Default: Generalise, optimise and simplify grass spread function

Credit to tenplus1 for the suggestion to generalise for mod use.
Mods can add mod nodes to 'group:spreading_dirt_type' enabling the
function to work with mod nodes.

Add some nodes to this group.

Removing 'dirt_with_grass' etc. from 'neighbors' stops the ABM action
running everywhere and constantly, on the dirt nodes immediately below
the surface nodes. Now the action only runs in the rare case of a dirt
node with neighbouring air, grass decorations or snow.

Remove check for air above to allow grass to spread under light-
transmitting nodes such as fences, walls, plants. This causes spread
under slabs, stairs and glass, when near air, but seems worth it.

Remove unnecessary check for nil node.

diff --git a/mods/default/functions.lua b/mods/default/functions.lua
index 3c8a871a1667db3f8f21fce24a341e9ba8e8b0d8..901dd93429bea2e1e021af4f8570b9fa1bbbb6b2 100644 (file)
--- a/mods/default/functions.lua
+++ b/mods/default/functions.lua
@@ -348,9 +348,7 @@ minetest.register_abm({
        label = "Grass spread",
        nodenames = {"default:dirt"},
        neighbors = {
-               "default:dirt_with_grass",
-               "default:dirt_with_dry_grass",
-               "default:dirt_with_snow",
+               "air",
                "group:grass",
                "group:dry_grass",
                "default:snow",
@@ -359,36 +357,27 @@ minetest.register_abm({
        chance = 67,
        catch_up = false,
        action = function(pos, node)
-               -- Most likely case, half the time it's too dark for this.
+               -- Check for darkness: night, shadow or under a light-blocking node
+               -- Returns if ignore above
                local above = {x = pos.x, y = pos.y + 1, z = pos.z}
                if (minetest.get_node_light(above) or 0) < 13 then
                        return
                end
 
-               -- Look for likely neighbors.
-               local p2 = minetest.find_node_near(pos, 1, {"default:dirt_with_grass",
-                               "default:dirt_with_dry_grass", "default:dirt_with_snow"})
+               -- Look for spreading dirt-type neighbours
+               local p2 = minetest.find_node_near(pos, 1, "group:spreading_dirt_type")
                if p2 then
-                       -- But the node needs to be under air in this case.
-                       local n2 = minetest.get_node(above)
-                       if n2 and n2.name == "air" then
-                               local n3 = minetest.get_node(p2)
-                               minetest.set_node(pos, {name = n3.name})
-                               return
-                       end
-               end
-
-               -- Anything on top?
-               local n2 = minetest.get_node(above)
-               if not n2 then
+                       local n3 = minetest.get_node(p2)
+                       minetest.set_node(pos, {name = n3.name})
                        return
                end
 
-               local name = n2.name
-               -- Snow check is cheapest, so comes first.
+               -- Else, any seeding nodes on top?
+               local name = minetest.get_node(above).name
+               -- Snow check is cheapest, so comes first
                if name == "default:snow" then
                        minetest.set_node(pos, {name = "default:dirt_with_snow"})
-               -- Most likely case first.
+               -- Most likely case first
                elseif minetest.get_item_group(name, "grass") ~= 0 then
                        minetest.set_node(pos, {name = "default:dirt_with_grass"})
                elseif minetest.get_item_group(name, "dry_grass") ~= 0 then
@@ -404,11 +393,7 @@ minetest.register_abm({
 
 minetest.register_abm({
        label = "Grass covered",
-       nodenames = {
-               "default:dirt_with_grass",
-               "default:dirt_with_dry_grass",
-               "default:dirt_with_snow",
-       },
+       nodenames = {"group:spreading_dirt_type"},
        interval = 8,
        chance = 50,
        catch_up = false,

diff --git a/mods/default/nodes.lua b/mods/default/nodes.lua
index 79aea5bbc26b848fad9e44ac899fd31b19e5ad68..c5d05232b63723f54a85198099a9f4824338868c 100644 (file)
--- a/mods/default/nodes.lua
+++ b/mods/default/nodes.lua
@@ -332,7 +332,7 @@ minetest.register_node("default:dirt_with_grass", {
        tiles = {"default_grass.png", "default_dirt.png",
                {name = "default_dirt.png^default_grass_side.png",
                        tileable_vertical = false}},
-       groups = {crumbly = 3, soil = 1},
+       groups = {crumbly = 3, soil = 1, spreading_dirt_type = 1},
        drop = 'default:dirt',
        sounds = default.node_sound_dirt_defaults({
                footstep = {name = "default_grass_footstep", gain = 0.25},
@@ -357,7 +357,7 @@ minetest.register_node("default:dirt_with_dry_grass", {
                "default_dirt.png",
                {name = "default_dirt.png^default_dry_grass_side.png",
                        tileable_vertical = false}},
-       groups = {crumbly = 3, soil = 1},
+       groups = {crumbly = 3, soil = 1, spreading_dirt_type = 1},
        drop = 'default:dirt',
        sounds = default.node_sound_dirt_defaults({
                footstep = {name = "default_grass_footstep", gain = 0.4},
@@ -369,7 +369,7 @@ minetest.register_node("default:dirt_with_snow", {
        tiles = {"default_snow.png", "default_dirt.png",
                {name = "default_dirt.png^default_snow_side.png",
                        tileable_vertical = false}},
-       groups = {crumbly = 3, soil = 1},
+       groups = {crumbly = 3, soil = 1, spreading_dirt_type = 1},
        drop = 'default:dirt',
        sounds = default.node_sound_dirt_defaults({
                footstep = {name = "default_snow_footstep", gain = 0.15},