area of two overlapping nodes?</p>
  
  <p>A <a href="https://imgur.com/UhJmxxg" rel="nofollow noreferrer">simple example</a> to illustrate the problem: when the circle collides with the black area, the part of the circle which overlaps black rectangle should change colour - how can I get that overlap area's path?</p>