FastTween Reference & Vocabulary

1. Core Vocabulary

Tween (FastTweenOpt): The core mathematical container representing an interpolation over time. It holds the start value, end value, duration, and the current progress.
Easing (Ease Enum): The mathematical curve applied to the interpolation. It defines how the value accelerates and decelerates (e.g., Linear, Quad, Elastic, Bounce).
TweenPool: The internal pre-allocated object pool. When FastTween.to() is called, an idle tween is fetched from this pool rather than allocating a new object on the JVM heap.
Zero-Allocation Hotpath: The critical code path executed during the rendering loop where zero objects are instantiated, completely bypassing the Garbage Collector.

FastTween.to(float start, float end, long durationMs): Fetches a pooled tween and configures it to interpolate between the given values over the specified duration.

ease(Ease easing): Applies a specific easing curve to the interpolation (e.g., Ease.CUBIC_IN_OUT). Default is LINEAR.
onUpdate(Consumer<Float> callback): Attaches a lambda callback that is triggered every time the tween's value changes.
onComplete(Runnable callback): Attaches a callback triggered exactly once when the tween finishes.
start(): Marks the tween as active and records the start time.
update(): The core tick method. Calculates the delta time, applies the easing math, fires the onUpdate callback, and returns true if still running or false if completed. Once completed, it automatically recycles itself back to the TweenPool.

Part of the FastJava Ecosystem — Making the JVM faster.

Made with ❤️ by Andre Stubbe