First pass of validation of EXT_mesh_features - WIP

package.json

@@ -23,11 +23,12 @@
     "3d-tiles-validator": "./build/main"
   },
   "dependencies": {
-    "3d-tiles-tools": "^0.3.0",
+    "3d-tiles-tools": "file:../3d-tiles-tools",
     "cesium": "^1.97.0",
     "gltf-validator": "^2.0.0-dev.3.9",
     "minimatch": "^5.1.0",
     "node-stream-zip": "^1.10.1",
+    "sharp": "^0.32.1",
     "yargs": "^17.5.1"
   },
   "devDependencies": {

src/issues/GltfExtensionValidationIssues.ts

@@ -20,4 +20,71 @@ export class GltfExtensionValidationIssues {
     const issue = new ValidationIssue(type, path, message, severity);
     return issue;
   }
+
+  /**
+   * Indicates that the extension referred to an element in the
+   * glTF assset that did not match the requirements of the
+   * extension specification. (For example, a 'texCoord' that
+   * referred to a VEC3 accessor). Further details should be
+   * encoded in the 'message'.
+   *
+   * @param path - The path for the `ValidationIssue`
+   * @param message - The message for the `ValidationIssue`
+   * @returns The `ValidationIssue`
+   */
+  static INVALID_GLTF_STRUCTURE(path: string, message: string) {
+    const type = "INVALID_GLTF_STRUCTURE";
+    const severity = ValidationIssueSeverity.ERROR;
+    const issue = new ValidationIssue(type, path, message, severity);
+    return issue;
+  }
+
+  /**
+   * Indicates that the feature ID texture 'channels' property
+   * had a structure that did not match the actual image data,
+   * meaning that the `channels` array contained an element
+   * that was not smaller than the number of actual channels
+   * in the image.
+   *
+   * @param path - The path for the `ValidationIssue`
+   * @param message - The message for the `ValidationIssue`
+   * @returns The `ValidationIssue`
+   */
+  static TEXTURE_CHANNELS_OUT_OF_RANGE(path: string, message: string) {
+    const type = "TEXTURE_CHANNELS_OUT_OF_RANGE";
+    const severity = ValidationIssueSeverity.ERROR;
+    const issue = new ValidationIssue(type, path, message, severity);
+    return issue;
+  }
+
+  /**
+   * Indicates that the featureCount of a feature ID did not
+   * match the actual number of IDs
+   *
+   * @param path - The path for the `ValidationIssue`
+   * @param message - The message for the `ValidationIssue`
+   * @returns The `ValidationIssue`
+   */
+  static FEATURE_COUNT_MISMATCH(path: string, message: string) {
+    const type = "FEATURE_COUNT_MISMATCH";
+    const severity = ValidationIssueSeverity.ERROR;
+    const issue = new ValidationIssue(type, path, message, severity);
+    return issue;
+  }
+
+  /**
+   * Indicates that a feature ID texture sampler used a filtering
+   * method (`minFilter` or `magFilter`) that was not `undefined`
+   * and not 9728 (`NEAREST`).
+   *
+   * @param path - The path for the `ValidationIssue`
+   * @param message - The message for the `ValidationIssue`
+   * @returns The `ValidationIssue`
+   */
+  static INVALID_FILTER_MODE(path: string, message: string) {
+    const type = "INVALID_FILTER_MODE";
+    const severity = ValidationIssueSeverity.ERROR;
+    const issue = new ValidationIssue(type, path, message, severity);
+    return issue;
+  }
 }

src/validation/gltfExtensions/Accessors.ts

@@ -0,0 +1,142 @@
+import { BinaryBufferData } from "3d-tiles-tools";
+
+/**
+ * Utility methods related to glTF accessors.
+ *
+ * NOTE: These methods are only intended for the use in the
+ * glTF extension validation. They make assumptions about
+ * the validity of the glTF asset (as established by the
+ * glTF Validator), and the structure of the glTF asset
+ * (as established by the extension validator).
+ *
+ * @internal
+ */
+export class Accessors {
+  /**
+   * Read the values of the given accessor into an array of numbers.
+   *
+   * This assumes that the accessor has the type SCALAR, and is
+   * valid (in terms of its bufferView etc), as validated with
+   * the glTF Validator.
+   *
+   * @param accessor - The glTF accessor
+   * @param gltf - The glTF object
+   * @param binaryBufferData - The binary buffer data of the glTF
+   * @returns The accessor values (or undefined if the input
+   * glTF data was invalid)
+   */
+  static readScalarAccessorValues(
+    accessor: any,
+    gltf: any,
+    binaryBufferData: BinaryBufferData
+  ): number[] | undefined {
+    const bufferViewIndex = accessor.bufferView;
+    const bufferViews = gltf.bufferViews || [];
+    const bufferView = bufferViews[bufferViewIndex];
+    const componentType = accessor.componentType;
+    let byteStride = bufferView.byteStride;
+    if (byteStride === undefined) {
+      byteStride = Accessors.sizeForComponentType(componentType);
+      if (byteStride === undefined) {
+        // Invalid component type, should have been
+        // detected by the glTF-Validator
+        return undefined;
+      }
+    }
+    const bufferViewData = binaryBufferData.bufferViewsData[bufferViewIndex];
+    const count = accessor.count;
+    const byteOffset = accessor.byteOffset;
+    const byteLength = count * byteStride;
+    const accessorData = bufferViewData.subarray(
+      byteOffset,
+      byteOffset + byteLength
+    );
+
+    const values = [];
+    for (let i = 0; i < count; i++) {
+      const value = Accessors.readValue(
+        accessorData,
+        i,
+        byteStride,
+        componentType
+      );
+      if (value === undefined) {
+        // Invalid component type, should have been
+        // detected by the glTF-Validator
+        return undefined;
+      }
+      values.push(value);
+    }
+    return values;
+  }
+
+  /**
+   * Returns the size in bytes for the given accessor component type,
+   * or undefined if the given component type is not valid.
+   *
+   * @param componentType - The component type
+   * @returns The size in bytes
+   */
+  private static sizeForComponentType(
+    componentType: number
+  ): number | undefined {
+    const BYTE = 5120;
+    const UNSIGNED_BYTE = 5121;
+    const SHORT = 5122;
+    const UNSIGNED_SHORT = 5123;
+    const UNSIGNED_INT = 5125;
+    const FLOAT = 5126;
+    switch (componentType) {
+      case BYTE:
+      case UNSIGNED_BYTE:
+        return 1;
+      case SHORT:
+      case UNSIGNED_SHORT:
+        return 2;
+      case UNSIGNED_INT:
+      case FLOAT:
+        return 4;
+    }
+    return undefined;
+  }
+
+  /**
+   * Read a single numeric value from a buffer that contains
+   * the accessor data
+   *
+   * @param buffer - The buffer
+   * @param index - The index
+   * @param byteStide - The byte stride
+   * @param componentType - The component type
+   * @returns The value
+   */
+  private static readValue(
+    buffer: Buffer,
+    index: number,
+    byteStide: number,
+    componentType: number
+  ): number | undefined {
+    const BYTE = 5120;
+    const UNSIGNED_BYTE = 5121;
+    const SHORT = 5122;
+    const UNSIGNED_SHORT = 5123;
+    const UNSIGNED_INT = 5125;
+    const FLOAT = 5126;
+    const byteOffset = index * byteStide;
+    switch (componentType) {
+      case BYTE:
+        return buffer.readInt8(byteOffset);
+      case UNSIGNED_BYTE:
+        return buffer.readUint8(byteOffset);
+      case SHORT:
+        return buffer.readInt16LE(byteOffset);
+      case UNSIGNED_SHORT:
+        return buffer.readUInt16LE(byteOffset);
+      case UNSIGNED_INT:
+        return buffer.readUInt32LE(byteOffset);
+      case FLOAT:
+        return buffer.readFloatLE(byteOffset);
+    }
+    return undefined;
+  }
+}