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Getting Started — Swift SDK

Alpha — GoudEngine is under active development. APIs change frequently. Report issues

Prerequisites

  • Swift 5.9+ (ships with Xcode 15+, or install via swift.org)
  • macOS 13+ (Ventura or later)
  • Rust toolchain — needed to build the native engine library

Building the Native Library

The Swift SDK wraps the native Rust engine through its C FFI. Build the engine first:

git clone https://github.com/aram-devdocs/GoudEngine.git
cd GoudEngine
cargo build --release

This produces target/release/libgoud_engine.dylib (macOS) which the Swift package links against.

Installation via SPM

Add GoudEngine as a local Swift Package Manager dependency. In your project’s Package.swift:

// swift-tools-version: 5.9

import Foundation
import PackageDescription

// Point to the built native library.
// Override with GOUD_ENGINE_LIB_DIR for custom layouts.
let libSearchPath: String = ProcessInfo.processInfo.environment["GOUD_ENGINE_LIB_DIR"]
    ?? "../../target/release"

let package = Package(
    name: "MyGame",
    platforms: [
        .macOS(.v13),
    ],
    dependencies: [
        .package(path: "../../sdks/swift"),  // adjust relative path to GoudEngine repo
    ],
    targets: [
        .executableTarget(
            name: "MyGame",
            dependencies: [
                .product(name: "GoudEngine", package: "swift"),
            ],
            path: "Sources/MyGame",
            linkerSettings: [
                .unsafeFlags(["-L", libSearchPath]),
            ]
        ),
    ]
)

The linkerSettings tell the Swift compiler where to find libgoud_engine.dylib. Adjust the path to match your project layout relative to the GoudEngine repository root.

First Project

Create Sources/MyGame/main.swift with a minimal window that closes on Escape:

import GoudEngine

let config = EngineConfig()
config
    .setSize(width: 800, height: 600)
    .setTitle(title: "My First Game")

let game = config.build()

while !game.shouldClose() {
    game.beginFrame(r: 0.2, g: 0.2, b: 0.2, a: 1.0)

    if game.isKeyPressed(key: .ESCAPE) {
        game.requestClose()
    }

    game.endFrame()
}

beginFrame clears the screen to the given color and prepares the frame. endFrame swaps buffers and polls events. game.deltaTime gives seconds since the last frame – use it to keep movement frame-rate independent.

Build and run:

swift build && swift run

Drawing a Sprite

Load textures once before the loop. Drawing happens between beginFrame and endFrame.

import GoudEngine

let config = EngineConfig()
config.setSize(width: 800, height: 600).setTitle(title: "Sprite Demo")
let game = config.build()

let texture = game.loadTexture(path: "assets/player.png")

while !game.shouldClose() {
    game.beginFrame(r: 0.1, g: 0.1, b: 0.1, a: 1.0)

    game.drawSprite(
        textureId: texture,
        x: 100, y: 100,
        width: 64, height: 64,
        rotation: 0,
        color: Color.white()
    )

    if game.isKeyPressed(key: .ESCAPE) {
        game.requestClose()
    }

    game.endFrame()
}

Put your image files in an assets/ folder next to your project. The path is relative to the working directory when you run the executable.

Handling Input

isKeyPressed returns true every frame the key is held. Use it for movement. For one-shot actions, track state yourself.

var x: Float = 400
var y: Float = 300
let speed: Float = 200

while !game.shouldClose() {
    game.beginFrame()
    let dt = game.deltaTime

    if game.isKeyPressed(key: .W) { y -= speed * dt }
    if game.isKeyPressed(key: .S) { y += speed * dt }
    if game.isKeyPressed(key: .A) { x -= speed * dt }
    if game.isKeyPressed(key: .D) { x += speed * dt }

    if game.isMouseButtonPressed(button: .LEFT) {
        // click action
    }

    let mouseX = game.mouseX()
    let mouseY = game.mouseY()

    game.endFrame()
}

Running the Flappy Bird Example

The repository includes a complete Flappy Bird clone in Swift that mirrors the C# flappy_goud example for parity testing:

cd GoudEngine
cargo build --release
./dev.sh --sdk swift --game flappy_bird

Source is in examples/swift/flappy_bird/.

Next Steps