added a few ABMs for plants.

mods/common/functions.lua

@@ -0,0 +1,48 @@
+function common.plant_spread(nodename, pos, spread, undernode, replacing, needed_air)
+   local ran_num = math.random(1,8)
+   local location = {}
+   if ran_num == 1 then
+      location = {x=pos.x+spread, y=pos.y, z=pos.z}
+   end
+   if ran_num == 2 then
+      location = {x=pos.x+spread, y=pos.y, z=pos.z+spread}
+   end
+   if ran_num == 3 then
+      location = {x=pos.x, y=pos.y, z=pos.z+spread}
+   end
+   if ran_num == 4 then
+      location = {x=pos.x-spread, y=pos.y, z=pos.z+spread}
+   end
+   if ran_num == 5 then
+      location = {x=pos.x-spread, y=pos.y, z=pos.z}
+   end
+   if ran_num == 6 then
+      location = {x=pos.x-spread, y=pos.y, z=pos.z-spread}
+   end
+   if ran_num == 7 then
+      location = {x=pos.x, y=pos.y, z=pos.z-spread}
+   end
+   if ran_num == 8 then
+      location = {x=pos.x+spread, y=pos.y, z=pos.z-spread}
+   end
+   local under_location = ({x=location.x, y=location.y-1, z=location.z})
+   local under_name = minetest.get_node_or_nil(under_location)
+   local location_name = minetest.get_node_or_nil(location)
+   if under_name == nil then
+      return -- Should under_name somehow not be a node this will keep the script from crashing.
+   end
+   if under_name.name == undernode then
+      if location_name.name == replacing then
+         local diff = spread + 1
+         local pos1 = {x=location.x+diff, y=location.y, z=location.z+diff}
+   		local pos0 = {x=location.x-diff, y=location.y, z=location.z-diff}
+   		local can_replace = minetest.find_nodes_in_area(pos0, pos1, nodename)
+         local replace_num = #can_replace
+         print (replace_num)
+         if replace_num <= needed_air then --increase to decrease number of plants.
+            local face_ran = math.random(0,3)
+            minetest.set_node(location, {name = nodename, param2 = face_ran})
+         end
+      end
+   end
+end

mods/common/init.lua

@@ -2,3 +2,4 @@ common = {}
 
 dofile(minetest.get_modpath('common')..'/colbox.lua')
 dofile(minetest.get_modpath('common')..'/formspec.lua')
+dofile(minetest.get_modpath('common')..'/functions.lua')

mods/ground/ABMs.lua

@@ -0,0 +1,29 @@
+minetest.register_abm({
+   label = 'grass spread',
+   nodenames = {'ground:dirt'},
+   neighbors = {'ground:dirt_with_grass'},
+   interval = 3,
+   chance = 2,
+   action = function(pos)
+      local above_node = {x=pos.x, y=pos.y+1, z=pos.z}
+      local above_node_name = minetest.get_node_or_nil(above_node).name
+      local nodedef = minetest.registered_nodes[above_node_name]
+      if nodedef.sunlight_propagates then
+         minetest.add_node(pos, {name = 'ground:dirt_with_grass'})
+      end
+   end,
+})
+
+minetest.register_abm({
+   nodenames = {'ground:dirt_with_grass'},
+   interval = 3,
+   chance = 2,
+   action = function(pos)
+      local above_node = {x=pos.x, y=pos.y+1, z=pos.z}
+      local above_node_name = minetest.get_node_or_nil(above_node).name
+      local nodedef = minetest.registered_nodes[above_node_name]
+      if not nodedef.sunlight_propagates then
+         minetest.add_node(pos, {name = 'ground:dirt'})
+      end
+   end,
+})

mods/ground/init.lua

@@ -1,2 +1,3 @@
 dofile(minetest.get_modpath('ground')..'/nodes.lua')
 dofile(minetest.get_modpath('ground')..'/mapgen.lua')
+dofile(minetest.get_modpath('ground')..'/ABMs.lua')

mods/plants/ABMs.lua

@@ -0,0 +1,19 @@
+minetest.register_abm{
+	nodenames = {'group:grass'},
+	interval = 2,
+	chance = 2,
+   action = function(pos)
+      local month = mymonths.month_counter
+      local node_name = minetest.get_node_or_nil(pos).name
+      local nodedef = minetest.registered_nodes[node_name]
+      local thing_that_grows = nodedef.grows_to
+      local time_of_growing = nodedef.grows_in_month
+      if tonumber(month) == time_of_growing then
+         if thing_that_grows ~= 'spread' then
+            minetest.set_node(pos, {name = thing_that_grows})
+         elseif thing_that_grows == 'spread' then
+            common.plant_spread('plants:grass_4', pos, 2, 'ground:dirt_with_grass', 'air', 16)
+         end
+      end
+   end,
+}

mods/plants/grasses.lua

@@ -16,7 +16,9 @@ minetest.register_node('plants:grass_1', {
       local stack = ItemStack('plants:grass_' .. math.random(1,4))
       local ret = minetest.item_place(stack, placer, pointed_thing)
       return ItemStack('plants:grass_1 '.. itemstack:get_count() - (1 - ret:get_count()))
-   end
+   end,
+   grows_in_month = 5,
+   grows_to = 'plants:grass_2',
 })
 
 minetest.register_node('plants:grass_2', {
@@ -31,6 +33,8 @@ minetest.register_node('plants:grass_2', {
    buildable_to = true,
    paramtype = 'light',
    selection_box = plants.grass_sel,
+   grows_in_month = 5,
+   grows_to = 'plants:grass_3',
 })
 
 minetest.register_node('plants:grass_3', {
@@ -45,6 +49,8 @@ minetest.register_node('plants:grass_3', {
    buildable_to = true,
    paramtype = 'light',
    selection_box = plants.grass_sel,
+   grows_in_month = 5,
+   grows_to = 'plants:grass_4',
 })
 
 minetest.register_node('plants:grass_4', {
@@ -59,4 +65,6 @@ minetest.register_node('plants:grass_4', {
    buildable_to = true,
    paramtype = 'light',
    selection_box = plants.grass_sel,
+   grows_to = 'spread',
+   grows_in_month = 5,
 })

mods/plants/init.lua

@@ -3,3 +3,5 @@ plants.grass_sel = {type = 'fixed',
    fixed = {{-0.4, -0.5, -0.4, 0.4, -0.3, 0.4},}}
 
 dofile(minetest.get_modpath('plants')..'/grasses.lua')
+dofile(minetest.get_modpath('plants')..'/mapgen.lua')
+dofile(minetest.get_modpath('plants')..'/ABMs.lua')

mods/plants/mapgen.lua

@@ -0,0 +1,16 @@
+minetest.register_decoration({
+		deco_type = "simple",
+		place_on = {"ground:dirt_with_grass"},
+		sidelen = 16,
+		noise_params = {
+			offset = 0,
+			scale = 0.02,
+			spread = {x = 100, y = 100, z = 100},
+			seed = 219,
+			octaves = 3,
+			persist = 0.6
+		},
+		y_min = 1,
+		y_max = 30,
+		decoration = "plants:grass_1",
+})