Add 3D BFS iterator

utils.py

@@ -1,4 +1,5 @@
 import importlib
+import collections
 from math import floor, ceil, sqrt, hypot
 
 import blocks
@@ -94,3 +95,50 @@ def break_time(block_id, held_item=0, in_water=False, on_ground=True, enchantmen
     if not on_ground: time *= 5.0
 
     return time
+
+def search_3d(distance=0, y_limit=0):
+    def get_neighbors(x,y,z):
+        return [
+            (x+1, y+1, z+0),
+            (x+1, y-1, z+0),
+            (x+1, y+1, z+1),
+            (x+1, y+0, z+1),
+            (x+1, y-1, z+1),
+            (x+1, y+1, z-1),
+            (x+1, y+0, z-1),
+            (x+1, y-1, z-1),
+            (x+1, y+0, z+0),
+            (x+0, y+1, z+0),
+            (x+0, y-1, z+0),
+            (x+0, y+1, z+1),
+            (x+0, y+0, z+1),
+            (x+0, y-1, z+1),
+            (x+0, y+1, z-1),
+            (x+0, y+0, z-1),
+            (x+0, y-1, z-1),
+            (x-1, y+1, z+0),
+            (x-1, y-1, z+0),
+            (x-1, y+1, z+1),
+            (x-1, y+0, z+1),
+            (x-1, y-1, z+1),
+            (x-1, y+1, z-1),
+            (x-1, y+0, z-1),
+            (x-1, y-1, z-1),
+            (x-1, y+0, z+0),
+        ]
+
+    to_visit = collections.deque([(0, 0, 0)])
+    visited = set()
+
+    while to_visit:
+        cur = to_visit.pop()
+        if cur in visited:
+            continue
+        if y_limit and abs(cur[1]) > y_limit:
+            continue
+        if distance and hypot(*cur) > distance:
+            continue
+        for neighbor in get_neighbors(*cur):
+            to_visit.appendleft(neighbor)
+        visited.add(cur)
+        yield cur