設定シーン

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    
    UITouch *touch = [touches anyObject];
    CGPoint positionInScene = [touch locationInNode:self];
    CGPoint previousPosition = [touch previousLocationInNode:self];
    
    CGFloat translationY = positionInScene.y - previousPosition.y;
    
    SKSpriteNode *scrollNode = [self scrollNode];
    CGPoint position = CGPointMake(scrollNode.position.x, scrollNode.position.y + translationY);
    
    CGFloat top = -(scrollNode.size.height - self.frame.size.height);
    CGFloat bottom = 0;
    if (position.y < top) {
        position.y = top;
    } else if (position.y > bottom) {
        position.y = bottom;
    }

    scrollNode.position = position;
}