Time for action – creating our object pools

The pools are just vectors of objects. And here are the steps to create them:

1. Inside the createPools method, we first create a pool for meteors:

   void GameLayer::createPools() {
     int i;
     _meteorPoolIndex = 0;
     for (i = 0; i < 50; i++) {
     auto sprite = Sprite::createWithSpriteFrameName("meteor.png");
     sprite->setVisible(false);
     _gameBatchNode->addChild(sprite, kMiddleground, kSpriteMeteor);
     _meteorPool.pushBack(sprite);
   }

2. Then we create an object pool for health packs:

   _healthPoolIndex = 0;
   for (i = 0; i < 20; i++) {
     auto sprite = Sprite::createWithSpriteFrameName("health.png");
     sprite->setVisible(false);
     sprite->setAnchorPoint(Vec2(0.5f, 0.8f));
     _gameBatchNode->addChild(sprite, kMiddleground, kSpriteHealth);
     _healthPool.pushBack(sprite);
   }

3. We'll use the corresponding pool index to retrieve objects from the vectors as the game progresses.

What just happened?

We now have a vector of invisible meteor sprites and a...