import Check from "../Core/Check.js";
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import defaultValue from "../Core/defaultValue.js";
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import deprecationWarning from "../Core/deprecationWarning.js";
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import getJsonFromTypedArray from "../Core/getJsonFromTypedArray.js";
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import RuntimeError from "../Core/RuntimeError.js";
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/**
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* Handles parsing of a Batched 3D Model.
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*
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* @namespace B3dmParser
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* @private
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*/
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var B3dmParser = {};
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B3dmParser._deprecationWarning = deprecationWarning;
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var sizeOfUint32 = Uint32Array.BYTES_PER_ELEMENT;
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/**
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* Parses the contents of a {@link https://github.com/CesiumGS/3d-tiles/tree/main/specification/TileFormats/Batched3DModel|Batched 3D Model}.
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*
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* @private
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*
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* @param {ArrayBuffer} arrayBuffer The array buffer containing the B3DM.
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* @param {Number} [byteOffset=0] The byte offset of the beginning of the B3DM in the array buffer.
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* @returns {Object} Returns an object with the batch length, feature table (binary and json), batch table (binary and json) and glTF parts of the B3DM.
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*/
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B3dmParser.parse = function (arrayBuffer, byteOffset) {
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var byteStart = defaultValue(byteOffset, 0);
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//>>includeStart('debug', pragmas.debug);
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Check.defined("arrayBuffer", arrayBuffer);
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//>>includeEnd('debug');
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byteOffset = byteStart;
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var uint8Array = new Uint8Array(arrayBuffer);
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var view = new DataView(arrayBuffer);
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byteOffset += sizeOfUint32; // Skip magic
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var version = view.getUint32(byteOffset, true);
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if (version !== 1) {
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throw new RuntimeError(
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"Only Batched 3D Model version 1 is supported. Version " +
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version +
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" is not."
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);
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}
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byteOffset += sizeOfUint32;
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var byteLength = view.getUint32(byteOffset, true);
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byteOffset += sizeOfUint32;
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var featureTableJsonByteLength = view.getUint32(byteOffset, true);
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byteOffset += sizeOfUint32;
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var featureTableBinaryByteLength = view.getUint32(byteOffset, true);
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byteOffset += sizeOfUint32;
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var batchTableJsonByteLength = view.getUint32(byteOffset, true);
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byteOffset += sizeOfUint32;
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var batchTableBinaryByteLength = view.getUint32(byteOffset, true);
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byteOffset += sizeOfUint32;
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var batchLength;
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// Legacy header #1: [batchLength] [batchTableByteLength]
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// Legacy header #2: [batchTableJsonByteLength] [batchTableBinaryByteLength] [batchLength]
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// Current header: [featureTableJsonByteLength] [featureTableBinaryByteLength] [batchTableJsonByteLength] [batchTableBinaryByteLength]
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// If the header is in the first legacy format 'batchTableJsonByteLength' will be the start of the JSON string (a quotation mark) or the glTF magic.
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// Accordingly its first byte will be either 0x22 or 0x67, and so the minimum uint32 expected is 0x22000000 = 570425344 = 570MB. It is unlikely that the feature table JSON will exceed this length.
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// The check for the second legacy format is similar, except it checks 'batchTableBinaryByteLength' instead
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if (batchTableJsonByteLength >= 570425344) {
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// First legacy check
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byteOffset -= sizeOfUint32 * 2;
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batchLength = featureTableJsonByteLength;
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batchTableJsonByteLength = featureTableBinaryByteLength;
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batchTableBinaryByteLength = 0;
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featureTableJsonByteLength = 0;
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featureTableBinaryByteLength = 0;
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B3dmParser._deprecationWarning(
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"b3dm-legacy-header",
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"This b3dm header is using the legacy format [batchLength] [batchTableByteLength]. The new format is [featureTableJsonByteLength] [featureTableBinaryByteLength] [batchTableJsonByteLength] [batchTableBinaryByteLength] from https://github.com/CesiumGS/3d-tiles/tree/main/specification/TileFormats/Batched3DModel."
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);
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} else if (batchTableBinaryByteLength >= 570425344) {
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// Second legacy check
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byteOffset -= sizeOfUint32;
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batchLength = batchTableJsonByteLength;
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batchTableJsonByteLength = featureTableJsonByteLength;
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batchTableBinaryByteLength = featureTableBinaryByteLength;
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featureTableJsonByteLength = 0;
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featureTableBinaryByteLength = 0;
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B3dmParser._deprecationWarning(
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"b3dm-legacy-header",
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"This b3dm header is using the legacy format [batchTableJsonByteLength] [batchTableBinaryByteLength] [batchLength]. The new format is [featureTableJsonByteLength] [featureTableBinaryByteLength] [batchTableJsonByteLength] [batchTableBinaryByteLength] from https://github.com/CesiumGS/3d-tiles/tree/main/specification/TileFormats/Batched3DModel."
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);
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}
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var featureTableJson;
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if (featureTableJsonByteLength === 0) {
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featureTableJson = {
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BATCH_LENGTH: defaultValue(batchLength, 0),
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};
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} else {
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featureTableJson = getJsonFromTypedArray(
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uint8Array,
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byteOffset,
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featureTableJsonByteLength
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);
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byteOffset += featureTableJsonByteLength;
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}
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var featureTableBinary = new Uint8Array(
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arrayBuffer,
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byteOffset,
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featureTableBinaryByteLength
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);
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byteOffset += featureTableBinaryByteLength;
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var batchTableJson;
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var batchTableBinary;
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if (batchTableJsonByteLength > 0) {
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// PERFORMANCE_IDEA: is it possible to allocate this on-demand? Perhaps keep the
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// arraybuffer/string compressed in memory and then decompress it when it is first accessed.
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//
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// We could also make another request for it, but that would make the property set/get
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// API async, and would double the number of numbers in some cases.
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batchTableJson = getJsonFromTypedArray(
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uint8Array,
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byteOffset,
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batchTableJsonByteLength
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);
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byteOffset += batchTableJsonByteLength;
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if (batchTableBinaryByteLength > 0) {
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// Has a batch table binary
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batchTableBinary = new Uint8Array(
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arrayBuffer,
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byteOffset,
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batchTableBinaryByteLength
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);
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// Copy the batchTableBinary section and let the underlying ArrayBuffer be freed
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batchTableBinary = new Uint8Array(batchTableBinary);
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byteOffset += batchTableBinaryByteLength;
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}
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}
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var gltfByteLength = byteStart + byteLength - byteOffset;
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if (gltfByteLength === 0) {
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throw new RuntimeError("glTF byte length must be greater than 0.");
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}
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var gltfView;
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if (byteOffset % 4 === 0) {
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gltfView = new Uint8Array(arrayBuffer, byteOffset, gltfByteLength);
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} else {
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// Create a copy of the glb so that it is 4-byte aligned
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B3dmParser._deprecationWarning(
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"b3dm-glb-unaligned",
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"The embedded glb is not aligned to a 4-byte boundary."
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);
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gltfView = new Uint8Array(
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uint8Array.subarray(byteOffset, byteOffset + gltfByteLength)
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);
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}
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return {
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batchLength: batchLength,
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featureTableJson: featureTableJson,
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featureTableBinary: featureTableBinary,
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batchTableJson: batchTableJson,
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batchTableBinary: batchTableBinary,
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gltf: gltfView,
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};
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};
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export default B3dmParser;
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