title: How to find the normal vector of the contact point between two sprites
body: <p>I am creating a game where the character can jump in the direction opposite of the surface he lands on. For example if he is on the ground he can only jump up. If he is on a right edge he can only jump left...etc etc.. Currently I have set up my SKNodes into leftWall, rightWall, bottomSurface, topSurface and have a huge if/else... this works but will become way more complicated as I add different surfaces with different angles etc...</p>
  
  <p>I thought a better way to implement this would be to find the normal vector direction at the point of contact between the character sprite and a general wallNode sprites.</p>
  
  <p>Can anyone help me determine A) the point of contact between sprites assuming the character has a circle physics body and the walls are always straight edges. and B) the normal to the contact point
  thank you!</p>