GodotHat.Attributes 0.4.5

godothat

Alternate C# source generators for godot.

Attributes

OnReady

Implements _Ready for you. More interesting if you return an IDisposable

[OnReady]
private void DoReadyThings()
{
  // do your OnReady things
}

That's mildly useful, mostly down to style, though not much reason to not just override _Ready yourself. But godothat will also perform automatic cleanup of IDisposables on tree exit:

[OnReady]
private IDisposable SubscribeToFoos() => FooManager.WhenFoosUpdated.Subscribe(this.FoosUpdated);

private void FoosUpdated(IEnumerable<Foo> foos) {
  // Do things with the new Foos 
}

You can have multiple [OnReady] methods.

OnEnterTree / OnExitTree

Like [OnReady], but for EnterTree. [OnExitTree] for other explicit cleanup options.

[OnEnterTree]
private void ConnectMultiplayerEvents() {
   var multiplayer = GetTree().GetMultiplayer();
   multiplayer.PeerConnected += this.OnNetworkPeerConnected;
   multiplayer.PeerDisconnected += this.OnNetworkPeerDisconnected;
}

[OnExitTree]
private void CleanupMultiplayerEvents() {
   var multiplayer = GetTree().GetMultiplayer();
   multiplayer.PeerConnected -= this.OnNetworkPeerConnected;
   multiplayer.PeerDisconnected -= this.OnNetworkPeerDisconnected;
}

Or with an IDisposable:

[OnEnterTree]
private IDisposable SetupMultiplayerEvents() {
    var multiplayer = GetTree().GetMultiplayer();
    multiplayer.PeerConnected += this.OnNetworkPeerConnected;
    multiplayer.PeerDisconnected += this.OnNetworkPeerDisconnected;
    return Disposable.Create(() => {
        multiplayer.PeerConnected -= this.OnNetworkPeerConnected;
        multiplayer.PeerDisconnected -= this.OnNetworkPeerDisconnected;
    });
}

SceneUniqueName

Automatically resolve named nodes within children on enter tree, on fields or properties.

[SceneUniqueName("%MyLabel", required: false)]
private RichTextLabel? OptionalLabel { get; set; }

[SceneUniqueName("%MyLabel")]
private RichTextLabel Label { get; set; }

[SceneUniqueName]
private RichTextLabel MyLabel;

This resolves via GetNode (or GetNodeOrNull if not required) in a generated _EnterTree, so you will get useful godot errors if it is not found.

Technically you don't have to limit this to Unique Names (ie %...), but that is what it was intended for and given it is called in the EnterTree lifecycle you may need to be cautious.

AutoDispose

Wraps a method with an Update version, and tracks cleanup via an IDisposable.

[OnReady] and [OnEnterTree] above described some utility in returning IDisposable, however this allows disposable tracking for ad-hoc methods that will still get cleaned up.

For example

[AutoDispose]
private IDisposable Foo(Foo foo) {
  this.foo = foo;
  foo.Add(this);
  return Disposable.create(() => {
    foo.Remove(this);
    this.foo = null;
  });
}

// This will automatically create UpdateFoo and DisposeFoo methods.
public void UpdateFoo(Foo foo);
private void DisposeFoo();

Accessibility of the Update method can be controlled with the accessibility argument, eg [AutoDispose(Accessibility = Accessibility.Private)].

DisposeFoo will be called on tree exit.

Other notes

Ordering of calls is by occurence within the source file, and in reverse on dispose (if applicable). This means you likely want [SceneUniqueName] fields and properties before any [OnEnterTree] methods that depend on them.

[SceneUniqueName("%MyNode")]
Node MyNodePopulatedFirst;

[OnEnterTree]
IDisposable FirstMethod() { /* ... */ }

[OnEnterTree]
IDisposable? SecondMethod() { /* ... */ }

[OnEnterTree]
IDisposable? ThirdMethod() { /* ... */ }

// Generated _EnterTree is conceptually:
public override void _EnterTree()
{
  MyNodePopulatedFirst = GetNode("%MyNode");
  _disposable_FirstMethod = FirstMethod();
  SecondMethod();
  _disposable_ThirdMethod = ThirdMethod();
}

// Generated _ExitTree is conceptually:
public override void _ExitTree()
{
  _disposable_ThirdMethod?.Dispose();
  _disposable_ThirdMethod = null;
  _disposable_FirstMethod.Dispose();
  _disposable_FirstMethod = null;
}

Using godothat

1. Add the following property to your project's .csproj to disable Godot's standard ScriptMethods generator:

<GodotDisabledSourceGenerators>ScriptMethods</GodotDisabledSourceGenerators>

2. Add the godohat nupkg dep to your project.
3. Add annotations and enjoy

Acknowledgements

Godot Code / Inspiration

ScriptMethodsGenerator is a reimplementation godot's ScriptMethodsGenerator to produce similar output.