From be96530e20d0a584334b4f876b7b74e13e46122e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=93=D0=B5=D1=80=D1=85=D0=B0=D1=80=D0=B4=20PICCORO=20Len?=
 =?UTF-8?q?z=20McKAY?= <mckaygerhard@gmail.com>
Date: Fri, 10 Dec 2021 15:24:32 -0400
Subject: [PATCH] Mushroom spread: make overridable and reduce spread

* Move mushroom spread ABM action into a global and overridable function.
  but do not optimise spread code
* backported bcf98df5fac3eb59b02d9fdb066ab92c6228d787
* Reduce spread range to reduce spread through walls.
---
 mods/flowers/init.lua | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/mods/flowers/init.lua b/mods/flowers/init.lua
index 51ade79..00a82ee 100644
--- a/mods/flowers/init.lua
+++ b/mods/flowers/init.lua
@@ -214,19 +214,28 @@ function flowers.mushroom_spread(pos, node)
 		minetest.remove_node(pos)
 		return
 	end
-	local positions = minetest.find_nodes_in_area_under_air(
-		{x = pos.x - 1, y = pos.y - 2, z = pos.z - 1},
-		{x = pos.x + 1, y = pos.y + 1, z = pos.z + 1},
-		{"group:soil", "group:tree"})
-	if #positions == 0 then
-		return
+	local random = {
+	    x = pos.x + math.random(-2, 2),
+	    y = pos.y + math.random(-1, 1),
+	    z = pos.z + math.random(-2, 2)
+	}
+	local random_node = minetest.get_node_or_nil(random)
+	if not random_node or random_node.name ~= "air" then
+	    return
 	end
-	local pos2 = positions[math.random(#positions)]
-	pos2.y = pos2.y + 1
-	if minetest.get_node_light(pos, 0.5) <= 3 and
-			minetest.get_node_light(pos2, 0.5) <= 3 then
-		minetest.set_node(pos2, {name = node.name})
+	local node_under = minetest.get_node_or_nil({x = random.x,
+	    y = random.y - 1, z = random.z})
+	if not node_under then
+	    return
 	end
+
+	if (minetest.get_item_group(node_under.name, "soil") ~= 0 or
+		minetest.get_item_group(node_under.name, "tree") ~= 0) and
+		minetest.get_node_light(pos, 0.5) <= 3 and
+		minetest.get_node_light(random, 0.5) <= 3 then
+	    minetest.set_node(random, {name = node.name})
+	end
+
 end
 
 minetest.register_abm({