More variations of mega spruces and large oaks

[MineClone/MineClone2.git] / mods / ITEMS / mcl_core / functions.lua

--
-- Lava vs water interactions
--

local mg_name = minetest.get_mapgen_setting("mg_name")

minetest.register_abm({
        label = "Lava cooling",
        nodenames = {"group:lava"},
        neighbors = {"group:water"},
        interval = 1,
        chance = 1,
        action = function(pos, node, active_object_count, active_object_count_wider)
                local water = minetest.find_nodes_in_area({x=pos.x-1, y=pos.y-1, z=pos.z-1}, {x=pos.x+1, y=pos.y+1, z=pos.z+1}, "group:water")

                local lavatype = minetest.registered_nodes[node.name].liquidtype

                for w=1, #water do
                        local waternode = minetest.get_node(water[w])
                        local watertype = minetest.registered_nodes[waternode.name].liquidtype
                        -- Lava on top of water: Water turns into stone
                        if water[w].y < pos.y and water[w].x == pos.x and water[w].z == pos.z then
                                minetest.set_node(water[w], {name="mcl_core:stone"})
                                minetest.sound_play("fire_extinguish_flame", {pos = water[w], gain = 0.25, max_hear_distance = 16})
                        -- Flowing lava vs water on same level: Lava turns into cobblestone
                        elseif lavatype == "flowing" and water[w].y == pos.y and (water[w].x == pos.x or water[w].z == pos.z) then
                                minetest.set_node(pos, {name="mcl_core:cobble"})
                                minetest.sound_play("fire_extinguish_flame", {pos = pos, gain = 0.25, max_hear_distance = 16})
                        -- Lava source vs flowing water above or horizontally neighbored: Lava turns into obsidian
                        elseif lavatype == "source" and
                                        ((water[w].y > pos.y and water[w].x == pos.x and water[w].z == pos.z) or
                                        (water[w].y == pos.y and (water[w].x == pos.x or water[w].z == pos.z))) then
                                minetest.set_node(pos, {name="mcl_core:obsidian"})
                                minetest.sound_play("fire_extinguish_flame", {pos = pos, gain = 0.25, max_hear_distance = 16})
                        -- Flowing water above flowing lava: Lava turns into cobblestone
                        elseif watertype == "flowing" and lavatype == "flowing" and water[w].y > pos.y and water[w].x == pos.x and water[w].z == pos.z then
                                minetest.set_node(pos, {name="mcl_core:cobble"})
                                minetest.sound_play("fire_extinguish_flame", {pos = pos, gain = 0.25, max_hear_distance = 16})
                        end
                end
        end,
})

--
-- Papyrus and cactus growing
--

-- Functions
mcl_core.grow_cactus = function(pos, node)
        pos.y = pos.y-1
        local name = minetest.get_node(pos).name
        if minetest.get_item_group(name, "sand") ~= 0 then
                pos.y = pos.y+1
                local height = 0
                while minetest.get_node(pos).name == "mcl_core:cactus" and height < 4 do
                        height = height+1
                        pos.y = pos.y+1
                end
                if height < 3 then
                        if minetest.get_node(pos).name == "air" then
                                minetest.set_node(pos, {name="mcl_core:cactus"})
                        end
                end
        end
end

mcl_core.grow_reeds = function(pos, node)
        pos.y = pos.y-1
        local name = minetest.get_node(pos).name
        if minetest.get_item_group(name, "soil_sugarcane") ~= 0 then
                if minetest.find_node_near(pos, 1, {"group:water"}) == nil and minetest.find_node_near(pos, 1, {"group:frosted_ice"}) == nil then
                        return
                end
                pos.y = pos.y+1
                local height = 0
                while minetest.get_node(pos).name == "mcl_core:reeds" and height < 3 do
                        height = height+1
                        pos.y = pos.y+1
                end
                if height < 3 then
                        if minetest.get_node(pos).name == "air" then
                                minetest.set_node(pos, {name="mcl_core:reeds"})
                        end
                end
        end
end

-- ABMs


local function drop_attached_node(p)
        local nn = minetest.get_node(p).name
        if nn == "air" or nn == "ignore" then
                return
        end
        minetest.remove_node(p)
        for _, item in pairs(minetest.get_node_drops(nn, "")) do
                local pos = {
                        x = p.x + math.random()/2 - 0.25,
                        y = p.y + math.random()/2 - 0.25,
                        z = p.z + math.random()/2 - 0.25,
                }
                if item ~= "" then
                        minetest.add_item(pos, item)
                end
        end
end

-- Helper function for node actions for liquid flow
local liquid_flow_action = function(pos, group, action)
        local check_detach = function(pos, xp, yp, zp)
                local p = {x=pos.x+xp, y=pos.y+yp, z=pos.z+zp}
                local n = minetest.get_node_or_nil(p)
                if not n then
                        return false
                end
                local d = minetest.registered_nodes[n.name]
                if not d then
                        return false
                end
                --[[ Check if we want to perform the liquid action.
                * 1: Item must be in liquid group
                * 2a: If target node is below liquid, always succeed
                * 2b: If target node is horizontal to liquid: succeed if source, otherwise check param2 for horizontal flow direction ]]
                local range = d.liquid_range or 8
                if (minetest.get_item_group(n.name, group) ~= 0) and
                                ((yp > 0) or
                                (yp == 0 and ((d.liquidtype == "source") or (n.param2 > (8-range) and n.param2 < 9)))) then
                        action(pos)
                end
        end
        local posses = {
                { x=-1, y=0, z=0 },
                { x=1, y=0, z=0 },
                { x=0, y=0, z=-1 },
                { x=0, y=0, z=1 },
                { x=0, y=1, z=0 },
        }
        for p=1,#posses do
                check_detach(pos, posses[p].x, posses[p].y, posses[p].z)
        end
end

-- Drop some nodes next to flowing water, if it would flow into the node
minetest.register_abm({
        label = "Wash away dig_by_water nodes by water flow",
        nodenames = {"group:dig_by_water"},
        neighbors = {"group:water"},
        interval = 1,
        chance = 1,
        action = function(pos, node, active_object_count, active_object_count_wider)
                liquid_flow_action(pos, "water", function(pos)
                        drop_attached_node(pos)
                        minetest.dig_node(pos)
                end)
        end,
})

-- Destroy some nodes next to flowing lava, if it would flow into the node
minetest.register_abm({
        label = "Destroy destroy_by_lava_flow nodes by lava flow",
        nodenames = {"group:destroy_by_lava_flow"},
        neighbors = {"group:lava"},
        interval = 1,
        chance = 1,
        action = function(pos, node, active_object_count, active_object_count_wider)
                liquid_flow_action(pos, "lava", function(pos)
                        minetest.remove_node(pos)
                        minetest.sound_play("builtin_item_lava", {pos = pos, gain = 0.25, max_hear_distance = 16})
                        core.check_for_falling(pos)
                end)
        end,
})

minetest.register_abm({
        label = "Cactus growth",
        nodenames = {"mcl_core:cactus"},
        neighbors = {"group:sand"},
        interval = 25,
        chance = 10,
        action = function(pos)
                mcl_core.grow_cactus(pos)
        end,
})

minetest.register_abm({
        label = "Sugar canes growth",
        nodenames = {"mcl_core:reeds"},
        neighbors = {"group:soil_sugarcane"},
        interval = 25,
        chance = 10,
        action = function(pos)
                mcl_core.grow_reeds(pos)
        end,
})

--
-- Sugar canes drop
--

local timber_nodenames={"mcl_core:reeds"}

minetest.register_on_dignode(function(pos, node)
        local i=1
        while timber_nodenames[i]~=nil do
                local np={x=pos.x, y=pos.y+1, z=pos.z}
                while minetest.get_node(np).name==timber_nodenames[i] do
                        minetest.remove_node(np)
                        minetest.add_item(np, timber_nodenames[i])
                        np={x=np.x, y=np.y+1, z=np.z}
                end
                i=i+1
        end
end)

local function air_leaf(leaftype)
        if math.random(0, 50) == 3 then
                return {name = "air"}
        else
                return {name = leaftype}
        end
end

function mcl_core.generate_tree(pos, tree_type, two_by_two)
        pos.y = pos.y-1
        local nodename = minetest.get_node(pos).name
                
        pos.y = pos.y+1
        if not minetest.get_node_light(pos) then
                return
        end
        local node

        if tree_type == nil or tree_type == 1 then
                if mg_name == "v6" then
                        mcl_core.generate_v6_oak_tree(pos)
                else
                        mcl_core.generate_oak_tree(pos)
                end
        elseif tree_type == 2 and two_by_two then
                mcl_core.generate_dark_oak_tree(pos)
        elseif tree_type == 3 then
                if two_by_two then
                        mcl_core.generate_huge_spruce_tree(pos)
                else
                        if mg_name == "v6" then
                                mcl_core.generate_v6_spruce_tree(pos)
                        else
                                mcl_core.generate_spruce_tree(pos)
                        end
                end
        elseif tree_type == 4 then
                mcl_core.generate_acacia_tree(pos)
        elseif tree_type == 5 then
                if two_by_two then
                        mcl_core.generate_huge_jungle_tree(pos)
                else
                        if mg_name == "v6" then
                                mcl_core.generate_v6_jungle_tree(pos)
                        else
                                mcl_core.generate_jungle_tree(pos)
                        end
                end
        elseif tree_type == 6 then
                mcl_core.generate_birch_tree(pos)
        end
end

-- Classic oak in v6 style
function mcl_core.generate_v6_oak_tree(pos)
        local trunk = "mcl_core:tree"
        local leaves = "mcl_core:leaves"
        local node = {name = ""}
        for dy=1,4 do
                pos.y = pos.y+dy
                if minetest.get_node(pos).name ~= "air" then
                        return
                end
                pos.y = pos.y-dy
        end
        node = {name = trunk}
        for dy=0,4 do
                pos.y = pos.y+dy
                if minetest.get_node(pos).name == "air" then
                        minetest.add_node(pos, node)
                end
                pos.y = pos.y-dy
        end

        node = {name = leaves}
        pos.y = pos.y+3
        local rarity = 0
        if math.random(0, 10) == 3 then
                rarity = 1
        end
        for dx=-2,2 do
                for dz=-2,2 do
                        for dy=0,3 do
                                pos.x = pos.x+dx
                                pos.y = pos.y+dy
                                pos.z = pos.z+dz

                                if dx == 0 and dz == 0 and dy==3 then
                                        if minetest.get_node(pos).name == "air" and math.random(1, 5) <= 4 then
                                                minetest.add_node(pos, node)
                                                minetest.add_node(pos, air_leaf(leaves))
                                        end
                                elseif dx == 0 and dz == 0 and dy==4 then
                                        if minetest.get_node(pos).name == "air" and math.random(1, 5) <= 4 then
                                                minetest.add_node(pos, node)
                                                minetest.add_node(pos, air_leaf(leaves))
                                        end
                                elseif math.abs(dx) ~= 2 and math.abs(dz) ~= 2 then
                                        if minetest.get_node(pos).name == "air" then
                                                minetest.add_node(pos, node)
                                                minetest.add_node(pos, air_leaf(leaves))
                                        end
                                else
                                        if math.abs(dx) ~= 2 or math.abs(dz) ~= 2 then
                                                if minetest.get_node(pos).name == "air" and math.random(1, 5) <= 4 then
                                                        minetest.add_node(pos, node)
                                                        minetest.add_node(pos, air_leaf(leaves))
                                                end
                                        end
                                end
                                pos.x = pos.x-dx
                                pos.y = pos.y-dy
                                pos.z = pos.z-dz
                        end
                end
        end
end

-- Oak
function mcl_core.generate_oak_tree(pos)
        local r = math.random(1, 12)
        local path
        local offset
        -- Balloon oak
        if r == 1 then
                local s = math.random(1, 12)
                if s == 1 then
                        -- Small balloon oak
                        path = minetest.get_modpath("mcl_core") .. "/schematics/mcl_core_oak_balloon.mts"
                        offset = { x = -2, y = -1, z = -2 }
                else
                        -- Large balloon oak
                        local t = math.random(1, 4)
                        path = minetest.get_modpath("mcl_core") .. "/schematics/mcl_core_oak_large_"..t..".mts"
                        if t == 1 or t == 3 then
                                offset = { x = -3, y = -1, z = -3 }
                        elseif t == 2 or t == 4 then
                                offset = { x = -4, y = -1, z = -4 }
                        end
                end
        -- Classic oak
        else
                path = minetest.get_modpath("mcl_core") .. "/schematics/mcl_core_oak_classic.mts"
                offset = { x = -2, y = -1, z = -2 }

        end
        minetest.place_schematic(vector.add(pos, offset), path, "random", nil, false)
end

-- Birch
function mcl_core.generate_birch_tree(pos)
        local path = minetest.get_modpath("mcl_core") ..
                "/schematics/mcl_core_birch.mts"
        minetest.place_schematic({x = pos.x - 2, y = pos.y - 1, z = pos.z - 2}, path, "random", nil, false)
end

-- BEGIN of spruce tree generation functions --
-- Copied from Minetest Game 0.4.15 from the pine tree (default.generate_pine_tree)

-- Pine tree (=spruce tree in MCL2) from mg mapgen mod, design by sfan5, pointy top added by paramat
local function add_spruce_leaves(data, vi, c_air, c_ignore, c_snow, c_spruce_leaves)
        local node_id = data[vi]
        if node_id == c_air or node_id == c_ignore or node_id == c_snow then
                data[vi] = c_spruce_leaves
        end
end

function mcl_core.generate_v6_spruce_tree(pos)
        local x, y, z = pos.x, pos.y, pos.z
        local maxy = y + math.random(9, 13) -- Trunk top

        local c_air = minetest.get_content_id("air")
        local c_ignore = minetest.get_content_id("ignore")
        local c_spruce_tree = minetest.get_content_id("mcl_core:sprucetree")
        local c_spruce_leaves  = minetest.get_content_id("mcl_core:spruceleaves")
        local c_snow = minetest.get_content_id("mcl_core:snow")

        local vm = minetest.get_voxel_manip()
        local minp, maxp = vm:read_from_map(
                {x = x - 3, y = y, z = z - 3},
                {x = x + 3, y = maxy + 3, z = z + 3}
        )
        local a = VoxelArea:new({MinEdge = minp, MaxEdge = maxp})
        local data = vm:get_data()

        -- Upper branches layer
        local dev = 3
        for yy = maxy - 1, maxy + 1 do
                for zz = z - dev, z + dev do
                        local vi = a:index(x - dev, yy, zz)
                        local via = a:index(x - dev, yy + 1, zz)
                        for xx = x - dev, x + dev do
                                if math.random() < 0.95 - dev * 0.05 then
                                        add_spruce_leaves(data, vi, c_air, c_ignore, c_snow,
                                                c_spruce_leaves)
                                end
                                vi  = vi + 1
                                via = via + 1
                        end
                end
                dev = dev - 1
        end

        -- Centre top nodes
        add_spruce_leaves(data, a:index(x, maxy + 1, z), c_air, c_ignore, c_snow,
                c_spruce_leaves)
        add_spruce_leaves(data, a:index(x, maxy + 2, z), c_air, c_ignore, c_snow,
                c_spruce_leaves) -- Paramat added a pointy top node

        -- Lower branches layer
        local my = 0
        for i = 1, 20 do -- Random 2x2 squares of leaves
                local xi = x + math.random(-3, 2)
                local yy = maxy + math.random(-6, -5)
                local zi = z + math.random(-3, 2)
                if yy > my then
                        my = yy
                end
                for zz = zi, zi+1 do
                        local vi = a:index(xi, yy, zz)
                        local via = a:index(xi, yy + 1, zz)
                        for xx = xi, xi + 1 do
                                add_spruce_leaves(data, vi, c_air, c_ignore, c_snow,
                                        c_spruce_leaves)
                                vi  = vi + 1
                                via = via + 1
                        end
                end
        end

        dev = 2
        for yy = my + 1, my + 2 do
                for zz = z - dev, z + dev do
                        local vi = a:index(x - dev, yy, zz)
                        local via = a:index(x - dev, yy + 1, zz)
                        for xx = x - dev, x + dev do
                                if math.random() < 0.95 - dev * 0.05 then
                                        add_spruce_leaves(data, vi, c_air, c_ignore, c_snow,
                                                c_spruce_leaves)
                                end
                                vi  = vi + 1
                                via = via + 1
                        end
                end
                dev = dev - 1
        end

        -- Trunk
        -- Force-place lowest trunk node to replace sapling
        data[a:index(x, y, z)] = c_spruce_tree
        for yy = y + 1, maxy do
                local vi = a:index(x, yy, z)
                local node_id = data[vi]
                if node_id == c_air or node_id == c_ignore or
                                node_id == c_spruce_leaves or node_id == c_snow then
                        data[vi] = c_spruce_tree
                end
        end

        vm:set_data(data)
        vm:write_to_map()
end

mcl_core.generate_spruce_tree = function(pos)
        local r = math.random(1, 3)
        local path = minetest.get_modpath("mcl_core") .. "/schematics/mcl_core_spruce_"..r..".mts"
        minetest.place_schematic({ x = pos.x - 3, y = pos.y - 1, z = pos.z - 3 }, path, "0", nil, false)
end

mcl_core.generate_huge_spruce_tree = function(pos)
        local r1 = math.random(1, 2)
        local r2 = math.random(1, 4)
        local path
        local offset = { x = -4, y = -1, z = -5 }
        if r1 <= 2 then
                -- Mega Spruce Taiga (full canopy)
                path = minetest.get_modpath("mcl_core") .. "/schematics/mcl_core_spruce_huge_"..r2..".mts"
        else
                -- Mega Taiga (leaves only at top)
                if r2 == 1 or r2 == 3 then
                        offset = { x = -3, y = -1, z = -4}
                end
                path = minetest.get_modpath("mcl_core") .. "/schematics/mcl_core_spruce_huge_up_"..r2..".mts"
        end
        minetest.place_schematic(vector.add(pos, offset), path, "0", nil, false)
end

-- END of spruce tree functions --

-- Acacia tree (multiple variants)
function mcl_core.generate_acacia_tree(pos)
        local r = math.random(1, 7)
        local offset = vector.new()
        if r == 2 or r == 3 then
                offset = { x = -4, y = -1, z = -4 }
        elseif r == 4 or r == 6 or r == 7 then
                offset = { x = -3, y = -1, z = -3 }
        elseif r == 1 or r == 5 then
                offset = { x = -5, y = -1, z = -5 }
        end
        local path = minetest.get_modpath("mcl_core") .. "/schematics/mcl_core_acacia_"..r..".mts"
        minetest.place_schematic(vector.add(pos, offset), path, "random", nil, false)
end

-- Generate dark oak tree with 2×2 trunk.
-- With pos being the lower X and the higher Z value of the trunk
function mcl_core.generate_dark_oak_tree(pos)
        local path = minetest.get_modpath("mcl_core") ..
                "/schematics/mcl_core_dark_oak.mts"
        minetest.place_schematic({x = pos.x - 3, y = pos.y - 1, z = pos.z - 4}, path, "random", nil, false)
end

-- Helper function for jungle tree, form Minetest Game 0.4.15
local function add_trunk_and_leaves(data, a, pos, tree_cid, leaves_cid,
                height, size, iters)
        local x, y, z = pos.x, pos.y, pos.z
        local c_air = minetest.CONTENT_AIR
        local c_ignore = minetest.CONTENT_IGNORE

        -- Trunk
        data[a:index(x, y, z)] = tree_cid -- Force-place lowest trunk node to replace sapling
        for yy = y + 1, y + height - 1 do
                local vi = a:index(x, yy, z)
                local node_id = data[vi]
                if node_id == c_air or node_id == c_ignore or node_id == leaves_cid then
                        data[vi] = tree_cid
                end
        end

        -- Force leaves near the trunk
        for z_dist = -1, 1 do
        for y_dist = -size, 1 do
                local vi = a:index(x - 1, y + height + y_dist, z + z_dist)
                for x_dist = -1, 1 do
                        if data[vi] == c_air or data[vi] == c_ignore then
                                data[vi] = leaves_cid
                        end
                        vi = vi + 1
                end
        end
        end

        -- Randomly add leaves in 2x2x2 clusters.
        for i = 1, iters do
                local clust_x = x + math.random(-size, size - 1)
                local clust_y = y + height + math.random(-size, 0)
                local clust_z = z + math.random(-size, size - 1)

                for xi = 0, 1 do
                for yi = 0, 1 do
                for zi = 0, 1 do
                        local vi = a:index(clust_x + xi, clust_y + yi, clust_z + zi)
                        if data[vi] == c_air or data[vi] == c_ignore then
                                data[vi] = leaves_cid
                        end
                end
                end
                end
        end
end

-- Old jungle tree grow function from Minetest Game 0.4.15, imitating v6 jungle trees
function mcl_core.generate_v6_jungle_tree(pos)
        --[[
                NOTE: Jungletree-placing code is currently duplicated in the engine
                and in games that have saplings; both are deprecated but not
                replaced yet
        --]]

        local x, y, z = pos.x, pos.y, pos.z
        local height = math.random(8, 12)
        local c_air = minetest.get_content_id("air")
        local c_ignore = minetest.get_content_id("ignore")
        local c_jungletree = minetest.get_content_id("mcl_core:jungletree")
        local c_jungleleaves = minetest.get_content_id("mcl_core:jungleleaves")

        local vm = minetest.get_voxel_manip()
        local minp, maxp = vm:read_from_map(
                {x = x - 3, y = y - 1, z = z - 3},
                {x = x + 3, y = y + height + 1, z = z + 3}
        )
        local a = VoxelArea:new({MinEdge = minp, MaxEdge = maxp})
        local data = vm:get_data()

        add_trunk_and_leaves(data, a, pos, c_jungletree, c_jungleleaves, height, 3, 30)

        -- Roots
        for z_dist = -1, 1 do
                local vi_1 = a:index(x - 1, y - 1, z + z_dist)
                local vi_2 = a:index(x - 1, y, z + z_dist)
                for x_dist = -1, 1 do
                        if math.random(1, 3) >= 2 then
                                if data[vi_1] == c_air or data[vi_1] == c_ignore then
                                        data[vi_1] = c_jungletree
                                elseif data[vi_2] == c_air or data[vi_2] == c_ignore then
                                        data[vi_2] = c_jungletree
                                end
                        end
                        vi_1 = vi_1 + 1
                        vi_2 = vi_2 + 1
                end
        end

        vm:set_data(data)
        vm:write_to_map()
end

function mcl_core.generate_jungle_tree(pos)
        local path = minetest.get_modpath("mcl_core") ..
                "/schematics/mcl_core_jungle_tree.mts"
        minetest.place_schematic({x = pos.x - 2, y = pos.y - 1, z = pos.z - 2}, path, "random", nil, false)
end

-- Generate huge jungle tree with 2×2 trunk.
-- With pos being the lower X and the higher Z value of the trunk.
function mcl_core.generate_huge_jungle_tree(pos)
        -- 2 variants
        local r = math.random(1, 2)
        local path = minetest.get_modpath("mcl_core") ..
                "/schematics/mcl_core_jungle_tree_huge_"..r..".mts"
        minetest.place_schematic({x = pos.x - 6, y = pos.y - 1, z = pos.z - 7}, path, "random", nil, false)
end


local grass_spread_randomizer = PseudoRandom(minetest.get_mapgen_setting("seed"))

------------------------------
-- Spread grass blocks and mycelium on neighbor dirt
------------------------------
minetest.register_abm({
        label = "Grass Block and Mycelium spread",
        nodenames = {"mcl_core:dirt"},
        neighbors = {"air", "group:grass_block_no_snow", "mcl_core:mycelium"},
        interval = 30,
        chance = 20,
        catch_up = false,
        action = function(pos)
                if pos == nil then
                        return
                end
                local can_change = false
                local above = {x=pos.x, y=pos.y+1, z=pos.z}
                local abovenode = minetest.get_node(above)
                if minetest.get_item_group(abovenode.name, "liquid") ~= 0 or minetest.get_item_group(abovenode.name, "opaque") == 1 then
                        -- Never grow directly below liquids or opaque blocks
                        return
                end
                local light_self = minetest.get_node_light(above)
                if not light_self then return end
                --[[ Try to find a spreading dirt-type block (e.g. grass block or mycelium)
                within a 3×5×3 area, with the source block being on the 2nd-topmost layer. ]]
                local nodes = minetest.find_nodes_in_area({x=pos.x-1, y=pos.y-1, z=pos.z-1}, {x=pos.x+1, y=pos.y+3, z=pos.z+1}, "group:spreading_dirt_type")
                local p2
                -- Nothing found ? Bail out!
                if #nodes <= 0 then
                        return
                else
                        p2 = nodes[grass_spread_randomizer:next(1, #nodes)]
                end

                -- Found it! Now check light levels!
                local source_above = {x=p2.x, y=p2.y+1, z=p2.z}
                local light_source = minetest.get_node_light(source_above)
                if not light_source then return end

                if light_self >= 4 and light_source >= 9 then
                        -- All checks passed! Let's spread the grass/mycelium!
                        local n2 = minetest.get_node(p2)
                        minetest.set_node(pos, {name=n2.name})

                        -- If this was mycelium, uproot plant above
                        if n2.name == "mcl_core:mycelium" then
                                local tad = minetest.registered_nodes[minetest.get_node(above).name]
                                if tad.groups and tad.groups.non_mycelium_plant then
                                        minetest.dig_node(above)
                                end
                        end
                end
        end
})

-- Grass/mycelium death in darkness
minetest.register_abm({
        label = "Grass Block / Mycelium in darkness",
        nodenames = {"group:spreading_dirt_type"},
        interval = 8,
        chance = 50,
        catch_up = false,
        action = function(pos, node)
                local above = {x = pos.x, y = pos.y + 1, z = pos.z}
                local name = minetest.get_node(above).name
                -- Kill grass/mycelium when below opaque block or liquid
                if name ~= "ignore" and (minetest.get_item_group(name, "opaque") == 1 or minetest.get_item_group(name, "liquid") ~= 0) then
                        minetest.set_node(pos, {name = "mcl_core:dirt"})
                end
        end
})

-- Turn Grass Path and similar nodes to Dirt if a solid node is placed above it
minetest.register_on_placenode(function(pos, newnode, placer, oldnode, itemstack, pointed_thing)
        if minetest.get_item_group(newnode.name, "solid") ~= 0 or
                        minetest.get_item_group(newnode.name, "dirtifier") ~= 0 then
                local below = {x=pos.x, y=pos.y-1, z=pos.z}
                local belownode = minetest.get_node(below)
                if minetest.get_item_group(belownode.name, "dirtifies_below_solid") == 1 then
                        minetest.set_node(below, {name="mcl_core:dirt"})
                end
        end
end)

minetest.register_abm({
        label = "Turn Grass Path below solid block into Dirt",
        nodenames = {"mcl_core:grass_path"},
        neighbors = {"group:solid"},
        interval = 8,
        chance = 50,
        action = function(pos, node)
                local above = {x = pos.x, y = pos.y + 1, z = pos.z}
                local name = minetest.get_node(above).name
                local nodedef = minetest.registered_nodes[name]
                if name ~= "ignore" and nodedef and (nodedef.groups and nodedef.groups.solid) then
                        minetest.set_node(pos, {name = "mcl_core:dirt"})
                end
        end,
})

--------------------------
-- Try generate tree   ---
--------------------------
local treelight = 9

local sapling_grow_action = function(tree_id, soil_needed, one_by_one, two_by_two, sapling)
        return function(pos)
                -- Checks if the sapling at pos has enough light and the correct soil
                local sapling_is_growable = function(pos)
                        local light = minetest.get_node_light(pos)
                        local soilnode = minetest.get_node({x=pos.x, y=pos.y-1, z=pos.z})
                        local soiltype = minetest.get_item_group(soilnode.name, "soil_sapling")
                        return soiltype >= soil_needed and light and light >= treelight
                end
                if sapling_is_growable(pos) then
                        -- Increase and check growth stage
                        local meta = minetest.get_meta(pos)
                        local stage = meta:get_int("stage")
                        if stage == nil then stage = 0 end
                        stage = stage + 1
                        if stage >= 3 then
                                -- This sapling grows in a special way when there are 4 saplings in a 2×2 pattern
                                if two_by_two then
                                        -- Check 8 surrounding saplings and try to find a 2×2 pattern
                                        local is_sapling = function(pos, sapling)
                                                return minetest.get_node(pos).name == sapling
                                        end
                                        local p2 = {x=pos.x+1, y=pos.y, z=pos.z}
                                        local p3 = {x=pos.x, y=pos.y, z=pos.z-1}
                                        local p4 = {x=pos.x+1, y=pos.y, z=pos.z-1}
                                        local p5 = {x=pos.x-1, y=pos.y, z=pos.z-1}
                                        local p6 = {x=pos.x-1, y=pos.y, z=pos.z}
                                        local p7 = {x=pos.x-1, y=pos.y, z=pos.z+1}
                                        local p8 = {x=pos.x, y=pos.y, z=pos.z+1}
                                        local p9 = {x=pos.x+1, y=pos.y, z=pos.z+1}
                                        local s2 = is_sapling(p2, sapling)
                                        local s3 = is_sapling(p3, sapling)
                                        local s4 = is_sapling(p4, sapling)
                                        local s5 = is_sapling(p5, sapling)
                                        local s6 = is_sapling(p6, sapling)
                                        local s7 = is_sapling(p7, sapling)
                                        local s8 = is_sapling(p8, sapling)
                                        local s9 = is_sapling(p9, sapling)
                                        -- In a 9×9 field there are 4 possible 2×2 squares. We check them all.
                                        if s2 and s3 and s4 then
                                                -- Success: Remove saplings and place tree
                                                minetest.remove_node(pos, {name="air"})
                                                minetest.remove_node(p2, {name="air"})
                                                minetest.remove_node(p3, {name="air"})
                                                minetest.remove_node(p4, {name="air"})
                                                mcl_core.generate_tree(pos, tree_id, true)
                                                return
                                        elseif s3 and s5 and s6 then
                                                minetest.remove_node(pos, {name="air"})
                                                minetest.remove_node(p3, {name="air"})
                                                minetest.remove_node(p5, {name="air"})
                                                minetest.remove_node(p6, {name="air"})
                                                mcl_core.generate_tree(p6, tree_id, true)
                                                return
                                        elseif s6 and s7 and s8 then
                                                minetest.remove_node(pos, {name="air"})
                                                minetest.remove_node(p6, {name="air"})
                                                minetest.remove_node(p7, {name="air"})
                                                minetest.remove_node(p8, {name="air"})
                                                mcl_core.generate_tree(p7, tree_id, true)
                                                return
                                        elseif s2 and s8 and s9 then
                                                minetest.remove_node(pos, {name="air"})
                                                minetest.remove_node(p2, {name="air"})
                                                minetest.remove_node(p8, {name="air"})
                                                minetest.remove_node(p9, {name="air"})
                                                mcl_core.generate_tree(p8, tree_id, true)
                                                return
                                        end
                                end
                                -- If this sapling can grow alone
                                if one_by_one then
                                        -- Single sapling
                                        minetest.set_node(pos, {name="air"})
                                        mcl_core.generate_tree(pos, tree_id)
                                        return
                                end
                        else
                                meta:set_int("stage", stage)
                        end
                end
        end
end

local grow_oak = sapling_grow_action(1, 1, true, false)
local grow_dark_oak = sapling_grow_action(2, 2, false, true, "mcl_core:darksapling")
local grow_jungle_tree = sapling_grow_action(5, 1, true, true, "mcl_core:junglesapling")
local grow_acacia = sapling_grow_action(4, 2, true, false)
local grow_spruce = sapling_grow_action(3, 1, true, true, "mcl_core:sprucesapling")
local grow_birch = sapling_grow_action(6, 1, true, false)

-- Attempts to grow the sapling at the specified position
-- pos: Position
-- node: Node table of the node at this position, from minetest.get_node
-- Returns true on success and false on failure
mcl_core.grow_sapling = function(pos, node)
        local grow
        if node.name == "mcl_core:sapling" then
                grow = grow_oak
        elseif node.name == "mcl_core:darksapling" then
                grow = grow_dark_oak
        elseif node.name == "mcl_core:junglesapling" then
                grow = grow_jungle_tree
        elseif node.name == "mcl_core:acaciasapling" then
                grow = grow_acacia
        elseif node.name == "mcl_core:sprucesapling" then
                grow = grow_spruce
        elseif node.name == "mcl_core:birchsapling" then
                grow = grow_birch
        end
        if grow then
                grow(pos)
                return true
        else
                return false
        end
end

-- TODO: Use better tree models for everything
-- TODO: Support 2×2 saplings

-- Oak tree
minetest.register_abm({
        label = "Oak tree growth",
        nodenames = {"mcl_core:sapling"},
        neighbors = {"group:soil_sapling"},
        interval = 25,
        chance = 2,
        action = grow_oak,
})

-- Dark oak tree
minetest.register_abm({
        label = "Dark oak tree growth",
        nodenames = {"mcl_core:darksapling"},
        neighbors = {"group:soil_sapling"},
        interval = 25,
        chance = 2,
        action = grow_dark_oak,
})

-- Jungle Tree
minetest.register_abm({
        label = "Jungle tree growth",
        nodenames = {"mcl_core:junglesapling"},
        neighbors = {"group:soil_sapling"},
        interval = 25,
        chance = 2,
        action = grow_jungle_tree,
})

-- Spruce tree
minetest.register_abm({
        label = "Spruce tree growth",
        nodenames = {"mcl_core:sprucesapling"},
        neighbors = {"group:soil_sapling"},
        interval = 25,
        chance = 2,
        action = grow_spruce
})

-- Birch tree
minetest.register_abm({
        label = "Birch tree growth",
        nodenames = {"mcl_core:birchsapling"},
        neighbors = {"group:soil_sapling"},
        interval = 25,
        chance = 2,
        action = grow_birch,
})

-- Acacia tree
minetest.register_abm({
        label = "Acacia tree growth",
        nodenames = {"mcl_core:acaciasapling"},
        neighbors = {"group:soil_sapling"},
        interval = 20,
        chance = 2,
        action = grow_acacia,
})

---------------------
-- Vine generating --
---------------------
minetest.register_abm({
        label = "Vines growth",
        nodenames = {"mcl_core:vine"},
        interval = 47,
        chance = 4,
        action = function(pos, node, active_object_count, active_object_count_wider)

                -- First of all, check if we are even supported, otherwise, let's die!
                if not mcl_core.check_vines_supported(pos, node) then
                        minetest.remove_node(pos)
                        core.check_for_falling(pos)
                        return
                end

                -- Add vines below pos (if empty)
                local spread_down = function(origin, target, dir, node)
                        if math.random(1, 2) == 1 then
                                if minetest.get_node(target).name == "air" then
                                        minetest.add_node(target, {name = "mcl_core:vine", param2 = node.param2})
                                end
                        end
                end

                -- Add vines above pos if it is backed up
                local spread_up = function(origin, target, dir, node)
                        local vines_in_area = minetest.find_nodes_in_area({x=origin.x-4, y=origin.y-1, z=origin.z-4}, {x=origin.x+4, y=origin.y+1, z=origin.z+4}, "mcl_core:vine")
                        -- Less then 4 vines blocks around the ticked vines block (remember the ticked block is counted by above function as well)
                        if #vines_in_area < 5 then
                                if math.random(1, 2) == 1 then
                                        if minetest.get_node(target).name == "air" then
                                                local backup_dir = minetest.wallmounted_to_dir(node.param2)
                                                local backup = vector.subtract(target, backup_dir)
                                                local backupnodename = minetest.get_node(backup).name

                                                -- Check if the block above is supported
                                                if mcl_core.supports_vines(backupnodename) then
                                                        minetest.add_node(target, {name = "mcl_core:vine", param2 = node.param2})
                                                end
                                        end
                                end
                        end
                end

                local spread_horizontal = function(origin, target, dir, node)
                        local vines_in_area = minetest.find_nodes_in_area({x=origin.x-4, y=origin.y-1, z=origin.z-4}, {x=origin.x+4, y=origin.y+1, z=origin.z+4}, "mcl_core:vine")
                        -- Less then 4 vines blocks around the ticked vines block (remember the ticked block is counted by above function as well)
                        if #vines_in_area < 5 then
                                -- Spread horizontally
                                local backup_dir = minetest.wallmounted_to_dir(node.param2)
                                if not vector.equals(backup_dir, dir) then
                                        local target_node = minetest.get_node(target)
                                        if target_node.name == "air" then
                                                local backup = vector.add(target, backup_dir)
                                                local backupnodename = minetest.get_node(backup).name
                                                if mcl_core.supports_vines(backupnodename) then
                                                        minetest.add_node(target, {name = "mcl_core:vine", param2 = node.param2})
                                                end
                                        end
                                end
                        end
                end

                local directions = {
                        { { x= 1, y= 0, z= 0 }, spread_horizontal },
                        { { x=-1, y= 0, z= 0 }, spread_horizontal },
                        { { x= 0, y= 1, z= 0 }, spread_up },
                        { { x= 0, y=-1, z= 0 }, spread_down },
                        { { x= 0, y= 0, z= 1 }, spread_horizontal },
                        { { x= 0, y= 0, z=-1 }, spread_horizontal },
                }

                local d = math.random(1, #directions)
                local dir = directions[d][1]
                local spread = directions[d][2]

                spread(pos, vector.add(pos, dir), dir, node)
        end
})

-- Returns true of the node supports vines
mcl_core.supports_vines = function(nodename)
        local def = minetest.registered_nodes[nodename]
        -- Rules: 1) walkable 2) full cube
        return def.walkable and
                        (def.node_box == nil or def.node_box.type == "regular") and
                        (def.collision_box == nil or def.collision_box.type == "regular")
end

-- Leaf Decay

-- To enable leaf decay for a node, add it to the "leafdecay" group.
--
-- The rating of the group determines how far from a node in the group "tree"
-- the node can be without decaying.
--
-- If param2 of the node is ~= 0, the node will always be preserved. Thus, if
-- the player places a node of that kind, you will want to set param2=1 or so.
--

mcl_core.leafdecay_trunk_cache = {}
mcl_core.leafdecay_enable_cache = true
-- Spread the load of finding trunks
mcl_core.leafdecay_trunk_find_allow_accumulator = 0

minetest.register_globalstep(function(dtime)
        local finds_per_second = 5000
        mcl_core.leafdecay_trunk_find_allow_accumulator =
                        math.floor(dtime * finds_per_second)
end)

minetest.register_abm({
        label = "Leaf decay",
        nodenames = {"group:leafdecay"},
        neighbors = {"air", "group:liquid"},
        -- A low interval and a high inverse chance spreads the load
        interval = 2,
        chance = 5,

        action = function(p0, node, _, _)
                local do_preserve = false
                local d = minetest.registered_nodes[node.name].groups.leafdecay
                if not d or d == 0 then
                        return
                end
                local n0 = minetest.get_node(p0)
                if n0.param2 ~= 0 then
                        -- Prevent leafdecay for player-placed leaves.
                        -- param2 is set to 1 after it was placed by the player
                        return
                end
                local p0_hash = nil
                if mcl_core.leafdecay_enable_cache then
                        p0_hash = minetest.hash_node_position(p0)
                        local trunkp = mcl_core.leafdecay_trunk_cache[p0_hash]
                        if trunkp then
                                local n = minetest.get_node(trunkp)
                                local reg = minetest.registered_nodes[n.name]
                                -- Assume ignore is a trunk, to make the thing work at the border of the active area
                                if n.name == "ignore" or (reg and reg.groups.tree and reg.groups.tree ~= 0) then
                                        return
                                end
                                -- Cache is invalid
                                table.remove(mcl_core.leafdecay_trunk_cache, p0_hash)
                        end
                end
                if mcl_core.leafdecay_trunk_find_allow_accumulator <= 0 then
                        return
                end
                mcl_core.leafdecay_trunk_find_allow_accumulator =
                                mcl_core.leafdecay_trunk_find_allow_accumulator - 1
                -- Assume ignore is a trunk, to make the thing work at the border of the active area
                local p1 = minetest.find_node_near(p0, d, {"ignore", "group:tree"})
                if p1 then
                        do_preserve = true
                        if mcl_core.leafdecay_enable_cache then
                                -- Cache the trunk
                                mcl_core.leafdecay_trunk_cache[p0_hash] = p1
                        end
                end
                if not do_preserve then
                        -- Drop stuff other than the node itself
                        local itemstacks = minetest.get_node_drops(n0.name)
                        for _, itemname in ipairs(itemstacks) do
                                local p_drop = {
                                        x = p0.x - 0.5 + math.random(),
                                        y = p0.y - 0.5 + math.random(),
                                        z = p0.z - 0.5 + math.random(),
                                }
                                minetest.add_item(p_drop, itemname)
                        end
                        -- Remove node
                        minetest.remove_node(p0)
                        core.check_for_falling(p0)

                        -- Kill depending vines immediately to skip the vines decay delay
                        local surround = {
                                { x = 0, y = 0, z = -1 },
                                { x = 0, y = 0, z = 1 },
                                { x = -1, y = 0, z = 0 },
                                { x = 1, y = 0, z = 0 },
                                { x = 0, y = -1, z = -1 },
                        }
                        for s=1, #surround do
                                local spos = vector.add(p0, surround[s])
                                local maybe_vine = minetest.get_node(spos)
                                local surround_inverse = vector.multiply(surround[s], -1)
                                if maybe_vine.name == "mcl_core:vine" and (not mcl_core.check_vines_supported(spos, maybe_vine)) then
                                        minetest.remove_node(spos)
                                        core.check_for_falling(spos)
                                end
                        end
                end
        end
})

-- Remove vines which are not supported by anything, similar to leaf decay.
--[[ TODO: Vines are supposed to die immediately when they supporting block is destroyed.
But doing this in Minetest would be too complicated / hacky. This vines decay is a simple
way to make sure that all floating vines are destroyed eventually. ]]
minetest.register_abm({
        label = "Vines decay",
        nodenames = {"mcl_core:vine"},
        neighbors = {"air"},
        -- A low interval and a high inverse chance spreads the load
        interval = 4,
        chance = 8,
        action = function(p0, node, _, _)
                if not mcl_core.check_vines_supported(p0, node) then
                        -- Vines must die!
                        minetest.remove_node(p0)
                        -- Just in case a falling node happens to float above vines
                        core.check_for_falling(p0)
                end
        end
})

-- Melt snow
minetest.register_abm({
        label = "Top snow and ice melting",
        nodenames = {"mcl_core:snow", "mcl_core:ice"},
        interval = 16,
        chance = 8,
        action = function(pos, node)
                if minetest.get_node_light(pos, 0) >= 12 then
                        minetest.remove_node(pos)
                end
        end
})

--[[ Call this for vines nodes only.
Given the pos and node of a vines node, this returns true if the vines are supported
and false if the vines are currently floating.
Vines are considered “supported” if they face a walkable+solid block or “hang” from a vines node above. ]]
function mcl_core.check_vines_supported(pos, node)
        local supported = false
        local dir = minetest.wallmounted_to_dir(node.param2)
        local pos1 = vector.add(pos, dir)
        local node_neighbor = minetest.get_node(pos1)
        -- Check if vines are attached to a solid block.
        -- If ignore, we assume its solid.
        if node_neighbor.name == "ignore" or mcl_core.supports_vines(node_neighbor.name) then
                supported = true
        elseif dir.y == 0 then
                -- Vines are not attached, now we check if the vines are “hanging” below another vines block
                -- of equal orientation.
                local pos2 = vector.add(pos, {x=0, y=1, z=0})
                local node2 = minetest.get_node(pos2)
                -- Again, ignore means we assume its supported
                if node2.name == "ignore" or (node2.name == "mcl_core:vine" and node2.param2 == node.param2) then
                        supported = true
                end
        end
        return supported
end

---- FUNCTIONS FOR SNOWED NODES ----
-- These are nodes which change their appearence when they are below a snow cover
-- and turn back into “normal” when the snow cover is removed.

-- Registers a snowed variant of a node (e.g. grass block, podzol, mycelium).
-- * itemstring_snowed: Itemstring of the snowed node to add
-- * itemstring_clear: Itemstring of the original “clear” node without snow
-- * tiles: Optional custom tiles
-- * sounds: Optional custom sounds
--
-- The snowable nodes also MUST have _mcl_snowed defined to contain the name
-- of the snowed node.
mcl_core.register_snowed_node = function(itemstring_snowed, itemstring_clear, tiles, sounds)
        local def = table.copy(minetest.registered_nodes[itemstring_clear])
        local create_doc_alias
        if def.description then
                create_doc_alias = true
        else
                create_doc_alias = false
        end
        -- Just some group clearing
        def.description = nil
        def._doc_items_longdesc = nil
        def._doc_items_usagehelp = nil
        def._doc_items_create_entry = false
        def.groups.not_in_creative_inventory = 1
        if def.groups.grass_block == 1 then
                def.groups.grass_block_no_snow = nil
                def.groups.grass_block_snow = 1
        end

        -- Enderman must never take this because this block is supposed to be always buried below snow.
        def.groups.enderman_takable = nil

        -- Snowed blocks never spread
        def.groups.spreading_dirt_type = nil

        -- Add the clear node to the item definition for easy lookup
        def._mcl_snowless = itemstring_clear

        -- Note: _mcl_snowed must be added to the clear node manually!

        if not tiles then
                def.tiles = {"default_snow.png", "default_dirt.png", "mcl_core_grass_side_snowed.png"}
        else
                def.tiles = tiles
        end
        if not sounds then
                def.sounds = mcl_sounds.node_sound_dirt_defaults({
                        footstep = { name = "pedology_snow_soft_footstep", gain = 0.5 }
                })
        else
                def.sounds = sounds
        end

        -- Register stuff
        minetest.register_node(itemstring_snowed, def)

        if create_doc_alias and minetest.get_modpath("doc") then
                doc.add_entry_alias("nodes", itemstring_clear, "nodes", itemstring_snowed)
        end
end

-- Reverts a snowed dirtlike node at pos to its original snow-less form.
-- This function assumes there is no snow cover node above. This function
-- MUST NOT be called if there is a snow cover node above pos.
mcl_core.clear_snow_dirt = function(pos, node)
        local def = minetest.registered_nodes[node.name]
        if def._mcl_snowless then
                minetest.swap_node(pos, {name = def._mcl_snowless})
        end
end

---- [[[[[ Functions for snowable nodes (nodes that can become snowed). ]]]]] ----
-- Always add these for snowable nodes.

-- on_construct
-- Makes constructed snowable node snowed if placed below a snow cover node.
mcl_core.on_snowable_construct = function(pos)
        -- Myself
        local node = minetest.get_node(pos)

        -- Above
        local apos = {x=pos.x, y=pos.y+1, z=pos.z}
        local anode = minetest.get_node(apos)

        -- Make snowed if needed
        if minetest.get_item_group(anode.name, "snow_cover") == 1 then
                local def = minetest.registered_nodes[node.name]
                if def._mcl_snowed then
                        minetest.swap_node(pos, {name = def._mcl_snowed})
                end
        end
end


---- [[[[[ Functions for snow cover nodes. ]]]]] ----

-- A snow cover node is a node which turns a snowed dirtlike --
-- node into its snowed form while it is placed above.
-- MCL2's snow cover nodes are Top Snow (mcl_core:snow) and Snow (mcl_core:snowblock).

-- Always add the following functions to snow cover nodes:

-- on_construct
-- Makes snowable node below snowed.
mcl_core.on_snow_construct = function(pos)
        local npos = {x=pos.x, y=pos.y-1, z=pos.z}
        local node = minetest.get_node(npos)
        local def = minetest.registered_nodes[node.name]
        if def._mcl_snowed then
                minetest.swap_node(npos, {name = def._mcl_snowed})
        end
end
-- after_destruct
-- Clears snowed dirtlike node below.
mcl_core.after_snow_destruct = function(pos)
        local nn = minetest.get_node(pos).name
        -- No-op if snow was replaced with snow
        if minetest.get_item_group(nn, "snow_cover") == 1 then
                return
        end
        local npos = {x=pos.x, y=pos.y-1, z=pos.z}
        local node = minetest.get_node(npos)
        mcl_core.clear_snow_dirt(npos, node)
end