How To

Mirror Engine API / LayerComposition

Class: LayerComposition

Layer Composition is a collection of Layer that is fed to Scene#layers to define rendering order.

Extends

EventHandler

Constructors

new LayerComposition()

new LayerComposition(name?: string): LayerComposition

Create a new layer composition.

Parameters

name?

string = 'Untitled'

Optional non-unique name of the layer composition. Defaults to "Untitled" if not specified.

Returns

LayerComposition

Overrides

EventHandler.constructor

Properties

layerList

layerList: Layer[] = [];

A read-only array of Layer sorted in the order they will be rendered.

subLayerEnabled

subLayerEnabled: boolean[] = [];

A read-only array of boolean values, matching LayerComposition#layerList. True means the layer is rendered, false means it's skipped.

Methods

fire()

fire(
   name: string,
   arg1?: any,
   arg2?: any,
   arg3?: any,
   arg4?: any,
   arg5?: any,
   arg6?: any,
   arg7?: any,
   arg8?: any): EventHandler

Fire an event, all additional arguments are passed on to the event listener.

Parameters

name

string

Name of event to fire.

arg1?

any

First argument that is passed to the event handler.

arg2?

any

Second argument that is passed to the event handler.

arg3?

any

Third argument that is passed to the event handler.

arg4?

any

Fourth argument that is passed to the event handler.

arg5?

any

Fifth argument that is passed to the event handler.

arg6?

any

Sixth argument that is passed to the event handler.

arg7?

any

Seventh argument that is passed to the event handler.

arg8?

any

Eighth argument that is passed to the event handler.

Returns

EventHandler

Self for chaining.

Example

obj.fire('test', 'This is the message')

Inherited from

EventHandler.fire

getLayerById()

getLayerById(id: number): null | Layer

Finds a layer inside this composition by its ID. Null is returned, if nothing is found.

Parameters

id

number

An ID of the layer to find.

Returns

null | Layer

The layer corresponding to the specified ID. Returns null if layer is not found.

getLayerByName()

getLayerByName(name: string): null | Layer

Finds a layer inside this composition by its name. Null is returned, if nothing is found.

Parameters

name

string

The name of the layer to find.

Returns

null | Layer

The layer corresponding to the specified name. Returns null if layer is not found.

getOpaqueIndex()

getOpaqueIndex(layer: Layer): number

Gets index of the opaque part of the supplied layer in the LayerComposition#layerList.

Parameters

layer

Layer

A Layer to find index of.

Returns

number

The index of the opaque part of the specified layer, or -1 if it is not part of the composition.

getTransparentIndex()

getTransparentIndex(layer: Layer): number

Gets index of the semi-transparent part of the supplied layer in the LayerComposition#layerList.

Parameters

layer

Layer

A Layer to find index of.

Returns

number

The index of the semi-transparent part of the specified layer, or -1 if it is not part of the composition.

hasEvent()

hasEvent(name: string): boolean

Test if there are any handlers bound to an event name.

Parameters

name

string

The name of the event to test.

Returns

boolean

True if the object has handlers bound to the specified event name.

Example

obj.on('test', () => {}) // bind an event to 'test'
obj.hasEvent('test') // returns true
obj.hasEvent('hello') // returns false

Inherited from

EventHandler.hasEvent

insert()

insert(layer: Layer, index: number): void

Inserts a layer (both opaque and semi-transparent parts) at the chosen index in the LayerComposition#layerList.

Parameters

layer

Layer

A Layer to add.

index

number

Insertion position.

Returns

void

insertOpaque()

insertOpaque(layer: Layer, index: number): void

Inserts an opaque part of the layer (non semi-transparent mesh instances) at the chosen index in the LayerComposition#layerList.

Parameters

layer

Layer

A Layer to add.

index

number

Insertion position.

Returns

void

insertTransparent()

insertTransparent(layer: Layer, index: number): void

Inserts a semi-transparent part of the layer at the chosen index in the LayerComposition#layerList.

Parameters

layer

Layer

A Layer to add.

index

number

Insertion position.

Returns

void

off()

off(
   name?: string,
   callback?: HandleEventCallback,
   scope?: any): EventHandler

Detach an event handler from an event. If callback is not provided then all callbacks are unbound from the event, if scope is not provided then all events with the callback will be unbound.

Parameters

name?

string

Name of the event to unbind.

callback?

HandleEventCallback

Function to be unbound.

scope?

any

Scope that was used as the this when the event is fired.

Returns

EventHandler

Self for chaining.

Example

const handler = () => {}
obj.on('test', handler)

obj.off() // Removes all events
obj.off('test') // Removes all events called 'test'
obj.off('test', handler) // Removes all handler functions, called 'test'
obj.off('test', handler, this) // Removes all handler functions, called 'test' with scope this

Inherited from

EventHandler.off

on()

on(
   name: string,
   callback: HandleEventCallback,
   scope?: any): EventHandle

Attach an event handler to an event.

Parameters

name

string

Name of the event to bind the callback to.

callback

HandleEventCallback

Function that is called when event is fired. Note the callback is limited to 8 arguments.

scope?

any = ...

Object to use as 'this' when the event is fired, defaults to current this.

Returns

EventHandle

Can be used for removing event in the future.

Examples

obj.on('test', (a, b) => {
  console.log(a + b)
})
obj.fire('test', 1, 2) // prints 3 to the console

const evt = obj.on('test', (a, b) => {
  console.log(a + b)
})
// some time later
evt.off()

Inherited from

EventHandler.on

once()

once(
   name: string,
   callback: HandleEventCallback,
   scope?: any): EventHandle

Attach an event handler to an event. This handler will be removed after being fired once.

Parameters

name

string

Name of the event to bind the callback to.

callback

HandleEventCallback

Function that is called when event is fired. Note the callback is limited to 8 arguments.

scope?

any = ...

Object to use as 'this' when the event is fired, defaults to current this.

Returns

EventHandle

can be used for removing event in the future.

Example

obj.once('test', (a, b) => {
  console.log(a + b)
})
obj.fire('test', 1, 2) // prints 3 to the console
obj.fire('test', 1, 2) // not going to get handled