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Getting Started -- Go SDK

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

This guide covers installing the Go SDK, opening a window, drawing a sprite, and handling input.

See also: C# guide -- Python guide -- TypeScript guide -- Rust guide -- Swift guide -- Kotlin guide

Prerequisites

  • Go 1.21 or later
  • A C compiler (GCC or Clang) -- required for cgo
  • Rust toolchain -- needed to build the native engine library

Building the Native Library

The Go 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), libgoud_engine.so (Linux), or goud_engine.dll (Windows).

Installation

The Go SDK uses cgo to call into the native library. Add the module to your project:

go get github.com/aram-devdocs/GoudEngine/sdks/go

For local development from the repository, the SDK is at sdks/go/. Set CGO flags to find the native library:

export CGO_CFLAGS="-I$(pwd)/sdks/go/include"
export CGO_LDFLAGS="-L$(pwd)/target/release"

First Project

Create main.go:

package main

import "github.com/aram-devdocs/GoudEngine/sdks/go/goud"

func main() {
    game := goud.NewGame(800, 600, "My First Game")
    defer game.Destroy()

    for !game.ShouldClose() {
        game.BeginFrame(0.2, 0.2, 0.2, 1.0)

        if game.IsKeyJustPressed(goud.KeyEscape) {
            game.Close()
        }

        game.EndFrame()
    }
}

Run it:

CGO_ENABLED=1 go run main.go

A window opens at 800x600 and closes when you press Escape.

BeginFrame clears the screen to the given RGBA color and prepares the frame. EndFrame swaps buffers and polls events. Everything you draw goes between those two calls.

Drawing a Sprite

Load textures once before the game loop, then draw each frame.

package main

import "github.com/aram-devdocs/GoudEngine/sdks/go/goud"

func main() {
    game := goud.NewGame(800, 600, "Sprite Demo")
    defer game.Destroy()

    tex := game.LoadTexture("assets/player.png")

    for !game.ShouldClose() {
        game.BeginFrame(0.1, 0.1, 0.1, 1.0)

        game.DrawSprite(tex, 400, 300, 64, 64, 0, goud.ColorWhite())

        if game.IsKeyJustPressed(goud.KeyEscape) {
            game.Close()
        }

        game.EndFrame()
    }
}

DrawSprite takes the center position of the sprite, width, height, rotation in radians, and a color tint.

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

Handling Input

Keyboard

Two modes are available: just pressed this frame, or held continuously.

// One-shot: true only on the frame the key goes down
if game.IsKeyJustPressed(goud.KeySpace) {
    // jump
}

// Held: true every frame the key is down
if game.IsKeyPressed(goud.KeyW) {
    y -= speed * game.DeltaTime()
}
if game.IsKeyPressed(goud.KeyS) {
    y += speed * game.DeltaTime()
}

DeltaTime() is the elapsed seconds since the last frame. Use it to make movement frame-rate independent.

Common key constants: goud.KeyEscape, goud.KeySpace, goud.KeyEnter, goud.KeyW, goud.KeyA, goud.KeyS, goud.KeyD, goud.KeyLeft, goud.KeyRight, goud.KeyUp, goud.KeyDown.

Mouse

if game.IsMouseButtonPressed(goud.MouseButtonLeft) {
    // click action
}

mouseX := game.MouseX()
mouseY := game.MouseY()

Mouse button constants: goud.MouseButtonLeft, goud.MouseButtonRight, goud.MouseButtonMiddle.

Available Types

Import Description
goud.NewGame Create a windowed game instance
goud.Color RGBA color (goud.ColorWhite(), goud.ColorRGB(r, g, b))
goud.Vec2 2D vector with arithmetic methods
goud.Vec3 3D vector
goud.Rect Rectangle (x, y, width, height)
goud.Transform2D 2D position, rotation, scale
goud.EntityID ECS entity handle

Running an Example Game

The repository includes a complete Flappy Bird clone in Go:

git clone https://github.com/aram-devdocs/GoudEngine.git
cd GoudEngine
cargo build --release
./dev.sh --sdk go --game flappy_bird

dev.sh builds the native library and launches the example. Source is in examples/go/flappy_bird/.

Code Generation

All files in sdks/go/goud/ and sdks/go/internal/ffi/helpers.go are auto-generated. Do not hand-edit them. Regenerate with:

python3 codegen/gen_go_sdk.py    # Wrapper package
python3 codegen/gen_go.py        # Internal cgo bindings

Next Steps