blueprint-node overview

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Table of contents

• utils
• BlueprintNode (class)
  • subjectFor (method)
  • output (method)
  • emit (method)
  • trigger (method)
  • dispose (method)
  • inputs (property)
  • outputs (property)
• BlueprintPinDefinition (interface)
• BlueprintPinKind (type alias)

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utils

BlueprintNode (class)

One node in a {@link Blueprint} graph - the engine's analogue of a single Unreal Blueprint graph node: a small unit of behavior with named input pins that trigger it, named output pins it can fire in response, and a settings bag of static (non-pin) configuration baked in from its {@link BlueprintNodeJson} (e.g. RemoveEntity's dispose flag). Register a concrete subclass's factory against a type alias via LevelLoader.registerBlueprintNode so Blueprint can instantiate it from JSON, the same way LevelLoader.registerClass works for entity classes.

Signature

export declare class BlueprintNode<D, R, TypeDoc> {
  constructor(protected readonly world: GgWorld<D, R, TypeDoc>, protected readonly settings: Record<string, any>)
}

subjectFor (method)

Signature

private subjectFor(name: string): Subject<unknown>

output (method)

Observe one of this node's output pins firing - what a {@link BlueprintLinkJson} subscribes to in order to feed a downstream node's input, or what an embedding Blueprint's own outputs entry bubbles up to whatever triggered the blueprint.

Signature

public output(name: string): Observable<unknown>

emit (method)

Fire one of this node's output pins - call from within {@link trigger} once the node has done whatever that output represents. A no-op if nothing is subscribed.

Signature

protected emit(name: string, value?: unknown): void

trigger (method)

Feed a value/pulse into one of this node's input pins (per {@link inputs}), running whatever behavior that pin represents. Called by Blueprint both for external triggers (via its own inputs aliasing) and for links from another node's output pin.

Signature

public abstract trigger(inputName: string, value?: unknown): void;

dispose (method)

Release anything this node set up outside of its output subjects (timers, subscriptions, etc). Default no-op - override when a node needs it. Blueprint.dispose calls this on every node in its graph.

Signature

public dispose(): void

inputs (property)

This node's input pins - see {@link trigger} for how they're fed.

Signature

readonly inputs: readonly BlueprintPinDefinition[]

outputs (property)

This node's output pins - see {@link output} for how to observe them.

Signature

readonly outputs: readonly BlueprintPinDefinition[]

BlueprintPinDefinition (interface)

Declares one named pin a {@link BlueprintNode} exposes - either an input (fed a value via {@link BlueprintNode.trigger}) or an output (fired via {@link BlueprintNode.output}).

Signature

export interface BlueprintPinDefinition {
  name: string
  kind: BlueprintPinKind
}

BlueprintPinKind (type alias)

Whether a {@link BlueprintNode} pin carries an execution pulse ("do this now", no meaningful payload - e.g. Unreal's white exec pins) or a data value ("here's a value", not itself a trigger - e.g. Unreal's colored data pins). Purely descriptive for now (introspection/future editor tooling) - {@link BlueprintNode.trigger} treats every input pin the same way at runtime, since a node is free to both react to and read a value from the same pin (see {@link RemoveEntityBlueprintNode}, whose single "entity" pin is a data pin that also triggers the node when fed a value - the same way an Unreal event node's payload pins double as the thing that fires the node).

Signature

export type BlueprintPinKind = 'exec' | 'data'