title: How to rotate something using spritekit relative to user touch coordinates
body: <p>I want to rotate a gun based on the user dragging their finger on the screen. I figure i will need my cartesian points in polar coordinates and that i will need a long press gesture which is both things that i have. I am just wondering how i would go about programming this? sorry i'm really new to sprite kit i have read all of apple's documentation and i'm having a hard time finding this. My anchor point is 0,0.</p>
  
  <pre><code>-(void)shootBullets:(UILongPressGestureRecognizer *) gestureRecognizer
  {
      double radius;
      double angle;
        SKSpriteNode *gun = [self newGun];
   }
  </code></pre>
  
  <p>i figured out how to get the angle but now my zrotation wont work. Like i nslog and the angles are right but when i click gun.zrotation and i tap nothing happens? please help i'm getting uber mad.</p>
  
  <pre><code>-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
  {
  UITouch *touch = [[event allTouches] anyObject];
  CGPoint location = [touch locationInView:touch.view];
  SKSpriteNode *gun = [self newGun];
  self.gunRotation = atanf(location.y/location.x)/0.0174532925;
  gun.zRotation = self.gunRotation;
  NSLog(@"%f",gun.zRotation);
  }
  </code></pre>