Merge pull request #154 from CesiumGS/dequantize-web3d-quantized-attr…

…ibutes

Dequantize `WEB3D_quantized_attributes`

demos/tools/TilesetUpgraderDemos.ts

@@ -57,16 +57,22 @@ async function upgradeTileset(
 }
 
 async function tilesetUpgraderDemos() {
-  await upgradeTilesetJson(
+  await upgradeTileset(
     SPECS_DATA_BASE_DIRECTORY +
-      "/upgradeTileset/tilesetWithContentUrls/tileset.json",
-    "./output/upgradeTileset/tilesetWithContentUrls-upgraded/tileset.json"
+      "/upgradeTileset/tilesetWithB3dmWithGltf1/tileset.json",
+    "./output/upgradeTileset/tilesetWithB3dmWithGltf1-upgraded/tileset.json"
   );
 
   await upgradeTileset(
     SPECS_DATA_BASE_DIRECTORY +
-      "/upgradeTileset/tilesetWithB3dmWithGltf1/tileset.json",
-    "./output/upgradeTileset/tilesetWithB3dmWithGltf1-upgraded/tileset.json"
+      "/upgradeTileset/tilesetWithB3dmWithGltf1WithWeb3dQuantizedAttributes/tileset.json",
+    "./output/upgradeTileset/tilesetWithB3dmWithGltf1WithWeb3dQuantizedAttributes-upgraded/tileset.json"
+  );
+
+  await upgradeTilesetJson(
+    SPECS_DATA_BASE_DIRECTORY +
+      "/upgradeTileset/tilesetWithContentUrls/tileset.json",
+    "./output/upgradeTileset/tilesetWithContentUrls-upgraded/tileset.json"
   );
 
   await upgradeTileset(

specs/data/upgradeTileset/tilesetWithB3dmWithGltf1WithWeb3dQuantizedAttributes/tileset.json

@@ -0,0 +1,16 @@
+{
+  "asset" : {
+    "version" : "1.1"
+  },
+  "geometricError" : 1024.0,
+  "root" : {
+    "boundingVolume" : {
+      "box" : [ 0.5, 0.00625, 0.5, 0.5, 0.0, 0.0, 0.00625, 0.0, 0.0, 0.0, 0.0, 0.5 ]
+    },
+    "geometricError" : 32.0,
+    "refine" : "ADD",
+    "content" : {
+      "uri" : "b3dmWithGltf1WithWeb3dQuantizedAttributes.b3dm"
+    }
+  }
+}

src/tilesets/tilesets/Extensions.ts

@@ -105,6 +105,30 @@ export class Extensions {
     Extensions.removeFrom(extensible, "extensionsRequired", extension);
   }
 
+  /**
+   * Returns whether the given extensible object declares the given
+   * extension in its `extensionsUsed` array.
+   *
+   * @param extensible - The object that may declare the used extension
+   * @param extension - The extension (i.e. its name as a string)
+   * @returns Whether the object declares the extension to be used
+   */
+  static usesExtension(extensible: Extensible, extension: string) {
+    return Extensions.contains(extensible, "extensionsUsed", extension);
+  }
+
+  /**
+   * Returns whether the given extensible object declares the given
+   * extension in its `extensionsRequired` array.
+   *
+   * @param extensible - The object that may declare the required extension
+   * @param extension - The extension (i.e. its name as a string)
+   * @returns Whether the object declares the extension to be required
+   */
+  static requiresExtension(extensible: Extensible, extension: string) {
+    return Extensions.contains(extensible, "extensionsRequired", extension);
+  }
+
   /**
    * Adds the given element to the specified array if it was not
    * contained yet, creating a new array if it did not exist yet.
@@ -153,4 +177,24 @@ export class Extensions {
       delete object[key];
     }
   }
+
+  /**
+   * Returns whether the specified array property is defined and
+   * includes the given element
+   *
+   * @param object - The object containing the array
+   * @param key - The name of the array property
+   * @param element - The element
+   */
+  private static contains<T>(
+    object: { [key: string]: T[] | undefined },
+    key: string,
+    element: T
+  ): boolean {
+    const array = object[key];
+    if (!array) {
+      return false;
+    }
+    return array.includes(element);
+  }
 }

src/tools/contentProcessing/GltfTransform.ts

@@ -26,7 +26,7 @@ import { StructuralMetadataMerger } from "../gltfExtensionsUtils/StructuralMetad
  */
 export class GltfTransform {
   /**
-   * The `gltf-transform` IO handler, intialized lazily and cached
+   * The `gltf-transform` IO handler, initialized lazily and cached
    * in `getIO`.
    */
   private static io: NodeIO | undefined;

src/tools/contentProcessing/GltfUtilities.ts

@@ -6,6 +6,7 @@ import { TileFormatError } from "../../tilesets";
 import { Extensions } from "../../tilesets";
 
 import { GltfPipelineLegacy } from "./GltfPipelineLegacy";
+import { GltfWeb3dQuantizedAttributes } from "./GltfWeb3dQuantizedAttributes";
 
 /**
  * Internal utility methods related to glTF/GLB data.
@@ -320,4 +321,64 @@ export class GltfUtilities {
     Extensions.removeExtensionUsed(gltf, "CESIUM_RTC");
     Extensions.removeExtension(gltf, "CESIUM_RTC");
   }
+
+  /**
+   * Given an input buffer containing a binary glTF 2.0 asset, remove
+   * its use of the `WEB3D_quantized_attributes` extension.
+   *
+   * See `GltfWeb3dQuantizedAttributes` for further notes about
+   * the context where this is used.
+   *
+   * @param glbBuffer - The buffer containing the binary glTF.
+   * @returns A promise that resolves to the resulting binary glTF.
+   */
+  static async replaceWeb3dQuantizedAttributesExtension(
+    glbBuffer: Buffer
+  ): Promise<Buffer> {
+    // Process the GLB data with a custom gltf-pipeline stage that removes
+    // the WEB3D_quantized_attributes from the extensionsUsed/Required
+    // arrays, and collects the 'decodeMatrix' arrays from the extension
+    // objects in the accessors.
+    const extensionName = "WEB3D_quantized_attributes";
+    let usedExtension = false;
+    const decodeMatrices: (number[] | undefined)[] = [];
+
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    const customStage = (gltf: any, options: any) => {
+      usedExtension = Extensions.usesExtension(gltf, extensionName);
+      if (usedExtension) {
+        Extensions.removeExtensionUsed(gltf, extensionName);
+
+        // Collect the 'decodeMatrix' arrays, one for each accessor
+        // (or 'undefined' if the accessor did not use the extension)
+        const accessors = gltf.accessors || [];
+        for (let i = 0; i < accessors.length; i++) {
+          const accessor = accessors[i];
+          const extensions = accessor.extensions || {};
+          const extension = extensions[extensionName] || {};
+          const decodeMatrix = extension.decodeMatrix;
+          decodeMatrices.push(decodeMatrix);
+        }
+      }
+      return gltf;
+    };
+    const options = {
+      customStages: [customStage],
+      keepUnusedElements: true,
+    };
+    const result = await GltfPipeline.processGlb(glbBuffer, options);
+    const preprocessedGlb = result.glb;
+
+    // If the glTF did not use the extension, then just return the result
+    if (!usedExtension) {
+      return preprocessedGlb;
+    }
+
+    // Otherwise, post-process the glTF to dequantize the accessors
+    // using the decode matrices that have been found for them.
+    return GltfWeb3dQuantizedAttributes.replaceWeb3dQuantizedAttributesExtension(
+      preprocessedGlb,
+      decodeMatrices
+    );
+  }
 }