Fire: move fire node removal out of ABM.

Because the fire nodes are not removed 100% when there are
no more burnable nodes nearby, they can potentially stay around
for very, very long times, leading to ABM trains every 5 seconds
for no good reason (only 1 in 16 will be removed every interval).

A much better method to remove fire nodes is to remove them by
timer, and give removal a 100% chance if no flammable nodes are
adjacent. This makes fire cleanup a lot faster and more natural,
and will reduce the amount of ABM hits making fire overall more
responsive.

We also remove the 1 in 4 chance and fold the removal of flammable
nodes into the ABM chance.

There's some low hanging fruit cleanups in here as well.

diff --git a/mods/fire/init.lua b/mods/fire/init.lua
index 457f6b5e68f0f1167f96a243dc5c2ebd3ec9d535..832b7014ae5b0c1098449f6ef76dd0f22fc097ab 100644 (file)
--- a/mods/fire/init.lua
+++ b/mods/fire/init.lua
@@ -28,14 +28,24 @@ minetest.register_node("fire:basic_flame", {
        sunlight_propagates = true,
        damage_per_second = 4,
        groups = {igniter = 2, dig_immediate = 3, not_in_creative_inventory = 1},
+       on_timer = function(pos)
+               local f = minetest.find_node_near(pos, 1, {"group:flammable"})
+               if not f then
+                       minetest.remove_node(pos)
+                       return
+               end
+               -- restart timer
+               return true
+       end,
        drop = "",
 
        on_construct = function(pos)
-               minetest.after(0, fire.on_flame_add_at, pos)
+               minetest.get_node_timer(pos):start(math.random(30, 60))
+               minetest.after(0, fire.update_sounds_around, pos)
        end,
 
        on_destruct = function(pos)
-               minetest.after(0, fire.on_flame_remove_at, pos)
+               minetest.after(0, fire.update_sounds_around, pos)
        end,
 
        on_blast = function()
@@ -169,32 +179,6 @@ function fire.update_sounds_around(pos)
 end
 
 
--- Update fire sounds on flame node construct or destruct
-
-function fire.on_flame_add_at(pos)
-       fire.update_sounds_around(pos)
-end
-
-
-function fire.on_flame_remove_at(pos)
-       fire.update_sounds_around(pos)
-end
-
-
--- Return positions for flames around a burning node
-
-function fire.find_pos_for_flame_around(pos)
-       return minetest.find_node_near(pos, 1, {"air"})
-end
-
-
--- Detect nearby extinguishing nodes
-
-function fire.flame_should_extinguish(pos)
-       return minetest.find_node_near(pos, 1, {"group:puts_out_fire"})
-end
-
-
 -- Extinguish all flames quickly with water, snow, ice
 
 minetest.register_abm({
@@ -239,31 +223,27 @@ else
                catch_up = false,
                action = function(p0, node, _, _)
                        -- If there is water or stuff like that around node, don't ignite
-                       if fire.flame_should_extinguish(p0) then
+                       if minetest.find_node_near(p0, 1, {"group:puts_out_fire"}) then
                                return
                        end
-                       local p = fire.find_pos_for_flame_around(p0)
+                       local p = minetest.find_node_near(p0, 1, {"air"})
                        if p then
                                minetest.set_node(p, {name = "fire:basic_flame"})
                        end
                end,
        })
 
-       -- Remove basic flames and flammable nodes
+       -- Remove flammable nodes
 
        minetest.register_abm({
                nodenames = {"fire:basic_flame"},
+               neighbors = "group:flammable",
                interval = 5,
-               chance = 6,
+               chance = 18,
                catch_up = false,
                action = function(p0, node, _, _)
-                       -- If there are no flammable nodes around flame, remove flame
                        local p = minetest.find_node_near(p0, 1, {"group:flammable"})
-                       if not p then
-                               minetest.remove_node(p0)
-                               return
-                       end
-                       if math.random(1, 3) == 1 then
+                       if p then
                                -- remove flammable nodes around flame
                                local node = minetest.get_node(p)
                                local def = minetest.registered_nodes[node.name]