GodotExt 0.2.0

GodotExt - Extension methods for the Godot C# API

This library contains a set of useful extension methods that augment Godot's C# API to make it easier to use and more type-safe. The extension methods are defined for a handful of types.

Installation

GodotExt is published on NuGet. To add it use this command line command (or the NuGet facilities of your IDE):

dotnet add package GodotExt --version 0.2.0

If you are targeting netstandard2.1 also add the following lines to your .csproj file to make it work with Godot:

<PropertyGroup>
    <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
</PropertyGroup>

What's inside

Finding nodes

You can use the AtPath and WithName extension methods as a type-safe and verified replacement for Godot's GetNode and FindNode methods. Both replacements will verify that the node exists and throw an exception if it doesn't.

var button = GetNode<Button>("Some/Path/To/Button");

// becomes
var button = this.AtPath<Button>("Some/Path/to/Button");

var button = FindNode<Button>("Button", true, false);

// becomes
var button = this.WithName<Button>("Button");

You can use FindAllDescendants and FindClosestDescendants to find all nodes in a subtree that are of a certain type and match additional criteria.

// find the red buttons below the current node
var allRedButtons = FindAllDescendants<Button>(b => b.GetColor() == Color.Red);

// find the outermost containers that are in the "Alpha" group
var allContainersInGroupAlpha = FindClosestDescendants<Container>(c => c.IsInGroup("Alpha"));

The difference between FindAllDescendants and FindClosestDescendants is that FindAllDescendants will return all nodes in the whole sub-tree that match the criteria, while FindClosestDescendants will return the first node in each branch of the sub-tree that matches the criteria (e.g. FindClosestDescendants will stop searching a branch when it has found a match).

Also, be aware that these functions traverse the node tree so they can be expensive and should not be used in tight loops. Their main use case is for saving games where they allow you to quickly find interesting nodes in the tree that need saving and where it is ok to wait a few milliseconds for the result.

Parent-child relationships

GetChildNodes<T> is a type-safe replacement for GetChildren. It will only return nodes of the given type back:

foreach(var child in this.GetChildren()) {
   if (child is Button button) {
      button.Disabled = true;
   }
}

// becomes   

foreach(var button in this.GetChildNodes<Button>()) {
    button.Disabled = true;
}

MoveToNewParent moves a node to a new parent:

if (player.GetParent() != null) {
    player.GetParent().RemoveChild(player);
}
airship.AddChild(player);

// becomes

player.MoveToNewParent(airship);

RemoveFromParent removes a node from its parent:

if (node.GetParent() != null) {
    node.GetParent().RemoveChild(node);
}

// becomes

node.RemoveFromParent();

RemoveAndFree is a safer alternative to QueueFree. It ensures the node is actually removed from the tree before QueueFree is called, which helps avoiding strange behaviour when the node is still in the tree for the remainder of the current frame:

if (node.GetParent() != null) {
    node.GetParent().RemoveChild(node);
}
node.QueueFree();

// becomes

node.RemoveAndFree();

Nodes in groups

FindBelowInGroup finds all nodes below a given node that are in a given group:

var myNode = ...; // this is the node below which we want to find all nodes that are in a certain group

var nodesInGroup = GetTree().GetNodesInGroup("SomeGroup");
var result = new List<Node>();
foreach (var node in nodesInGroup) {
    if (myNode.IsAParentOf(node)) {
        result.Add(node);
    }
}

// becomes

var nodesInGroup = myNode.FindBelowInGroup("SomeGroup");

GetNodesInGroup gets an override that will filter the group nodes to only return nodes of the given type:

var enemies = GetTree().GetNodesInGroup("SomeGroup")
    .OfType<Enemy>();
    
// becomes

var enemies = GetTree().GetNodesInGroup<Enemy>("SomeGroup");

Signals

FiresSignal provides a better-readable alternative to the built-in ToSignal when you want to wait for a certain signal with await.

await ToSignal(timer,"timeout");

// becomes

await timer.FiresSignal("timeout");

Timers and Tweens

For timers and tweens there are additional methods that make using them easier:

// make a one-off 500ms timer and wait on it
await ToSignal(GetTree().CreateTimer(0.5), "timeout");

// becomes
await this.Sleep(0.5);

await ToSignal(timer, "timeout");

// becomes
await timer.Timeout();

await ToSignal(tween, "tween_completed");

// becomes
await tween.IsCompleted();

Fluent API for signal connections

Connect gets an override which allows you to fluently create signal connections:

button
    .Connect(
        "pressed",  
        this, nameof(OnButtonPressed)
    );

// becomes
button
    .Connect("pressed")
    .To(this, nameof(OnButtonPressed));

In addition to the vanilla API it also directly checks for errors during binding and throws an exception if the binding fails instead of silently failing. Also, this API allows for easier additional binds and binding flags, which can use the actual enum's instead of uints and don't require you to manually create Godot's Array instances:

button.Connect(
    "pressed", 
    this, nameof(OnButtonPressed),
    new Array(button), 
    ((uint) ConnectFlags.Deferred) | ((uint) ConnectFlags.OneShot)));

// becomes
button
    .Connect("pressed")
    .WithBinds(button)
    .WithFlags(ConnectFlags.Deferred, ConnectFlags.OneShot)
    .To(this, nameof(OnButtonPressed))

The fluent API also returns a binding object which allows you to easily disconnect the binding again without having to write all the parameters again:

button.Connect("pressed", this, nameof(OnButtonPressed));
// later...
button.Disconnect("pressed", this, nameof(OnButtonPressed));

// becomes

var connection = button
    .Connect("pressed")
    .To(this, nameof(OnButtonPressed));
// later...    
connection.Disconnect();    

Miscellaneous

Type-safe cloning of nodes

Clone is a type-safe variant of Duplicate:

var monsterClone = monster.Duplicate() as Monster;

// becomes
var monsterClone = monster.Clone(); // no casting necessary

Snake-case conversion for CallDeferred

When calling Godot-API through CallDeferred you need to translate the method name into snake-case. This can easily introduce typos. Therefore string gets an extension method that converts the string to snake-case:

someNode.CallDeferred("someMethod", new Array(1, 2, 3));

// becomes
someNode.CallDeferred(nameof(SomeNode.SomeMethod).ToSnakeCase(), new Array(1, 2, 3));

As an additional bonus the deferred call will now also appear in the usage search of your IDE.

2D World-Screen transformations on ViewPort

Viewport has some extensions that allow you to quickly transform screen coordinates to a world coordinates:

var worldCoordinates = GetGlobalMousePosition() * viewport.CanvasTransform;

// becomes

var worldCoordinates = viewport.ScreenToWorld(GetGlobalMousePosition());

and the reverse is also possible:

var playerPositionOnScreen = viewport.CanvasTransform * player.position;

// becomes

var playerPositionOnScreen = viewport.WorldToScreen(player.position);