title: SpriteKit PhysicsBody: Could not create physics body for basic shape
body: <p>I have an extremely basic polygon that is the texture for a sprite in my game, yet when I try and create a physicsBody from this texture for the sprite I get this error:</p>
  
  <pre><code>2016-06-19 08:25:21.707 Space Escape[14677:5651144] PhysicsBody: Could not create physics body.
  </code></pre>
  
  <p>Also, the game uses many different simple polygons and for some the physicsBody can be created, yet for others it gets an error.</p>
  
  <pre><code>func setPhysics(size: CGSize) {
  
      self.physicsBody = SKPhysicsBody(texture: asteroidTexture, size: size)
      self.physicsBody?.angularDamping = 0
      self.physicsBody?.angularVelocity = 2
  
  }
  </code></pre>
  
  <p>Here is the texture:</p>
  
  <p><a href="https://i.stack.imgur.com/AX8qW.png" rel="noreferrer"><img src="https://i.stack.imgur.com/AX8qW.png" alt="Simple Heptagon Sprite Texture"></a></p>