three.js/examples/jsm/nodes/accessors/SceneNode.js

import Node from '../core/Node.js';
import { addNodeClass } from '../core/Node.js';
import { nodeImmutable } from '../shadernode/ShaderNode.js';
import { reference } from './ReferenceNode.js';

class SceneNode extends Node {

	constructor( scope = SceneNode.BACKGROUND_BLURRINESS, scene = null ) {

		super();

		this.scope = scope;
		this.scene = scene;

	}

	setup( builder ) {

		const scope = this.scope;
		const scene = this.scene !== null ? this.scene : builder.scene;

		let output;

		if ( scope === SceneNode.BACKGROUND_BLURRINESS ) {

			output = reference( 'backgroundBlurriness', 'float', scene );

		} else if ( scope === SceneNode.BACKGROUND_INTENSITY ) {

			output = reference( 'backgroundIntensity', 'float', scene );

		} else {

			console.error( 'THREE.SceneNode: Unknown scope:', scope );

		}

		return output;

	}

}

SceneNode.BACKGROUND_BLURRINESS = 'backgroundBlurriness';
SceneNode.BACKGROUND_INTENSITY = 'backgroundIntensity';

export default SceneNode;

export const backgroundBlurriness = nodeImmutable( SceneNode, SceneNode.BACKGROUND_BLURRINESS );
export const backgroundIntensity = nodeImmutable( SceneNode, SceneNode.BACKGROUND_INTENSITY );

addNodeClass( 'SceneNode', SceneNode );