function fetchDataLength(path, callback) { let xhr = new XMLHttpRequest(); xhr.open('HEAD', path, true); xhr.onreadystatechange = function() { if (xhr.readyState === 4) { if (xhr.status === 200) { callback(xhr.getResponseHeader('Content-Length')); } } }; xhr.send(); } function fetchData(path, start, end, callback) { let xhr = new XMLHttpRequest(); xhr.open('GET', path, true); xhr.setRequestHeader('Range', 'bytes=' + start + "-" + (end - 1)); xhr.onreadystatechange = function() { if (xhr.readyState === 4) { if (xhr.status === 206) { callback(xhr.responseText); } } }; xhr.send(); } function parseLine(line) { let element = {}; let split = line.split(/[ \t]+/); if (split.length === 0) { return; } switch (split[0]) { case "v": element.type = Element.AddVertex; element.value = new THREE.Vector3( parseFloat(split[1]), parseFloat(split[2]), parseFloat(split[3]), ); return element; case "f": element.type = Element.AddFace; element.value = new THREE.Face3( parseInt(split[1], 10) - 1, parseInt(split[2], 10) - 1, parseInt(split[3], 10) - 1, ); return element; case "ts": element.type = Element.AddTriangleStrip; element.value = []; for (let i = 1; i < split.length - 2; i++) { element.value.push(new THREE.Face3( parseInt(split[i] , 10) - 1, i % 2 === 1 ? parseInt(split[i+1], 10) - 1 : parseInt(split[i+2], 10) - 1, i % 2 === 1 ? parseInt(split[i+2], 10) - 1 : parseInt(split[i+1], 10) - 1, )); } return element; case "tf": element.type = Element.AddTriangleFan; element.value = []; for (let i = 1; i < split.length - 2; i++) { element.value.push(new THREE.Face3( parseInt(split[1] , 10) - 1, parseInt(split[i+1], 10) - 1, parseInt(split[i+2], 10) - 1, )); } return element; case "ev": element.type = Element.EditVertex; element.id = parseInt(split[1], 10) - 1; element.value = new THREE.Vector3( parseFloat(split[2]), parseFloat(split[3]), parseFloat(split[4]), ); return element; case "ef": element.type = Element.EditFace; element.id = parseInt(split[1], 10) - 1; element.value = new THREE.Face3( parseInt(split[2], 10) - 1, parseInt(split[3], 10) - 1, parseInt(split[4], 10) - 1, ); return element; case "df": element.type = Element.DeleteFace; element.id = parseInt(split[1], 10) - 1; return element; case "": case "#": return; default: throw new Error(split[0] + " is not a defined macro"); } } const Element = {}; Element.AddVertex = "AddVertex"; Element.AddFace = "AddFace"; Element.AddTriangleStrip = "AddTriangleStrip"; Element.AddTriangleFan = "AddTriangleFan"; Element.EditVertex = "EditVertex"; Element.EditFace = "EditFace"; Element.DeleteFace = "DeleteFace"; class Loader { constructor(path, chunkSize = 1024, timeout = 20) { this.path = path; this.chunkSize = chunkSize; this.timeout = timeout; this.currentByte = 0; this.remainder = ""; } start(callback) { fetchDataLength(this.path, (length) => { this.dataLength = length; this.next(callback); }); } percentage() { return 100 * this.currentByte / this.dataLength; } next(callback) { this.downloadAndParseNextChunk((data) => { callback(data); setTimeout(() => { this.next(callback); }, this.timeout); }); } downloadAndParseNextChunk(callback) { let upperBound = Math.min(this.currentByte + this.chunkSize, this.dataLength); if (upperBound <= this.currentByte) { return; } fetchData(this.path, this.currentByte, upperBound, (data) => { this.currentByte = upperBound; let elements = []; let split = data.split('\n'); split[0] = this.remainder + split[0]; this.remainder = split.pop(); for (let line of split) { elements.push(parseLine(line)); } callback(elements); }); } }