hmm?

worldMap.js

@@ -8,6 +8,8 @@ const NEGATIVE_ONE_FIELDS = new Set([
   "prefectureRegionId",
   "regionId",
   "municipalityId",
+  "naturalCompartmentId",
+  "watershedId",
 ]);
 
 function isCellField(value) {
@@ -24,7 +26,7 @@ function defaultForField(name, Constructor) {
 }
 
 function makeWorldField(name, source, worldWidth, worldHeight, originX, originY) {
-  const Constructor = source.constructor;
+  const Constructor = NEGATIVE_ONE_FIELDS.has(name) ? Int32Array : source.constructor;
   const out = new Constructor(worldWidth * worldHeight);
   const fallback = defaultForField(name, Constructor);
   if (fallback !== 0) out.fill(fallback);
@@ -98,3 +100,73 @@ export function clampCameraToWorld(camera, world, viewWidth = MAP_W, viewHeight
     y: Math.min(Math.max(Math.round(camera.y || 0), 0), maxY),
   };
 }
+
+function expandRectByOffset(rect, dx, dy) {
+  if (!rect) return rect;
+  return { ...rect, x0: rect.x0 + dx, y0: rect.y0 + dy, x1: rect.x1 + dx, y1: rect.y1 + dy };
+}
+
+function shiftRectCollections(world, dx, dy) {
+  if (!dx && !dy) return;
+  for (const key of ["generatedRects", "invalidatedRects", "humanPatchHistory"]) {
+    if (!Array.isArray(world[key])) continue;
+    world[key] = world[key].map((item) => {
+      const out = expandRectByOffset(item, dx, dy);
+      for (const sub of ["coreRect", "writeRect", "repairRect", "contextRect", "blendRect", "transportReachRect"]) {
+        if (out?.[sub]) out[sub] = expandRectByOffset(out[sub], dx, dy);
+      }
+      return out;
+    });
+  }
+  if (world.lastPatchResult) {
+    world.lastPatchResult = { ...world.lastPatchResult };
+    for (const sub of ["coreRect", "writeRect", "repairRect", "contextRect", "blendRect", "transportReachRect"]) {
+      if (world.lastPatchResult[sub]) world.lastPatchResult[sub] = expandRectByOffset(world.lastPatchResult[sub], dx, dy);
+    }
+  }
+}
+
+export function expandWorldMap(world, margins = {}) {
+  if (!world) return { world, dx: 0, dy: 0, expanded: false };
+  const left = Math.max(0, Math.floor(margins.left || 0));
+  const right = Math.max(0, Math.floor(margins.right || 0));
+  const top = Math.max(0, Math.floor(margins.top || 0));
+  const bottom = Math.max(0, Math.floor(margins.bottom || 0));
+  if (!left && !right && !top && !bottom) return { world, dx: 0, dy: 0, expanded: false };
+  const oldWidth = world.width;
+  const oldHeight = world.height;
+  const newWidth = oldWidth + left + right;
+  const newHeight = oldHeight + top + bottom;
+  const newFields = {};
+  for (const [name, field] of Object.entries(world.fields || {})) {
+    if (!ArrayBuffer.isView(field)) continue;
+    const Constructor = NEGATIVE_ONE_FIELDS.has(name) ? Int32Array : field.constructor;
+    const out = new Constructor(newWidth * newHeight);
+    const fallback = defaultForField(name, Constructor);
+    if (fallback !== 0) out.fill(fallback);
+    for (let y = 0; y < oldHeight; y++) {
+      const srcRow = y * oldWidth;
+      const dstRow = (y + top) * newWidth + left;
+      for (let x = 0; x < oldWidth; x++) out[dstRow + x] = field[srcRow + x];
+    }
+    newFields[name] = out;
+  }
+  world.width = newWidth;
+  world.height = newHeight;
+  world.originX += left;
+  world.originY += top;
+  world.fields = newFields;
+  shiftRectCollections(world, left, top);
+  return { world, dx: left, dy: top, expanded: true };
+}
+
+export function ensureWorldPaddingForCamera(world, camera, viewWidth = MAP_W, viewHeight = MAP_H, padding = Math.floor(Math.min(MAP_W, MAP_H) * 0.45)) {
+  if (!world || !camera) return { dx: 0, dy: 0, expanded: false };
+  const grow = Math.max(64, Math.floor(padding));
+  const margins = { left: 0, right: 0, top: 0, bottom: 0 };
+  if (camera.x < grow) margins.left = grow;
+  if (camera.y < grow) margins.top = grow;
+  if (camera.x + viewWidth > world.width - grow) margins.right = grow;
+  if (camera.y + viewHeight > world.height - grow) margins.bottom = grow;
+  return expandWorldMap(world, margins);
+}