103 lines
2.8 KiB
JavaScript
103 lines
2.8 KiB
JavaScript
import defined from "../Core/defined.js";
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import getJsonFromTypedArray from "../Core/getJsonFromTypedArray.js";
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import getMagic from "../Core/getMagic.js";
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import RuntimeError from "../Core/RuntimeError.js";
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import Cesium3DTileContentType from "./Cesium3DTileContentType.js";
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/**
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* Results of the preprocess3DTileContent() function. This includes the
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* {@link Cesium3DTileContentType} and the payload. The payload is either
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* binary or JSON depending on the content type.
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*
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* @typedef {object} PreprocessedContent
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* @property {Cesium3DTileContentType} contentType The type of the content
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* @property {Uint8Array} [binaryPayload] For binary files, the payload is returned as a typed array with byteOffset of 0
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* @property {object} [jsonPayload] For JSON files, the results are returned as a JSON object.
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* @private
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*/
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/**
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* Preprocess a {@link Cesium3DTileContent}, to determine the type of content
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* and to parse JSON files into objects.
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*
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* @param {ArrayBuffer} arrayBuffer The raw binary payload
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* @return {PreprocessedContent}
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* @private
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*/
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function preprocess3DTileContent(arrayBuffer) {
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const uint8Array = new Uint8Array(arrayBuffer);
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let contentType = getMagic(uint8Array);
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// We use glTF for JSON glTF files. For binary glTF, we rename this
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// to glb to disambiguate
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if (contentType === "glTF") {
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contentType = "glb";
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}
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if (Cesium3DTileContentType.isBinaryFormat(contentType)) {
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return {
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// For binary files, the enum value is the magic number
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contentType: contentType,
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binaryPayload: uint8Array,
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};
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}
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const json = getJsonContent(uint8Array);
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if (defined(json.root)) {
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// Most likely a tileset JSON
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return {
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contentType: Cesium3DTileContentType.EXTERNAL_TILESET,
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jsonPayload: json,
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};
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}
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if (defined(json.asset)) {
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// Most likely a glTF. Tileset JSON also has an "asset" property
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// so this check needs to happen second
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return {
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contentType: Cesium3DTileContentType.GLTF,
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jsonPayload: json,
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};
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}
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if (defined(json.tileAvailability)) {
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// Most likely a subtree JSON.
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return {
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contentType: Cesium3DTileContentType.IMPLICIT_SUBTREE_JSON,
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jsonPayload: json,
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};
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}
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if (defined(json.type)) {
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// Most likely a GeoJSON
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return {
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contentType: Cesium3DTileContentType.GEOJSON,
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jsonPayload: json,
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};
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}
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if (defined(json.voxelTable)) {
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// Most likely a voxel JSON
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return {
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contentType: Cesium3DTileContentType.VOXEL_JSON,
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jsonPayload: json,
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};
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}
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throw new RuntimeError("Invalid tile content.");
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}
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function getJsonContent(uint8Array) {
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let json;
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try {
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json = getJsonFromTypedArray(uint8Array);
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} catch (error) {
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throw new RuntimeError("Invalid tile content.");
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}
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return json;
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}
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export default preprocess3DTileContent;
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