Add configurable area asset budgets

scripts/lib/area-config.js

@@ -2,6 +2,7 @@
 
 const fs = require("fs");
 const path = require("path");
+const { BUDGETS } = require("./stage-manifest");
 
 function readAreaConfig(file, options = {}) {
   if (!fs.existsSync(file)) {
@@ -23,6 +24,7 @@ function normalizeAreaConfig(raw, options = {}) {
   const areaDir = path.resolve(outputOverrides.areaDir || path.join(outputRoot, id));
   const fileStem = outputOverrides.fileStem || id;
   const compress = normalizeCompressConfig(raw.compress);
+  const budget = normalizeBudgetConfig(raw.budget);
   const compressedFileStem = outputOverrides.compressedFileStem ||
     `${fileStem}-compressed-webp${compress.textureSize}${compress.meshopt ? "-meshopt" : ""}`;
   const pipelineDir = path.resolve(outputOverrides.pipelineDir || path.join(areaDir, "_pipeline"));
@@ -92,10 +94,34 @@ function normalizeAreaConfig(raw, options = {}) {
       officeOverrides: raw.blender?.officeOverrides || raw.blender?.office_overrides || "",
     },
     compress,
+    budget,
     outputs,
   };
 }
 
+function normalizeBudgetConfig(raw) {
+  if (raw !== undefined && raw !== null && (typeof raw !== "object" || Array.isArray(raw))) {
+    throw new Error("budget must be an object");
+  }
+  const value = raw || {};
+  const budget = {
+    glbBytes: megabytesOption(value.glbSizeMb, BUDGETS.glbBytes, "budget.glbSizeMb"),
+    glbNodes: integerOption(value.nodes, BUDGETS.glbNodes, "budget.nodes"),
+    glbImages: integerOption(value.images, BUDGETS.glbImages, "budget.images"),
+    glbTriangles: integerOption(value.triangles, BUDGETS.glbTriangles, "budget.triangles"),
+    glbImageBytes: megabytesOption(value.embeddedImageBytesMb, BUDGETS.glbImageBytes, "budget.embeddedImageBytesMb"),
+    reason: value.reason ?? "",
+  };
+  if (typeof budget.reason !== "string") {
+    throw new Error("budget.reason must be a string");
+  }
+  const loosened = Object.keys(BUDGETS).some((key) => budget[key] > BUDGETS[key]);
+  if (loosened && budget.reason.trim() === "") {
+    throw new Error("budget.reason is required when a budget exceeds the default");
+  }
+  return budget;
+}
+
 function requireText(value, key) {
   if (typeof value !== "string" || value.trim() === "") {
     throw new Error(`Missing config key: ${key}`);
@@ -121,6 +147,22 @@ function numberOption(value, fallback, label, min, max) {
   return number;
 }
 
+function integerOption(value, fallback, label) {
+  const number = value === undefined ? fallback : Number(value);
+  if (!Number.isInteger(number) || number < 1) {
+    throw new Error(`${label} must be a positive integer`);
+  }
+  return number;
+}
+
+function megabytesOption(value, fallbackBytes, label) {
+  const megabytes = value === undefined ? fallbackBytes / 1024 / 1024 : Number(value);
+  if (!Number.isFinite(megabytes) || megabytes <= 0) {
+    throw new Error(`${label} must be a positive finite number`);
+  }
+  return Math.round(megabytes * 1024 * 1024);
+}
+
 function booleanOption(value, fallback, label) {
   if (value === undefined) return fallback;
   if (typeof value === "boolean") return value;