getNode( scene, camera ) {

		// ignore post-processing

		if ( scene.isQuadMesh ) return _defaultLights;

		_chainKeys[ 0 ] = scene;
		_chainKeys[ 1 ] = camera;

		let node = this.get( _chainKeys );

		if ( node === undefined ) {

			node = this.createNode();
			this.set( _chainKeys, node );

		}

		_chainKeys.length = 0;

		return node;

	}
Returns a lights node for the given scene and camera.

@param {Scene} scene - The scene.
@param {Camera} camera - The camera.
@return {LightsNode} The lights node.