CGPointMake的问题？

Question

我的游戏中有一只鸟在一个框架内飞行，但我只能让它们在两个不同的方向飞行。如果有2只鸟它们朝两个不同的方向前进。如果有3只鸟，其中2只朝一个方向前进，另一只朝不同方向前进。我希望这些鸟随机进入四个不同的方向。向上，向右，向上，向左和向下，这是我的代码。

-(void) AddBirdIntoArray: (int) BirdCount {
 for(int i=0; i< BirdCount ; i++){


  if(appDelegate.enemyselect == 0){

  imgBird[i]=[[UIImageView alloc] initWithImage:firstImage];
  [imgBird[i] setAnimationImages:birdArrayConstant];
  }

  else if(appDelegate.enemyselect == 1){

   imgBird[i]=[[UIImageView alloc] initWithImage:firstImagegreenorange];
   [imgBird[i] setAnimationImages:birdArrayConstant3];
  }

  else if(appDelegate.enemyselect == 2){
   imgBird[i]=[[UIImageView alloc] initWithImage:firstImageblueyellow];
   [imgBird[i] setAnimationImages:birdArrayConstant4];
  }

  else if(appDelegate.enemyselect == 3){
   imgBird[i]=[[UIImageView alloc] initWithImage:firstImagebluewhite];
   [imgBird[i] setAnimationImages:birdArrayConstant2];
  }

  else if(appDelegate.enemyselect == 4){
   imgBird[i]=[[UIImageView alloc] initWithImage:firstImagepinkpurple];
   [imgBird[i] setAnimationImages:birdArrayConstant5];
  }

  else if(appDelegate.enemyselect == 5){
   imgBird[i]=[[UIImageView alloc] initWithImage:firstImagebluegreen];
   [imgBird[i] setAnimationImages:birdArrayConstant6];
  }

  else if(appDelegate.enemyselect == 6){
   imgBird[i]=[[UIImageView alloc] initWithImage:firstImageorangewhite];
   [imgBird[i] setAnimationImages:birdArrayConstant7];
  }

  else if(appDelegate.enemyselect == 7){
   imgBird[i]=[[UIImageView alloc] initWithImage:firstImageredblue];
   [imgBird[i] setAnimationImages:birdArrayConstant8];
  }



  [imgBird[i] setAnimationDuration:1.0];
  [imgBird[i] startAnimating];

  if(i%2==0){
   pos[i]=CGPointMake(-1,1);
  }

  else{
   pos[i]=CGPointMake(1,-1);
  }

  xvalue = arc4random()%250;
  yvalue = arc4random()%250;
  CGRect TempRect = CGRectMake(xvalue ,yvalue , 22 , 22);
  imgBird[i].frame = TempRect;
  [birdImageViewArray addObject:imgBird[i]];
  [self addSubview:imgBird[i]];
  [imgBird[i] release];
  }




 [birdArray release];
}

Answer 1

我认为这是你的两个方向向量：

pos[i]=CGPointMake(-1,1);
pos[i]=CGPointMake(1,-1);

另外两个方向是：

pos[i]=CGPointMake(-1,-1);
pos[i]=CGPointMake(1,1);

当然，除了基于i%2的if / else之外，您应该使用基于以下内容的开关：

arc4random()%4