Tracking the player's progress

First, we need to keep track of how far the player has flown. We will use this later as well, for keeping track of a high score. This is easy to implement. Follow these steps to track how far the player has flown:

1. In the GameScene.swift file, add two new properties to the GameScene class:

           let initialPlayerPosition = CGPoint(x: 150, y: 250) 
           var playerProgress = CGFloat() 
   

2. In the didMove function, update the line that positions the player to use the new initialPlayerPosition constant instead of the old hardcoded value:

           // Add the player to the scene: 
           player.position = initialPlayerPosition 
   

3. In the didSimulatePhysics function, update the new playerProgress property with the player's new distance:

           // Keep track of how far the player has flown 
           playerProgress = player.position.x -
           initialPlayerPosition.x 
   

Perfect! We now have access to the player's progress at all times in the GameScene class. We can use the...