three.js/examples/js/loaders/VTKLoader.js

( function () {

	class VTKLoader extends THREE.Loader {

		constructor( manager ) {

			super( manager );

		}

		load( url, onLoad, onProgress, onError ) {

			const scope = this;
			const loader = new THREE.FileLoader( scope.manager );
			loader.setPath( scope.path );
			loader.setResponseType( 'arraybuffer' );
			loader.setRequestHeader( scope.requestHeader );
			loader.setWithCredentials( scope.withCredentials );
			loader.load( url, function ( text ) {

				try {

					onLoad( scope.parse( text ) );

				} catch ( e ) {

					if ( onError ) {

						onError( e );

					} else {

						console.error( e );

					}

					scope.manager.itemError( url );

				}

			}, onProgress, onError );

		}

		parse( data ) {

			function parseASCII( data ) {

				// connectivity of the triangles
				const indices = []; // triangles vertices

				const positions = []; // red, green, blue colors in the range 0 to 1

				const colors = []; // normal vector, one per vertex

				const normals = [];
				let result; // pattern for detecting the end of a number sequence

				const patWord = /^[^\d.\s-]+/; // pattern for reading vertices, 3 floats or integers

				const pat3Floats = /(\-?\d+\.?[\d\-\+e]*)\s+(\-?\d+\.?[\d\-\+e]*)\s+(\-?\d+\.?[\d\-\+e]*)/g; // pattern for connectivity, an integer followed by any number of ints
				// the first integer is the number of polygon nodes

				const patConnectivity = /^(\d+)\s+([\s\d]*)/; // indicates start of vertex data section

				const patPOINTS = /^POINTS /; // indicates start of polygon connectivity section

				const patPOLYGONS = /^POLYGONS /; // indicates start of triangle strips section

				const patTRIANGLE_STRIPS = /^TRIANGLE_STRIPS /; // POINT_DATA number_of_values

				const patPOINT_DATA = /^POINT_DATA[ ]+(\d+)/; // CELL_DATA number_of_polys

				const patCELL_DATA = /^CELL_DATA[ ]+(\d+)/; // Start of color section

				const patCOLOR_SCALARS = /^COLOR_SCALARS[ ]+(\w+)[ ]+3/; // NORMALS Normals float

				const patNORMALS = /^NORMALS[ ]+(\w+)[ ]+(\w+)/;
				let inPointsSection = false;
				let inPolygonsSection = false;
				let inTriangleStripSection = false;
				let inPointDataSection = false;
				let inCellDataSection = false;
				let inColorSection = false;
				let inNormalsSection = false;
				const lines = data.split( '\n' );

				for ( const i in lines ) {

					const line = lines[ i ].trim();

					if ( line.indexOf( 'DATASET' ) === 0 ) {

						const dataset = line.split( ' ' )[ 1 ];
						if ( dataset !== 'POLYDATA' ) throw new Error( 'Unsupported DATASET type: ' + dataset );

					} else if ( inPointsSection ) {

						// get the vertices
						while ( ( result = pat3Floats.exec( line ) ) !== null ) {

							if ( patWord.exec( line ) !== null ) break;
							const x = parseFloat( result[ 1 ] );
							const y = parseFloat( result[ 2 ] );
							const z = parseFloat( result[ 3 ] );
							positions.push( x, y, z );

						}

					} else if ( inPolygonsSection ) {

						if ( ( result = patConnectivity.exec( line ) ) !== null ) {

							// numVertices i0 i1 i2 ...
							const numVertices = parseInt( result[ 1 ] );
							const inds = result[ 2 ].split( /\s+/ );

							if ( numVertices >= 3 ) {

								const i0 = parseInt( inds[ 0 ] );
								let k = 1; // split the polygon in numVertices - 2 triangles

								for ( let j = 0; j < numVertices - 2; ++ j ) {

									const i1 = parseInt( inds[ k ] );
									const i2 = parseInt( inds[ k + 1 ] );
									indices.push( i0, i1, i2 );
									k ++;

								}

							}

						}

					} else if ( inTriangleStripSection ) {

						if ( ( result = patConnectivity.exec( line ) ) !== null ) {

							// numVertices i0 i1 i2 ...
							const numVertices = parseInt( result[ 1 ] );
							const inds = result[ 2 ].split( /\s+/ );

							if ( numVertices >= 3 ) {

								// split the polygon in numVertices - 2 triangles
								for ( let j = 0; j < numVertices - 2; j ++ ) {

									if ( j % 2 === 1 ) {

										const i0 = parseInt( inds[ j ] );
										const i1 = parseInt( inds[ j + 2 ] );
										const i2 = parseInt( inds[ j + 1 ] );
										indices.push( i0, i1, i2 );

									} else {

										const i0 = parseInt( inds[ j ] );
										const i1 = parseInt( inds[ j + 1 ] );
										const i2 = parseInt( inds[ j + 2 ] );
										indices.push( i0, i1, i2 );

									}

								}

							}

						}

					} else if ( inPointDataSection || inCellDataSection ) {

						if ( inColorSection ) {

							// Get the colors
							while ( ( result = pat3Floats.exec( line ) ) !== null ) {

								if ( patWord.exec( line ) !== null ) break;
								const r = parseFloat( result[ 1 ] );
								const g = parseFloat( result[ 2 ] );
								const b = parseFloat( result[ 3 ] );
								colors.push( r, g, b );

							}

						} else if ( inNormalsSection ) {

							// Get the normal vectors
							while ( ( result = pat3Floats.exec( line ) ) !== null ) {

								if ( patWord.exec( line ) !== null ) break;
								const nx = parseFloat( result[ 1 ] );
								const ny = parseFloat( result[ 2 ] );
								const nz = parseFloat( result[ 3 ] );
								normals.push( nx, ny, nz );

							}

						}

					}

					if ( patPOLYGONS.exec( line ) !== null ) {

						inPolygonsSection = true;
						inPointsSection = false;
						inTriangleStripSection = false;

					} else if ( patPOINTS.exec( line ) !== null ) {

						inPolygonsSection = false;
						inPointsSection = true;
						inTriangleStripSection = false;

					} else if ( patTRIANGLE_STRIPS.exec( line ) !== null ) {

						inPolygonsSection = false;
						inPointsSection = false;
						inTriangleStripSection = true;

					} else if ( patPOINT_DATA.exec( line ) !== null ) {

						inPointDataSection = true;
						inPointsSection = false;
						inPolygonsSection = false;
						inTriangleStripSection = false;

					} else if ( patCELL_DATA.exec( line ) !== null ) {

						inCellDataSection = true;
						inPointsSection = false;
						inPolygonsSection = false;
						inTriangleStripSection = false;

					} else if ( patCOLOR_SCALARS.exec( line ) !== null ) {

						inColorSection = true;
						inNormalsSection = false;
						inPointsSection = false;
						inPolygonsSection = false;
						inTriangleStripSection = false;

					} else if ( patNORMALS.exec( line ) !== null ) {

						inNormalsSection = true;
						inColorSection = false;
						inPointsSection = false;
						inPolygonsSection = false;
						inTriangleStripSection = false;

					}

				}

				let geometry = new THREE.BufferGeometry();
				geometry.setIndex( indices );
				geometry.setAttribute( 'position', new THREE.Float32BufferAttribute( positions, 3 ) );

				if ( normals.length === positions.length ) {

					geometry.setAttribute( 'normal', new THREE.Float32BufferAttribute( normals, 3 ) );

				}

				if ( colors.length !== indices.length ) {

					// stagger
					if ( colors.length === positions.length ) {

						geometry.setAttribute( 'color', new THREE.Float32BufferAttribute( colors, 3 ) );

					}

				} else {

					// cell
					geometry = geometry.toNonIndexed();
					const numTriangles = geometry.attributes.position.count / 3;

					if ( colors.length === numTriangles * 3 ) {

						const newColors = [];

						for ( let i = 0; i < numTriangles; i ++ ) {

							const r = colors[ 3 * i + 0 ];
							const g = colors[ 3 * i + 1 ];
							const b = colors[ 3 * i + 2 ];
							newColors.push( r, g, b );
							newColors.push( r, g, b );
							newColors.push( r, g, b );

						}

						geometry.setAttribute( 'color', new THREE.Float32BufferAttribute( newColors, 3 ) );

					}

				}

				return geometry;

			}

			function parseBinary( data ) {

				const buffer = new Uint8Array( data );
				const dataView = new DataView( data ); // Points and normals, by default, are empty

				let points = [];
				let normals = [];
				let indices = []; // Going to make a big array of strings

				const vtk = [];
				let index = 0;

				function findString( buffer, start ) {

					let index = start;
					let c = buffer[ index ];
					const s = [];

					while ( c !== 10 ) {

						s.push( String.fromCharCode( c ) );
						index ++;
						c = buffer[ index ];

					}

					return {
						start: start,
						end: index,
						next: index + 1,
						parsedString: s.join( '' )
					};

				}

				let state, line;

				while ( true ) {

					// Get a string
					state = findString( buffer, index );
					line = state.parsedString;

					if ( line.indexOf( 'DATASET' ) === 0 ) {

						const dataset = line.split( ' ' )[ 1 ];
						if ( dataset !== 'POLYDATA' ) throw new Error( 'Unsupported DATASET type: ' + dataset );

					} else if ( line.indexOf( 'POINTS' ) === 0 ) {

						vtk.push( line ); // Add the points

						const numberOfPoints = parseInt( line.split( ' ' )[ 1 ], 10 ); // Each point is 3 4-byte floats

						const count = numberOfPoints * 4 * 3;
						points = new Float32Array( numberOfPoints * 3 );
						let pointIndex = state.next;

						for ( let i = 0; i < numberOfPoints; i ++ ) {

							points[ 3 * i ] = dataView.getFloat32( pointIndex, false );
							points[ 3 * i + 1 ] = dataView.getFloat32( pointIndex + 4, false );
							points[ 3 * i + 2 ] = dataView.getFloat32( pointIndex + 8, false );
							pointIndex = pointIndex + 12;

						} // increment our next pointer


						state.next = state.next + count + 1;

					} else if ( line.indexOf( 'TRIANGLE_STRIPS' ) === 0 ) {

						const numberOfStrips = parseInt( line.split( ' ' )[ 1 ], 10 );
						const size = parseInt( line.split( ' ' )[ 2 ], 10 ); // 4 byte integers

						const count = size * 4;
						indices = new Uint32Array( 3 * size - 9 * numberOfStrips );
						let indicesIndex = 0;
						let pointIndex = state.next;

						for ( let i = 0; i < numberOfStrips; i ++ ) {

							// For each strip, read the first value, then record that many more points
							const indexCount = dataView.getInt32( pointIndex, false );
							const strip = [];
							pointIndex += 4;

							for ( let s = 0; s < indexCount; s ++ ) {

								strip.push( dataView.getInt32( pointIndex, false ) );
								pointIndex += 4;

							} // retrieves the n-2 triangles from the triangle strip


							for ( let j = 0; j < indexCount - 2; j ++ ) {

								if ( j % 2 ) {

									indices[ indicesIndex ++ ] = strip[ j ];
									indices[ indicesIndex ++ ] = strip[ j + 2 ];
									indices[ indicesIndex ++ ] = strip[ j + 1 ];

								} else {

									indices[ indicesIndex ++ ] = strip[ j ];
									indices[ indicesIndex ++ ] = strip[ j + 1 ];
									indices[ indicesIndex ++ ] = strip[ j + 2 ];

								}

							}

						} // increment our next pointer


						state.next = state.next + count + 1;

					} else if ( line.indexOf( 'POLYGONS' ) === 0 ) {

						const numberOfStrips = parseInt( line.split( ' ' )[ 1 ], 10 );
						const size = parseInt( line.split( ' ' )[ 2 ], 10 ); // 4 byte integers

						const count = size * 4;
						indices = new Uint32Array( 3 * size - 9 * numberOfStrips );
						let indicesIndex = 0;
						let pointIndex = state.next;

						for ( let i = 0; i < numberOfStrips; i ++ ) {

							// For each strip, read the first value, then record that many more points
							const indexCount = dataView.getInt32( pointIndex, false );
							const strip = [];
							pointIndex += 4;

							for ( let s = 0; s < indexCount; s ++ ) {

								strip.push( dataView.getInt32( pointIndex, false ) );
								pointIndex += 4;

							} // divide the polygon in n-2 triangle


							for ( let j = 1; j < indexCount - 1; j ++ ) {

								indices[ indicesIndex ++ ] = strip[ 0 ];
								indices[ indicesIndex ++ ] = strip[ j ];
								indices[ indicesIndex ++ ] = strip[ j + 1 ];

							}

						} // increment our next pointer


						state.next = state.next + count + 1;

					} else if ( line.indexOf( 'POINT_DATA' ) === 0 ) {

						const numberOfPoints = parseInt( line.split( ' ' )[ 1 ], 10 ); // Grab the next line

						state = findString( buffer, state.next ); // Now grab the binary data

						const count = numberOfPoints * 4 * 3;
						normals = new Float32Array( numberOfPoints * 3 );
						let pointIndex = state.next;

						for ( let i = 0; i < numberOfPoints; i ++ ) {

							normals[ 3 * i ] = dataView.getFloat32( pointIndex, false );
							normals[ 3 * i + 1 ] = dataView.getFloat32( pointIndex + 4, false );
							normals[ 3 * i + 2 ] = dataView.getFloat32( pointIndex + 8, false );
							pointIndex += 12;

						} // Increment past our data


						state.next = state.next + count;

					} // Increment index


					index = state.next;

					if ( index >= buffer.byteLength ) {

						break;

					}

				}

				const geometry = new THREE.BufferGeometry();
				geometry.setIndex( new THREE.BufferAttribute( indices, 1 ) );
				geometry.setAttribute( 'position', new THREE.BufferAttribute( points, 3 ) );

				if ( normals.length === points.length ) {

					geometry.setAttribute( 'normal', new THREE.BufferAttribute( normals, 3 ) );

				}

				return geometry;

			}

			function Float32Concat( first, second ) {

				const firstLength = first.length,
					result = new Float32Array( firstLength + second.length );
				result.set( first );
				result.set( second, firstLength );
				return result;

			}

			function Int32Concat( first, second ) {

				const firstLength = first.length,
					result = new Int32Array( firstLength + second.length );
				result.set( first );
				result.set( second, firstLength );
				return result;

			}

			function parseXML( stringFile ) {

				// Changes XML to JSON, based on https://davidwalsh.name/convert-xml-json
				function xmlToJson( xml ) {

					// Create the return object
					let obj = {};

					if ( xml.nodeType === 1 ) {

						// element
						// do attributes
						if ( xml.attributes ) {

							if ( xml.attributes.length > 0 ) {

								obj[ 'attributes' ] = {};

								for ( let j = 0; j < xml.attributes.length; j ++ ) {

									const attribute = xml.attributes.item( j );
									obj[ 'attributes' ][ attribute.nodeName ] = attribute.nodeValue.trim();

								}

							}

						}

					} else if ( xml.nodeType === 3 ) {

						// text
						obj = xml.nodeValue.trim();

					} // do children


					if ( xml.hasChildNodes() ) {

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

							const item = xml.childNodes.item( i );
							const nodeName = item.nodeName;

							if ( typeof obj[ nodeName ] === 'undefined' ) {

								const tmp = xmlToJson( item );
								if ( tmp !== '' ) obj[ nodeName ] = tmp;

							} else {

								if ( typeof obj[ nodeName ].push === 'undefined' ) {

									const old = obj[ nodeName ];
									obj[ nodeName ] = [ old ];

								}

								const tmp = xmlToJson( item );
								if ( tmp !== '' ) obj[ nodeName ].push( tmp );

							}

						}

					}

					return obj;

				} // Taken from Base64-js


				function Base64toByteArray( b64 ) {

					const Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array;
					const revLookup = [];
					const code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';

					for ( let i = 0, l = code.length; i < l; ++ i ) {

						revLookup[ code.charCodeAt( i ) ] = i;

					}

					revLookup[ '-'.charCodeAt( 0 ) ] = 62;
					revLookup[ '_'.charCodeAt( 0 ) ] = 63;
					const len = b64.length;

					if ( len % 4 > 0 ) {

						throw new Error( 'Invalid string. Length must be a multiple of 4' );

					}

					const placeHolders = b64[ len - 2 ] === '=' ? 2 : b64[ len - 1 ] === '=' ? 1 : 0;
					const arr = new Arr( len * 3 / 4 - placeHolders );
					const l = placeHolders > 0 ? len - 4 : len;
					let L = 0;
					let i, j;

					for ( i = 0, j = 0; i < l; i += 4, j += 3 ) {

						const tmp = revLookup[ b64.charCodeAt( i ) ] << 18 | revLookup[ b64.charCodeAt( i + 1 ) ] << 12 | revLookup[ b64.charCodeAt( i + 2 ) ] << 6 | revLookup[ b64.charCodeAt( i + 3 ) ];
						arr[ L ++ ] = ( tmp & 0xFF0000 ) >> 16;
						arr[ L ++ ] = ( tmp & 0xFF00 ) >> 8;
						arr[ L ++ ] = tmp & 0xFF;

					}

					if ( placeHolders === 2 ) {

						const tmp = revLookup[ b64.charCodeAt( i ) ] << 2 | revLookup[ b64.charCodeAt( i + 1 ) ] >> 4;
						arr[ L ++ ] = tmp & 0xFF;

					} else if ( placeHolders === 1 ) {

						const tmp = revLookup[ b64.charCodeAt( i ) ] << 10 | revLookup[ b64.charCodeAt( i + 1 ) ] << 4 | revLookup[ b64.charCodeAt( i + 2 ) ] >> 2;
						arr[ L ++ ] = tmp >> 8 & 0xFF;
						arr[ L ++ ] = tmp & 0xFF;

					}

					return arr;

				}

				function parseDataArray( ele, compressed ) {

					let numBytes = 0;

					if ( json.attributes.header_type === 'UInt64' ) {

						numBytes = 8;

					} else if ( json.attributes.header_type === 'UInt32' ) {

						numBytes = 4;

					}

					let txt, content; // Check the format

					if ( ele.attributes.format === 'binary' && compressed ) {

						if ( ele.attributes.type === 'Float32' ) {

							txt = new Float32Array();

						} else if ( ele.attributes.type === 'Int64' ) {

							txt = new Int32Array();

						} // VTP data with the header has the following structure:
						// [#blocks][#u-size][#p-size][#c-size-1][#c-size-2]...[#c-size-#blocks][DATA]
						//
						// Each token is an integer value whose type is specified by "header_type" at the top of the file (UInt32 if no type specified). The token meanings are:
						// [#blocks] = Number of blocks
						// [#u-size] = Block size before compression
						// [#p-size] = Size of last partial block (zero if it not needed)
						// [#c-size-i] = Size in bytes of block i after compression
						//
						// The [DATA] portion stores contiguously every block appended together. The offset from the beginning of the data section to the beginning of a block is
						// computed by summing the compressed block sizes from preceding blocks according to the header.


						const rawData = ele[ '#text' ];
						const byteData = Base64toByteArray( rawData );
						let blocks = byteData[ 0 ];

						for ( let i = 1; i < numBytes - 1; i ++ ) {

							blocks = blocks | byteData[ i ] << i * numBytes;

						}

						let headerSize = ( blocks + 3 ) * numBytes;
						const padding = headerSize % 3 > 0 ? 3 - headerSize % 3 : 0;
						headerSize = headerSize + padding;
						const dataOffsets = [];
						let currentOffset = headerSize;
						dataOffsets.push( currentOffset ); // Get the blocks sizes after the compression.
						// There are three blocks before c-size-i, so we skip 3*numBytes

						const cSizeStart = 3 * numBytes;

						for ( let i = 0; i < blocks; i ++ ) {

							let currentBlockSize = byteData[ i * numBytes + cSizeStart ];

							for ( let j = 1; j < numBytes - 1; j ++ ) {

								// Each data point consists of 8 bytes regardless of the header type
								currentBlockSize = currentBlockSize | byteData[ i * numBytes + cSizeStart + j ] << j * 8;

							}

							currentOffset = currentOffset + currentBlockSize;
							dataOffsets.push( currentOffset );

						}

						for ( let i = 0; i < dataOffsets.length - 1; i ++ ) {

							const data = fflate.unzlibSync( byteData.slice( dataOffsets[ i ], dataOffsets[ i + 1 ] ) ); // eslint-disable-line no-undef

							content = data.buffer;

							if ( ele.attributes.type === 'Float32' ) {

								content = new Float32Array( content );
								txt = Float32Concat( txt, content );

							} else if ( ele.attributes.type === 'Int64' ) {

								content = new Int32Array( content );
								txt = Int32Concat( txt, content );

							}

						}

						delete ele[ '#text' ];

						if ( ele.attributes.type === 'Int64' ) {

							if ( ele.attributes.format === 'binary' ) {

								txt = txt.filter( function ( el, idx ) {

									if ( idx % 2 !== 1 ) return true;

								} );

							}

						}

					} else {

						if ( ele.attributes.format === 'binary' && ! compressed ) {

							content = Base64toByteArray( ele[ '#text' ] ); //  VTP data for the uncompressed case has the following structure:
							// [#bytes][DATA]
							// where "[#bytes]" is an integer value specifying the number of bytes in the block of data following it.

							content = content.slice( numBytes ).buffer;

						} else {

							if ( ele[ '#text' ] ) {

								content = ele[ '#text' ].split( /\s+/ ).filter( function ( el ) {

									if ( el !== '' ) return el;

								} );

							} else {

								content = new Int32Array( 0 ).buffer;

							}

						}

						delete ele[ '#text' ]; // Get the content and optimize it

						if ( ele.attributes.type === 'Float32' ) {

							txt = new Float32Array( content );

						} else if ( ele.attributes.type === 'Int32' ) {

							txt = new Int32Array( content );

						} else if ( ele.attributes.type === 'Int64' ) {

							txt = new Int32Array( content );

							if ( ele.attributes.format === 'binary' ) {

								txt = txt.filter( function ( el, idx ) {

									if ( idx % 2 !== 1 ) return true;

								} );

							}

						}

					} // endif ( ele.attributes.format === 'binary' && compressed )


					return txt;

				} // Main part
				// Get Dom


				const dom = new DOMParser().parseFromString( stringFile, 'application/xml' ); // Get the doc

				const doc = dom.documentElement; // Convert to json

				const json = xmlToJson( doc );
				let points = [];
				let normals = [];
				let indices = [];

				if ( json.PolyData ) {

					const piece = json.PolyData.Piece;
					const compressed = json.attributes.hasOwnProperty( 'compressor' ); // Can be optimized
					// Loop through the sections

					const sections = [ 'PointData', 'Points', 'Strips', 'Polys' ]; // +['CellData', 'Verts', 'Lines'];

					let sectionIndex = 0;
					const numberOfSections = sections.length;

					while ( sectionIndex < numberOfSections ) {

						const section = piece[ sections[ sectionIndex ] ]; // If it has a DataArray in it

						if ( section && section.DataArray ) {

							// Depending on the number of DataArrays
							let arr;

							if ( Object.prototype.toString.call( section.DataArray ) === '[object Array]' ) {

								arr = section.DataArray;

							} else {

								arr = [ section.DataArray ];

							}

							let dataArrayIndex = 0;
							const numberOfDataArrays = arr.length;

							while ( dataArrayIndex < numberOfDataArrays ) {

								// Parse the DataArray
								if ( '#text' in arr[ dataArrayIndex ] && arr[ dataArrayIndex ][ '#text' ].length > 0 ) {

									arr[ dataArrayIndex ].text = parseDataArray( arr[ dataArrayIndex ], compressed );

								}

								dataArrayIndex ++;

							}

							switch ( sections[ sectionIndex ] ) {

								// if iti is point data
								case 'PointData':
									{

										const numberOfPoints = parseInt( piece.attributes.NumberOfPoints );
										const normalsName = section.attributes.Normals;

										if ( numberOfPoints > 0 ) {

											for ( let i = 0, len = arr.length; i < len; i ++ ) {

												if ( normalsName === arr[ i ].attributes.Name ) {

													const components = arr[ i ].attributes.NumberOfComponents;
													normals = new Float32Array( numberOfPoints * components );
													normals.set( arr[ i ].text, 0 );

												}

											}

										}

									}

									break;
									// if it is points

								case 'Points':
									{

										const numberOfPoints = parseInt( piece.attributes.NumberOfPoints );

										if ( numberOfPoints > 0 ) {

											const components = section.DataArray.attributes.NumberOfComponents;
											points = new Float32Array( numberOfPoints * components );
											points.set( section.DataArray.text, 0 );

										}

									}

									break;
									// if it is strips

								case 'Strips':
									{

										const numberOfStrips = parseInt( piece.attributes.NumberOfStrips );

										if ( numberOfStrips > 0 ) {

											const connectivity = new Int32Array( section.DataArray[ 0 ].text.length );
											const offset = new Int32Array( section.DataArray[ 1 ].text.length );
											connectivity.set( section.DataArray[ 0 ].text, 0 );
											offset.set( section.DataArray[ 1 ].text, 0 );
											const size = numberOfStrips + connectivity.length;
											indices = new Uint32Array( 3 * size - 9 * numberOfStrips );
											let indicesIndex = 0;

											for ( let i = 0, len = numberOfStrips; i < len; i ++ ) {

												const strip = [];

												for ( let s = 0, len1 = offset[ i ], len0 = 0; s < len1 - len0; s ++ ) {

													strip.push( connectivity[ s ] );
													if ( i > 0 ) len0 = offset[ i - 1 ];

												}

												for ( let j = 0, len1 = offset[ i ], len0 = 0; j < len1 - len0 - 2; j ++ ) {

													if ( j % 2 ) {

														indices[ indicesIndex ++ ] = strip[ j ];
														indices[ indicesIndex ++ ] = strip[ j + 2 ];
														indices[ indicesIndex ++ ] = strip[ j + 1 ];

													} else {

														indices[ indicesIndex ++ ] = strip[ j ];
														indices[ indicesIndex ++ ] = strip[ j + 1 ];
														indices[ indicesIndex ++ ] = strip[ j + 2 ];

													}

													if ( i > 0 ) len0 = offset[ i - 1 ];

												}

											}

										}

									}

									break;
									// if it is polys

								case 'Polys':
									{

										const numberOfPolys = parseInt( piece.attributes.NumberOfPolys );

										if ( numberOfPolys > 0 ) {

											const connectivity = new Int32Array( section.DataArray[ 0 ].text.length );
											const offset = new Int32Array( section.DataArray[ 1 ].text.length );
											connectivity.set( section.DataArray[ 0 ].text, 0 );
											offset.set( section.DataArray[ 1 ].text, 0 );
											const size = numberOfPolys + connectivity.length;
											indices = new Uint32Array( 3 * size - 9 * numberOfPolys );
											let indicesIndex = 0,
												connectivityIndex = 0;
											let i = 0,
												len0 = 0;
											const len = numberOfPolys;

											while ( i < len ) {

												const poly = [];
												let s = 0;
												const len1 = offset[ i ];

												while ( s < len1 - len0 ) {

													poly.push( connectivity[ connectivityIndex ++ ] );
													s ++;

												}

												let j = 1;

												while ( j < len1 - len0 - 1 ) {

													indices[ indicesIndex ++ ] = poly[ 0 ];
													indices[ indicesIndex ++ ] = poly[ j ];
													indices[ indicesIndex ++ ] = poly[ j + 1 ];
													j ++;

												}

												i ++;
												len0 = offset[ i - 1 ];

											}

										}

									}

									break;

								default:
									break;

							}

						}

						sectionIndex ++;

					}

					const geometry = new THREE.BufferGeometry();
					geometry.setIndex( new THREE.BufferAttribute( indices, 1 ) );
					geometry.setAttribute( 'position', new THREE.BufferAttribute( points, 3 ) );

					if ( normals.length === points.length ) {

						geometry.setAttribute( 'normal', new THREE.BufferAttribute( normals, 3 ) );

					}

					return geometry;

				} else {

					throw new Error( 'Unsupported DATASET type' );

				}

			} // get the 5 first lines of the files to check if there is the key word binary


			const meta = THREE.LoaderUtils.decodeText( new Uint8Array( data, 0, 250 ) ).split( '\n' );

			if ( meta[ 0 ].indexOf( 'xml' ) !== - 1 ) {

				return parseXML( THREE.LoaderUtils.decodeText( data ) );

			} else if ( meta[ 2 ].includes( 'ASCII' ) ) {

				return parseASCII( THREE.LoaderUtils.decodeText( data ) );

			} else {

				return parseBinary( data );

			}

		}

	}

	THREE.VTKLoader = VTKLoader;

} )();