滚动背景后，将精灵移动到触摸位置不再有效

Question

我希望能在ios游戏中获得一些帮助。这是一个简单的游戏，我使用一个垂直滚动的tilemap。我通过触摸不同的位置移动我的精灵，并在那里出现精灵。但是我最近实现了滚动从下到上和滚动几秒后。我的精灵不再去触摸的位置，而是坚持到屏幕的底部。

这是我的NSLog的打印

2014-05-01 17:44:06.628 Toygame[3735:a0b] X location: 359.500000
2014-05-01 17:44:06.629 Toygame[3735:a0b] Y Location: 301.000000
2014-05-01 17:44:10.794 Toygame[3735:a0b] X location: 396.500000
2014-05-01 17:44:10.794 Toygame[3735:a0b] Y Location: 288.500000

2014-05-01 17:44:14.427 Toygame[3735:a0b] X location: 401.500000
2014-05-01 17:44:14.428 Toygame[3735:a0b] Y Location: 261.000000

2014-05-01 17:44:16.811 Toygame[3735:a0b] X location: 397.000000
2014-05-01 17:44:16.812 Toygame[3735:a0b] Y Location: 256.500000

2014-05-01 17:44:18.880 Toygame[3735:a0b] X location: 399.000000
2014-05-01 17:44:18.881 Toygame[3735:a0b] Y Location: 245.000000

2014-05-01 17:44:21.444 Toygame[3735:a0b] X location: 405.000000
2014-05-01 17:44:21.445 Toygame[3735:a0b] Y Location: 297.500000

2014-05-01 17:44:23.544 Toygame[3735:a0b] X location: 405.000000
2014-05-01 17:44:23.544 Toygame[3735:a0b] Y Location: 289.500000

似乎无法超过300 Y，无论屏幕有多高，我点击屏幕，因为它一直向上滚动，我的精灵只是出现在底部

感谢您提供的任何帮助

触摸代​​码

 (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
  CGPoint location = [touch locationInNode:self];
  SKNode *node = [self nodeAtPoint:location]; 



    if (teleports>0 & actPower==1) { 
      _player.position=location;
      NSLog(@"X location: %f", location.x);
      NSLog(@"Y Location: %f",location.y);
      teleports--;
      actPower=0;
    }

 }

- (void)moveBg
{
  if (_gameState!=PCGameStateStartingLevel)
  {
  [self enumerateChildNodesWithName:@"bg" usingBlock:
   ^(SKNode *node, BOOL *stop) {
     SKSpriteNode * bg = (SKSpriteNode *) node;
   //  CGPoint bgVelocity = CGPointMake(-BG_POINTS_PER_SEC, 0.0);
     CGPoint bgVelocity = CGPointMake( 0.0,-BG_POINTS_PER_SEC);
     CGPoint amtToMove =     CGPointMultiplyScalar(bgVelocity, _dt);
    bg.position = CGPointAdd(bg.position, amtToMove);


   }];
  }
}