Renderer

Core generic renderer

Renderer is the core visualization part of any application. It’s attached to Engine. Results of processing and captured frame are provided to renderer that updates scene, visualization and application logic according to this data. Basically, renders define two methods load() and update(). The first one is used to initialize all assets and prepare the scene e.g. set up lightning, environment map. Engine will call load() method during pipeline initialization. The second one is used to update the scene using results of video processing. This’s where all the logic happens. By overriding/extending load() and update() you can add any custom logic, interactions, animations, post-processing effects, gesture recognition, physics, etc. to an app. Renderer is a generic abstract class defining common core interfaces.

Extends

• EventEmitterT<RendererEvents>

Extended by

• PluginRenderer

Type Parameters

ResultT

ResultT

Type of processing results

Constructors

Constructor

new Renderer<ResultT>(): Renderer<ResultT>

Constructor

Returns

Renderer<ResultT>

Overrides

EventEmitterT.constructor

Properties

cameraAngle

protected cameraAngle: number

Camera vertical angle in radians

---

cameraRatio

protected cameraRatio: number

Camera aspect ratio

---

loaded

protected loaded: boolean = false

Loaded state

---

videoRatio

protected videoRatio: number

Aspect ratio of input video

---

videoSize

protected videoSize: Size

Resolution of input video

Methods

addListener()

addListener<E>(event, listener): this

Adds the listener function to the end of the listeners array

Type Parameters

E

E extends keyof RendererEvents

Parameters

event

E

The name of the event

listener

RendererEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

EventEmitterT.addListener

---

dispose()

dispose(): void

Dispose renderer object

Returns

void

---

emit()

emit<E>(event, …args): boolean

Synchronously calls each of the listeners registered for the event

Type Parameters

E

E extends keyof RendererEvents

Parameters

event

E

The name of the event

args

…Args<RendererEvents[E]>

Arguments passed to the listeners

Returns

boolean

True if the event had listeners, False otherwise

Inherited from

EventEmitterT.emit

---

eventNames()

eventNames(): (string | symbol)[]

List of emitter’s events

Returns

(string | symbol)[]

List of emitter’s events

Inherited from

EventEmitterT.eventNames

---

getMaxListeners()

getMaxListeners(): number

Maximum number of listeners per event

Returns

number

Maximum number of listeners per event

Inherited from

EventEmitterT.getMaxListeners

---

listenerCount()

listenerCount<E>(event): number

The number of listeners listening to the event

Type Parameters

E

E extends keyof RendererEvents

Parameters

event

E

The name of the event

Returns

number

Number of listeners

Inherited from

EventEmitterT.listenerCount

---

listeners()

listeners<E>(event): Function[]

Copy of the array of listeners for the event

Type Parameters

E

E extends keyof RendererEvents

Parameters

event

E

The name of the event

Returns

Function[]

Copy of the listeners array

Inherited from

EventEmitterT.listeners

---

load()

load(): Promise<void>

Initialize renderer

Initializes renderer, all required assets, and the scene. Overridden by derived classes for particular application.

Returns

Promise<void>

Promise resolving when initialization is finished

---

off()

off<E>(event, listener): this

Removes the listener from the listener array for the event

Type Parameters

E

E extends keyof RendererEvents

Parameters

event

E

The name of the event

listener

RendererEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

EventEmitterT.off

---

on()

on<E>(event, listener): this

Adds the listener function to the event

Type Parameters

E

E extends keyof RendererEvents

Parameters

event

E

The name of the event

listener

RendererEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

EventEmitterT.on

---

once()

once<E>(event, listener): this

Adds a one-time listener function for the event

Type Parameters

E

E extends keyof RendererEvents

Parameters

event

E

The name of the event

listener

RendererEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

EventEmitterT.once

---

prependListener()

prependListener<E>(event, listener): this

Adds the listener function to the beginning of the listeners array

Type Parameters

E

E extends keyof RendererEvents

Parameters

event

E

The name of the event

listener

RendererEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

EventEmitterT.prependListener

---

prependOnceListener()

prependOnceListener<E>(event, listener): this

Adds a one-time listener function to the beginning of the listeners array

Type Parameters

E

E extends keyof RendererEvents

Parameters

event

E

The name of the event

listener

RendererEvents[E]

The callback function

Returns

this

Inherited from

EventEmitterT.prependOnceListener

---

rawListeners()

rawListeners<E>(event): Function[]

Copy of the array of listeners for the event including wrappers

Type Parameters

E

E extends keyof RendererEvents

Parameters

event

E

The name of the event

Returns

Function[]

Copy of the listeners array

Inherited from

EventEmitterT.rawListeners

---

removeAllListeners()

removeAllListeners<E>(event?): this

Removes all listeners, or those of the specified event

Type Parameters

E

E extends keyof RendererEvents

Parameters

event?

E

The name of the event

Returns

this

This EventEmitter

Inherited from

EventEmitterT.removeAllListeners

---

removeListener()

removeListener<E>(event, listener): this

Removes the specified listener from the listener array

Type Parameters

E

E extends keyof RendererEvents

Parameters

event

E

The name of the event

listener

RendererEvents[E]

The callback function

Returns

this

This EventEmitter

Inherited from

EventEmitterT.removeListener

---

setMaxListeners()

setMaxListeners(n): this

Sets maximum number of listeners per event

Parameters

n

number

Maximum number of listeners

Returns

this

This EventEmitter

Inherited from

EventEmitterT.setMaxListeners

---

setupCamera()

setupCamera(ratio, angle): void

Set camera parameters

Some video processors statically define camera parameters from just a video resolution. In this cases setupCamera() is used to pass these static camera parameters to renderer.

Parameters

ratio

number

Camera aspect ratio

angle

number

Camera vertical angle in radians

Returns

void

---

setupVideo()

setupVideo(size, ratio?): void

Set video parameters

Could be overridden to adjust rendering pipeline.

Parameters

size

Size

Resolution of input video

ratio?

number

Aspect ration of input video

Returns

void

---

unload()

unload(): void

Reset renderer

Releases all resources and instances created in load(). Overridden by derived classes for particular application.

Returns

void

---

update()

update(result, stream): Promise<void>

Update the scene

Main method defining the logic of the renderer. Updates the scene according to provided results. Overridden by derived classes for the application.

Parameters

result

ResultT

Results of video processing

stream

HTMLCanvasElement

Captured video frame

Returns

Promise<void>

Promise resolving when update is finished

---

updateScene()

protected updateScene(): void

Update and render the scene

Virtual method updating and rendering the scene. Overridden by implementation of derived renderer.

Returns

void

---

updateVideo()

protected updateVideo(stream): void

Update the video layer

Virtual method drawing input video frame. Derived renderer provides implementation.

Parameters

stream

HTMLCanvasElement

Captured video frame

Returns

void