ecs-swift

ecs-swift is a library that implements the Entity Component System (ECS) in Swift. It is used for developing games with ECS design in frameworks such as SpriteKit and SceneKit.

This library has been greatly influenced by the ECS crate of Rust, the Bevy ECS! Particularly, ecs-swift is designed with a focus on protocol-oriented programming, allowing you to define components using structures!

However, the creator acknowledges that ecs-swift is not a complete copy of the Bevy ECS but rather a degraded version created in Swift. For more details, please refer to the Wiki for ecs-swift as a degraded version of the Bevy ECS.

📎 Japanese

Warning

I believe I may not be able to actively update this package very often. I sincerely apologize for that. The reason behind this is my personal focus on creating 2D games. Please understand that incorporating new features promptly is rare for me. Additionally, due to this background, support for 3D games is limited.

However, it doesn't mean that I won't update it at all. I plan to maintain, add features, refactor, and debug as needed (though it might be at a slower pace). If you have any opinions or requests, please feel free to share them in the Discussions!

From the developer of this tool, @rrbox.

Getting started

Requirements

• Xcode 14.3
• Swift 5.8

Swift package

// swift-tools-version:5.8

import PackageDescription

let package = Package(
  name: "Your project",
  dependencies: [
    .package(url: "https://github.com/rrbox/ecs-swift.git", from: "0.1.0")
  ],
  targets: [
    .target(name: "Your project", dependencies: ["ECS", "PlugIns"])
  ]
)

Examples

import ECS

Create Component

struct Position: Component {
    var x: CGFloat
    var y: CGFlaot
}

Create System

func moveableEntitySpawnSystem(commands: Commands) {
    commands.spawn()
        .addComponent(Position(x: 50, y: 100))
}

func movementSystem(query: Query<Position>, deltaTime: Resource<DeltaTime>) {
    query.update { _, position, deltaTime in
        position.value.x += 120 * deltaTime.resource
    }
}

func presentPositionSystem(query: Query<Position>) {
    query.update { _, position in
        print(position.value)
    }
}

Create World

let world = World()
    .addSystem(.startUp, moveableEntitySpawnSystem(commands:))
    .addSystem(.update, movementSystem(query:deltaTime:))
    .addSystem(.update, presentPositionSystem(query:))

Run World (SpriteKit)

import SpriteKit
import ECS

class Scene: SKScene {
    override func didMove(to view: SKView) {
        world.setUp()
    }
    
    override func update(_ currentTime: TimeInterval) {
        world.update(currentTime)
    }
}

Detailed explanations can be found in the Wiki (under construction)!

Dependencies

This project uses the following third-party packages:

• swift-syntax

License

This is licensed under the following:

• MIT License

As mentioned in the "Warning," it seems that the creator may not be actively working on package updates. If you cannot wait for updates or if you seek implementations outside the creator's direction, don't forget the option of modifying "this ecs-swift" into "your ecs-swift."