Split code and tidy up

Split to growth.lua and search_functions.lua
New function populate_single_surface for a single position check
Use 'return' to reduce indent levels

growth.lua

@@ -0,0 +1,78 @@
+-- The growing ABM
+
+function biome_lib:grow_plants(opts)
+
+	local options = opts
+
+	options.height_limit = options.height_limit or 5
+	options.ground_nodes = options.ground_nodes or { "default:dirt_with_grass" }
+	options.grow_nodes = options.grow_nodes or { "default:dirt_with_grass" }
+	options.seed_diff = options.seed_diff or 0
+
+	local n
+
+	if type(options.grow_plant) == "table" then
+		n = "multi: "..options.grow_plant[1]..", ..."
+	else
+		n = options.grow_plant
+	end
+
+	options.label = options.label or "biome_lib grow_plants(): "..n
+
+	if options.grow_delay*time_scale >= 1 then
+		options.interval = options.grow_delay*time_scale
+	else
+		options.interval = 1
+	end
+
+	minetest.register_abm({
+		nodenames = { options.grow_plant },
+		interval = options.interval,
+		chance = options.grow_chance,
+		label = options.label,
+		action = function(pos, node, active_object_count, active_object_count_wider)
+			local p_top = {x=pos.x, y=pos.y+1, z=pos.z}
+			local p_bot = {x=pos.x, y=pos.y-1, z=pos.z}
+			local n_top = minetest.get_node(p_top)
+			local n_bot = minetest.get_node(p_bot)
+			local root_node = minetest.get_node({x=pos.x, y=pos.y-options.height_limit, z=pos.z})
+			local walldir = nil
+			if options.need_wall and options.verticals_list then
+				walldir = biome_lib:find_adjacent_wall(p_top, options.verticals_list, options.choose_random_wall)
+			end
+			if (n_top.name == "air" or n_top.name == "default:snow")
+			  and (not options.need_wall or (options.need_wall and walldir)) then
+				-- corner case for changing short junglegrass
+				-- to dry shrub in desert
+				if n_bot.name == options.dry_early_node and options.grow_plant == "junglegrass:short" then
+					minetest.swap_node(pos, { name = "default:dry_shrub" })
+
+				elseif options.grow_vertically and walldir then
+					if biome_lib:search_downward(pos, options.height_limit, options.ground_nodes) then
+						minetest.swap_node(p_top, { name = options.grow_plant, param2 = walldir})
+					end
+
+				elseif not options.grow_result and not options.grow_function then
+					minetest.swap_node(pos, biome_lib.air)
+
+				else
+					biome_lib:replace_object(pos, options.grow_result, options.grow_function, options.facedir, options.seed_diff)
+				end
+			end
+		end
+	})
+end
+
+
+-- spawn_tree() on generate is routed through here so that other mods can hook
+-- into it.
+
+function biome_lib:generate_tree(pos, nodes_or_function_or_model)
+	minetest.spawn_tree(pos, nodes_or_function_or_model)
+end
+
+-- and this one's for the call used in the growing code
+
+function biome_lib:grow_tree(pos, nodes_or_function_or_model)
+	minetest.spawn_tree(pos, nodes_or_function_or_model)
+end

init.lua

@@ -198,21 +198,28 @@ function biome_lib:register_generate_plant(biomedef, nodes_or_function_or_model)
 	end
 end
 
-function biome_lib:populate_surfaces(biome, nodes_or_function_or_model, snodes, checkair)
+-- Function to check whether a position matches the given biome definition
+-- Returns true when the surface can be populated
 
-	biome_lib:set_defaults(biome)
+local function populate_single_surface(biome, pos, perlin_fertile_area)
-
-	-- filter stage 1 - find nodes from the supplied surfaces that are within the current biome.
-
-	local in_biome_nodes = {}
-	local perlin_fertile_area = minetest.get_perlin(biome.seed_diff, perlin_octaves, perlin_persistence, perlin_scale)
-
-	for i = 1, #snodes do
-		local pos = snodes[i]
 	local p_top = { x = pos.x, y = pos.y + 1, z = pos.z }
 	local noise1 = perlin_fertile_area:get2d({x=pos.x, y=pos.z})
 	local noise2 = biome_lib.perlin_temperature:get2d({x=pos.x, y=pos.z})
 	local noise3 = biome_lib.perlin_humidity:get2d({x=pos.x+150, y=pos.z+50})
+
+	if math.random(1, 100) <= biome.rarity then
+		return
+	end
+
+	local pos_biome_ok = pos.y >= biome.min_elevation and pos.y <= biome.max_elevation
+		and noise1 > biome.plantlife_limit
+		and noise2 <= biome.temp_min and noise2 >= biome.temp_max
+		and noise3 <= biome.humidity_min and noise3 >= biome.humidity_max
+	
+	if not pos_biome_ok then
+		return -- Y position mismatch, outside of biome
+	end
+
 	local biome_surfaces_string = dump(biome.surface)
 	local surface_ok = false
 
@@ -231,24 +238,60 @@ function biome_lib:populate_surfaces(biome, nodes_or_function_or_model, snodes,
 				end
 			end
 		end
-		elseif not string.find(biome_surfaces_string, minetest.get_node({ x = pos.x, y = pos.y-biome.depth-1, z = pos.z }).name) then
+	elseif not string.find(biome_surfaces_string,
+			minetest.get_node({ x = pos.x, y = pos.y-biome.depth-1, z = pos.z }).name) then
 		surface_ok = true
 	end
 	
-		if surface_ok
+	if not surface_ok then
-		  and pos.y >= biome.min_elevation
+		return -- Surface does not match the given node group/name
-		  and pos.y <= biome.max_elevation
+	end
-		  and noise1 > biome.plantlife_limit
+
-		  and noise2 <= biome.temp_min
+	if checkair and minetest.get_node(p_top).name ~= "air" then
-		  and noise2 >= biome.temp_max
+		return
-		  and noise3 <= biome.humidity_min
+	end
-		  and noise3 >= biome.humidity_max
+
-		  and (not checkair or minetest.get_node(p_top).name == "air")
+	if biome.below_nodes and
-		  and (not biome.ncount or #(minetest.find_nodes_in_area({x=pos.x-1, y=pos.y, z=pos.z-1}, {x=pos.x+1, y=pos.y, z=pos.z+1}, biome.neighbors)) > biome.ncount)
+			not string.find(dump(biome.below_nodes),
-		  and (not biome.near_nodes or #(minetest.find_nodes_in_area({x=pos.x-biome.near_nodes_size, y=pos.y-biome.near_nodes_vertical, z=pos.z-biome.near_nodes_size}, {x=pos.x+biome.near_nodes_size, y=pos.y+biome.near_nodes_vertical, z=pos.z+biome.near_nodes_size}, biome.near_nodes)) >= biome.near_nodes_count)
+				minetest.get_node({x=pos.x, y=pos.y-1, z=pos.z}).name
-		  and math.random(1,100) > biome.rarity
+			) then
-		  and (not biome.below_nodes or string.find(dump(biome.below_nodes), minetest.get_node({x=pos.x, y=pos.y-1, z=pos.z}).name) )
+		return -- Node below does not match
-		  then
+	end
+
+	if biome.ncount and
+			#minetest.find_nodes_in_area(
+				{x=pos.x-1, y=pos.y, z=pos.z-1},
+				{x=pos.x+1, y=pos.y, z=pos.z+1},
+				biome.neighbors
+			) <= biome.ncount then
+		return -- Not enough similar biome nodes around
+	end
+
+	if biome.near_nodes and
+			#minetest.find_nodes_in_area(
+				{x=pos.x-biome.near_nodes_size, y=pos.y-biome.near_nodes_vertical, z=pos.z-biome.near_nodes_size},
+				{x=pos.x+biome.near_nodes_size, y=pos.y+biome.near_nodes_vertical, z=pos.z+biome.near_nodes_size}, 
+				biome.near_nodes
+			) < biome.near_nodes_count then
+		return -- Long distance neighbours do not match
+	end
+
+	-- Position fits into given biome
+	return true
+end
+
+function biome_lib:populate_surfaces(biome, nodes_or_function_or_model, snodes, checkair)
+
+	biome_lib:set_defaults(biome)
+
+	-- filter stage 1 - find nodes from the supplied surfaces that are within the current biome.
+
+	local in_biome_nodes = {}
+	local perlin_fertile_area = minetest.get_perlin(biome.seed_diff, perlin_octaves, perlin_persistence, perlin_scale)
+
+	for i = 1, #snodes do
+		local pos = vector.new(snodes[i])
+		if populate_single_surface(biome, pos, perlin_fertile_area) then
 			in_biome_nodes[#in_biome_nodes + 1] = pos
 		end
 	end
@@ -257,7 +300,10 @@ function biome_lib:populate_surfaces(biome, nodes_or_function_or_model, snodes,
 
 	local num_in_biome_nodes = #in_biome_nodes
 
-	if num_in_biome_nodes > 0 then
+	if num_in_biome_nodes == 0 then
+		return
+	end
+
 	for i = 1, math.min(biome.max_count, num_in_biome_nodes) do
 		local tries = 0
 		local spawned = false
@@ -268,7 +314,9 @@ function biome_lib:populate_surfaces(biome, nodes_or_function_or_model, snodes,
 			end
 			local p_top = { x = pos.x, y = pos.y + 1, z = pos.z }
 
-				if not (biome.avoid_nodes and biome.avoid_radius and minetest.find_node_near(p_top, biome.avoid_radius + math.random(-1.5,2), biome.avoid_nodes)) then
+			if not (biome.avoid_nodes and biome.avoid_radius
+					and minetest.find_node_near(p_top, biome.avoid_radius
+					+ math.random(-1.5,2), biome.avoid_nodes)) then
 				if biome.delete_above then
 					minetest.swap_node(p_top, biome_lib.air)
 					minetest.swap_node({x=p_top.x, y=p_top.y+1, z=p_top.z}, biome_lib.air)
@@ -326,14 +374,15 @@ function biome_lib:populate_surfaces(biome, nodes_or_function_or_model, snodes,
 			end
 		end
 	end
-	end
 end
 
 -- Primary mapgen spawner, for mods that can work with air checking enabled on
 -- a surface during the initial map read stage.
 
 function biome_lib:generate_block_with_air_checking()
-	if #biome_lib.blocklist_aircheck > 0 then
+	if #biome_lib.blocklist_aircheck == 0 then
+		return
+	end
 
 	local minp =		biome_lib.blocklist_aircheck[1][1]
 	local maxp =		biome_lib.blocklist_aircheck[1][2]
@@ -380,14 +429,15 @@ function biome_lib:generate_block_with_air_checking()
 			end
 		end
 	end
-	end
 end
 
 -- Secondary mapgen spawner, for mods that require disabling of
 -- checking for air during the initial map read stage.
 
 function biome_lib:generate_block_no_aircheck()
-	if #biome_lib.blocklist_no_aircheck > 0 then
+	if #biome_lib.blocklist_no_aircheck == 0 then
+		return
+	end
 
 	local minp =		biome_lib.blocklist_no_aircheck[1][1]
 	local maxp =		biome_lib.blocklist_no_aircheck[1][2]
@@ -416,7 +466,6 @@ function biome_lib:generate_block_no_aircheck()
 			end
 		end
 	end
-	end
 end
 
 -- "Record" the chunks being generated by the core mapgen
@@ -432,9 +481,12 @@ end)
 -- "Play" them back, populating them with new stuff in the process
 
 minetest.register_globalstep(function(dtime)
-	if dtime < 0.2    -- don't attempt to populate if lag is already too high
+	if dtime >= 0.2 -- don't attempt to populate if lag is already too high
-	  and math.random(100) <= biome_lib.queue_run_ratio
+			or math.random(100) > biome_lib.queue_run_ratio
-	  and (#biome_lib.blocklist_aircheck > 0 or #biome_lib.blocklist_no_aircheck > 0) then
+			or (#biome_lib.blocklist_aircheck == 0 and #biome_lib.blocklist_no_aircheck == 0) then
+		return
+	end
+
 	biome_lib.globalstep_start_time = minetest.get_us_time()
 	biome_lib.globalstep_runtime = 0
 	while (#biome_lib.blocklist_aircheck > 0 or #biome_lib.blocklist_no_aircheck > 0)
@@ -447,31 +499,32 @@ minetest.register_globalstep(function(dtime)
 		end
 		biome_lib.globalstep_runtime = minetest.get_us_time() - biome_lib.globalstep_start_time
 	end
-	end
 end)
 
 -- Play out the entire log all at once on shutdown
 -- to prevent unpopulated map areas
 
 minetest.register_on_shutdown(function()
-	if #biome_lib.blocklist_aircheck > 0 then
+	if #biome_lib.blocklist_aircheck == 0 then
+		return
+	end
+
 	print("[biome_lib] Stand by, playing out the rest of the aircheck mapblock log")
 	print("(there are "..#biome_lib.blocklist_aircheck.." entries)...")
-		while true do
+	while #biome_lib.blocklist_aircheck > 0 do
 		biome_lib:generate_block_with_air_checking(0.1)
-			if #biome_lib.blocklist_aircheck == 0 then return end
-		end
 	end
 end)
 
 minetest.register_on_shutdown(function()
-	if #biome_lib.blocklist_no_aircheck > 0 then
+	if #biome_lib.blocklist_aircheck == 0 then
+		return
+	end
+
 	print("[biome_lib] Stand by, playing out the rest of the no-aircheck mapblock log")
 	print("(there are "..#biome_lib.blocklist_no_aircheck.." entries)...")
-		while true do
+	while #biome_lib.blocklist_no_aircheck > 0 do
 		biome_lib:generate_block_no_aircheck(0.1)
-			if #biome_lib.blocklist_no_aircheck == 0 then return end
-		end
 	end
 end)
 
@@ -581,71 +634,6 @@ function biome_lib:spawn_on_surfaces(sd,sp,sr,sc,ss,sa)
 	})
 end
 
--- The growing ABM
-
-function biome_lib:grow_plants(opts)
-
-	local options = opts
-
-	options.height_limit = options.height_limit or 5
-	options.ground_nodes = options.ground_nodes or { "default:dirt_with_grass" }
-	options.grow_nodes = options.grow_nodes or { "default:dirt_with_grass" }
-	options.seed_diff = options.seed_diff or 0
-
-	local n
-
-	if type(options.grow_plant) == "table" then
-		n = "multi: "..options.grow_plant[1]..", ..."
-	else
-		n = options.grow_plant
-	end
-
-	options.label = options.label or "biome_lib grow_plants(): "..n
-
-	if options.grow_delay*time_scale >= 1 then
-		options.interval = options.grow_delay*time_scale
-	else
-		options.interval = 1
-	end
-
-	minetest.register_abm({
-		nodenames = { options.grow_plant },
-		interval = options.interval,
-		chance = options.grow_chance,
-		label = options.label,
-		action = function(pos, node, active_object_count, active_object_count_wider)
-			local p_top = {x=pos.x, y=pos.y+1, z=pos.z}
-			local p_bot = {x=pos.x, y=pos.y-1, z=pos.z}
-			local n_top = minetest.get_node(p_top)
-			local n_bot = minetest.get_node(p_bot)
-			local root_node = minetest.get_node({x=pos.x, y=pos.y-options.height_limit, z=pos.z})
-			local walldir = nil
-			if options.need_wall and options.verticals_list then
-				walldir = biome_lib:find_adjacent_wall(p_top, options.verticals_list, options.choose_random_wall)
-			end
-			if (n_top.name == "air" or n_top.name == "default:snow")
-			  and (not options.need_wall or (options.need_wall and walldir)) then
-				-- corner case for changing short junglegrass
-				-- to dry shrub in desert
-				if n_bot.name == options.dry_early_node and options.grow_plant == "junglegrass:short" then
-					minetest.swap_node(pos, { name = "default:dry_shrub" })
-
-				elseif options.grow_vertically and walldir then
-					if biome_lib:search_downward(pos, options.height_limit, options.ground_nodes) then
-						minetest.swap_node(p_top, { name = options.grow_plant, param2 = walldir})
-					end
-
-				elseif not options.grow_result and not options.grow_function then
-					minetest.swap_node(pos, biome_lib.air)
-
-				else
-					biome_lib:replace_object(pos, options.grow_result, options.grow_function, options.facedir, options.seed_diff)
-				end
-			end
-		end
-	})
-end
-
 -- Function to decide how to replace a plant - either grow it, replace it with
 -- a tree, run a function, or die with an error.
 
@@ -675,71 +663,12 @@ function biome_lib:replace_object(pos, replacement, grow_function, walldir, seed
 	end
 end
 
--- function to decide if a node has a wall that's in verticals_list{}
--- returns wall direction of valid node, or nil if invalid.
 
-function biome_lib:find_adjacent_wall(pos, verticals, randomflag)
-	local verts = dump(verticals)
-	if randomflag then
-		local walltab = {}
 
-		if string.find(verts, minetest.get_node({ x=pos.x-1, y=pos.y, z=pos.z   }).name) then walltab[#walltab + 1] = 3 end
+dofile(biome_lib.modpath .. "/search_functions.lua")
-		if string.find(verts, minetest.get_node({ x=pos.x+1, y=pos.y, z=pos.z   }).name) then walltab[#walltab + 1] = 2 end
+dofile(biome_lib.modpath .. "/growth.lua")
-		if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z-1 }).name) then walltab[#walltab + 1] = 5 end
-		if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z+1 }).name) then walltab[#walltab + 1] = 4 end
 
-		if #walltab > 0 then return walltab[math.random(1, #walltab)] end
 
-	else
-		if string.find(verts, minetest.get_node({ x=pos.x-1, y=pos.y, z=pos.z   }).name) then return 3 end
-		if string.find(verts, minetest.get_node({ x=pos.x+1, y=pos.y, z=pos.z   }).name) then return 2 end
-		if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z-1 }).name) then return 5 end
-		if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z+1 }).name) then return 4 end
-	end
-	return nil
-end
-
--- Function to search downward from the given position, looking for the first
--- node that matches the ground table.  Returns the new position, or nil if
--- height limit is exceeded before finding it.
-
-function biome_lib:search_downward(pos, heightlimit, ground)
-	for i = 0, heightlimit do
-		if string.find(dump(ground), minetest.get_node({x=pos.x, y=pos.y-i, z = pos.z}).name) then
-			return {x=pos.x, y=pos.y-i, z = pos.z}
-		end
-	end
-	return false
-end
-
-function biome_lib:find_open_side(pos)
-	if minetest.get_node({ x=pos.x-1, y=pos.y, z=pos.z }).name == "air" then
-		return {newpos = { x=pos.x-1, y=pos.y, z=pos.z }, facedir = 2}
-	end
-	if minetest.get_node({ x=pos.x+1, y=pos.y, z=pos.z }).name == "air" then
-		return {newpos = { x=pos.x+1, y=pos.y, z=pos.z }, facedir = 3}
-	end
-	if minetest.get_node({ x=pos.x, y=pos.y, z=pos.z-1 }).name == "air" then
-		return {newpos = { x=pos.x, y=pos.y, z=pos.z-1 }, facedir = 4}
-	end
-	if minetest.get_node({ x=pos.x, y=pos.y, z=pos.z+1 }).name == "air" then
-		return {newpos = { x=pos.x, y=pos.y, z=pos.z+1 }, facedir = 5}
-	end
-	return nil
-end
-
--- spawn_tree() on generate is routed through here so that other mods can hook
--- into it.
-
-function biome_lib:generate_tree(pos, nodes_or_function_or_model)
-	minetest.spawn_tree(pos, nodes_or_function_or_model)
-end
-
--- and this one's for the call used in the growing code
-
-function biome_lib:grow_tree(pos, nodes_or_function_or_model)
-	minetest.spawn_tree(pos, nodes_or_function_or_model)
-end
 
 -- Check for infinite stacks
 

search_functions.lua

@@ -0,0 +1,53 @@
+
+-- function to decide if a node has a wall that's in verticals_list{}
+-- returns wall direction of valid node, or nil if invalid.
+
+function biome_lib:find_adjacent_wall(pos, verticals, randomflag)
+	local verts = dump(verticals)
+	if randomflag then
+		local walltab = {}
+		
+		if string.find(verts, minetest.get_node({ x=pos.x-1, y=pos.y, z=pos.z   }).name) then walltab[#walltab + 1] = 3 end
+		if string.find(verts, minetest.get_node({ x=pos.x+1, y=pos.y, z=pos.z   }).name) then walltab[#walltab + 1] = 2 end
+		if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z-1 }).name) then walltab[#walltab + 1] = 5 end
+		if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z+1 }).name) then walltab[#walltab + 1] = 4 end
+
+		if #walltab > 0 then return walltab[math.random(1, #walltab)] end
+
+	else
+		if string.find(verts, minetest.get_node({ x=pos.x-1, y=pos.y, z=pos.z   }).name) then return 3 end
+		if string.find(verts, minetest.get_node({ x=pos.x+1, y=pos.y, z=pos.z   }).name) then return 2 end
+		if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z-1 }).name) then return 5 end
+		if string.find(verts, minetest.get_node({ x=pos.x  , y=pos.y, z=pos.z+1 }).name) then return 4 end
+	end
+	return nil
+end
+
+-- Function to search downward from the given position, looking for the first
+-- node that matches the ground table.  Returns the new position, or nil if
+-- height limit is exceeded before finding it.
+
+function biome_lib:search_downward(pos, heightlimit, ground)
+	for i = 0, heightlimit do
+		if string.find(dump(ground), minetest.get_node({x=pos.x, y=pos.y-i, z = pos.z}).name) then
+			return {x=pos.x, y=pos.y-i, z = pos.z}
+		end
+	end
+	return false
+end
+
+function biome_lib:find_open_side(pos)
+	if minetest.get_node({ x=pos.x-1, y=pos.y, z=pos.z }).name == "air" then
+		return {newpos = { x=pos.x-1, y=pos.y, z=pos.z }, facedir = 2}
+	end
+	if minetest.get_node({ x=pos.x+1, y=pos.y, z=pos.z }).name == "air" then
+		return {newpos = { x=pos.x+1, y=pos.y, z=pos.z }, facedir = 3}
+	end
+	if minetest.get_node({ x=pos.x, y=pos.y, z=pos.z-1 }).name == "air" then
+		return {newpos = { x=pos.x, y=pos.y, z=pos.z-1 }, facedir = 4}
+	end
+	if minetest.get_node({ x=pos.x, y=pos.y, z=pos.z+1 }).name == "air" then
+		return {newpos = { x=pos.x, y=pos.y, z=pos.z+1 }, facedir = 5}
+	end
+	return nil
+end