godot-scala-native

Write your Godot 4 game classes in Scala 3. They are compiled to a native GDExtension library with Scala Native, with no JVM at runtime.

package game

import gdext.classes.Node2D
import gdext.annotations.*
import gdext.api.*

final class Player(var speed: Double = 120.0) extends Node2D {
  @func def getScore(): Long = 42
  @signal def pinged(): Unit = ()

  override def _process(delta: Double): Unit =
    Gd.print(s"moving at $speed")
}

Run sbt godotBuild and Player shows up in Godot's Add Node dialog. speed is editable in the inspector, and get_score() and the pinged signal can be used from GDScript.

Highlights

• Extend engine classes directly. class Player extends Node2D inherits every engine method and virtual. Around 1000 engine classes are generated from Godot's own extension_api.json.
• Zero registration code. A build-time scanner finds every class that extends a Godot class, and the GDExtension entry point is generated too.
• Inspector exports. Every var constructor parameter becomes an inspector property. This covers primitives, enums, math types, Color, typed Arr/Dict, node and resource references, and Tscn scenes. Range, file, and other hints are supported, as are inspector groups.
• Deterministic memory. Engine objects follow Godot's lifetimes, not the GC's. A RefCounted you receive is owned until unref() or the end of a Gd.scoped block, exported properties release what they hold, wrappers of freed objects throw instead of crashing, and leaks are reported at shutdown.
• Allocation-free hot path. Engine calls, signals, _process, and @func calls from GDScript allocate nothing on the Scala heap: method binds are cached, marshalling is specialized at compile time, and wrappers are cached on the engine object. The 16 math types are a native port of Godot's core/math, checked against the engine.
• Editor hot reload. The bundled godot_scala editor plugin runs a warm sbt watch and swaps the rebuilt library while the editor stays open.
• One sbt plugin. A game project adds one addSbtPlugin line. The plugin brings the binding, Scala Native config, codegen, and the godotBuild task.

Quick start

Install the toolchain first. Then run:

sbt new optical002/godot-scala-native-template.g8

cd my-godot-scala-game/scala
sbt godotBuild

godot --path ../godot

Continue with Create a project.

Versions

Component	Version
Scala	3.8.1
Scala Native	0.5.10
Godot	4.6.x (standard build, not .NET)
Latest release	see Artifacts and versions

Early stage

The binding is pre-1.0. APIs can change between minor releases; check the changelog before upgrading.