three.js/examples/js/loaders/RGBELoader.js

( function () {

	// https://github.com/mrdoob/three.js/issues/5552
	// http://en.wikipedia.org/wiki/RGBE_image_format

	class RGBELoader extends THREE.DataTextureLoader {

		constructor( manager ) {

			super( manager );
			this.type = THREE.HalfFloatType;

		}

		// adapted from http://www.graphics.cornell.edu/~bjw/rgbe.html

		parse( buffer ) {

			const /* return codes for rgbe routines */
				//RGBE_RETURN_SUCCESS = 0,
				RGBE_RETURN_FAILURE = - 1,
				/* default error routine.  change this to change error handling */
				rgbe_read_error = 1,
				rgbe_write_error = 2,
				rgbe_format_error = 3,
				rgbe_memory_error = 4,
				rgbe_error = function ( rgbe_error_code, msg ) {

					switch ( rgbe_error_code ) {

						case rgbe_read_error:
							console.error( 'THREE.RGBELoader Read Error: ' + ( msg || '' ) );
							break;
						case rgbe_write_error:
							console.error( 'THREE.RGBELoader Write Error: ' + ( msg || '' ) );
							break;
						case rgbe_format_error:
							console.error( 'THREE.RGBELoader Bad File Format: ' + ( msg || '' ) );
							break;
						default:
						case rgbe_memory_error:
							console.error( 'THREE.RGBELoader: Error: ' + ( msg || '' ) );

					}

					return RGBE_RETURN_FAILURE;

				},
				/* offsets to red, green, and blue components in a data (float) pixel */
				//RGBE_DATA_RED = 0,
				//RGBE_DATA_GREEN = 1,
				//RGBE_DATA_BLUE = 2,

				/* number of floats per pixel, use 4 since stored in rgba image format */
				//RGBE_DATA_SIZE = 4,

				/* flags indicating which fields in an rgbe_header_info are valid */
				RGBE_VALID_PROGRAMTYPE = 1,
				RGBE_VALID_FORMAT = 2,
				RGBE_VALID_DIMENSIONS = 4,
				NEWLINE = '\n',
				fgets = function ( buffer, lineLimit, consume ) {

					const chunkSize = 128;
					lineLimit = ! lineLimit ? 1024 : lineLimit;
					let p = buffer.pos,
						i = - 1,
						len = 0,
						s = '',
						chunk = String.fromCharCode.apply( null, new Uint16Array( buffer.subarray( p, p + chunkSize ) ) );
					while ( 0 > ( i = chunk.indexOf( NEWLINE ) ) && len < lineLimit && p < buffer.byteLength ) {

						s += chunk;
						len += chunk.length;
						p += chunkSize;
						chunk += String.fromCharCode.apply( null, new Uint16Array( buffer.subarray( p, p + chunkSize ) ) );

					}

					if ( - 1 < i ) {

						/*for (i=l-1; i>=0; i--) {
          	byteCode = m.charCodeAt(i);
          	if (byteCode > 0x7f && byteCode <= 0x7ff) byteLen++;
          	else if (byteCode > 0x7ff && byteCode <= 0xffff) byteLen += 2;
          	if (byteCode >= 0xDC00 && byteCode <= 0xDFFF) i--; //trail surrogate
          }*/
						if ( false !== consume ) buffer.pos += len + i + 1;
						return s + chunk.slice( 0, i );

					}

					return false;

				},
				/* minimal header reading.  modify if you want to parse more information */
				RGBE_ReadHeader = function ( buffer ) {

					// regexes to parse header info fields
					const magic_token_re = /^#\?(\S+)/,
						gamma_re = /^\s*GAMMA\s*=\s*(\d+(\.\d+)?)\s*$/,
						exposure_re = /^\s*EXPOSURE\s*=\s*(\d+(\.\d+)?)\s*$/,
						format_re = /^\s*FORMAT=(\S+)\s*$/,
						dimensions_re = /^\s*\-Y\s+(\d+)\s+\+X\s+(\d+)\s*$/,
						// RGBE format header struct
						header = {
							valid: 0,
							/* indicate which fields are valid */

							string: '',
							/* the actual header string */

							comments: '',
							/* comments found in header */

							programtype: 'RGBE',
							/* listed at beginning of file to identify it after "#?". defaults to "RGBE" */

							format: '',
							/* RGBE format, default 32-bit_rle_rgbe */

							gamma: 1.0,
							/* image has already been gamma corrected with given gamma. defaults to 1.0 (no correction) */

							exposure: 1.0,
							/* a value of 1.0 in an image corresponds to <exposure> watts/steradian/m^2. defaults to 1.0 */

							width: 0,
							height: 0 /* image dimensions, width/height */
						};

					let line, match;
					if ( buffer.pos >= buffer.byteLength || ! ( line = fgets( buffer ) ) ) {

						return rgbe_error( rgbe_read_error, 'no header found' );

					}

					/* if you want to require the magic token then uncomment the next line */
					if ( ! ( match = line.match( magic_token_re ) ) ) {

						return rgbe_error( rgbe_format_error, 'bad initial token' );

					}

					header.valid |= RGBE_VALID_PROGRAMTYPE;
					header.programtype = match[ 1 ];
					header.string += line + '\n';
					while ( true ) {

						line = fgets( buffer );
						if ( false === line ) break;
						header.string += line + '\n';
						if ( '#' === line.charAt( 0 ) ) {

							header.comments += line + '\n';
							continue; // comment line

						}

						if ( match = line.match( gamma_re ) ) {

							header.gamma = parseFloat( match[ 1 ] );

						}

						if ( match = line.match( exposure_re ) ) {

							header.exposure = parseFloat( match[ 1 ] );

						}

						if ( match = line.match( format_re ) ) {

							header.valid |= RGBE_VALID_FORMAT;
							header.format = match[ 1 ]; //'32-bit_rle_rgbe';

						}

						if ( match = line.match( dimensions_re ) ) {

							header.valid |= RGBE_VALID_DIMENSIONS;
							header.height = parseInt( match[ 1 ], 10 );
							header.width = parseInt( match[ 2 ], 10 );

						}

						if ( header.valid & RGBE_VALID_FORMAT && header.valid & RGBE_VALID_DIMENSIONS ) break;

					}

					if ( ! ( header.valid & RGBE_VALID_FORMAT ) ) {

						return rgbe_error( rgbe_format_error, 'missing format specifier' );

					}

					if ( ! ( header.valid & RGBE_VALID_DIMENSIONS ) ) {

						return rgbe_error( rgbe_format_error, 'missing image size specifier' );

					}

					return header;

				},
				RGBE_ReadPixels_RLE = function ( buffer, w, h ) {

					const scanline_width = w;
					if (
					// run length encoding is not allowed so read flat
						scanline_width < 8 || scanline_width > 0x7fff ||
        // this file is not run length encoded
        2 !== buffer[ 0 ] || 2 !== buffer[ 1 ] || buffer[ 2 ] & 0x80 ) {

						// return the flat buffer
						return new Uint8Array( buffer );

					}

					if ( scanline_width !== ( buffer[ 2 ] << 8 | buffer[ 3 ] ) ) {

						return rgbe_error( rgbe_format_error, 'wrong scanline width' );

					}

					const data_rgba = new Uint8Array( 4 * w * h );
					if ( ! data_rgba.length ) {

						return rgbe_error( rgbe_memory_error, 'unable to allocate buffer space' );

					}

					let offset = 0,
						pos = 0;
					const ptr_end = 4 * scanline_width;
					const rgbeStart = new Uint8Array( 4 );
					const scanline_buffer = new Uint8Array( ptr_end );
					let num_scanlines = h;

					// read in each successive scanline
					while ( num_scanlines > 0 && pos < buffer.byteLength ) {

						if ( pos + 4 > buffer.byteLength ) {

							return rgbe_error( rgbe_read_error );

						}

						rgbeStart[ 0 ] = buffer[ pos ++ ];
						rgbeStart[ 1 ] = buffer[ pos ++ ];
						rgbeStart[ 2 ] = buffer[ pos ++ ];
						rgbeStart[ 3 ] = buffer[ pos ++ ];
						if ( 2 != rgbeStart[ 0 ] || 2 != rgbeStart[ 1 ] || ( rgbeStart[ 2 ] << 8 | rgbeStart[ 3 ] ) != scanline_width ) {

							return rgbe_error( rgbe_format_error, 'bad rgbe scanline format' );

						}

						// read each of the four channels for the scanline into the buffer
						// first red, then green, then blue, then exponent
						let ptr = 0,
							count;
						while ( ptr < ptr_end && pos < buffer.byteLength ) {

							count = buffer[ pos ++ ];
							const isEncodedRun = count > 128;
							if ( isEncodedRun ) count -= 128;
							if ( 0 === count || ptr + count > ptr_end ) {

								return rgbe_error( rgbe_format_error, 'bad scanline data' );

							}

							if ( isEncodedRun ) {

								// a (encoded) run of the same value
								const byteValue = buffer[ pos ++ ];
								for ( let i = 0; i < count; i ++ ) {

									scanline_buffer[ ptr ++ ] = byteValue;

								}
								//ptr += count;

							} else {

								// a literal-run
								scanline_buffer.set( buffer.subarray( pos, pos + count ), ptr );
								ptr += count;
								pos += count;

							}

						}

						// now convert data from buffer into rgba
						// first red, then green, then blue, then exponent (alpha)
						const l = scanline_width; //scanline_buffer.byteLength;
						for ( let i = 0; i < l; i ++ ) {

							let off = 0;
							data_rgba[ offset ] = scanline_buffer[ i + off ];
							off += scanline_width; //1;
							data_rgba[ offset + 1 ] = scanline_buffer[ i + off ];
							off += scanline_width; //1;
							data_rgba[ offset + 2 ] = scanline_buffer[ i + off ];
							off += scanline_width; //1;
							data_rgba[ offset + 3 ] = scanline_buffer[ i + off ];
							offset += 4;

						}

						num_scanlines --;

					}

					return data_rgba;

				};

			const RGBEByteToRGBFloat = function ( sourceArray, sourceOffset, destArray, destOffset ) {

				const e = sourceArray[ sourceOffset + 3 ];
				const scale = Math.pow( 2.0, e - 128.0 ) / 255.0;
				destArray[ destOffset + 0 ] = sourceArray[ sourceOffset + 0 ] * scale;
				destArray[ destOffset + 1 ] = sourceArray[ sourceOffset + 1 ] * scale;
				destArray[ destOffset + 2 ] = sourceArray[ sourceOffset + 2 ] * scale;
				destArray[ destOffset + 3 ] = 1;

			};

			const RGBEByteToRGBHalf = function ( sourceArray, sourceOffset, destArray, destOffset ) {

				const e = sourceArray[ sourceOffset + 3 ];
				const scale = Math.pow( 2.0, e - 128.0 ) / 255.0;

				// clamping to 65504, the maximum representable value in float16
				destArray[ destOffset + 0 ] = THREE.DataUtils.toHalfFloat( Math.min( sourceArray[ sourceOffset + 0 ] * scale, 65504 ) );
				destArray[ destOffset + 1 ] = THREE.DataUtils.toHalfFloat( Math.min( sourceArray[ sourceOffset + 1 ] * scale, 65504 ) );
				destArray[ destOffset + 2 ] = THREE.DataUtils.toHalfFloat( Math.min( sourceArray[ sourceOffset + 2 ] * scale, 65504 ) );
				destArray[ destOffset + 3 ] = THREE.DataUtils.toHalfFloat( 1 );

			};

			const byteArray = new Uint8Array( buffer );
			byteArray.pos = 0;
			const rgbe_header_info = RGBE_ReadHeader( byteArray );
			if ( RGBE_RETURN_FAILURE !== rgbe_header_info ) {

				const w = rgbe_header_info.width,
					h = rgbe_header_info.height,
					image_rgba_data = RGBE_ReadPixels_RLE( byteArray.subarray( byteArray.pos ), w, h );
				if ( RGBE_RETURN_FAILURE !== image_rgba_data ) {

					let data, type;
					let numElements;
					switch ( this.type ) {

						case THREE.FloatType:
							numElements = image_rgba_data.length / 4;
							const floatArray = new Float32Array( numElements * 4 );
							for ( let j = 0; j < numElements; j ++ ) {

								RGBEByteToRGBFloat( image_rgba_data, j * 4, floatArray, j * 4 );

							}

							data = floatArray;
							type = THREE.FloatType;
							break;
						case THREE.HalfFloatType:
							numElements = image_rgba_data.length / 4;
							const halfArray = new Uint16Array( numElements * 4 );
							for ( let j = 0; j < numElements; j ++ ) {

								RGBEByteToRGBHalf( image_rgba_data, j * 4, halfArray, j * 4 );

							}

							data = halfArray;
							type = THREE.HalfFloatType;
							break;
						default:
							console.error( 'THREE.RGBELoader: unsupported type: ', this.type );
							break;

					}

					return {
						width: w,
						height: h,
						data: data,
						header: rgbe_header_info.string,
						gamma: rgbe_header_info.gamma,
						exposure: rgbe_header_info.exposure,
						type: type
					};

				}

			}

			return null;

		}
		setDataType( value ) {

			this.type = value;
			return this;

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

			function onLoadCallback( texture, texData ) {

				switch ( texture.type ) {

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

				}

				if ( onLoad ) onLoad( texture, texData );

			}

			return super.load( url, onLoadCallback, onProgress, onError );

		}

	}

	THREE.RGBELoader = RGBELoader;

} )();