#### Overview of this book

Getting Started with SpriteKit
Credits
www.PacktPub.com
Preface
Free Chapter
The First Step toward SpriteKit
What Makes a Game a Game?
Taking Games One Step Further
From Basic to Professional Games
Utilizing the Hardware and Graphics Processor
Auxiliary Techniques
Index

## 2-star challenge: moving lights

In this challenge, I want you to simulate the sun moving along the day so that you can see how we can treat lights as nodes. So, try to move the sun from left to right as the game moves forward.

### Solution

To achieve this behavior, we are going to update the sun's position every time a wave finishes so that it will change gradually.

Let's start by calling a new method at the end of `initializeWave`:

```// Update sun position

Implement this using the following lines of code:

```func updateSunPosition() {
// Move sun on the x coordinates
sunLight.position.x += 10.0

// Reset sun position if needed
if sunLight.position.x >= view!.bounds.size.width + 65.8 {
sunLight.position.x = -65.8
}
}```

As you can see, we move the sun along the x coordinate by increasing its position by `10.0` every time a wave is initialized.

Also, we reset its position when `sunLight.position.x` achieves the last position on the right-hand side, as we want...