Factor out windmill check in shape patch generation

src/js/game/map_chunk.js

@@ -226,24 +226,35 @@ export class MapChunk {
             ];
         }
 
-        // Makes sure windmills never spawn as whole
+        this.filterShapePatch({ subShapes, distanceToOriginInChunks });
+
+        const definition = this.root.shapeDefinitionMgr.getDefinitionFromSimpleShapes(subShapes);
+        this.internalGeneratePatch(
+            rng,
+            shapePatchSize,
+            this.root.shapeDefinitionMgr.getShapeItemFromDefinition(definition)
+        );
+    }
+
+    /**
+     * Makes sure windmills never spawn as whole
+     *
+     * @param {object} param0
+     * @param {[enumSubShape, enumSubShape, enumSubShape, enumSubShape]} param0.subShapes
+     * @param {number} param0.distanceToOriginInChunks
+     */
+    filterShapePatch({ subShapes, distanceToOriginInChunks }) {
         let windmillCount = 0;
         for (let i = 0; i < subShapes.length; ++i) {
             if (subShapes[i] === enumSubShape.windmill) {
                 ++windmillCount;
             }
         }
+
         if (windmillCount > 1) {
             subShapes[0] = enumSubShape.rect;
             subShapes[1] = enumSubShape.rect;
         }
-
-        const definition = this.root.shapeDefinitionMgr.getDefinitionFromSimpleShapes(subShapes);
-        this.internalGeneratePatch(
-            rng,
-            shapePatchSize,
-            this.root.shapeDefinitionMgr.getShapeItemFromDefinition(definition)
-        );
     }
 
     /**