three.js/examples/jsm/loaders/EXRLoader.js

/**
 * @author Richard M. / https://github.com/richardmonette
 *
 * OpenEXR loader which, currently, supports reading 16 bit half data, in either
 * uncompressed or PIZ wavelet compressed form.
 *
 * Referred to the original Industrial Light & Magic OpenEXR implementation and the TinyEXR / Syoyo Fujita
 * implementation, so I have preserved their copyright notices.
 */

import {
	DataTextureLoader,
	FloatType,
	HalfFloatType,
	LinearEncoding,
	LinearFilter,
	RGBAFormat,
	RGBFormat
} from "../../../build/three.module.js";
import { Zlib } from "../libs/inflate.module.min.js";

// /*
// Copyright (c) 2014 - 2017, Syoyo Fujita
// All rights reserved.

// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//     * Neither the name of the Syoyo Fujita nor the
//       names of its contributors may be used to endorse or promote products
//       derived from this software without specific prior written permission.

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// */

// // TinyEXR contains some OpenEXR code, which is licensed under ------------

// ///////////////////////////////////////////////////////////////////////////
// //
// // Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
// // Digital Ltd. LLC
// //
// // All rights reserved.
// //
// // Redistribution and use in source and binary forms, with or without
// // modification, are permitted provided that the following conditions are
// // met:
// // *       Redistributions of source code must retain the above copyright
// // notice, this list of conditions and the following disclaimer.
// // *       Redistributions in binary form must reproduce the above
// // copyright notice, this list of conditions and the following disclaimer
// // in the documentation and/or other materials provided with the
// // distribution.
// // *       Neither the name of Industrial Light & Magic nor the names of
// // its contributors may be used to endorse or promote products derived
// // from this software without specific prior written permission.
// //
// // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// //
// ///////////////////////////////////////////////////////////////////////////

// // End of OpenEXR license -------------------------------------------------

var EXRLoader = function ( manager ) {

	DataTextureLoader.call( this, manager );

	this.type = FloatType;

};

EXRLoader.prototype = Object.assign( Object.create( DataTextureLoader.prototype ), {

	constructor: EXRLoader,

	parse: function ( buffer ) {

		const USHORT_RANGE = ( 1 << 16 );
		const BITMAP_SIZE = ( USHORT_RANGE >> 3 );

		const HUF_ENCBITS = 16; // literal (value) bit length
		const HUF_DECBITS = 14; // decoding bit size (>= 8)

		const HUF_ENCSIZE = ( 1 << HUF_ENCBITS ) + 1; // encoding table size
		const HUF_DECSIZE = 1 << HUF_DECBITS; // decoding table size
		const HUF_DECMASK = HUF_DECSIZE - 1;

		const SHORT_ZEROCODE_RUN = 59;
		const LONG_ZEROCODE_RUN = 63;
		const SHORTEST_LONG_RUN = 2 + LONG_ZEROCODE_RUN - SHORT_ZEROCODE_RUN;

		const BYTES_PER_HALF = 2;

		const ULONG_SIZE = 8;
		const FLOAT32_SIZE = 4;
		const INT32_SIZE = 4;
		const INT16_SIZE = 2;
		const INT8_SIZE = 1;

		function reverseLutFromBitmap( bitmap, lut ) {

			var k = 0;

			for ( var i = 0; i < USHORT_RANGE; ++ i ) {

				if ( ( i == 0 ) || ( bitmap[ i >> 3 ] & ( 1 << ( i & 7 ) ) ) ) {

					lut[ k ++ ] = i;

				}

			}

			var n = k - 1;

			while ( k < USHORT_RANGE ) lut[ k ++ ] = 0;

			return n;

		}

		function hufClearDecTable( hdec ) {

			for ( var i = 0; i < HUF_DECSIZE; i ++ ) {

				hdec[ i ] = {};
				hdec[ i ].len = 0;
				hdec[ i ].lit = 0;
				hdec[ i ].p = null;

			}

		}

		const getBitsReturn = { l: 0, c: 0, lc: 0 };

		function getBits( nBits, c, lc, uInt8Array, inOffset ) {

			while ( lc < nBits ) {

				c = ( c << 8 ) | parseUint8Array( uInt8Array, inOffset );
				lc += 8;

			}

			lc -= nBits;

			getBitsReturn.l = ( c >> lc ) & ( ( 1 << nBits ) - 1 );
			getBitsReturn.c = c;
			getBitsReturn.lc = lc;

		}

		const hufTableBuffer = new Array( 59 );

		function hufCanonicalCodeTable( hcode ) {

			for ( var i = 0; i <= 58; ++ i ) hufTableBuffer[ i ] = 0;
			for ( var i = 0; i < HUF_ENCSIZE; ++ i ) hufTableBuffer[ hcode[ i ] ] += 1;

			var c = 0;

			for ( var i = 58; i > 0; -- i ) {

				var nc = ( ( c + hufTableBuffer[ i ] ) >> 1 );
				hufTableBuffer[ i ] = c;
				c = nc;

			}

			for ( var i = 0; i < HUF_ENCSIZE; ++ i ) {

				var l = hcode[ i ];
				if ( l > 0 ) hcode[ i ] = l | ( hufTableBuffer[ l ] ++ << 6 );

			}

		}

		function hufUnpackEncTable( uInt8Array, inDataView, inOffset, ni, im, iM, hcode ) {

			var p = inOffset;
			var c = 0;
			var lc = 0;

			for ( ; im <= iM; im ++ ) {

				if ( p.value - inOffset.value > ni ) return false;

				getBits( 6, c, lc, uInt8Array, p );

				var l = getBitsReturn.l;
				c = getBitsReturn.c;
				lc = getBitsReturn.lc;

				hcode[ im ] = l;

				if ( l == LONG_ZEROCODE_RUN ) {

					if ( p.value - inOffset.value > ni ) {

						throw 'Something wrong with hufUnpackEncTable';

					}

					getBits( 8, c, lc, uInt8Array, p );

					var zerun = getBitsReturn.l + SHORTEST_LONG_RUN;
					c = getBitsReturn.c;
					lc = getBitsReturn.lc;

					if ( im + zerun > iM + 1 ) {

						throw 'Something wrong with hufUnpackEncTable';

					}

					while ( zerun -- ) hcode[ im ++ ] = 0;

					im --;

				} else if ( l >= SHORT_ZEROCODE_RUN ) {

					var zerun = l - SHORT_ZEROCODE_RUN + 2;

					if ( im + zerun > iM + 1 ) {

						throw 'Something wrong with hufUnpackEncTable';

					}

					while ( zerun -- ) hcode[ im ++ ] = 0;

					im --;

				}

			}

			hufCanonicalCodeTable( hcode );

		}

		function hufLength( code ) {

			return code & 63;

		}

		function hufCode( code ) {

			return code >> 6;

		}

		function hufBuildDecTable( hcode, im, iM, hdecod ) {

			for ( ; im <= iM; im ++ ) {

				var c = hufCode( hcode[ im ] );
				var l = hufLength( hcode[ im ] );

				if ( c >> l ) {

					throw 'Invalid table entry';

				}

				if ( l > HUF_DECBITS ) {

					var pl = hdecod[ ( c >> ( l - HUF_DECBITS ) ) ];

					if ( pl.len ) {

						throw 'Invalid table entry';

					}

					pl.lit ++;

					if ( pl.p ) {

						var p = pl.p;
						pl.p = new Array( pl.lit );

						for ( var i = 0; i < pl.lit - 1; ++ i ) {

							pl.p[ i ] = p[ i ];

						}

					} else {

						pl.p = new Array( 1 );

					}

					pl.p[ pl.lit - 1 ] = im;

				} else if ( l ) {

					var plOffset = 0;

					for ( var i = 1 << ( HUF_DECBITS - l ); i > 0; i -- ) {

						var pl = hdecod[ ( c << ( HUF_DECBITS - l ) ) + plOffset ];

						if ( pl.len || pl.p ) {

							throw 'Invalid table entry';

						}

						pl.len = l;
						pl.lit = im;

						plOffset ++;

					}

				}

			}

			return true;

		}

		const getCharReturn = { c: 0, lc: 0 };

		function getChar( c, lc, uInt8Array, inOffset ) {

			c = ( c << 8 ) | parseUint8Array( uInt8Array, inOffset );
			lc += 8;

			getCharReturn.c = c;
			getCharReturn.lc = lc;

		}

		const getCodeReturn = { c: 0, lc: 0 };

		function getCode( po, rlc, c, lc, uInt8Array, inDataView, inOffset, outBuffer, outBufferOffset, outBufferEndOffset ) {

			if ( po == rlc ) {

				if ( lc < 8 ) {

					getChar( c, lc, uInt8Array, inOffset );
					c = getCharReturn.c;
					lc = getCharReturn.lc;

				}

				lc -= 8;

				var cs = ( c >> lc );
				var cs = new Uint8Array( [ cs ] )[ 0 ];

				if ( outBufferOffset.value + cs > outBufferEndOffset ) {

					return false;

				}

				var s = outBuffer[ outBufferOffset.value - 1 ];

				while ( cs -- > 0 ) {

					outBuffer[ outBufferOffset.value ++ ] = s;

				}

			} else if ( outBufferOffset.value < outBufferEndOffset ) {

				outBuffer[ outBufferOffset.value ++ ] = po;

			} else {

				return false;

			}

			getCodeReturn.c = c;
			getCodeReturn.lc = lc;

		}

		function UInt16( value ) {

			return ( value & 0xFFFF );

		}

		function Int16( value ) {

			var ref = UInt16( value );
			return ( ref > 0x7FFF ) ? ref - 0x10000 : ref;

		}

		const wdec14Return = { a: 0, b: 0 };

		function wdec14( l, h ) {

			var ls = Int16( l );
			var hs = Int16( h );

			var hi = hs;
			var ai = ls + ( hi & 1 ) + ( hi >> 1 );

			var as = ai;
			var bs = ai - hi;

			wdec14Return.a = as;
			wdec14Return.b = bs;

		}

		function wav2Decode( j, buffer, nx, ox, ny, oy ) {

			var n = ( nx > ny ) ? ny : nx;
			var p = 1;
			var p2;

			while ( p <= n ) p <<= 1;

			p >>= 1;
			p2 = p;
			p >>= 1;

			while ( p >= 1 ) {

				var py = 0;
				var ey = py + oy * ( ny - p2 );
				var oy1 = oy * p;
				var oy2 = oy * p2;
				var ox1 = ox * p;
				var ox2 = ox * p2;
				var i00, i01, i10, i11;

				for ( ; py <= ey; py += oy2 ) {

					var px = py;
					var ex = py + ox * ( nx - p2 );

					for ( ; px <= ex; px += ox2 ) {

						var p01 = px + ox1;
						var p10 = px + oy1;
						var p11 = p10 + ox1;

						wdec14( buffer[ px + j ], buffer[ p10 + j ] );

						i00 = wdec14Return.a;
						i10 = wdec14Return.b;

						wdec14( buffer[ p01 + j ], buffer[ p11 + j ] );

						i01 = wdec14Return.a;
						i11 = wdec14Return.b;

						wdec14( i00, i01 );

						buffer[ px + j ] = wdec14Return.a;
						buffer[ p01 + j ] = wdec14Return.b;

						wdec14( i10, i11 );

						buffer[ p10 + j ] = wdec14Return.a;
						buffer[ p11 + j ] = wdec14Return.b;

					}

					if ( nx & p ) {

						var p10 = px + oy1;

						wdec14( buffer[ px + j ], buffer[ p10 + j ] );

						i00 = wdec14Return.a;
						buffer[ p10 + j ] = wdec14Return.b;

						buffer[ px + j ] = i00;

					}

				}

				if ( ny & p ) {

					var px = py;
					var ex = py + ox * ( nx - p2 );

					for ( ; px <= ex; px += ox2 ) {

						var p01 = px + ox1;

						wdec14( buffer[ px + j ], buffer[ p01 + j ] );

						i00 = wdec14Return.a;
						buffer[ p01 + j ] = wdec14Return.b;

						buffer[ px + j ] = i00;

					}

				}

				p2 = p;
				p >>= 1;

			}

			return py;

		}

		function hufDecode( encodingTable, decodingTable, uInt8Array, inDataView, inOffset, ni, rlc, no, outBuffer, outOffset ) {

			var c = 0;
			var lc = 0;
			var outBufferEndOffset = no;
			var inOffsetEnd = Math.trunc( inOffset.value + ( ni + 7 ) / 8 );

			while ( inOffset.value < inOffsetEnd ) {

				getChar( c, lc, uInt8Array, inOffset );

				c = getCharReturn.c;
				lc = getCharReturn.lc;

				while ( lc >= HUF_DECBITS ) {

					var index = ( c >> ( lc - HUF_DECBITS ) ) & HUF_DECMASK;
					var pl = decodingTable[ index ];

					if ( pl.len ) {

						lc -= pl.len;

						getCode( pl.lit, rlc, c, lc, uInt8Array, inDataView, inOffset, outBuffer, outOffset, outBufferEndOffset );

						c = getCodeReturn.c;
						lc = getCodeReturn.lc;

					} else {

						if ( ! pl.p ) {

							throw 'hufDecode issues';

						}

						var j;

						for ( j = 0; j < pl.lit; j ++ ) {

							var l = hufLength( encodingTable[ pl.p[ j ] ] );

							while ( lc < l && inOffset.value < inOffsetEnd ) {

								getChar( c, lc, uInt8Array, inOffset );

								c = getCharReturn.c;
								lc = getCharReturn.lc;

							}

							if ( lc >= l ) {

								if ( hufCode( encodingTable[ pl.p[ j ] ] ) == ( ( c >> ( lc - l ) ) & ( ( 1 << l ) - 1 ) ) ) {

									lc -= l;

									getCode( pl.p[ j ], rlc, c, lc, uInt8Array, inDataView, inOffset, outBuffer, outOffset, outBufferEndOffset );

									c = getCodeReturn.c;
									lc = getCodeReturn.lc;

									break;

								}

							}

						}

						if ( j == pl.lit ) {

							throw 'hufDecode issues';

						}

					}

				}

			}

			var i = ( 8 - ni ) & 7;

			c >>= i;
			lc -= i;

			while ( lc > 0 ) {

				var pl = decodingTable[ ( c << ( HUF_DECBITS - lc ) ) & HUF_DECMASK ];

				if ( pl.len ) {

					lc -= pl.len;

					getCode( pl.lit, rlc, c, lc, uInt8Array, inDataView, inOffset, outBuffer, outOffset, outBufferEndOffset );

					c = getCodeReturn.c;
					lc = getCodeReturn.lc;

				} else {

					throw 'hufDecode issues';

				}

			}

			return true;

		}

		function hufUncompress( uInt8Array, inDataView, inOffset, nCompressed, outBuffer, outOffset, nRaw ) {

			var initialInOffset = inOffset.value;

			var im = parseUint32( inDataView, inOffset );
			var iM = parseUint32( inDataView, inOffset );

			inOffset.value += 4;

			var nBits = parseUint32( inDataView, inOffset );

			inOffset.value += 4;

			if ( im < 0 || im >= HUF_ENCSIZE || iM < 0 || iM >= HUF_ENCSIZE ) {

				throw 'Something wrong with HUF_ENCSIZE';

			}

			var freq = new Array( HUF_ENCSIZE );
			var hdec = new Array( HUF_DECSIZE );

			hufClearDecTable( hdec );

			var ni = nCompressed - ( inOffset.value - initialInOffset );

			hufUnpackEncTable( uInt8Array, inDataView, inOffset, ni, im, iM, freq );

			if ( nBits > 8 * ( nCompressed - ( inOffset.value - initialInOffset ) ) ) {

				throw 'Something wrong with hufUncompress';

			}

			hufBuildDecTable( freq, im, iM, hdec );

			hufDecode( freq, hdec, uInt8Array, inDataView, inOffset, nBits, iM, nRaw, outBuffer, outOffset );

		}

		function applyLut( lut, data, nData ) {

			for ( var i = 0; i < nData; ++ i ) {

				data[ i ] = lut[ data[ i ] ];

			}

		}

		function decompressPIZ( outBuffer, outOffset, uInt8Array, inDataView, inOffset, tmpBufSize, num_channels, exrChannelInfos, dataWidth, num_lines ) {

			var bitmap = new Uint8Array( BITMAP_SIZE );

			var minNonZero = parseUint16( inDataView, inOffset );
			var maxNonZero = parseUint16( inDataView, inOffset );

			if ( maxNonZero >= BITMAP_SIZE ) {

				throw 'Something is wrong with PIZ_COMPRESSION BITMAP_SIZE';

			}

			if ( minNonZero <= maxNonZero ) {

				for ( var i = 0; i < maxNonZero - minNonZero + 1; i ++ ) {

					bitmap[ i + minNonZero ] = parseUint8( inDataView, inOffset );

				}

			}

			var lut = new Uint16Array( USHORT_RANGE );
			reverseLutFromBitmap( bitmap, lut );

			var length = parseUint32( inDataView, inOffset );

			hufUncompress( uInt8Array, inDataView, inOffset, length, outBuffer, outOffset, tmpBufSize );

			var pizChannelData = new Array( num_channels );

			var outBufferEnd = 0;

			for ( var i = 0; i < num_channels; i ++ ) {

				pizChannelData[ i ] = {};
				pizChannelData[ i ][ 'start' ] = outBufferEnd;
				pizChannelData[ i ][ 'end' ] = pizChannelData[ i ][ 'start' ];
				pizChannelData[ i ][ 'nx' ] = dataWidth;
				pizChannelData[ i ][ 'ny' ] = num_lines;
				pizChannelData[ i ][ 'size' ] = 1;

				outBufferEnd += pizChannelData[ i ].nx * pizChannelData[ i ].ny * pizChannelData[ i ].size;

			}

			var fooOffset = 0;

			for ( var i = 0; i < num_channels; i ++ ) {

				for ( var j = 0; j < pizChannelData[ i ].size; ++ j ) {

					fooOffset += wav2Decode(
						j + fooOffset,
						outBuffer,
						pizChannelData[ i ].nx,
						pizChannelData[ i ].size,
						pizChannelData[ i ].ny,
						pizChannelData[ i ].nx * pizChannelData[ i ].size
					);

				}

			}

			applyLut( lut, outBuffer, outBufferEnd );

			return true;

		}

		function decompressZIP( inDataView, offset, compressedSize, pixelType ) {

			var raw;

			var compressed = new Uint8Array( inDataView.buffer.slice( offset.value, offset.value + compressedSize ) );

			if ( typeof Zlib === 'undefined' ) {

				console.error( 'THREE.EXRLoader: External library Inflate.min.js required, obtain or import from https://github.com/imaya/zlib.js' );

			}

			var inflate = new Zlib.Inflate( compressed, { resize: true, verify: true } ); // eslint-disable-line no-undef

			var rawBuffer = new Uint8Array( inflate.decompress().buffer );
			var tmpBuffer = new Uint8Array( rawBuffer.length );
			
			reconstruct_scalar( rawBuffer ); // reorder pixels

			interleave_scalar( rawBuffer, tmpBuffer ); // interleave pixels

			if ( pixelType == 1 ) {

				raw = new Uint16Array( tmpBuffer.buffer );

			} else if ( pixelType == 2 ) {

				raw = new Float32Array( tmpBuffer.buffer );

			}
			
			return raw;

		}

		function reconstruct_scalar( source ) {

			for ( let t = 1; t < source.length; t++ ) {

				var d = source[ t-1 ] + source[ t ] - 128;
				source[ t ] = d;

			}

		}

		function interleave_scalar( source, out ) {

			var t1 = 0;
			var t2 = Math.floor( ( source.length + 1 ) / 2 );
			var s = 0;
			var stop = source.length - 1;

			while ( true ) {

				if ( s > stop ) break;
				out[ s++ ] = source[ t1++ ];

				if ( s > stop ) break;
				out[ s++ ] = source[ t2++ ];

			}

		}

		function parseNullTerminatedString( buffer, offset ) {

			var uintBuffer = new Uint8Array( buffer );
			var endOffset = 0;

			while ( uintBuffer[ offset.value + endOffset ] != 0 ) {

				endOffset += 1;

			}

			var stringValue = new TextDecoder().decode(
				uintBuffer.slice( offset.value, offset.value + endOffset )
			);

			offset.value = offset.value + endOffset + 1;

			return stringValue;

		}

		function parseFixedLengthString( buffer, offset, size ) {

			var stringValue = new TextDecoder().decode(
				new Uint8Array( buffer ).slice( offset.value, offset.value + size )
			);

			offset.value = offset.value + size;

			return stringValue;

		}

		function parseUlong( dataView, offset ) {

			var uLong = dataView.getUint32( 0, true );

			offset.value = offset.value + ULONG_SIZE;

			return uLong;

		}

		function parseUint32( dataView, offset ) {

			var Uint32 = dataView.getUint32( offset.value, true );

			offset.value = offset.value + INT32_SIZE;

			return Uint32;

		}

		function parseUint8Array( uInt8Array, offset ) {

			var Uint8 = uInt8Array[ offset.value ];

			offset.value = offset.value + INT8_SIZE;

			return Uint8;

		}

		function parseUint8( dataView, offset ) {

			var Uint8 = dataView.getUint8( offset.value );

			offset.value = offset.value + INT8_SIZE;

			return Uint8;

		}

		function parseFloat32( dataView, offset ) {

			var float = dataView.getFloat32( offset.value, true );

			offset.value += FLOAT32_SIZE;

			return float;

		}

		// https://stackoverflow.com/questions/5678432/decompressing-half-precision-floats-in-javascript
		function decodeFloat16( binary ) {

			var exponent = ( binary & 0x7C00 ) >> 10,
				fraction = binary & 0x03FF;

			return ( binary >> 15 ? - 1 : 1 ) * (
				exponent ?
					(
						exponent === 0x1F ?
							fraction ? NaN : Infinity :
							Math.pow( 2, exponent - 15 ) * ( 1 + fraction / 0x400 )
					) :
					6.103515625e-5 * ( fraction / 0x400 )
			);

		}

		function parseUint16( dataView, offset ) {

			var Uint16 = dataView.getUint16( offset.value, true );

			offset.value += INT16_SIZE;

			return Uint16;

		}

		function parseFloat16( buffer, offset ) {

			return decodeFloat16( parseUint16( buffer, offset ) );

		}

		function parseChlist( dataView, buffer, offset, size ) {

			var startOffset = offset.value;
			var channels = [];

			while ( offset.value < ( startOffset + size - 1 ) ) {

				var name = parseNullTerminatedString( buffer, offset );
				var pixelType = parseUint32( dataView, offset ); // TODO: Cast this to UINT, HALF or FLOAT
				var pLinear = parseUint8( dataView, offset );
				offset.value += 3; // reserved, three chars
				var xSampling = parseUint32( dataView, offset );
				var ySampling = parseUint32( dataView, offset );

				channels.push( {
					name: name,
					pixelType: pixelType,
					pLinear: pLinear,
					xSampling: xSampling,
					ySampling: ySampling
				} );

			}

			offset.value += 1;

			return channels;

		}

		function parseChromaticities( dataView, offset ) {

			var redX = parseFloat32( dataView, offset );
			var redY = parseFloat32( dataView, offset );
			var greenX = parseFloat32( dataView, offset );
			var greenY = parseFloat32( dataView, offset );
			var blueX = parseFloat32( dataView, offset );
			var blueY = parseFloat32( dataView, offset );
			var whiteX = parseFloat32( dataView, offset );
			var whiteY = parseFloat32( dataView, offset );

			return { redX: redX, redY: redY, greenX: greenX, greenY: greenY, blueX: blueX, blueY: blueY, whiteX: whiteX, whiteY: whiteY };

		}

		function parseCompression( dataView, offset ) {

			var compressionCodes = [
				'NO_COMPRESSION',
				'RLE_COMPRESSION',
				'ZIPS_COMPRESSION',
				'ZIP_COMPRESSION',
				'PIZ_COMPRESSION',
				'PXR24_COMPRESSION',
				'B44_COMPRESSION',
				'B44A_COMPRESSION',
				'DWAA_COMPRESSION',
				'DWAB_COMPRESSION'
			];

			var compression = parseUint8( dataView, offset );

			return compressionCodes[ compression ];

		}

		function parseBox2i( dataView, offset ) {

			var xMin = parseUint32( dataView, offset );
			var yMin = parseUint32( dataView, offset );
			var xMax = parseUint32( dataView, offset );
			var yMax = parseUint32( dataView, offset );

			return { xMin: xMin, yMin: yMin, xMax: xMax, yMax: yMax };

		}

		function parseLineOrder( dataView, offset ) {

			var lineOrders = [
				'INCREASING_Y'
			];

			var lineOrder = parseUint8( dataView, offset );

			return lineOrders[ lineOrder ];

		}

		function parseV2f( dataView, offset ) {

			var x = parseFloat32( dataView, offset );
			var y = parseFloat32( dataView, offset );

			return [ x, y ];

		}

		function parseValue( dataView, buffer, offset, type, size ) {

			if ( type === 'string' || type === 'iccProfile' ) {

				return parseFixedLengthString( buffer, offset, size );

			} else if ( type === 'chlist' ) {

				return parseChlist( dataView, buffer, offset, size );

			} else if ( type === 'chromaticities' ) {

				return parseChromaticities( dataView, offset );

			} else if ( type === 'compression' ) {

				return parseCompression( dataView, offset );

			} else if ( type === 'box2i' ) {

				return parseBox2i( dataView, offset );

			} else if ( type === 'lineOrder' ) {

				return parseLineOrder( dataView, offset );

			} else if ( type === 'float' ) {

				return parseFloat32( dataView, offset );

			} else if ( type === 'v2f' ) {

				return parseV2f( dataView, offset );

			} else if ( type === 'int' ) {

				return parseUint32( dataView, offset );

			} else {

				throw 'Cannot parse value for unsupported type: ' + type;

			}

		}

		var bufferDataView = new DataView( buffer );
		var uInt8Array = new Uint8Array( buffer );

		var EXRHeader = {};

		bufferDataView.getUint32( 0, true ); // magic
		bufferDataView.getUint8( 4, true ); // versionByteZero
		bufferDataView.getUint8( 5, true ); // fullMask

		// start of header

		var offset = { value: 8 }; // start at 8, after magic stuff

		var keepReading = true;

		while ( keepReading ) {

			var attributeName = parseNullTerminatedString( buffer, offset );

			if ( attributeName == 0 ) {

				keepReading = false;

			} else {

				var attributeType = parseNullTerminatedString( buffer, offset );
				var attributeSize = parseUint32( bufferDataView, offset );
				var attributeValue = parseValue( bufferDataView, buffer, offset, attributeType, attributeSize );

				EXRHeader[ attributeName ] = attributeValue;

			}

		}

		// offsets

		var dataWindowHeight = EXRHeader.dataWindow.yMax + 1;
		var scanlineBlockSize = 1; // 1 for NO_COMPRESSION

		if ( EXRHeader.compression === 'PIZ_COMPRESSION' ) {

			scanlineBlockSize = 32;

		} else if ( EXRHeader.compression === 'ZIP_COMPRESSION' ) {

			scanlineBlockSize = 16;

		}

		var numBlocks = dataWindowHeight / scanlineBlockSize;

		for ( var i = 0; i < numBlocks; i ++ ) {

			parseUlong( bufferDataView, offset ); // scanlineOffset

		}

		// we should be passed the scanline offset table, start reading pixel data

		var width = EXRHeader.dataWindow.xMax - EXRHeader.dataWindow.xMin + 1;
		var height = EXRHeader.dataWindow.yMax - EXRHeader.dataWindow.yMin + 1;
		// Firefox only supports RGBA (half) float textures
		// var numChannels = EXRHeader.channels.length;
		var numChannels = 4;
		var size = width * height * numChannels;

		// Fill initially with 1s for the alpha value if the texture is not RGBA, RGB values will be overwritten
		switch ( this.type ) {

			case FloatType:

				var byteArray = new Float32Array( size );

				if ( EXRHeader.channels.length < numChannels ) {

					byteArray.fill( 1, 0, size );

				}

				break;

			case HalfFloatType:

				var byteArray = new Uint16Array( size );

				if ( EXRHeader.channels.length < numChannels ) {

					byteArray.fill( 0x3C00, 0, size ); // Uint16Array holds half float data, 0x3C00 is 1

				}

				break;

			default:

				console.error( 'THREE.EXRLoader: unsupported type: ', this.type );
				break;

		}

		var channelOffsets = {
			R: 0,
			G: 1,
			B: 2,
			A: 3
		};

		if ( EXRHeader.compression === 'NO_COMPRESSION' ) {

			for ( var y = 0; y < height; y ++ ) {

				var y_scanline = parseUint32( bufferDataView, offset );
				parseUint32( bufferDataView, offset ); // dataSize

				for ( var channelID = 0; channelID < EXRHeader.channels.length; channelID ++ ) {

					var cOff = channelOffsets[ EXRHeader.channels[ channelID ].name ];

					if ( EXRHeader.channels[ channelID ].pixelType === 1 ) { // half

						for ( var x = 0; x < width; x ++ ) {

							switch ( this.type ) {

								case FloatType:

									var val = parseFloat16( bufferDataView, offset );
									break;

								case HalfFloatType:

									var val = parseUint16( bufferDataView, offset );
									break;

							}

							byteArray[ ( ( ( height - y_scanline ) * ( width * numChannels ) ) + ( x * numChannels ) ) + cOff ] = val;

						}

					} else {

						throw 'EXRLoader.parse: unsupported pixelType ' + EXRHeader.channels[ channelID ].pixelType + ' for ' + EXRHeader.compression + '.';

					}

				}

			}

		} else if ( EXRHeader.compression === 'PIZ_COMPRESSION' ) {

			for ( var scanlineBlockIdx = 0; scanlineBlockIdx < height / scanlineBlockSize; scanlineBlockIdx ++ ) {

				parseUint32( bufferDataView, offset ); // line_no
				parseUint32( bufferDataView, offset ); // data_len

				var tmpBufferSize = width * scanlineBlockSize * ( EXRHeader.channels.length * BYTES_PER_HALF );
				var tmpBuffer = new Uint16Array( tmpBufferSize );
				var tmpOffset = { value: 0 };

				decompressPIZ( tmpBuffer, tmpOffset, uInt8Array, bufferDataView, offset, tmpBufferSize, EXRHeader.channels.length, EXRHeader.channels, width, scanlineBlockSize );

				for ( var line_y = 0; line_y < scanlineBlockSize; line_y ++ ) {

					for ( var channelID = 0; channelID < EXRHeader.channels.length; channelID ++ ) {

						var cOff = channelOffsets[ EXRHeader.channels[ channelID ].name ];

						if ( EXRHeader.channels[ channelID ].pixelType === 1 ) { // half

							for ( var x = 0; x < width; x ++ ) {

								var idx = ( channelID * ( scanlineBlockSize * width ) ) + ( line_y * width ) + x;

								switch ( this.type ) {

									case FloatType:

										var val = decodeFloat16( tmpBuffer[ idx ] );
										break;

									case HalfFloatType:

										var val = tmpBuffer[ idx ];
										break;

								}

								var true_y = line_y + ( scanlineBlockIdx * scanlineBlockSize );

								byteArray[ ( ( ( height - true_y ) * ( width * numChannels ) ) + ( x * numChannels ) ) + cOff ] = val;

							}

						} else {

							throw 'EXRLoader.parse: unsupported pixelType ' + EXRHeader.channels[ channelID ].pixelType + ' for ' + EXRHeader.compression + '.';

						}

					}

				}

			}

		} else if ( EXRHeader.compression === 'ZIP_COMPRESSION' || 
					EXRHeader.compression === 'ZIPS_COMPRESSION' ) {

			for ( var scanlineBlockIdx = 0; scanlineBlockIdx < height / scanlineBlockSize; scanlineBlockIdx ++ ) {

				parseUint32( bufferDataView, offset ); // line_no
				var compressedSize = parseUint32( bufferDataView, offset ); // data_len

				var raw = decompressZIP( bufferDataView, offset, compressedSize, EXRHeader.channels[ 0 ].pixelType );

				offset.value += compressedSize;
				
				for ( var line_y = 0; line_y < scanlineBlockSize; line_y ++ ) {

					for ( var channelID = 0; channelID < EXRHeader.channels.length; channelID ++ ) {

						for ( var x = 0; x < width; x ++ ) {

							var cOff = channelOffsets[ EXRHeader.channels[ channelID ].name ];

							var idx = ( line_y * ( EXRHeader.channels.length * width ) ) + ( channelID * width ) + x;

							if ( EXRHeader.channels[ channelID ].pixelType === 1 ) { // half

								switch ( this.type ) {

									case FloatType:

										var val = decodeFloat16( raw[ idx ] );
										break;

									case HalfFloatType:

										var val = raw[ idx ];
										break;

								}

							} else if ( EXRHeader.channels[ channelID ].pixelType === 2 ) { // float

								switch ( this.type ) {

									case FloatType:

										var val = raw[ idx ];
										break;

									case HalfFloatType:

										throw 'EXRLoader.parse: unsupported HalfFloatType texture for FloatType image file.'
								}

							} else {

								throw 'EXRLoader.parse: unsupported pixelType ' + EXRHeader.channels[ channelID ].pixelType + ' for ' + EXRHeader.compression + '.';

							}

							var true_y = line_y + ( scanlineBlockIdx * scanlineBlockSize );

							byteArray[ ( ( ( height - true_y ) * ( width * numChannels ) ) + ( x * numChannels ) ) + cOff ] = val;

						}	

					}

				}

			}

		} else {

			throw 'EXRLoader.parse: ' + EXRHeader.compression + ' is unsupported';

		}

		return {
			header: EXRHeader,
			width: width,
			height: height,
			data: byteArray,
			format: numChannels == 4 ? RGBAFormat : RGBFormat,
			type: this.type
		};

	},

	setDataType: function ( value ) {

		this.type = value;
		return this;

	},

	load: function ( url, onLoad, onProgress, onError ) {

		function onLoadCallback( texture, texData ) {

			switch ( texture.type ) {

				case FloatType:

					texture.encoding = LinearEncoding;
					texture.minFilter = LinearFilter;
					texture.magFilter = LinearFilter;
					texture.generateMipmaps = false;
					texture.flipY = false;
					break;

				case HalfFloatType:

					texture.encoding = LinearEncoding;
					texture.minFilter = LinearFilter;
					texture.magFilter = LinearFilter;
					texture.generateMipmaps = false;
					texture.flipY = false;
					break;

			}

			if ( onLoad ) onLoad( texture, texData );

		}

		return DataTextureLoader.prototype.load.call( this, url, onLoadCallback, onProgress, onError );

	}

} );

export { EXRLoader };