three.js/examples/js/loaders/BasisTextureLoader.js

( function () {

	/**
 * THREE.Loader for Basis Universal GPU Texture Codec.
 *
 * Basis Universal is a "supercompressed" GPU texture and texture video
 * compression system that outputs a highly compressed intermediate file format
 * (.basis) that can be quickly transcoded to a wide variety of GPU texture
 * compression formats.
 *
 * This loader parallelizes the transcoding process across a configurable number
 * of web workers, before transferring the transcoded compressed texture back
 * to the main thread.
 */

	const _taskCache = new WeakMap();
	class BasisTextureLoader extends THREE.Loader {

		constructor( manager ) {

			super( manager );
			this.transcoderPath = '';
			this.transcoderBinary = null;
			this.transcoderPending = null;
			this.workerLimit = 4;
			this.workerPool = [];
			this.workerNextTaskID = 1;
			this.workerSourceURL = '';
			this.workerConfig = null;
			console.warn( 'THREE.BasisTextureLoader: This loader is deprecated, and will be removed in a future release. ' + 'Instead, use Basis Universal compression in KTX2 (.ktx2) files with THREE.KTX2Loader.' );

		}
		setTranscoderPath( path ) {

			this.transcoderPath = path;
			return this;

		}
		setWorkerLimit( workerLimit ) {

			this.workerLimit = workerLimit;
			return this;

		}
		detectSupport( renderer ) {

			this.workerConfig = {
				astcSupported: renderer.extensions.has( 'WEBGL_compressed_texture_astc' ),
				etc1Supported: renderer.extensions.has( 'WEBGL_compressed_texture_etc1' ),
				etc2Supported: renderer.extensions.has( 'WEBGL_compressed_texture_etc' ),
				dxtSupported: renderer.extensions.has( 'WEBGL_compressed_texture_s3tc' ),
				bptcSupported: renderer.extensions.has( 'EXT_texture_compression_bptc' ),
				pvrtcSupported: renderer.extensions.has( 'WEBGL_compressed_texture_pvrtc' ) || renderer.extensions.has( 'WEBKIT_WEBGL_compressed_texture_pvrtc' )
			};
			return this;

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

			const loader = new THREE.FileLoader( this.manager );
			loader.setResponseType( 'arraybuffer' );
			loader.setWithCredentials( this.withCredentials );
			const texture = new THREE.CompressedTexture();
			loader.load( url, buffer => {

				// Check for an existing task using this buffer. A transferred buffer cannot be transferred
				// again from this thread.
				if ( _taskCache.has( buffer ) ) {

					const cachedTask = _taskCache.get( buffer );
					return cachedTask.promise.then( onLoad ).catch( onError );

				}

				this._createTexture( [ buffer ] ).then( function ( _texture ) {

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

				} ).catch( onError );

			}, onProgress, onError );
			return texture;

		}

		/** Low-level transcoding API, exposed for use by KTX2Loader. */
		parseInternalAsync( options ) {

			const {
				levels
			} = options;
			const buffers = new Set();
			for ( let i = 0; i < levels.length; i ++ ) {

				buffers.add( levels[ i ].data.buffer );

			}

			return this._createTexture( Array.from( buffers ), {
				...options,
				lowLevel: true
			} );

		}

		/**
   * @param {ArrayBuffer[]} buffers
   * @param {object?} config
   * @return {Promise<CompressedTexture>}
   */
		_createTexture( buffers, config = {} ) {

			let worker;
			let taskID;
			const taskConfig = config;
			let taskCost = 0;
			for ( let i = 0; i < buffers.length; i ++ ) {

				taskCost += buffers[ i ].byteLength;

			}

			const texturePending = this._allocateWorker( taskCost ).then( _worker => {

				worker = _worker;
				taskID = this.workerNextTaskID ++;
				return new Promise( ( resolve, reject ) => {

					worker._callbacks[ taskID ] = {
						resolve,
						reject
					};
					worker.postMessage( {
						type: 'transcode',
						id: taskID,
						buffers: buffers,
						taskConfig: taskConfig
					}, buffers );

				} );

			} ).then( message => {

				const {
					mipmaps,
					width,
					height,
					format
				} = message;
				const texture = new THREE.CompressedTexture( mipmaps, width, height, format, THREE.UnsignedByteType );
				texture.minFilter = mipmaps.length === 1 ? THREE.LinearFilter : THREE.LinearMipmapLinearFilter;
				texture.magFilter = THREE.LinearFilter;
				texture.generateMipmaps = false;
				texture.needsUpdate = true;
				return texture;

			} );

			// Note: replaced '.finally()' with '.catch().then()' block - iOS 11 support (#19416)
			texturePending.catch( () => true ).then( () => {

				if ( worker && taskID ) {

					worker._taskLoad -= taskCost;
					delete worker._callbacks[ taskID ];

				}

			} );

			// Cache the task result.
			_taskCache.set( buffers[ 0 ], {
				promise: texturePending
			} );
			return texturePending;

		}
		_initTranscoder() {

			if ( ! this.transcoderPending ) {

				// Load transcoder wrapper.
				const jsLoader = new THREE.FileLoader( this.manager );
				jsLoader.setPath( this.transcoderPath );
				jsLoader.setWithCredentials( this.withCredentials );
				const jsContent = new Promise( ( resolve, reject ) => {

					jsLoader.load( 'basis_transcoder.js', resolve, undefined, reject );

				} );

				// Load transcoder WASM binary.
				const binaryLoader = new THREE.FileLoader( this.manager );
				binaryLoader.setPath( this.transcoderPath );
				binaryLoader.setResponseType( 'arraybuffer' );
				binaryLoader.setWithCredentials( this.withCredentials );
				const binaryContent = new Promise( ( resolve, reject ) => {

					binaryLoader.load( 'basis_transcoder.wasm', resolve, undefined, reject );

				} );
				this.transcoderPending = Promise.all( [ jsContent, binaryContent ] ).then( ( [ jsContent, binaryContent ] ) => {

					const fn = BasisTextureLoader.BasisWorker.toString();
					const body = [ '/* constants */', 'let _EngineFormat = ' + JSON.stringify( BasisTextureLoader.EngineFormat ), 'let _TranscoderFormat = ' + JSON.stringify( BasisTextureLoader.TranscoderFormat ), 'let _BasisFormat = ' + JSON.stringify( BasisTextureLoader.BasisFormat ), '/* basis_transcoder.js */', jsContent, '/* worker */', fn.substring( fn.indexOf( '{' ) + 1, fn.lastIndexOf( '}' ) ) ].join( '\n' );
					this.workerSourceURL = URL.createObjectURL( new Blob( [ body ] ) );
					this.transcoderBinary = binaryContent;

				} );

			}

			return this.transcoderPending;

		}
		_allocateWorker( taskCost ) {

			return this._initTranscoder().then( () => {

				if ( this.workerPool.length < this.workerLimit ) {

					const worker = new Worker( this.workerSourceURL );
					worker._callbacks = {};
					worker._taskLoad = 0;
					worker.postMessage( {
						type: 'init',
						config: this.workerConfig,
						transcoderBinary: this.transcoderBinary
					} );
					worker.onmessage = function ( e ) {

						const message = e.data;
						switch ( message.type ) {

							case 'transcode':
								worker._callbacks[ message.id ].resolve( message );
								break;
							case 'error':
								worker._callbacks[ message.id ].reject( message );
								break;
							default:
								console.error( 'THREE.BasisTextureLoader: Unexpected message, "' + message.type + '"' );

						}

					};

					this.workerPool.push( worker );

				} else {

					this.workerPool.sort( function ( a, b ) {

						return a._taskLoad > b._taskLoad ? - 1 : 1;

					} );

				}

				const worker = this.workerPool[ this.workerPool.length - 1 ];
				worker._taskLoad += taskCost;
				return worker;

			} );

		}
		dispose() {

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

				this.workerPool[ i ].terminate();

			}

			this.workerPool.length = 0;
			return this;

		}

	}

	/* CONSTANTS */

	BasisTextureLoader.BasisFormat = {
		ETC1S: 0,
		UASTC_4x4: 1
	};
	BasisTextureLoader.TranscoderFormat = {
		ETC1: 0,
		ETC2: 1,
		BC1: 2,
		BC3: 3,
		BC4: 4,
		BC5: 5,
		BC7_M6_OPAQUE_ONLY: 6,
		BC7_M5: 7,
		PVRTC1_4_RGB: 8,
		PVRTC1_4_RGBA: 9,
		ASTC_4x4: 10,
		ATC_RGB: 11,
		ATC_RGBA_INTERPOLATED_ALPHA: 12,
		RGBA32: 13,
		RGB565: 14,
		BGR565: 15,
		RGBA4444: 16
	};
	BasisTextureLoader.EngineFormat = {
		RGBAFormat: THREE.RGBAFormat,
		RGBA_ASTC_4x4_Format: THREE.RGBA_ASTC_4x4_Format,
		RGBA_BPTC_Format: THREE.RGBA_BPTC_Format,
		RGBA_ETC2_EAC_Format: THREE.RGBA_ETC2_EAC_Format,
		RGBA_PVRTC_4BPPV1_Format: THREE.RGBA_PVRTC_4BPPV1_Format,
		RGBA_S3TC_DXT5_Format: THREE.RGBA_S3TC_DXT5_Format,
		RGB_ETC1_Format: THREE.RGB_ETC1_Format,
		RGB_ETC2_Format: THREE.RGB_ETC2_Format,
		RGB_PVRTC_4BPPV1_Format: THREE.RGB_PVRTC_4BPPV1_Format,
		RGB_S3TC_DXT1_Format: THREE.RGB_S3TC_DXT1_Format
	};

	/* WEB WORKER */

	BasisTextureLoader.BasisWorker = function () {

		let config;
		let transcoderPending;
		let BasisModule;
		const EngineFormat = _EngineFormat; // eslint-disable-line no-undef
		const TranscoderFormat = _TranscoderFormat; // eslint-disable-line no-undef
		const BasisFormat = _BasisFormat; // eslint-disable-line no-undef

		onmessage = function ( e ) {

			const message = e.data;
			switch ( message.type ) {

				case 'init':
					config = message.config;
					init( message.transcoderBinary );
					break;
				case 'transcode':
					transcoderPending.then( () => {

						try {

							const {
								width,
								height,
								hasAlpha,
								mipmaps,
								format
							} = message.taskConfig.lowLevel ? transcodeLowLevel( message.taskConfig ) : transcode( message.buffers[ 0 ] );
							const buffers = [];
							for ( let i = 0; i < mipmaps.length; ++ i ) {

								buffers.push( mipmaps[ i ].data.buffer );

							}

							self.postMessage( {
								type: 'transcode',
								id: message.id,
								width,
								height,
								hasAlpha,
								mipmaps,
								format
							}, buffers );

						} catch ( error ) {

							console.error( error );
							self.postMessage( {
								type: 'error',
								id: message.id,
								error: error.message
							} );

						}

					} );
					break;

			}

		};

		function init( wasmBinary ) {

			transcoderPending = new Promise( resolve => {

				BasisModule = {
					wasmBinary,
					onRuntimeInitialized: resolve
				};
				BASIS( BasisModule ); // eslint-disable-line no-undef

			} ).then( () => {

				BasisModule.initializeBasis();

			} );

		}

		function transcodeLowLevel( taskConfig ) {

			const {
				basisFormat,
				width,
				height,
				hasAlpha
			} = taskConfig;
			const {
				transcoderFormat,
				engineFormat
			} = getTranscoderFormat( basisFormat, width, height, hasAlpha );
			const blockByteLength = BasisModule.getBytesPerBlockOrPixel( transcoderFormat );
			assert( BasisModule.isFormatSupported( transcoderFormat ), 'THREE.BasisTextureLoader: Unsupported format.' );
			const mipmaps = [];
			if ( basisFormat === BasisFormat.ETC1S ) {

				const transcoder = new BasisModule.LowLevelETC1SImageTranscoder();
				const {
					endpointCount,
					endpointsData,
					selectorCount,
					selectorsData,
					tablesData
				} = taskConfig.globalData;
				try {

					let ok;
					ok = transcoder.decodePalettes( endpointCount, endpointsData, selectorCount, selectorsData );
					assert( ok, 'THREE.BasisTextureLoader: decodePalettes() failed.' );
					ok = transcoder.decodeTables( tablesData );
					assert( ok, 'THREE.BasisTextureLoader: decodeTables() failed.' );
					for ( let i = 0; i < taskConfig.levels.length; i ++ ) {

						const level = taskConfig.levels[ i ];
						const imageDesc = taskConfig.globalData.imageDescs[ i ];
						const dstByteLength = getTranscodedImageByteLength( transcoderFormat, level.width, level.height );
						const dst = new Uint8Array( dstByteLength );
						ok = transcoder.transcodeImage( transcoderFormat, dst, dstByteLength / blockByteLength, level.data, getWidthInBlocks( transcoderFormat, level.width ), getHeightInBlocks( transcoderFormat, level.height ), level.width, level.height, level.index, imageDesc.rgbSliceByteOffset, imageDesc.rgbSliceByteLength, imageDesc.alphaSliceByteOffset, imageDesc.alphaSliceByteLength, imageDesc.imageFlags, hasAlpha, false, 0, 0 );
						assert( ok, 'THREE.BasisTextureLoader: transcodeImage() failed for level ' + level.index + '.' );
						mipmaps.push( {
							data: dst,
							width: level.width,
							height: level.height
						} );

					}

				} finally {

					transcoder.delete();

				}

			} else {

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

					const level = taskConfig.levels[ i ];
					const dstByteLength = getTranscodedImageByteLength( transcoderFormat, level.width, level.height );
					const dst = new Uint8Array( dstByteLength );
					const ok = BasisModule.transcodeUASTCImage( transcoderFormat, dst, dstByteLength / blockByteLength, level.data, getWidthInBlocks( transcoderFormat, level.width ), getHeightInBlocks( transcoderFormat, level.height ), level.width, level.height, level.index, 0, level.data.byteLength, 0, hasAlpha, false, 0, 0, - 1, - 1 );
					assert( ok, 'THREE.BasisTextureLoader: transcodeUASTCImage() failed for level ' + level.index + '.' );
					mipmaps.push( {
						data: dst,
						width: level.width,
						height: level.height
					} );

				}

			}

			return {
				width,
				height,
				hasAlpha,
				mipmaps,
				format: engineFormat
			};

		}

		function transcode( buffer ) {

			const basisFile = new BasisModule.BasisFile( new Uint8Array( buffer ) );
			const basisFormat = basisFile.isUASTC() ? BasisFormat.UASTC_4x4 : BasisFormat.ETC1S;
			const width = basisFile.getImageWidth( 0, 0 );
			const height = basisFile.getImageHeight( 0, 0 );
			const levels = basisFile.getNumLevels( 0 );
			const hasAlpha = basisFile.getHasAlpha();
			function cleanup() {

				basisFile.close();
				basisFile.delete();

			}

			const {
				transcoderFormat,
				engineFormat
			} = getTranscoderFormat( basisFormat, width, height, hasAlpha );
			if ( ! width || ! height || ! levels ) {

				cleanup();
				throw new Error( 'THREE.BasisTextureLoader:	Invalid texture' );

			}

			if ( ! basisFile.startTranscoding() ) {

				cleanup();
				throw new Error( 'THREE.BasisTextureLoader: .startTranscoding failed' );

			}

			const mipmaps = [];
			for ( let mip = 0; mip < levels; mip ++ ) {

				const mipWidth = basisFile.getImageWidth( 0, mip );
				const mipHeight = basisFile.getImageHeight( 0, mip );
				const dst = new Uint8Array( basisFile.getImageTranscodedSizeInBytes( 0, mip, transcoderFormat ) );
				const status = basisFile.transcodeImage( dst, 0, mip, transcoderFormat, 0, hasAlpha );
				if ( ! status ) {

					cleanup();
					throw new Error( 'THREE.BasisTextureLoader: .transcodeImage failed.' );

				}

				mipmaps.push( {
					data: dst,
					width: mipWidth,
					height: mipHeight
				} );

			}

			cleanup();
			return {
				width,
				height,
				hasAlpha,
				mipmaps,
				format: engineFormat
			};

		}

		//

		// Optimal choice of a transcoder target format depends on the Basis format (ETC1S or UASTC),
		// device capabilities, and texture dimensions. The list below ranks the formats separately
		// for ETC1S and UASTC.
		//
		// In some cases, transcoding UASTC to RGBA32 might be preferred for higher quality (at
		// significant memory cost) compared to ETC1/2, BC1/3, and PVRTC. The transcoder currently
		// chooses RGBA32 only as a last resort and does not expose that option to the caller.
		const FORMAT_OPTIONS = [ {
			if: 'astcSupported',
			basisFormat: [ BasisFormat.UASTC_4x4 ],
			transcoderFormat: [ TranscoderFormat.ASTC_4x4, TranscoderFormat.ASTC_4x4 ],
			engineFormat: [ EngineFormat.RGBA_ASTC_4x4_Format, EngineFormat.RGBA_ASTC_4x4_Format ],
			priorityETC1S: Infinity,
			priorityUASTC: 1,
			needsPowerOfTwo: false
		}, {
			if: 'bptcSupported',
			basisFormat: [ BasisFormat.ETC1S, BasisFormat.UASTC_4x4 ],
			transcoderFormat: [ TranscoderFormat.BC7_M5, TranscoderFormat.BC7_M5 ],
			engineFormat: [ EngineFormat.RGBA_BPTC_Format, EngineFormat.RGBA_BPTC_Format ],
			priorityETC1S: 3,
			priorityUASTC: 2,
			needsPowerOfTwo: false
		}, {
			if: 'dxtSupported',
			basisFormat: [ BasisFormat.ETC1S, BasisFormat.UASTC_4x4 ],
			transcoderFormat: [ TranscoderFormat.BC1, TranscoderFormat.BC3 ],
			engineFormat: [ EngineFormat.RGB_S3TC_DXT1_Format, EngineFormat.RGBA_S3TC_DXT5_Format ],
			priorityETC1S: 4,
			priorityUASTC: 5,
			needsPowerOfTwo: false
		}, {
			if: 'etc2Supported',
			basisFormat: [ BasisFormat.ETC1S, BasisFormat.UASTC_4x4 ],
			transcoderFormat: [ TranscoderFormat.ETC1, TranscoderFormat.ETC2 ],
			engineFormat: [ EngineFormat.RGB_ETC2_Format, EngineFormat.RGBA_ETC2_EAC_Format ],
			priorityETC1S: 1,
			priorityUASTC: 3,
			needsPowerOfTwo: false
		}, {
			if: 'etc1Supported',
			basisFormat: [ BasisFormat.ETC1S, BasisFormat.UASTC_4x4 ],
			transcoderFormat: [ TranscoderFormat.ETC1, TranscoderFormat.ETC1 ],
			engineFormat: [ EngineFormat.RGB_ETC1_Format, EngineFormat.RGB_ETC1_Format ],
			priorityETC1S: 2,
			priorityUASTC: 4,
			needsPowerOfTwo: false
		}, {
			if: 'pvrtcSupported',
			basisFormat: [ BasisFormat.ETC1S, BasisFormat.UASTC_4x4 ],
			transcoderFormat: [ TranscoderFormat.PVRTC1_4_RGB, TranscoderFormat.PVRTC1_4_RGBA ],
			engineFormat: [ EngineFormat.RGB_PVRTC_4BPPV1_Format, EngineFormat.RGBA_PVRTC_4BPPV1_Format ],
			priorityETC1S: 5,
			priorityUASTC: 6,
			needsPowerOfTwo: true
		} ];
		const ETC1S_OPTIONS = FORMAT_OPTIONS.sort( function ( a, b ) {

			return a.priorityETC1S - b.priorityETC1S;

		} );
		const UASTC_OPTIONS = FORMAT_OPTIONS.sort( function ( a, b ) {

			return a.priorityUASTC - b.priorityUASTC;

		} );
		function getTranscoderFormat( basisFormat, width, height, hasAlpha ) {

			let transcoderFormat;
			let engineFormat;
			const options = basisFormat === BasisFormat.ETC1S ? ETC1S_OPTIONS : UASTC_OPTIONS;
			for ( let i = 0; i < options.length; i ++ ) {

				const opt = options[ i ];
				if ( ! config[ opt.if ] ) continue;
				if ( ! opt.basisFormat.includes( basisFormat ) ) continue;
				if ( opt.needsPowerOfTwo && ! ( isPowerOfTwo( width ) && isPowerOfTwo( height ) ) ) continue;
				transcoderFormat = opt.transcoderFormat[ hasAlpha ? 1 : 0 ];
				engineFormat = opt.engineFormat[ hasAlpha ? 1 : 0 ];
				return {
					transcoderFormat,
					engineFormat
				};

			}

			console.warn( 'THREE.BasisTextureLoader: No suitable compressed texture format found. Decoding to RGBA32.' );
			transcoderFormat = TranscoderFormat.RGBA32;
			engineFormat = EngineFormat.RGBAFormat;
			return {
				transcoderFormat,
				engineFormat
			};

		}

		function assert( ok, message ) {

			if ( ! ok ) throw new Error( message );

		}

		function getWidthInBlocks( transcoderFormat, width ) {

			return Math.ceil( width / BasisModule.getFormatBlockWidth( transcoderFormat ) );

		}

		function getHeightInBlocks( transcoderFormat, height ) {

			return Math.ceil( height / BasisModule.getFormatBlockHeight( transcoderFormat ) );

		}

		function getTranscodedImageByteLength( transcoderFormat, width, height ) {

			const blockByteLength = BasisModule.getBytesPerBlockOrPixel( transcoderFormat );
			if ( BasisModule.formatIsUncompressed( transcoderFormat ) ) {

				return width * height * blockByteLength;

			}

			if ( transcoderFormat === TranscoderFormat.PVRTC1_4_RGB || transcoderFormat === TranscoderFormat.PVRTC1_4_RGBA ) {

				// GL requires extra padding for very small textures:
				// https://www.khronos.org/registry/OpenGL/extensions/IMG/IMG_texture_compression_pvrtc.txt
				const paddedWidth = width + 3 & ~ 3;
				const paddedHeight = height + 3 & ~ 3;
				return ( Math.max( 8, paddedWidth ) * Math.max( 8, paddedHeight ) * 4 + 7 ) / 8;

			}

			return getWidthInBlocks( transcoderFormat, width ) * getHeightInBlocks( transcoderFormat, height ) * blockByteLength;

		}

		function isPowerOfTwo( value ) {

			if ( value <= 2 ) return true;
			return ( value & value - 1 ) === 0 && value !== 0;

		}

	};

	THREE.BasisTextureLoader = BasisTextureLoader;

} )();