GodotSharp.SourceGenerators

C# Source Generators for use with the Godot Game Engine (supports Godot 4 and .NET 9!)

• SceneTree class attribute:
  • Generates class property for uniquely named nodes
  • Provides strongly typed access to the scene hierarchy (via _ operator)
• GodotOverride method attribute:
  • Allows use of On*, instead of virtual _* overrides
  • (Requires partial method declaration for use with Godot 4)
• Notify property attribute:
  • Generates boiler plate code, triggering only when values differ
  • (Automagically triggers nested changes for Resource and Resource[])
• InputMap class attribute:
  • Provides strongly typed access to input actions defined in godot.project
• LayerNames class attribute:
  • Provide strongly typed access to layer names defined in godot.project
• CodeComments class attribute:
  • Provides a nested static class to access property comments from code (useful for in-game tooltips, etc)
• OnInstantiate method attribute:
  • Generates a static Instantiate method with matching args that calls attributed method as part of the instantiation process
  • (Also generates a protected constructor to ensure proper initialisation - can be deactivated via attribute)
• OnImport method attribute (GD4 only):
  • Generates default plugin overrides and options to make plugin class cleaner (inherit from OnImportEditorPlugin)
• Includes base classes/helpers to create project specific source generators

• Version 2.x supports Godot 4
• Version 1.x supports Godot 3

(See GodotSharp.BuildingBlocks or local tests for example usage patterns)

Table of Contents

• GodotSharp.SourceGenerators
  • Table of Contents
  • Installation
  • Attributes
    • SceneTree
    • GodotOverride
    • Notify
    • InputMap
    • LayerNames
    • CodeComments
    • OnInstantiate
    • OnImport

Installation

Install via NuGet

Attributes

SceneTree

• Class attribute
• Generates class property for uniquely named nodes
• Provides strongly typed access to the scene hierarchy (via _ operator)
• Nodes are cached on first retrieval to avoid interop overhead
• Advanced options available as attribute arguments
  • tscnRelativeToClassPath: (default null) Specify path to tscn relative to current class
  • traverseInstancedScenes: (default false) Include instanced scenes in the generated hierarchy
  • root: (default _) Provide alternative to _ operator (eg, to allow use of C# discard variable)

// Attach a C# script on the root node of the scene with the same name.
// [SceneTree] will generate the members as the scene hierarchy.
[SceneTree]
public partial class MyScene : Node2D 
{
    public override void _Ready() 
    {
        // You can access the node via '_' object.
        GD.Print(_.Node1.Node11.Node12.Node121);
        GD.Print(_.Node4.Node41.Node412);

        // You can also directly access nodes marked as having a unique name in the editor
        GD.Print(MyNodeWithUniqueName);
        GD.Print(_.Path.To.MyNodeWithUniqueName); // Long equivalent

        // Only leaf nodes are Godot types (call .Get() on branch nodes)
        // Lets say you have _.Node1.Node2, observe the following code
        GD.Print(_.Node1.Name); // invalid
        GD.Print(_.Node1.Get().Name); // valid
        Node node1 = _.Node1; // implicit conversion also possible!
        GD.Print(node1.Name); // valid
        GD.Print(_.Node1.Node2.Name); // valid
    }
}

GodotOverride

• Method attribute
• Allows use of On*, instead of virtual _* overrides
• (Requires partial method declaration for use with Godot 4.0)
• Advanced options available as attribute arguments
  • replace: (default false) Skip base call generation (ie, override will replace base)

public partial class MyNode : Node2D 
{
    [GodotOverride]
    protected virtual void OnReady()
        => GD.Print("Ready");

    [GodotOverride(replace: true)]
    private void OnProcess(double delta)
        => GD.Print("Processing");

    // Requires partial method declaration for use with Godot 4.0
    public override partial void _Ready(); 
    public override partial void _Process(double delta); 
}

Generates:

    public override void _Ready()
    {
        base._Ready();
        OnReady();
    }

    public override _Process(double delta)
        => OnProcess(delta);

Notify

• Property attribute
• Generates public events Value1Changed & Value1Changing and a private class to manage field and event delivery
• (Automagically triggers nested changes for Resource and Resource[])
• Events are triggered only if value is different
• Initial value can be set without triggering update (useful when using a non-nullable reference type)
• [NEW] Supports partial properties!

public partial class NotifyTest : Node
{
    [Notify] public partial int Value { get; set; } // [NEW] Partial properties now supported

    [Notify]
    public float Value1
    {
        get => _value1.Get();
        set => _value1.Set(value); // You can also pass onchanged event handler here
    }

    public override void _Ready()
    {
        Value1Changing += () => GD.Print("Value1Changing raised before value is changed");
        Value1Changed += () => GD.Print("Value1Changed raised after value is changed");

        // You can also subscribe to private events if needed 
        //   _value1.Changing += OnValue1Changing;
        //   _value1.Changed += OnValue1Changed;
        // This might be useful... erm... if you need to clear the public listeners for some reason...?

        Value1 = 1; // Raise Value1Changing and Value1Changed
        Value1 = 2; // Raise Value1Changing and Value1Changed
        Value1 = 2; // No event is raised since value is the same
    }

    public NotifyTest()
        => InitValue1(7); // Set initial value without triggering events (optional)
}

InputMap

• Class attribute
• Provides strongly typed access to input actions defined in godot.project (set via editor)
• If you want access to built-in actions, see BuiltinInputActions.cs

[InputMap]
public static partial class MyInput { }

Equivalent (for defined input actions) to:

// (static optional)
// (string rather than StringName for Godot 3)
// (does not provide access to built-in actions)
partial static class MyInput
{
    public static readonly StringName MoveLeft = "move_left";
    public static readonly StringName MoveRight = "move_right";
    public static readonly StringName MoveUp = "move_up";
    public static readonly StringName MoveDown = "move_down";
}

LayerNames

• Class attribute
• Provides strongly typed access to layer names defined in godot.project (set via editor)

[LayerNames]
public static partial class MyLayers { }

Equivalent (for defined layers) to:

// (static optional)
partial static partial class MyLayers
{
    public static class Render2D
    {
        public const int MyLayer1 = 0; // Yes, layers start at 1 in editor, but 0 in code
        public const int MyLayer2 = 1;
        public const int MyLayer7 = 6;
        public const int _11reyaLyM = 10; // Yes, we will append an underscore if required...

        public static class Mask
        {
            public const uint MyLayer1 = 1 << 0;
            public const uint MyLayer2 = 1 << 1;
            public const uint MyLayer7 = 1 << 6;
            public const uint _11reyaLyM = 1 << 10;
        }
    }
    public static class Render3D
    {
        public const int MyLayer1 = 0;

        public static class Mask
        {
            public const uint MyLayer1 = 1 << 0;
        }
    }
    // Also for Physics2D, Physics3D, Navigation2D, Navigation3D, Avoidance, etc...
}

CodeComments

• Class attribute
• Provides a nested static class to access property comments from code
• Advanced options available as attribute arguments
  • strip: (default "// ") The characters to remove from the start of each line

[CodeComments]
public partial class CodeCommentsTest : Node 
{
    // This a comment for Value1
    // [CodeComments] only works with Property
    [Export] public float Value1 { get; set; }

    // Value 2 is a field so no comment
    [Export] public float value2;

    public override void _Ready() 
    {
        GD.Print(GetComment(nameof(Value1))); // output: "This a comment for Value1\n[CodeComments] only works with Property"
        GD.Print(GetComment(nameof(value2))); // output: "" (No output for fields, but could be added if needed)
    }
}

OnInstantiate

• Method attribute
• Generates a static Instantiate method with matching args that calls attributed method as part of the instantiation process
• (Also generates a protected constructor to ensure proper initialisation - can be deactivated via attribute)
• Advanced options available as attribute arguments
  • ctor: (default "protected") Scope of generated constructor (null, "" or "none" to skip)

// Initialise can be public or protected if required; args also optional
// Currently assumes tscn is in same folder with same name
// Obviously only valid for root nodes
public partial class MyScene : Node
{
    [OnInstantiate]
    private void Initialise(string myArg1, int myArg2)
        => GD.PrintS("Init", myArg1, myArg2);
}

Generates (simplified):

    private static PackedScene __scene__;
    private static PackedScene __Scene__ => __scene__ ??= GD.Load<PackedScene>("res://Path/To/MyScene.tscn");

    public static MyScene Instantiate(string myArg1, int myArg2)
    {
        var scene = __Scene__.Instantiate<MyScene>();
        scene.Initialise(myArg1, myArg2);
        return scene;
    }

    private Test3Arg() {}

Usage:

    // ... in some class
    private void AddSceneToWorld()
    {
        var myScene = MyScene.Instantiate("str", 3);
        MyWorld.AddChild(myScene);
    }

OnImport

• Method attribute (GD4 only)
• Generates default plugin overrides and options to make plugin class cleaner (inherit from OnImportEditorPlugin)
• Includes base classes/helpers to create project specific source generators
• (Not that useful unless writing lots of plugins - might remove in v3)