renderShadow( frame ) {

		const { shadow, shadowMap, light } = this;
		const { renderer, scene } = frame;

		const shadowFrameExtents = shadow.getFrameExtents();

		_shadowMapSize.copy( shadow.mapSize );
		_shadowMapSize.multiply( shadowFrameExtents );

		shadowMap.setSize( _shadowMapSize.width, _shadowMapSize.height );

		_viewportSize.copy( shadow.mapSize );

		//

		const previousAutoClear = renderer.autoClear;

		const previousClearColor = renderer.getClearColor( _clearColor$1 );
		const previousClearAlpha = renderer.getClearAlpha();

		renderer.autoClear = false;
		renderer.setClearColor( shadow.clearColor, shadow.clearAlpha );
		renderer.clear();

		const viewportCount = shadow.getViewportCount();

		for ( let vp = 0; vp < viewportCount; vp ++ ) {

			const viewport = shadow.getViewport( vp );

			const x = _viewportSize.x * viewport.x;
			const y = _shadowMapSize.y - _viewportSize.y - ( _viewportSize.y * viewport.y );

			_viewport.set(
				x,
				y,
				_viewportSize.x * viewport.z,
				_viewportSize.y * viewport.w
			);

			shadowMap.viewport.copy( _viewport );

			shadow.updateMatrices( light, vp );

			renderer.render( scene, shadow.camera );

		}

		//

		renderer.autoClear = previousAutoClear;
		renderer.setClearColor( previousClearColor, previousClearAlpha );

	}
Overwrites the default implementation with point light specific
rendering code.

@param {NodeFrame} frame - A reference to the current node frame.