three.js/examples/js/loaders/HDRCubeTextureLoader.js

( function () {

	class HDRCubeTextureLoader extends THREE.Loader {

		constructor( manager ) {

			super( manager );
			this.hdrLoader = new THREE.RGBELoader();
			this.type = THREE.HalfFloatType;

		}
		load( urls, onLoad, onProgress, onError ) {

			const texture = new THREE.CubeTexture();
			texture.type = this.type;
			switch ( texture.type ) {

				case THREE.FloatType:
					texture.encoding = THREE.LinearEncoding;
					texture.minFilter = THREE.LinearFilter;
					texture.magFilter = THREE.LinearFilter;
					texture.generateMipmaps = false;
					break;
				case THREE.HalfFloatType:
					texture.encoding = THREE.LinearEncoding;
					texture.minFilter = THREE.LinearFilter;
					texture.magFilter = THREE.LinearFilter;
					texture.generateMipmaps = false;
					break;

			}

			const scope = this;
			let loaded = 0;
			function loadHDRData( i, onLoad, onProgress, onError ) {

				new THREE.FileLoader( scope.manager ).setPath( scope.path ).setResponseType( 'arraybuffer' ).setWithCredentials( scope.withCredentials ).load( urls[ i ], function ( buffer ) {

					loaded ++;
					const texData = scope.hdrLoader.parse( buffer );
					if ( ! texData ) return;
					if ( texData.data !== undefined ) {

						const dataTexture = new THREE.DataTexture( texData.data, texData.width, texData.height );
						dataTexture.type = texture.type;
						dataTexture.encoding = texture.encoding;
						dataTexture.format = texture.format;
						dataTexture.minFilter = texture.minFilter;
						dataTexture.magFilter = texture.magFilter;
						dataTexture.generateMipmaps = texture.generateMipmaps;
						texture.images[ i ] = dataTexture;

					}

					if ( loaded === 6 ) {

						texture.needsUpdate = true;
						if ( onLoad ) onLoad( texture );

					}

				}, onProgress, onError );

			}

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

				loadHDRData( i, onLoad, onProgress, onError );

			}

			return texture;

		}
		setDataType( value ) {

			this.type = value;
			this.hdrLoader.setDataType( value );
			return this;

		}

	}

	THREE.HDRCubeTextureLoader = HDRCubeTextureLoader;

} )();