move sprite by touch

gistfile1.m

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
  UITouch *touch = [touches anyObject];
  if (self.fingerIsOnWheel) {
    CGPoint touchLocation = [touch locationInNode:self];
    CGPoint previousLocation = [touch previousLocationInNode:self];
    CGFloat angle1 = [self angleBetweenFirstPoint:previousLocation secondPoint:CGPointZero];
    CGFloat angle2 = [self angleBetweenFirstPoint:touchLocation secondPoint:CGPointZero];

    CGFloat bearingRadians = angle2 - angle1;
    [self rotateBy:bearingRadians];
  }
}