Validate battle map WebP dimensions

scripts/verify-battle-map-asset-data.mjs

@@ -4,6 +4,8 @@ import { createServer } from 'vite';
 
 const battleMapDir = join('src', 'assets', 'images', 'battle');
 const battleMapAssetsSourcePath = join('src', 'game', 'data', 'battleMapAssets.ts');
+const minimumRasterMapWidth = 1024;
+const minimumRasterMapHeight = 768;
 
 const server = await createServer({
   logLevel: 'error',
@@ -185,6 +187,18 @@ function validateMapFile(errors, context, path) {
       bytes.subarray(8, 12).toString('ascii') !== 'WEBP'
     ) {
       errors.push(`${context}: "${path}" does not have a WebP RIFF header`);
+      return;
+    }
+
+    const dimensions = readWebpDimensions(bytes);
+    if (!dimensions) {
+      errors.push(`${context}: "${path}" does not expose readable WebP dimensions`);
+      return;
+    }
+    if (dimensions.width < minimumRasterMapWidth || dimensions.height < minimumRasterMapHeight) {
+      errors.push(
+        `${context}: "${path}" is ${dimensions.width}x${dimensions.height}, expected at least ${minimumRasterMapWidth}x${minimumRasterMapHeight}`
+      );
     }
     return;
   }
@@ -192,6 +206,58 @@ function validateMapFile(errors, context, path) {
   errors.push(`${context}: "${path}" uses an unsupported map asset extension`);
 }
 
+function readWebpDimensions(bytes) {
+  let offset = 12;
+  while (offset + 8 <= bytes.length) {
+    const chunkType = bytes.subarray(offset, offset + 4).toString('ascii');
+    const chunkSize = bytes.readUInt32LE(offset + 4);
+    const dataOffset = offset + 8;
+    if (dataOffset + chunkSize > bytes.length) {
+      return undefined;
+    }
+
+    if (chunkType === 'VP8X' && chunkSize >= 10) {
+      return {
+        width: readUInt24LE(bytes, dataOffset + 4) + 1,
+        height: readUInt24LE(bytes, dataOffset + 7) + 1
+      };
+    }
+
+    if (chunkType === 'VP8L' && chunkSize >= 5 && bytes[dataOffset] === 0x2f) {
+      const bits =
+        bytes[dataOffset + 1] |
+        (bytes[dataOffset + 2] << 8) |
+        (bytes[dataOffset + 3] << 16) |
+        (bytes[dataOffset + 4] << 24);
+      return {
+        width: (bits & 0x3fff) + 1,
+        height: ((bits >>> 14) & 0x3fff) + 1
+      };
+    }
+
+    if (
+      chunkType === 'VP8 ' &&
+      chunkSize >= 10 &&
+      bytes[dataOffset + 3] === 0x9d &&
+      bytes[dataOffset + 4] === 0x01 &&
+      bytes[dataOffset + 5] === 0x2a
+    ) {
+      return {
+        width: bytes.readUInt16LE(dataOffset + 6) & 0x3fff,
+        height: bytes.readUInt16LE(dataOffset + 8) & 0x3fff
+      };
+    }
+
+    offset = dataOffset + chunkSize + (chunkSize % 2);
+  }
+
+  return undefined;
+}
+
+function readUInt24LE(bytes, offset) {
+  return bytes[offset] | (bytes[offset + 1] << 8) | (bytes[offset + 2] << 16);
+}
+
 function assetUrlToPath(url) {
   const marker = 'src/assets/images/battle/';
   const index = url.indexOf(marker);