Adding Scene Scrolling and Game Control - Beginning Swift Games Development for iOS - page 55

As you look over this code, you will see a variable named orbNodePosition that has
an x-coordinate matching the playerNode 's x-coordinate and a y-coordinate that is 100
points above the playerNode .
After that, there is a for loop that adds 20 orbNode objects centered above the player,
with each node 140 points above the previous node's anchorPoint . Go ahead and add
this code to the bottom of the GameScene 's init() method, and then let's move on to
the second set of orbNode objects.
To add the second set of nodes, you will use the following, similar code:
orbNodePosition = CGPointMake(playerNode!.position.x + 50,
orbNodePosition.y)
for i in 0...19 {
var orbNode = SKSpriteNode(imageNamed: "PowerUp")
orbNodePosition.y += 140
orbNode.position = orbNodePosition
orbNode.physicsBody = SKPhysicsBody(circleOfRadius:
orbNode.size.width / 2)
orbNode.physicsBody!.dynamic = false
orbNode.physicsBody!.categoryBitMask
= CollisionCategoryPowerUpOrbs
orbNode.physicsBody!.collisionBitMask = 0
orbNode.name = "POWER_UP_ORB"
foregroundNode!.addChild(orbNode)
}
As you look over this code, you will see that the only change is the modification of the
variable orbNodePosition . The value of the orbNodePosition 's x-coordinate is
increasing by 50, and everything else is the same. You could easily refactor this code into
a method and pass it the new x-coordinate, but the goal here is to see how everything
works. It will be refactored in the next chapter. Before moving on, go ahead and add this
code after the previous loop in the GameScene 's init() method.
After you have all of this code added to the game scene, run the application. Your screen
will now look like Figure 4-1 .