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Class: PlaybackController

Defined in: runtime/playback-controller.ts:44

Orchestrates playback of a compiled motion-script project.

On construction it runs the precomp pass (Precomp.run()) to build the global asset timeline and node lifespans, then wires the master clock to the audio device and render pipeline so every tick:

  1. Loads assets required at the current frame (AssetManager.loadAt).
  2. Evaluates scene state and lays out nodes (StateEvaluator).
  3. Renders the frame to the render context.
  4. Prefetches assets for upcoming frames.

External callers interact via play, pause, seek, seekWhilePlaying, screenshot, getTreeState, and getNodeState.

Constructors​

Constructor​

new PlaybackController(params): PlaybackController

Defined in: runtime/playback-controller.ts:78

Parameters​

params​

ControllerParams

Returns​

PlaybackController

Properties​

fps​

readonly fps: number

Defined in: runtime/playback-controller.ts:54

precomp​

readonly precomp: PrecompResult

Defined in: runtime/playback-controller.ts:56

viewport​

readonly viewport: Size2D

Defined in: runtime/playback-controller.ts:55

Accessors​

buildErrors​

Get Signature​

get buildErrors(): BuildError[]

Defined in: runtime/playback-controller.ts:74

Errors collected during the precomp pass (one entry per failing scene).

Returns​

BuildError[]

currentFrame​

Get Signature​

get currentFrame(): number

Defined in: runtime/playback-controller.ts:142

Current playback position in frames (float).

Returns​

number

currentTime​

Get Signature​

get currentTime(): number

Defined in: runtime/playback-controller.ts:137

Current playback position in seconds.

Returns​

number

isPlaying​

Get Signature​

get isPlaying(): boolean

Defined in: runtime/playback-controller.ts:132

Returns​

boolean

totalDuration​

Get Signature​

get totalDuration(): number

Defined in: runtime/playback-controller.ts:69

Total playback duration in seconds.

Returns​

number

totalFrames​

Get Signature​

get totalFrames(): number

Defined in: runtime/playback-controller.ts:64

Total frame count across all scenes.

Returns​

number

tracks​

Get Signature​

get tracks(): number[]

Defined in: runtime/playback-controller.ts:59

Per-scene frame counts in timeline order, used to build the track list.

Returns​

number[]

Methods​

dispose()​

dispose(): void

Defined in: runtime/playback-controller.ts:263

Returns​

void

getNodeState()​

getNodeState(nodeId): NodeState | null

Defined in: runtime/playback-controller.ts:239

Parameters​

nodeId​

string

Returns​

NodeState | null

getTreeState()​

getTreeState(): TreeState | null

Defined in: runtime/playback-controller.ts:218

Return the full node tree for the current scene, with lifespan frame ranges and waveform data attached. Used by the timeline UI. Returns null when no scene is active.

Returns​

TreeState | null

onPause()​

onPause(cb): void

Defined in: runtime/playback-controller.ts:157

Register a callback that fires when playback pauses.

Parameters​

cb​

() => void

Returns​

void

onPlay()​

onPlay(cb): void

Defined in: runtime/playback-controller.ts:152

Register a callback that fires when playback starts.

Parameters​

cb​

() => void

Returns​

void

onTime()​

onTime(cb): void

Defined in: runtime/playback-controller.ts:147

Register a callback that fires on every clock tick with the current time.

Parameters​

cb​

TimeCallback

Returns​

void

pause()​

pause(): void

Defined in: runtime/playback-controller.ts:255

Returns​

void

play()​

play(speed?, reverse?): void

Defined in: runtime/playback-controller.ts:247

Parameters​

speed?​

number = 1

reverse?​

boolean = false

Returns​

void

screenshot()​

screenshot(): string | undefined

Defined in: runtime/playback-controller.ts:208

Capture the current frame as a base-64 PNG data URL. Forces a fresh render before snapshotting because the WebGL drawing buffer may have been cleared since the last tick (we don't set preserveDrawingBuffer). Uses stateEvaluator.currentFrame (integer) rather than the clock's float so stateAt always hits its early-return and never resets scene state.

Returns​

string | undefined

seek()​

seek(frame): Promise<void>

Defined in: runtime/playback-controller.ts:183

Jump to frame, pausing playback first. Waits for required assets to load before rendering, then prefetches upcoming frames.

Parameters​

frame​

number

Returns​

Promise<void>

seekWhilePlaying()​

seekWhilePlaying(frame): void

Defined in: runtime/playback-controller.ts:196

Reposition the clock to frame without interrupting playback.

Parameters​

frame​

number

Returns​

void

setMuted()​

setMuted(muted): void

Defined in: runtime/playback-controller.ts:259

Parameters​

muted​

boolean

Returns​

void