JohnSundell/ImagineEngine

Welcome to Imagine Engine, an ongoing project that aims to create a fast, high performance Swift 2D game engine for Apple's platforms that is also a joy to use. You are hereby invited to participate in this new community to build a tool with an ambitious but clear goal - to enable you to easily build any game that you can imagine.

Imagine Engine uses Core Animation as its rendering backend - just like Apple's UI frameworks like UIKit and AppKit do. By leveraging the power of Core Animation's hardware accelerated 2D rendering capabilities, Imagine Engine is able to push lots of pixels onto the screen at the same time. That means more objects, more effects and less restrictions when designing your games.

Besides its goal of being blazingly fast at rendering & updating your games, Imagine Engine aims to provide an easy to use API that anyone can learn - regardless of game development experience.

Start with just a few lines of code...

let scene = Scene(size: UIScreen.main.bounds.size)

let label = Label(text: "Hello world")
label.position = scene.center
scene.add(label)

let window = GameWindow(scene: scene)
window.makeKeyAndVisible()

...and smoothly scale up as your game grows in complexity on either iOS, macOS or tvOS.

🌃 Scenes present your game content

A scene can be a level, a menu or a "Game over" screen. You can easily switch the active scene of a game. Here's how you can create a scene with a blue background color:

let scene = Scene(size: Size(width: 500, height: 300))
scene.backgroundColor = .blue
game.scene = scene

🎭 Actors bring your game to life

Actors are what will make up most of the active objects in any game. They are movable, animatable, can handle collisions and much more. Here's an example of how you can create a player that renders a "Running" animation, and constantly moves to the right:

let player = Actor()
player.animation = Animation(name: "Running", frameCount: 5, frameDuration: 0.15)
player.velocity.dx = 50
scene.add(player)

📦 Easily create platforms and tiled textures with Blocks

Using blocks you can easily tile textures together to form objects that can scale nicely to any size, without having to scale any texture. This is done by stitching together up to 9 different textures to form a block of textures rendered side by side. Here's how you can easily create a block from a folder named "Platform" that contains the textures that should be stitched together:

let block = Block(size: Size(width: 300, height: 300), textureCollectionName: "Platform")
scene.add(block)

🅰️ Render text using Labels

Labels let you add text content to your game. They automatically resize to fit your text content (unless you don't want them to) and can be used to implement things like UI, score counters, etc. Here's an example of adding a label to a scene:

let label = Label(text: "Welcome to my game!")
label.position = scene.center
scene.add(label)

⚡️ Use Events to drive your game logic

Events enable you to quickly script your games to drive your own logic. Imagine Engine's various objects contain built in events that can be used to observe whenever an object was moved, collided with something, etc. You can also define your own events that can be used to communicate between various parts of your code. Here's how you can observe whenever two actors collided with each other:

let player = Actor()
let enemy = Actor()

player.events.collided(with: enemy).observe {
    // Game over
}

🏃 Create animations and effects using Actions

Actions let you make objects do something over a period of time, for example moving, resizing, fading in and out etc. Imagine Engine contains a suite of built-in actions and also makes it easy for you to define your own. Here's how an actor can be moved over 3 seconds:

let actor = Actor()
scene.add(actor)
actor.move(byX: 200, y: 100, duration: 3)

🔌 Easily extend Imagine Engine with Plugins

Instead of relying on subclassing and overriding methods, Imagine Engine is designed to be easily extended through plugins. This enables you to share code between different games, and create new open source projects that add new functionality to the engine. You can attach plugins to most of Imagine Engine's objects, here's an example of creating a plugin that creates a new actor every time the scene is clicked or tapped:

class MyPlugin: Plugin {
    func activate(for scene: Scene, in game: Game) {
        scene.events.clicked.observe { scene in
            let actor = Actor()
            actor.position = scene.center
            scene.add(actor)
        }
    }
}

🕐 Precise timing using Timelines

Managing time and delayed events can sometimes be tricky in game development. Imagine Engine aims to make this a lot easier through its timeline API, that enables you to schedule single or repeated events in the future without having to worry about screen updates or if the game is paused. Here's how you can add an event to spawn a new enemy every 5 seconds:

scene.timeline.repeat(withInterval: 5) {
    let enemy = Actor()
    enemy.animation = Animation(name: "Enemy", frameCount: 5, frameDuration: 0.15)
    scene.add(enemy)
}

• 📱 iOS 9 or later
• 🖥 macOS 10.12 or later
• 📺 tvOS 10 or later

Imagine Engine supports all of Apple's platforms except watchOS. The API is also completely cross platform, so that you don't have to scatter #ifs all over your game code.

Imagine Engine ships with Xcode project templates that makes it super easy to get started with a new project. You can find more information & installation instructions here.

To get started, check out the tutorials section, which contains tutorials that will walk you through building your first Imagine Engine-powered games with very few lines of code. No previous game developer experience required!

If you need help getting started or have a question about Imagine Engine, feel free to open an issue! We're a friendly community who would love to get more people involved.

Imagine Engine is in active development, with new features being constantly added. Need something new, or want to help out making the engine even more capable? Browse and create new issues or open a PR.

Lets build some awesome games together! 🚀