Custom C# tweensCustom C# tweens

Use a callback value tween when there is no native property adapter. Use PropertyTween<TTarget, TValue> when you can supply a typed getter, setter, and interpolator. Neither approach needs reflection or property paths.

Callback values

Import Godot and tweens.gd, and run this in a Node method on Godot’s main thread:

var value = owner.Tween(new FloatTween
{
    From = 10,
    To = 100,
    Duration = 1,
    OnUpdate = (_, sample) => GD.Print(sample),
});

The owner is an in-tree Node. It controls lifetime; values are delivered through OnUpdate. The eight value definitions are FloatTween, DoubleTween, Vector2Tween, Vector3Tween, Vector4Tween, ColorTween, QuaternionTween, and Rect2Tween.

Custom managed properties

This complete example animates a managed object with a manually driven scheduler:

MeterExample.cs

using tweens.gd;

public sealed class Meter
{
    public float Value { get; set; }
}

public static class MeterExample
{
    public static float SampleMidpoint()
    {
        var meter = new Meter();
        using var scheduler = new TweenScheduler();
        var definition = new PropertyTween<Meter, float>(
            target => target.Value,
            (target, value) => target.Value = value,
            Interpolators.Float)
        {
            From = 0,
            To = 100,
            Duration = 1,
        };

        scheduler.Add(meter, definition);
        scheduler.Update(0.5);
        return meter.Value; // 50 with the default linear easing.
    }
}

TweenScheduler belongs to its creating thread. Drive it with Update(delta, unscaledDelta, mode) and dispose it when finished; disposal settles remaining work. A manual scheduler with no owner has no tree pause policy. Native targets still require Godot’s main thread, and nodes must have an in-tree owner.

For a custom property on a Node, pass its definition to node.Tween(definition) to use automatic scheduling instead. Automatic CancelTweens does not reach separate manual schedulers.

Custom definitions and bindings

Derive from TweenDefinition<TTarget, TValue> and implement protected Read, Write, and Interpolate methods. TTarget is a reference type; TValue is a value type. The Interpolators helpers cover the built-in numeric/vector types.

For per-playback bindings, override Prepare, Restore, and Release. Preparation runs on the private definition snapshot before its initial read. Restoration may restore a property value or remove an override. Cleanup also runs after failed preparation and must release only resources owned by that snapshot. Custom reference-valued configuration remains shared after the shallow snapshot; do not mutate shared configuration during independent playbacks.