Refactor grid loading and reorganize code

Move grid management functions out of polygons.lua, in a new file called gridmanager.lua
Explicitly call other files and grid management functions from init.lua
to make workflow more apparent
Move mapgen loop out of init.lua, into mapgen.lua

gridio.lua

@@ -4,7 +4,8 @@ local floor = math.floor
 local sbyte, schar = string.byte, string.char
 local unpk = unpack
 
-function mapgen_rivers.load_map(filename, bytes, signed, size, converter)
+-- Loading files
+local function load_full_map(filename, bytes, signed, size, converter)
 	local file = io.open(worldpath .. filename, 'rb')
 	local data = file:read('*all')
 	if #data < bytes*size then
@@ -62,18 +63,31 @@ local loader_mt = {
 	end,
 }
 
-function mapgen_rivers.interactive_loader(filename, bytes, signed, size, converter)
+local function interactive_loader(filename, bytes, signed, size, converter)
 	local file = io.open(worldpath .. filename, 'rb')
 	if file then
-		minetest.register_on_shutdown(function()
-			file:close()
-		end)
 		converter = converter or false
 		return setmetatable({file=file, bytes=bytes, signed=signed, size=size, conv=converter}, loader_mt)
 	end
 end
 
-function mapgen_rivers.write_map(filename, data, bytes)
+local load_methods = {
+	full        = load_full_map,
+	interactive = interactive_loader,
+}
+
+function mapgen_rivers.load_file(...)
+	local load_method = mapgen_rivers.settings.load_method
+	local load_func = load_methods[load_method]
+	if load_func then
+		return load_func(...)
+	else
+		minetest.log("error", ("[mapgen_rivers] Unknown load method %s"):format(load_method))
+	end
+end
+
+-- Writing files
+function mapgen_rivers.write_file(filename, data, bytes)
 	local size = #data
 	local file = io.open(worldpath .. filename, 'wb')
 

gridmanager.lua

@@ -0,0 +1,146 @@
+local world_data = mapgen_rivers.world_data_path
+
+local registered_on_grid_loaded = {}
+function mapgen_rivers.register_on_grid_loaded(func)
+	if type(func) == "function" then
+		registered_on_grid_loaded[#registered_on_grid_loaded+1] = func
+	else
+		minetest.log("error", "[mapgen_rivers] register_on_grid_loaded can only register functions!")
+	end
+end
+
+local function on_grid_loaded_callback(grid)
+	for _, func in ipairs(registered_on_grid_loaded) do
+		func(grid)
+	end
+end
+
+local function offset_conv(o)
+	return (o + 0.5) * (1/256)
+end
+
+local grid_maps_list = {
+	dem = {bytes=2, signed=true},
+	lakes = {bytes=2, signed=true},
+	dirs = {bytes=1, signed=false},
+	rivers = {bytes=4, signed=false},
+
+	offset_x = {bytes=1, signed=true, conv=offset_conv},
+	offset_y = {bytes=1, signed=true, conv=offset_conv},
+}
+
+local function apply_grid_conversion(grid)
+	if grid.load_method ~= "full" then
+		minetest.log("warning", ("Could not apply data conversion for load method %s"):format(grid.load_method))
+		return false
+	end
+	if grid.conv_applied then
+		return true
+	end
+
+	local size = grid.size.x * grid.size.y
+	for mapname, params in pairs(grid_maps_list) do
+		local conv = params.conv
+		if conv then
+			local map = grid[mapname]
+			for i=1, size do
+				map[i] = conv(map[i])
+			end
+		end
+	end
+	grid.conv_applied = true
+
+	return true
+end
+
+function mapgen_rivers.try_load_grid(grid)
+	local load_method = mapgen_rivers.settings.load_method
+
+	-- First, check whether a grid is already loaded with the appropriate method
+	if mapgen_rivers.grid and mapgen_rivers.grid.load_method == load_method then
+		if not mapgen_rivers.grid.conv_applied then
+			apply_grid_conversion(mapgen_rivers.grid)
+		end
+		return true
+	-- Then, check the provided argument is a valid grid
+	elseif grid and grid.load_method == load_method then
+		if not mapgen_rivers.grid.conv_applied then
+			apply_grid_conversion(grid)
+		end
+		mapgen_rivers.grid = grid
+		on_grid_loaded_callback(grid)
+		return true
+	end
+
+	-- Fall back to loading the grid from the files
+	local sfile = io.open(world_data .. 'size', 'r')
+	if not sfile then
+		return false
+	end
+
+	local x, z = sfile:read('*n'), sfile:read('*n')
+	if not x or not z then
+		return false
+	end
+
+	if load_method == "full" then
+		minetest.log("action", '[mapgen_rivers] Loading full grid')
+	elseif load_method == "interactive" then
+		minetest.log("action", '[mapgen_rivers] Loading grid as interactive loaders')
+	end
+
+	grid = {
+		load_method = load_method,
+		size = {x=x, y=z},
+	}
+
+	for map, params in pairs(grid_maps_list) do
+		grid[map] = mapgen_rivers.load_file(map, params.bytes, params.signed, x*z, params.conv)
+	end
+	grid.conv_applied = true
+
+	mapgen_rivers.grid = grid
+	on_grid_loaded_callback(grid)
+
+	return true
+end
+
+function mapgen_rivers.generate_grid()
+	minetest.log("action", '[mapgen_rivers] Generating grid, this may take a while...')
+	local grid = {}
+
+	local blocksize = mapgen_rivers.settings.blocksize
+	local xsize = math.floor(mapgen_rivers.settings.map_x_size / blocksize)
+	local zsize = math.floor(mapgen_rivers.settings.map_z_size / blocksize)
+	grid.size = {x=xsize, y=zsize}
+	grid.conv_applied = false
+
+	if not mapgen_rivers.pregenerate then
+		minetest.log("error", "[mapgen_rivers] Pre-generation function is not available.")
+		return false
+	end
+
+	mapgen_rivers.pregenerate(grid)
+
+	return grid
+end
+
+function mapgen_rivers.write_grid(grid)
+	minetest.mkdir(world_data)
+
+	if grid.conv_applied then
+		minetest.log("error", '[mapgen_rivers] Could not write grid if data conversion is already done')
+		return false
+	end
+
+	for map, params in pairs(grid_maps_list) do
+		mapgen_rivers.write_file(map, grid[map], params.bytes)
+	end
+
+	local sfile = io.open(world_data .. 'size', "w")
+	sfile:write(grid.size.x..'\n'..grid.size.y)
+	sfile:close()
+
+	return true
+end
+

init.lua

@@ -4,275 +4,21 @@ local modpath = minetest.get_modpath(minetest.get_current_modname()) .. '/'
 mapgen_rivers.modpath = modpath
 mapgen_rivers.world_data_path = minetest.get_worldpath() .. '/river_data/'
 
-if minetest.get_mapgen_setting("mg_name") ~= "singlenode" then
-	minetest.set_mapgen_setting("mg_name", "singlenode", true)
-	minetest.log("warning", "[mapgen_rivers] Mapgen set to singlenode")
-end
-
 dofile(modpath .. 'settings.lua')
+dofile(modpath .. 'gridmanager.lua')
+dofile(modpath .. 'gridio.lua')
 dofile(modpath .. 'polygons.lua')
 dofile(modpath .. 'heightmap.lua')
+dofile(modpath .. 'mapgen.lua')
 
-local sea_level = mapgen_rivers.settings.sea_level
+minetest.register_on_mods_loaded(function()
-local elevation_chill = mapgen_rivers.settings.elevation_chill
+	local exist = mapgen_rivers.try_load_grid()
-local use_distort = mapgen_rivers.settings.distort
-local use_biomes = mapgen_rivers.settings.biomes
-local use_biomegen_mod = use_biomes and minetest.global_exists('biomegen')
-use_biomes = use_biomes and minetest.global_exists('default') and not use_biomegen_mod
 
-if use_biomegen_mod then
+	if not exist then -- If grid does not exist yet, generate it
-	biomegen.set_elevation_chill(elevation_chill)
+		dofile(modpath .. 'pregenerate.lua')
-end
 
--- Linear interpolation
+		local grid = mapgen_rivers.generate_grid()
-local function interp(v00, v01, v11, v10, xf, zf)
+		mapgen_rivers.write_grid(grid)
-	local v0 = v01*xf + v00*(1-xf)
+		mapgen_rivers.try_load_grid(grid) -- Reload if needed
-	local v1 = v11*xf + v10*(1-xf)
-	return v1*zf + v0*(1-zf)
-end
-
--- Localize for performance
-local floor, min = math.floor, math.min
-
-local data = {}
-
-local noise_x_obj, noise_z_obj, noise_distort_obj, noise_heat_obj, noise_heat_blend_obj
-local noise_x_map = {}
-local noise_z_map = {}
-local noise_distort_map = {}
-local noise_heat_map = {}
-local noise_heat_blend_map = {}
-local mapsize
-local init = false
-
-local sumtime = 0
-local sumtime2 = 0
-local ngen = 0
-
-local function generate(minp, maxp, seed)
-	minetest.log("info", ("[mapgen_rivers] Generating from %s to %s"):format(minetest.pos_to_string(minp), minetest.pos_to_string(maxp)))
-
-	local chulens = {
-		x = maxp.x-minp.x+1,
-		y = maxp.y-minp.y+1,
-		z = maxp.z-minp.z+1,
-	}
-
-	if not init then
-		mapsize = {
-			x = chulens.x,
-			y = chulens.y+1,
-			z = chulens.z,
-		}
-		if use_distort then
-			noise_x_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.distort_x, mapsize)
-			noise_z_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.distort_z, mapsize)
-			noise_distort_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.distort_amplitude, chulens)
-		end
-		if use_biomes then
-			noise_heat_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.heat, chulens)
-			noise_heat_blend_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.heat_blend, chulens)
-		end
-		init = true
 	end
-
-	local t0 = os.clock()
-	local minp2d = {x=minp.x, y=minp.z}
-	if use_distort then
-		noise_x_obj:get_3d_map_flat(minp, noise_x_map)
-		noise_z_obj:get_3d_map_flat(minp, noise_z_map)
-		noise_distort_obj:get_2d_map_flat(minp2d, noise_distort_map)
-	end
-	if use_biomes then
-		noise_heat_obj:get_2d_map_flat(minp2d, noise_heat_map)
-		noise_heat_blend_obj:get_2d_map_flat(minp2d, noise_heat_blend_map)
-	end
-
-	local terrain_map, lake_map, incr, i_origin
-
-	if use_distort then
-		local xmin, xmax, zmin, zmax = minp.x, maxp.x, minp.z, maxp.z
-		local i = 0
-		local i2d = 0
-		for z=minp.z, maxp.z do
-			for y=minp.y, maxp.y+1 do
-				for x=minp.x, maxp.x do
-					i = i+1
-					i2d = i2d+1
-					local distort = noise_distort_map[i2d]
-					local xv = noise_x_map[i]*distort + x
-					if xv < xmin then xmin = xv end
-					if xv > xmax then xmax = xv end
-					noise_x_map[i] = xv
-					local zv = noise_z_map[i]*distort + z
-					if zv < zmin then zmin = zv end
-					if zv > zmax then zmax = zv end
-					noise_z_map[i] = zv
-				end
-				i2d = i2d-chulens.x
-			end
-		end
-
-		local pminp = {x=floor(xmin), z=floor(zmin)}
-		local pmaxp = {x=floor(xmax)+1, z=floor(zmax)+1}
-		incr = pmaxp.x-pminp.x+1
-		i_origin = 1 - pminp.z*incr - pminp.x
-		terrain_map, lake_map = mapgen_rivers.make_heightmaps(pminp, pmaxp)
-	else
-		terrain_map, lake_map = mapgen_rivers.make_heightmaps(minp, maxp)
-	end
-
-	-- Check that there is at least one position that reaches min y
-	if minp.y > sea_level then
-		local y0 = minp.y
-		local is_empty = true
-		for i=1, #terrain_map do
-			if terrain_map[i] >= y0 or lake_map[i] >= y0 then
-				is_empty = false
-				break
-			end
-		end
-
-		-- If not, skip chunk
-		if is_empty then
-			local t = os.clock() - t0
-			ngen = ngen + 1
-			sumtime = sumtime + t
-			sumtime2 = sumtime2 + t*t
-
-			minetest.log("verbose", "[mapgen_rivers] Skipping empty chunk (fully above ground level)")
-			minetest.log("verbose", ("[mapgen_rivers] Done in %5.3f s"):format(t))
-			return
-		end
-	end
-
-	local c_stone = minetest.get_content_id("mapgen_stone")
-	local c_water = minetest.get_content_id("mapgen_water_source")
-	local c_rwater = minetest.get_content_id("mapgen_river_water_source")
-
-	local c_dirt, c_lawn, c_dirtsnow, c_snow, c_sand, c_ice
-	if use_biomes then
-		c_dirt = minetest.get_content_id("default:dirt")
-		c_lawn = minetest.get_content_id("default:dirt_with_grass")
-		c_dirtsnow = minetest.get_content_id("default:dirt_with_snow")
-		c_snow = minetest.get_content_id("default:snowblock")
-		c_sand = minetest.get_content_id("default:sand")
-		c_ice = minetest.get_content_id("default:ice")
-	end
-
-	local vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
-	vm:get_data(data)
-
-	local a = VoxelArea:new({MinEdge = emin, MaxEdge = emax})
-	local ystride = a.ystride -- Tip : the ystride of a VoxelArea is the number to add to the array index to get the index of the position above. It's faster because it avoids to completely recalculate the index.
-
-	local nid = mapsize.x*(mapsize.y-1) + 1
-	local incrY = -mapsize.x
-	local incrX = 1 - mapsize.y*incrY
-	local incrZ = mapsize.x*mapsize.y - mapsize.x*incrX - mapsize.x*mapsize.y*incrY
-
-	local i2d = 1
-
-	for z = minp.z, maxp.z do
-		for x = minp.x, maxp.x do
-			local ivm = a:index(x, maxp.y+1, z)
-			local ground_above = false
-			local temperature
-			if use_biomes then
-				temperature = noise_heat_map[i2d]+noise_heat_blend_map[i2d]
-			end
-			local terrain, lake
-			if not use_distort then
-				terrain = terrain_map[i2d]
-				lake = lake_map[i2d]
-			end
-
-			for y = maxp.y+1, minp.y, -1 do
-				if use_distort then
-					local xn = noise_x_map[nid]
-					local zn = noise_z_map[nid]
-					local x0 = floor(xn)
-					local z0 = floor(zn)
-
-					local i0 = i_origin + z0*incr + x0
-					local i1 = i0+1
-					local i2 = i1+incr
-					local i3 = i2-1
-
-					terrain = interp(terrain_map[i0], terrain_map[i1], terrain_map[i2], terrain_map[i3], xn-x0, zn-z0)
-					lake = min(lake_map[i0], lake_map[i1], lake_map[i2], lake_map[i3])
-				end
-
-				if y <= maxp.y then
-
-					local is_lake = lake > terrain
-					if y <= terrain then
-						if not use_biomes or y <= terrain-1 or ground_above then
-							data[ivm] = c_stone
-						elseif is_lake or y < sea_level then
-							data[ivm] = c_sand
-						else
-							local temperature_y = temperature - y*elevation_chill
-							if temperature_y >= 15 then
-								data[ivm] = c_lawn
-							elseif temperature_y >= 0 then
-								data[ivm] = c_dirtsnow
-							else
-								data[ivm] = c_snow
-							end
-						end
-					elseif y <= lake and lake > sea_level then
-						if not use_biomes or temperature - y*elevation_chill >= 0 then
-							data[ivm] = c_rwater
-						else
-							data[ivm] = c_ice
-						end
-					elseif y <= sea_level then
-						data[ivm] = c_water
-					end
-				end
-
-				ground_above = y <= terrain
-
-				ivm = ivm - ystride
-				if use_distort then
-					nid = nid + incrY
-				end
-			end
-
-			if use_distort then
-				nid = nid + incrX
-			end
-			i2d = i2d + 1
-		end
-
-		if use_distort then
-			nid = nid + incrZ
-		end
-	end
-
-	if use_biomegen_mod then
-		biomegen.generate_all(data, a, vm, minp, maxp, seed)
-	else
-		vm:set_data(data)
-		minetest.generate_ores(vm, minp, maxp)
-	end
-
-	vm:set_lighting({day = 0, night = 0})
-	vm:calc_lighting()
-	vm:update_liquids()
-	vm:write_to_map()
-
-	local t = os.clock()-t0
-	ngen = ngen + 1
-	sumtime = sumtime + t
-	sumtime2 = sumtime2 + t*t
-	minetest.log("verbose", ("[mapgen_rivers] Done in %5.3f s"):format(t))
-end
-
-minetest.register_on_generated(generate)
-minetest.register_on_shutdown(function()
-	local avg = sumtime / ngen
-	local std = math.sqrt(sumtime2/ngen - avg*avg)
-	minetest.log("action", ("[mapgen_rivers] Mapgen statistics:\n- Mapgen calls: %4d\n- Mean time: %5.3f s\n- Standard deviation: %5.3f s"):format(ngen, avg, std))
 end)

mapgen.lua

@@ -0,0 +1,269 @@
+if minetest.get_mapgen_setting("mg_name") ~= "singlenode" then
+	minetest.set_mapgen_setting("mg_name", "singlenode", true)
+	minetest.log("warning", "[mapgen_rivers] Mapgen set to singlenode")
+end
+
+local sea_level = mapgen_rivers.settings.sea_level
+local elevation_chill = mapgen_rivers.settings.elevation_chill
+local use_distort = mapgen_rivers.settings.distort
+local use_biomes = mapgen_rivers.settings.biomes
+local use_biomegen_mod = use_biomes and minetest.global_exists('biomegen')
+use_biomes = use_biomes and minetest.global_exists('default') and not use_biomegen_mod
+
+if use_biomegen_mod then
+	biomegen.set_elevation_chill(elevation_chill)
+end
+
+-- Linear interpolation
+local function interp(v00, v01, v11, v10, xf, zf)
+	local v0 = v01*xf + v00*(1-xf)
+	local v1 = v11*xf + v10*(1-xf)
+	return v1*zf + v0*(1-zf)
+end
+
+-- Localize for performance
+local floor, min = math.floor, math.min
+
+local data = {}
+
+local noise_x_obj, noise_z_obj, noise_distort_obj, noise_heat_obj, noise_heat_blend_obj
+local noise_x_map = {}
+local noise_z_map = {}
+local noise_distort_map = {}
+local noise_heat_map = {}
+local noise_heat_blend_map = {}
+local mapsize
+local init = false
+
+local sumtime = 0
+local sumtime2 = 0
+local ngen = 0
+
+function mapgen_rivers.make_chunk(minp, maxp, seed)
+	minetest.log("info", ("[mapgen_rivers] Generating from %s to %s"):format(minetest.pos_to_string(minp), minetest.pos_to_string(maxp)))
+
+	local chulens = {
+		x = maxp.x-minp.x+1,
+		y = maxp.y-minp.y+1,
+		z = maxp.z-minp.z+1,
+	}
+
+	if not init then
+		mapsize = {
+			x = chulens.x,
+			y = chulens.y+1,
+			z = chulens.z,
+		}
+		if use_distort then
+			noise_x_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.distort_x, mapsize)
+			noise_z_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.distort_z, mapsize)
+			noise_distort_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.distort_amplitude, chulens)
+		end
+		if use_biomes then
+			noise_heat_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.heat, chulens)
+			noise_heat_blend_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.heat_blend, chulens)
+		end
+		init = true
+	end
+
+	local t0 = os.clock()
+	local minp2d = {x=minp.x, y=minp.z}
+	if use_distort then
+		noise_x_obj:get_3d_map_flat(minp, noise_x_map)
+		noise_z_obj:get_3d_map_flat(minp, noise_z_map)
+		noise_distort_obj:get_2d_map_flat(minp2d, noise_distort_map)
+	end
+	if use_biomes then
+		noise_heat_obj:get_2d_map_flat(minp2d, noise_heat_map)
+		noise_heat_blend_obj:get_2d_map_flat(minp2d, noise_heat_blend_map)
+	end
+
+	local terrain_map, lake_map, incr, i_origin
+
+	if use_distort then
+		local xmin, xmax, zmin, zmax = minp.x, maxp.x, minp.z, maxp.z
+		local i = 0
+		local i2d = 0
+		for z=minp.z, maxp.z do
+			for y=minp.y, maxp.y+1 do
+				for x=minp.x, maxp.x do
+					i = i+1
+					i2d = i2d+1
+					local distort = noise_distort_map[i2d]
+					local xv = noise_x_map[i]*distort + x
+					if xv < xmin then xmin = xv end
+					if xv > xmax then xmax = xv end
+					noise_x_map[i] = xv
+					local zv = noise_z_map[i]*distort + z
+					if zv < zmin then zmin = zv end
+					if zv > zmax then zmax = zv end
+					noise_z_map[i] = zv
+				end
+				i2d = i2d-chulens.x
+			end
+		end
+
+		local pminp = {x=floor(xmin), z=floor(zmin)}
+		local pmaxp = {x=floor(xmax)+1, z=floor(zmax)+1}
+		incr = pmaxp.x-pminp.x+1
+		i_origin = 1 - pminp.z*incr - pminp.x
+		terrain_map, lake_map = mapgen_rivers.make_heightmaps(pminp, pmaxp)
+	else
+		terrain_map, lake_map = mapgen_rivers.make_heightmaps(minp, maxp)
+	end
+
+	-- Check that there is at least one position that reaches min y
+	if minp.y > sea_level then
+		local y0 = minp.y
+		local is_empty = true
+		for i=1, #terrain_map do
+			if terrain_map[i] >= y0 or lake_map[i] >= y0 then
+				is_empty = false
+				break
+			end
+		end
+
+		-- If not, skip chunk
+		if is_empty then
+			local t = os.clock() - t0
+			ngen = ngen + 1
+			sumtime = sumtime + t
+			sumtime2 = sumtime2 + t*t
+
+			minetest.log("verbose", "[mapgen_rivers] Skipping empty chunk (fully above ground level)")
+			minetest.log("verbose", ("[mapgen_rivers] Done in %5.3f s"):format(t))
+			return
+		end
+	end
+
+	local c_stone = minetest.get_content_id("mapgen_stone")
+	local c_water = minetest.get_content_id("mapgen_water_source")
+	local c_rwater = minetest.get_content_id("mapgen_river_water_source")
+
+	local c_dirt, c_lawn, c_dirtsnow, c_snow, c_sand, c_ice
+	if use_biomes then
+		c_dirt = minetest.get_content_id("default:dirt")
+		c_lawn = minetest.get_content_id("default:dirt_with_grass")
+		c_dirtsnow = minetest.get_content_id("default:dirt_with_snow")
+		c_snow = minetest.get_content_id("default:snowblock")
+		c_sand = minetest.get_content_id("default:sand")
+		c_ice = minetest.get_content_id("default:ice")
+	end
+
+	local vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
+	vm:get_data(data)
+
+	local a = VoxelArea:new({MinEdge = emin, MaxEdge = emax})
+	local ystride = a.ystride -- Tip : the ystride of a VoxelArea is the number to add to the array index to get the index of the position above. It's faster because it avoids to completely recalculate the index.
+
+	local nid = mapsize.x*(mapsize.y-1) + 1
+	local incrY = -mapsize.x
+	local incrX = 1 - mapsize.y*incrY
+	local incrZ = mapsize.x*mapsize.y - mapsize.x*incrX - mapsize.x*mapsize.y*incrY
+
+	local i2d = 1
+
+	for z = minp.z, maxp.z do
+		for x = minp.x, maxp.x do
+			local ivm = a:index(x, maxp.y+1, z)
+			local ground_above = false
+			local temperature
+			if use_biomes then
+				temperature = noise_heat_map[i2d]+noise_heat_blend_map[i2d]
+			end
+			local terrain, lake
+			if not use_distort then
+				terrain = terrain_map[i2d]
+				lake = lake_map[i2d]
+			end
+
+			for y = maxp.y+1, minp.y, -1 do
+				if use_distort then
+					local xn = noise_x_map[nid]
+					local zn = noise_z_map[nid]
+					local x0 = floor(xn)
+					local z0 = floor(zn)
+
+					local i0 = i_origin + z0*incr + x0
+					local i1 = i0+1
+					local i2 = i1+incr
+					local i3 = i2-1
+
+					terrain = interp(terrain_map[i0], terrain_map[i1], terrain_map[i2], terrain_map[i3], xn-x0, zn-z0)
+					lake = min(lake_map[i0], lake_map[i1], lake_map[i2], lake_map[i3])
+				end
+
+				if y <= maxp.y then
+
+					local is_lake = lake > terrain
+					if y <= terrain then
+						if not use_biomes or y <= terrain-1 or ground_above then
+							data[ivm] = c_stone
+						elseif is_lake or y < sea_level then
+							data[ivm] = c_sand
+						else
+							local temperature_y = temperature - y*elevation_chill
+							if temperature_y >= 15 then
+								data[ivm] = c_lawn
+							elseif temperature_y >= 0 then
+								data[ivm] = c_dirtsnow
+							else
+								data[ivm] = c_snow
+							end
+						end
+					elseif y <= lake and lake > sea_level then
+						if not use_biomes or temperature - y*elevation_chill >= 0 then
+							data[ivm] = c_rwater
+						else
+							data[ivm] = c_ice
+						end
+					elseif y <= sea_level then
+						data[ivm] = c_water
+					end
+				end
+
+				ground_above = y <= terrain
+
+				ivm = ivm - ystride
+				if use_distort then
+					nid = nid + incrY
+				end
+			end
+
+			if use_distort then
+				nid = nid + incrX
+			end
+			i2d = i2d + 1
+		end
+
+		if use_distort then
+			nid = nid + incrZ
+		end
+	end
+
+	if use_biomegen_mod then
+		biomegen.generate_all(data, a, vm, minp, maxp, seed)
+	else
+		vm:set_data(data)
+		minetest.generate_ores(vm, minp, maxp)
+	end
+
+	vm:set_lighting({day = 0, night = 0})
+	vm:calc_lighting()
+	vm:update_liquids()
+	vm:write_to_map()
+
+	local t = os.clock()-t0
+	ngen = ngen + 1
+	sumtime = sumtime + t
+	sumtime2 = sumtime2 + t*t
+	minetest.log("verbose", ("[mapgen_rivers] Done in %5.3f s"):format(t))
+end
+
+minetest.register_on_generated(mapgen_rivers.make_chunk)
+
+minetest.register_on_shutdown(function()
+	local avg = sumtime / ngen
+	local std = math.sqrt(sumtime2/ngen - avg*avg)
+	minetest.log("action", ("[mapgen_rivers] Mapgen statistics:\n- Mapgen calls: %4d\n- Mean time: %5.3f s\n- Standard deviation: %5.3f s"):format(ngen, avg, std))
+end)

polygons.lua

@@ -1,94 +1,20 @@
-local modpath = mapgen_rivers.modpath
-local mod_data_path = modpath .. 'river_data/'
-if not io.open(mod_data_path .. 'size', 'r') then
-	mod_data_path = modpath .. 'demo_data/'
-end
-
-local world_data_path = mapgen_rivers.world_data_path
-minetest.mkdir(world_data_path)
-
-dofile(modpath .. 'load.lua')
-
-mapgen_rivers.grid = {}
-
 local blocksize = mapgen_rivers.settings.blocksize
 local X = math.floor(mapgen_rivers.settings.map_x_size / blocksize)
 local Z = math.floor(mapgen_rivers.settings.map_z_size / blocksize)
 
-local function offset_converter(o)
-	return (o + 0.5) * (1/256)
-end
-
-local load_all = mapgen_rivers.settings.load_all
-
--- Try to read file 'size'
-local sfile = io.open(world_data_path..'size', 'r')
-local first_mapgen = true
-if sfile then
-	X, Z = tonumber(sfile:read('*l')), tonumber(sfile:read('*l'))
-	sfile:close()
-	first_mapgen = false
-end
-
-if first_mapgen then
-	-- Generate a map!!
-	local pregenerate = dofile(mapgen_rivers.modpath .. '/pregenerate.lua')
-	minetest.register_on_mods_loaded(function()
-		minetest.log("action", '[mapgen_rivers] Generating grid, this may take a while...')
-		pregenerate(load_all)
-
-		if load_all then
-			local offset_x = mapgen_rivers.grid.offset_x
-			local offset_y = mapgen_rivers.grid.offset_y
-			for i=1, X*Z do
-				offset_x[i] = offset_converter(offset_x[i])
-				offset_y[i] = offset_converter(offset_y[i])
-			end
-		end
-	end)
-end
-
--- if data not already loaded
-if not (first_mapgen and load_all) then
-	local load_map
-	if load_all then
-		load_map = mapgen_rivers.load_map
-	else
-		load_map = mapgen_rivers.interactive_loader
-	end
-
-	minetest.register_on_mods_loaded(function()
-		if load_all then
-			minetest.log("action", '[mapgen_rivers] Loading full grid')
-		else
-			minetest.log("action", '[mapgen_rivers] Loading grid as interactive loaders')
-		end
-		local grid = mapgen_rivers.grid
-
-		grid.dem = load_map('dem', 2, true, X*Z)
-		grid.lakes = load_map('lakes', 2, true, X*Z)
-		grid.dirs = load_map('dirs', 1, false, X*Z)
-		grid.rivers = load_map('rivers', 4, false, X*Z)
-
-		grid.offset_x = load_map('offset_x', 1, true, X*Z, offset_converter)
-		grid.offset_y = load_map('offset_y', 1, true, X*Z, offset_converter)
-	end)
-end
-
-mapgen_rivers.grid.size = {x=X, y=Z}
-
 local function index(x, z)
 	return z*X+x+1
 end
 
-local min_catchment = mapgen_rivers.settings.min_catchment
-local max_catchment = mapgen_rivers.settings.max_catchment
-
 local map_offset = {x=0, z=0}
-if mapgen_rivers.settings.center then
+mapgen_rivers.register_on_grid_loaded(function(grid)
-	map_offset.x = blocksize*X/2
+	X = grid.size.x
-	map_offset.z = blocksize*Z/2
+	Z = grid.size.y
-end
+	if mapgen_rivers.settings.center then
+		map_offset.x = blocksize*X/2
+		map_offset.z = blocksize*Z/2
+	end
+end)
 
 -- Localize for performance
 local floor, ceil, min, max, abs = math.floor, math.ceil, math.min, math.max, math.abs

pregenerate.lua

@@ -46,8 +46,7 @@ local function margin(dem, width, elev)
 	end
 end
 
-local function pregenerate(keep_loaded)
+function mapgen_rivers.pregenerate(grid)
-	local grid = mapgen_rivers.grid
 	local size = grid.size
 
 	if size.x * size.y > 4e6 then
@@ -101,25 +100,14 @@ local function pregenerate(keep_loaded)
 		offset_y[i] = mmin(mmax(offset_y[i]*256, -128), 127)
 	end
 
-	mapgen_rivers.write_map('dem', model.dem, 2)
+	grid.dem = model.dem
-	mapgen_rivers.write_map('lakes', model.lakes, 2)
+	grid.lakes = model.lakes
-	mapgen_rivers.write_map('dirs', model.dirs, 1)
+	grid.dirs = model.dirs
-	mapgen_rivers.write_map('rivers', model.rivers, 4)
+	grid.rivers = model.rivers
-	mapgen_rivers.write_map('offset_x', offset_x, 1)
+	grid.offset_x = offset_x
-	mapgen_rivers.write_map('offset_y', offset_y, 1)
+	grid.offset_y = offset_y
-	local sfile = io.open(mapgen_rivers.world_data_path .. 'size', "w")
-	sfile:write(size.x..'\n'..size.y)
-	sfile:close()
 
-	if keep_loaded then
+	grid.load_method = "full"
-		grid.dem = model.dem
+	grid.conv_applied = false
-		grid.lakes = model.lakes
-		grid.dirs = model.dirs
-		grid.rivers = model.rivers
-		grid.offset_x = offset_x
-		grid.offset_y = offset_y
-	end
 	collectgarbage()
 end
-
-return pregenerate

settings.lua

@@ -111,6 +111,9 @@ mapgen_rivers.settings = {
 	load_all = mtsettings:get_bool('mapgen_rivers_load_all')
 }
 
+mapgen_rivers.settings.load_method =
+		mapgen_rivers.settings.load_all and "full" or "interactive"
+
 mapgen_rivers.noise_params = {
 	base = def_setting("np_base", "noise"),
 	distort_x = def_setting("np_distort_x", "noise"),