erial: false
				};

				const gui = new GUI( { width: 300 } );
				gui.add( params, 'Cube' );
				gui.add( params, 'Equirectangular' );
				gui.add( params, 'Refraction' ).onChange( function ( value ) {

					if ( value ) {

						textureEquirec.mapping = THREE.EquirectangularRefractionMapping;
						textureCube.mapping = THREE.CubeRefractionMapping;

					} else {

						textureEquirec.mapping = THREE.EquirectangularReflectionMapping;
						textureCube.mapping = THREE.CubeReflectionMapping;

					}

					