Add Chromium-only Blender WebEngine parity work

web/protocol/lod.ts

@@ -0,0 +1,104 @@
+import { parseLODManifest, SimplifyValidationError, type LODManifest, type SimplifyProfile } from "./simplify";
+
+export type LODPoseState = "REST" | "POSE";
+
+export interface LODGenerationLevelRequest {
+  profile: SimplifyProfile;
+  triangleBudget: number;
+  maxGeometricError?: number;
+  screenSpaceError?: number;
+}
+
+export interface LODGenerationRequest {
+  meshId: string;
+  sourceMeshRevision: number;
+  levels: LODGenerationLevelRequest[];
+}
+
+export interface LODCacheKeyInput {
+  objectId: string;
+  meshRevision: number;
+  modifierStackHash: string;
+  profileHash: string;
+  poseOrRestState: LODPoseState;
+}
+
+export interface LODCacheRecord extends LODManifest {
+  cacheKey: string;
+  objectId: string;
+  modifierStackHash: string;
+  profileHash: string;
+  poseOrRestState: LODPoseState;
+  generatedAt: string;
+  byteLength?: number;
+  lastAccessAt?: string;
+}
+
+function fnv1a(value: string, seed: number): number {
+  let hash = seed >>> 0;
+  for (let index = 0; index < value.length; index++) {
+    hash ^= value.charCodeAt(index);
+    hash = Math.imul(hash, 0x01000193);
+  }
+  return hash >>> 0;
+}
+
+function canonicalKey(input: LODCacheKeyInput): string {
+  return JSON.stringify([
+    input.objectId,
+    input.meshRevision,
+    input.modifierStackHash,
+    input.profileHash,
+    input.poseOrRestState,
+  ]);
+}
+
+/** Stable, path-safe key. It intentionally excludes mutable timestamps. */
+export function buildLODCacheKey(input: LODCacheKeyInput): string {
+  if (!input.objectId || !Number.isInteger(input.meshRevision) || input.meshRevision < 0) {
+    throw new Error("Invalid LOD cache key input");
+  }
+  if (!input.modifierStackHash || !input.profileHash) throw new Error("LOD cache hashes are required");
+  const value = canonicalKey(input);
+  const first = fnv1a(value, 0x811c9dc5).toString(16).padStart(8, "0");
+  const second = fnv1a(value, 0x9e3779b9).toString(16).padStart(8, "0");
+  return `lod-${first}${second}`;
+}
+
+export function lodManifestCacheKey(manifest: LODCacheRecord): string {
+  return buildLODCacheKey({
+    objectId: manifest.objectId,
+    meshRevision: manifest.sourceMeshRevision,
+    modifierStackHash: manifest.modifierStackHash,
+    profileHash: manifest.profileHash,
+    poseOrRestState: manifest.poseOrRestState,
+  });
+}
+
+export function parseLODCacheRecord(value: unknown): LODCacheRecord {
+  const manifest = parseLODManifest(value);
+  if (typeof value !== "object" || value === null || Array.isArray(value)) {
+    throw new SimplifyValidationError("INVALID_LOD_MANIFEST", "LOD cache record must be an object");
+  }
+  const input = value as Record<string, unknown>;
+  const fields = ["cacheKey", "objectId", "modifierStackHash", "profileHash", "generatedAt"];
+  if (fields.some((field) => typeof input[field] !== "string" || !input[field])) {
+    throw new SimplifyValidationError("INVALID_LOD_MANIFEST", "LOD cache record metadata is incomplete");
+  }
+  if (input.poseOrRestState !== "REST" && input.poseOrRestState !== "POSE") {
+    throw new SimplifyValidationError("INVALID_LOD_MANIFEST", "LOD poseOrRestState must be REST or POSE");
+  }
+  const record: LODCacheRecord = {
+    ...manifest,
+    cacheKey: input.cacheKey as string,
+    objectId: input.objectId as string,
+    modifierStackHash: input.modifierStackHash as string,
+    profileHash: input.profileHash as string,
+    poseOrRestState: input.poseOrRestState,
+    generatedAt: input.generatedAt as string,
+  };
+  if (lodManifestCacheKey(record) !== record.cacheKey) {
+    throw new SimplifyValidationError("INVALID_LOD_MANIFEST", "LOD cacheKey does not match its source inputs");
+  }
+  return record;
+}