load( urls, onLoad, onProgress, onError ) {

		const texture = new CubeTexture();
		texture.colorSpace = SRGBColorSpace;

		const loader = new ImageLoader( this.manager );
		loader.setCrossOrigin( this.crossOrigin );
		loader.setPath( this.path );

		let loaded = 0;

		function loadTexture( i ) {

			loader.load( urls[ i ], function ( image ) {

				texture.images[ i ] = image;

				loaded ++;

				if ( loaded === 6 ) {

					texture.needsUpdate = true;

					if ( onLoad ) onLoad( texture );

				}

			}, undefined, onError );

		}

		for ( let i = 0; i < urls.length; ++ i ) {

			loadTexture( i );

		}

		return texture;

	}
Starts loading from the given URL and pass the fully loaded cube texture
to the `onLoad()` callback. The method also returns a new cube texture object which can
directly be used for material creation. If you do it this way, the cube texture
may pop up in your scene once the respective loading process is finished.

@param {Array<string>} urls - Array of 6 URLs to images, one for each side of the
cube texture. The urls should be specified in the following order: pos-x,
neg-x, pos-y, neg-y, pos-z, neg-z. An array of data URIs are allowed as well.
@param {function(CubeTexture)} onLoad - Executed when the loading process has been finished.
@param {onProgressCallback} onProgress - Unsupported in this loader.
@param {onErrorCallback} onError - Executed when errors occur.
@return {CubeTexture} The cube texture.