# GDScript: Loops and delays

Source: https://tweens.gd/gdscript/loops/

Ping-pong sends a motion back to where it started; repeats play it again. Together they make idle motion that runs on its own.

Examples use the global `Tweens` class in a node script, with targets inside the scene tree.

## Loop forever

Godot's Tween

```gdscript
var tween := sprite.create_tween().set_loops()
tween.set_trans(Tween.TRANS_SINE).set_ease(Tween.EASE_IN_OUT)
tween.tween_property(sprite, "scale", Vector2(1.1, 1.1), 0.8)
tween.tween_property(sprite, "scale", Vector2.ONE, 0.8)
```

tweens.gd

```gdscript
var pulse := Tweens.scale_2d([1.1, 1.1], 0.8, InOut.SINE) \
    .with_ping_pong().with_repeats(Tweens.INFINITE)

Tweens.play(sprite, pulse)
```

The sprite grows for 0.8 seconds, shrinks for 0.8 seconds, and repeats until cancelled or removed from the tree. Ping-pong returns to the scale the sprite had at the start, so the return leg needs no value of its own.

## Count cycles

| Set | Effect |
| --- | --- |
| `with_repeats(2)` | Three cycles: the first plus two repeats |
| `with_ping_pong()` | Each cycle goes there and back; `duration` applies to each leg |
| `with_ping_pong_interval()` | Pause at the far end before the return leg |
| `with_repeat_interval()` | Pause between cycles |

**Try it:** raise `repeats`, then drag the timeline to see where each interval falls.

Interactive preview: https://tweens.gd/gdscript/loops/

## Hold during a delay

`fill` chooses what a delayed tween shows before it starts and after it ends. For an entrance, `Tweens.Fill.BOTH` applies the `from` value during the delay and keeps the final value:

```gdscript
var fade_in := Tweens.modulate_alpha()
fade_in.from_value = 0.0
fade_in.duration = 0.3
fade_in.delay = 0.5
fade_in.fill = Tweens.Fill.BOTH

Tweens.play(label, fade_in)
```

The label stays hidden for half a second, then fades in to its own alpha. The default fill, `RETAIN_FINAL_VALUE`, would leave it visible during the delay, so it would blink out before fading in.

Each row below plays one delayed tween with a different fill mode:

Initial delayPlayingNatural completion

`RETAIN_FINAL_VALUE`

`APPLY_FROM_DURING_DELAY`

`BOTH`

`NONE`

**From** at left**captured initial value** (dashed)**To** at right

Cancelling keeps the current value

Fill modes restore the initial value only on natural completion. A cancelled tween keeps its latest value.

[Timing reference](https://tweens.gd/gdscript/api/timing/)Every timing option, fill mode, and validation rule.