only look through holes to levels below

src/c3nav/mapdata/render/base.py

@@ -13,6 +13,13 @@ class LevelGeometries:
         self.altitudeareas = []
         self.walls = None
         self.doors = None
+        self.holes = None
+
+    @staticmethod
+    def crop(self, geometry, crop_to):
+        if crop_to is None:
+            return geometry
+        return geometry.intersection(crop_to)
 
     @staticmethod
     def rebuild():
@@ -32,6 +39,9 @@ class LevelGeometries:
             spaces_geom = unary_union([s.geometry for s in level.spaces.all()])
             geoms.doors = unary_union([d.geometry for d in level.doors.all()])
             walkable_geom = unary_union([s.walkable_geom for s in level.spaces.all()]).union(geoms.doors)
+            if level.on_top_of_id is None:
+                geoms.holes = spaces_geom.difference(walkable_geom)
+                print(level.pk, geoms.holes.area)
 
             for altitudearea in level.altitudeareas.all():
                 geoms.altitudeareas.append((altitudearea.geometry.intersection(walkable_geom), altitudearea.altitude))