Tween Interface

Properties and Interface

Interface

Interface	Description
tag	Add a number tag to the current tween
to	Create motion by interpolating the property’s value to an absolute value
by	Create motion by interpolate the property’s value to a value relative to the current one
set	Create an instant motion by setting the property to a value
delay	Create an instant motion of pausing for a period of time
call	Create an instant motion by calling a function
target	Define the target node or component to which the tween is applied
union	Combine multiple motions as one tween
then	Insert a new motion to the current tween queue
repeat	Define the number of times for the motion to be executed (In previous versions, this is used to define the number of times the motion is repeated.)
repeatForever	Set the motion to repeat for infinite times
sequence	Define a collection of motions to be executed in sequence
parallel	Define a collection of motions to be executed simultaneously
start	Start the tween
stop	Stop the tween
clone	Clone the tween
show	Enable the tween target to be rendered. Tween target is mandatory to be Node.
hide	Disable the tween target to be rendered. Tween target is mandatory to be Node.

Static Interface

Static methods in the Tween class are as follows:

Tween.stopAll()
Tween.stopAllByTag(0);
Tween.stopAllByTarget(this.node);

Interface	Description
stopAll	Stop all tween motions. This method will remove all registered tweens at root level. Note: this method will affect all tween targets.
stopAllByTag	Stop all tween motions by their number tags. This method will remove all registered tweens by the designated tag at the root level. Users may use the method parameter target?: object to check if the tween is attached with the tag.
stopAllByTarget	Stop all tween motions by their targets

Utility Function

Interface	Description
tween<T>	Utility function to help instantiate the Tween class. Note: This function is not a member of the Tween class. Users may call new Tween<T>(target:T) to instantiate a new tween instance.

Example

The following is an example of using to method to create tween motions:

let tweenDuration : number = 1.0;                                   // Duration of the tween
tween(this.node.position).to( tweenDuration, new Vec3(0, 10, 0),    // Here takes the target of the node's position
    {                                                               // Interface implementation of 'ITweenOption'.
    onUpdate : (target:Vec3, ratio:number)=>{                       // onUpdate accepts the current tween progress
        this.node.position = target;                                // Assign the position of the node to the result calculated by the tween system
    }
}).start();                                                         // Start the tween by calling 'start' function

For more examples, please see Tween Example.

Caveats

To avoid frequent updates to the transform data of nodes, Node class is constructed with an internal dirty state which only permits updating when modifications to the node’s transform data is called.

Due to pre-existing limitations, such as the position data returned by this.node.position being a public vector, certain coding conventions may not behave as expected.

For instance, when attempting to execute this.node.position.x = 1, the code only calls the getter for the position data and not the setter for the dirty state data to be updated, thus no transform data of the node will remain unchanged.

We advise against coding in such a manner and encourage users to call the setter for the position data via method setPosition instead, such as:

let _pos = new Vec3(0, 1, 0);
this.node.position = _pos;      // Use the setter of 'Transform.position'
this.node.setPosition(_pos);    // Or use the 'setPosition' function