refactor code structure

module/utils.py

@@ -0,0 +1,24 @@
+import random
+from module import WIDTH, BLOCK_SIZE, HEIGHT
+
+
+# 生成地形
+def generate_terrain():
+    world = []
+    ground_level = HEIGHT // BLOCK_SIZE // 2
+
+    for x in range(WIDTH // BLOCK_SIZE):
+        column = []
+        height = ground_level + random.randint(-3, 3)
+        for y in range(HEIGHT // BLOCK_SIZE):
+            if y > height + 2:
+                column.append("stone")
+            elif y == height:
+                column.append("grass")
+            elif y > height - 3:
+                column.append("dirt")
+            else:
+                column.append("air")
+        world.append(column)
+
+    return world