Lightweight object used for general-purpose animation via script, using [Tweener]s.
</brief_description>
<description>
[SceneTreeTween] is a tween managed by the scene tree. As opposed to [Tween], it does not require the instantiation of a node.
[SceneTreeTween]s are more light-weight than [AnimationPlayer], so they are very much suited for simple animations or general tasks that don't require visual tweaking provided by the editor. They can be used in a fire-and-forget manner for some logic that normally would be done by code. You can e.g. make something shoot periodically by using a looped [CallbackTweener] with a delay.
A [SceneTreeTween] can be created by using either [method SceneTree.create_tween] or [method Node.create_tween]. [SceneTreeTween]s created manually (i.e. by using [code]Tween.new()[/code]) are invalid. They can't be used for tweening values, but you can do manual interpolation with [method interpolate_value].
A tween animation is created by adding [Tweener]s to the [SceneTreeTween] object, using [method tween_property], [method tween_interval], [method tween_callback] or [method tween_method]:
This sequence will make the [code]$Sprite[/code] node turn red, then shrink, before finally calling [method Node.queue_free] to free the sprite. [Tweener]s are executed one after another by default. This behavior can be changed using [method parallel] and [method set_parallel].
When a [Tweener] is created with one of the [code]tween_*[/code] methods, a chained method call can be used to tweak the properties of this [Tweener]. For example, if you want to set a different transition type in the above example, you can use [method set_trans]:
Most of the [SceneTreeTween] methods can be chained this way too. In the following example the [SceneTreeTween] is bound to the running script's node and a default transition is set for its [Tweener]s:
Some [Tweener]s use transitions and eases. The first accepts a [enum Tween.TransitionType] constant, and refers to the way the timing of the animation is handled (see [url=https://easings.net/]easings.net[/url] for some examples). The second accepts an [enum Tween.EaseType] constant, and controls where the [code]trans_type[/code] is applied to the interpolation (in the beginning, the end, or both). If you don't know which transition and easing to pick, you can try different [enum Tween.TransitionType] constants with [constant Tween.EASE_IN_OUT], and use the one that looks best.
[b]Note:[/b] All [SceneTreeTween]s will automatically start by default. To prevent a [SceneTreeTween] from autostarting, you can call [method stop] immediately after it is created.
Binds this [SceneTreeTween] with the given [code]node[/code]. [SceneTreeTween]s are processed directly by the [SceneTree], so they run independently of the animated nodes. When you bind a [Node] with the [SceneTreeTween], the [SceneTreeTween] will halt the animation when the object is not inside tree and the [SceneTreeTween] will be automatically killed when the bound object is freed. Also [constant TWEEN_PAUSE_BOUND] will make the pausing behavior dependent on the bound node.
For a shorter way to create and bind a [SceneTreeTween], you can use [method Node.create_tween].
</description>
</method>
<methodname="chain">
<returntype="SceneTreeTween"/>
<description>
Used to chain two [Tweener]s after [method set_parallel] is called with [code]true[/code].
[codeblock]
var tween = create_tween().set_parallel(true)
tween.tween_property(...)
tween.tween_property(...) # Will run parallelly with above.
tween.chain().tween_property(...) # Will run after two above are finished.
Processes the [SceneTreeTween] by the given [code]delta[/code] value, in seconds. This is mostly useful for manual control when the [SceneTreeTween] is paused. It can also be used to end the [SceneTreeTween] animation immediately, by setting [code]delta[/code] longer than the whole duration of the [SceneTreeTween] animation.
[b]Note:[/b] The [SceneTreeTween] will become invalid in the next processing frame after its animation finishes. Calling [method stop] after performing [method custom_step] instead keeps and resets the [SceneTreeTween].
Returns the total time in seconds the [SceneTreeTween] has been animating (i.e. the time since it started, not counting pauses etc.). The time is affected by [method set_speed_scale], and [method stop] will reset it to [code]0[/code].
[b]Note:[/b] As it results from accumulating frame deltas, the time returned after the [SceneTreeTween] has finished animating will be slightly greater than the actual [SceneTreeTween] duration.
This method can be used for manual interpolation of a value, when you don't want [SceneTreeTween] to do animating for you. It's similar to [method @GDScript.lerp], but with support for custom transition and easing.
[code]initial_value[/code] is the starting value of the interpolation.
[code]delta_value[/code] is the change of the value in the interpolation, i.e. it's equal to [code]final_value - initial_value[/code].
[code]elapsed_time[/code] is the time in seconds that passed after the interpolation started and it's used to control the position of the interpolation. E.g. when it's equal to half of the [code]duration[/code], the interpolated value will be halfway between initial and final values. This value can also be greater than [code]duration[/code] or lower than 0, which will extrapolate the value.
[code]duration[/code] is the total time of the interpolation.
[b]Note:[/b] If [code]duration[/code] is equal to [code]0[/code], the method will always return the final value, regardless of [code]elapsed_time[/code] provided.
</description>
</method>
<methodname="is_running"qualifiers="const">
<returntype="bool"/>
<description>
Returns whether the [SceneTreeTween] is currently running, i.e. it wasn't paused and it's not finished.
Returns whether the [SceneTreeTween] is valid. A valid [SceneTreeTween] is a [SceneTreeTween] contained by the scene tree (i.e. the array from [method SceneTree.get_processed_tweens] will contain this [SceneTreeTween]). A [SceneTreeTween] might become invalid when it has finished tweening, is killed, or when created with [code]SceneTreeTween.new()[/code]. Invalid [SceneTreeTween]s can't have [Tweener]s appended. You can however still use [method interpolate_value].
Calling this method without arguments will make the [SceneTreeTween] run infinitely, until either it is killed with [method kill], the [SceneTreeTween]'s bound node is freed, or all the animated objects have been freed (which makes further animation impossible).
[b]Warning:[/b] Make sure to always add some duration/delay when using infinite loops. To prevent the game freezing, 0-duration looped animations (e.g. a single [CallbackTweener] with no delay) are stopped after a small number of loops, which may produce unexpected results. If a [SceneTreeTween]'s lifetime depends on some node, always use [method bind_node].
If [code]parallel[/code] is [code]true[/code], the [Tweener]s appended after this method will by default run simultaneously, as opposed to sequentially.
Determines whether the [SceneTreeTween] should run during idle frame (see [method Node._process]) or physics frame (see [method Node._physics_process].
Default value is [constant Tween.TWEEN_PROCESS_IDLE].
</description>
</method>
<methodname="set_speed_scale">
<returntype="SceneTreeTween"/>
<argumentindex="0"name="speed"type="float"/>
<description>
Scales the speed of tweening. This affects all [Tweener]s and their delays.
Creates and appends a [CallbackTweener]. This method can be used to call an arbitrary method in any object. Use [code]binds[/code] to bind additional arguments for the call.
Example: object that keeps shooting every 1 second.
[codeblock]
var tween = get_tree().create_tween().set_loops()
tween.tween_callback(self, "shoot").set_delay(1)
[/codeblock]
Example: turning a sprite red and then blue, with 2 second delay.
Creates and appends an [IntervalTweener]. This method can be used to create delays in the tween animation, as an alternative to using the delay in other [Tweener]s, or when there's no animation (in which case the [SceneTreeTween] acts as a timer). [code]time[/code] is the length of the interval, in seconds.
Creates and appends a [MethodTweener]. This method is similar to a combination of [method tween_callback] and [method tween_property]. It calls a method over time with a tweened value provided as an argument. The value is tweened between [code]from[/code] and [code]to[/code] over the time specified by [code]duration[/code], in seconds. Use [code]binds[/code] to bind additional arguments for the call. You can use [method MethodTweener.set_ease] and [method MethodTweener.set_trans] to tweak the easing and transition of the value or [method MethodTweener.set_delay] to delay the tweening.
Example: making a 3D object look from one point to another point.
[codeblock]
var tween = create_tween()
tween.tween_method(self, "look_at", Vector3(-1, 0, -1), Vector3(1, 0, -1), 1, [Vector3.UP]) # The look_at() method takes up vector as second argument.
[/codeblock]
Example: setting a text of a [Label], using an intermediate method and after a delay.
Creates and appends a [PropertyTweener]. This method tweens a [code]property[/code] of an [code]object[/code] between an initial value and [code]final_val[/code] in a span of time equal to [code]duration[/code], in seconds. The initial value by default is the property's value at the time the tweening of the [PropertyTweener] starts. For example:
will move the sprite to position (100, 200) and then to (200, 300). If you use [method PropertyTweener.from] or [method PropertyTweener.from_current], the starting position will be overwritten by the given value instead. See other methods in [PropertyTweener] to see how the tweening can be tweaked further.
[b]Note:[/b] You can find the correct property name by hovering over the property in the Inspector. You can also provide the components of a property directly by using [code]"property:component"[/code] (eg. [code]position:x[/code]), where it would only apply to that particular component.
Example: moving object twice from the same position, with different transition types.
Emitted when the [SceneTreeTween] has finished all tweening. Never emitted when the [SceneTreeTween] is set to infinite looping (see [method set_loops]).
[b]Note:[/b] The [SceneTreeTween] is removed (invalidated) in the next processing frame after this signal is emitted. Calling [method stop] inside the signal callback will prevent the [SceneTreeTween] from being removed.
Emitted when a full loop is complete (see [method set_loops]), providing the loop index. This signal is not emitted after the final loop, use [signal finished] instead for this case.
Emitted when one step of the [SceneTreeTween] is complete, providing the step index. One step is either a single [Tweener] or a group of [Tweener]s running in parallel.
If the [SceneTreeTween] has a bound node, it will process when that node can process (see [member Node.pause_mode]). Otherwise it's the same as [constant TWEEN_PAUSE_STOP].
