title: Sprite Kit - Determine vector of swipe gesture to flick sprite
body: <p>I have a game where circular objects shoot up from the bottom of the screen and I would like to be able to swipe them to flick them in the direction of my swipe. My issue is, I don't know how to calculate the vector/direction of the swipe in order to get the circular object to get flicked in the proper direction with the proper velocity.</p>
  
  <p>The static vector "(5,5)" I am using needs to be calculated by the swipe speed and direction of the swipe. Also, I need to make sure that once I make first contact with the object, it no longer happens, as to refrain from double hitting the object. Here's what I am doing currently:</p>
  
  <pre><code>-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
  
  for (UITouch *touch in touches) {
      CGPoint location = [touch locationInNode:self];
  
      SKNode* node = [self nodeAtPoint:location];
      [node.physicsBody applyImpulse:CGVectorMake(5, 5) atPoint:location];
  }
  }
  </code></pre>