loud_walking/mapgen.lua

local node = loud_walking.node


local data = {}
local p2data = {}  -- vm rotation data buffer
local lightmap = {}
local vm, emin, emax, a, csize, heightmap, biomemap
local div_sz_x, div_sz_z, minp, maxp, terrain, cave

local base_terrain_noise = {offset = 0,
scale = 20, seed = 8829, spread = {x = 40, y = 40, z = 40},
octaves = 6, persist = 0.4, lacunarity = 2}

local cave_noise = {offset = 0, scale = 1,
seed = -3977, spread = {x = 30, y = 30, z = 30}, octaves = 3,
persist = 0.8, lacunarity = 2}

local tree_biomes = {}
tree_biomes["deciduous_forest"] = {"deciduous_trees"}
tree_biomes["coniferous_forest"] = {"conifer_trees"}
tree_biomes["rainforest"] = {"jungle_trees"}

local biome_terrain_scale = {}
biome_terrain_scale["deciduous_forest"] = 0.5
biome_terrain_scale["coniferous_forest"] = 0.75
biome_terrain_scale["rainforest"] = 0.33


local function place_schematic(pos, schem, center)
	local yslice = {}
	if schem.yslice_prob then
		for _, ys in pairs(schem.yslice_prob) do
			yslice[ys.ypos] = ys.prob
		end
	end

	if center then
		pos.x = pos.x - math.floor(schem.size.x / 2)
		pos.z = pos.z - math.floor(schem.size.z / 2)
	end

	for z = 0, schem.size.z - 1 do
		for x = 0, schem.size.x - 1 do
			local ivm = a:index(pos.x + x, pos.y, pos.z + z)
			local isch = z * schem.size.y * schem.size.x + x + 1
			for y = 0, schem.size.y - 1 do
				if yslice[y] or 255 >= math.random(255) then
					local prob = schem.data[isch].prob or schem.data[isch].param1 or 255
					if prob >= math.random(255) and schem.data[isch].name ~= "air" then
						data[ivm] = node(schem.data[isch].name)
					end
					local param2 = schem.data[isch].param2 or 0
					p2data[ivm] = param2
				end
				ivm = ivm + a.ystride
				isch = isch + schem.size.x
			end
		end
	end
end

local function is_pod(x, y, z)
	local min_x = math.floor((x + 32) / csize.x)
	local min_y = math.floor((y + 32) / csize.y)
	local min_z = math.floor((z + 32) / csize.z)

	if min_x % 2 == 0 and min_y % 2 == 0 and min_z % 2 == 0 then
		return true
	end
	--if min_x % 2 == 1 and min_y % 4 == 0 and min_z % 2 == 1 then
	--	return true
	--elseif min_x % 2 == 0 and min_y % 4 == 2 and min_z % 2 == 0 then
	--	return true
	--end

	return false
end

local function connection(x, y, z)
	local min_x = math.floor((x + 32) / csize.x)
	local min_y = math.floor((y + 32) / csize.y)
	local min_z = math.floor((z + 32) / csize.z)

	--local seed_noise = minetest.get_perlin({offset = 0, scale = 32768,
	--seed = 5202, spread = {x = 80, y = 80, z = 80}, octaves = 2,
	--persist = 0.4, lacunarity = 2})
	--math.randomseed(seed_noise:get2d({x=minp.x, y=minp.z}))

	local ct = min_x % 2 + min_y % 2 + min_z % 2
	local r = min_x % 2 + 2 * (min_y % 2) + 4 * (min_z % 2)
	if ct == 1 then
		return r
	end

	return nil
end

local function get_height(dx, dz, biome, index)
	local terr

	if index == true then
		local terrain_noise = table.copy(base_terrain_noise)
		terrain_noise.scale = terrain_noise.scale * biome_terrain_scale[biome]
		terr = math.floor(minetest.get_perlin(terrain_noise):get2d({x=dx, y=dz}) + 0.5)
		-- Still need csize here...
		dx = (dx + 32) % 80
		dz = (dz + 32) % 80
	elseif not index then
		index = dz * csize.x + dx + 1
		terr = math.floor(terrain[index] + 0.5)
	else
		terr = math.floor(terrain[index] + 0.5)
	end

	local d = 38 - math.abs(math.abs(dx - 39.5) - math.abs(dz - 39.5))
	if math.abs(terr) > d then
		if terr > 0 then
			terr = math.floor(d + 0.5)
		else
			terr = math.floor(0.5 - d)
		end
	end

	return terr
end

local function get_biome(px, pz)
	return "deciduous_forest"
end


function loud_walking.generate(p_minp, p_maxp, seed)
	minp, maxp = p_minp, p_maxp
	vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
	vm:get_data(data)
	vm:set_lighting({day = 15, night = 0}, minp, maxp)
	lightmap = vm:get_light_data()
	--p2data = vm:get_param2_data()
	a = VoxelArea:new({MinEdge = emin, MaxEdge = emax})
	csize = vector.add(vector.subtract(maxp, minp), 1)

	local write = false

	-- Deal with memory issues. This, of course, is supposed to be automatic.
	local mem = math.floor(collectgarbage("count")/1024)
	if mem > 300 then
		print("Manually collecting garbage...")
		collectgarbage("collect")
	end

	local px = math.floor((minp.x + 32) / csize.x)
	local pz = math.floor((minp.z + 32) / csize.z)
	local biome = get_biome(px, pz)
	local top = node("default:dirt_with_grass")

	-- use the same seed (based on perlin noise).
	local seed_noise = minetest.get_perlin({offset = 0, scale = 32768,
	seed = 5202, spread = {x = 80, y = 80, z = 80}, octaves = 2,
	persist = 0.4, lacunarity = 2})
	math.randomseed(seed_noise:get2d({x=minp.x, y=minp.z}))

	local terrain_noise = table.copy(base_terrain_noise)
	terrain_noise.scale = terrain_noise.scale * biome_terrain_scale[biome]
	terrain = minetest.get_perlin_map(terrain_noise, csize):get2dMap_flat(minp)
	cave = minetest.get_perlin_map(cave_noise, csize):get3dMap_flat(minp)

	local pod = is_pod(minp.x, minp.y, minp.z)
	local connection = connection(minp.x, minp.y, minp.z)

	local index = 0
	local index3d = 0
	for z = minp.z, maxp.z do
		local dz = z - minp.z
		for x = minp.x, maxp.x do
			index = index + 1
			local dx = x - minp.x
			index3d = dz * csize.y * csize.x + dx + 1
			local ivm = a:index(x, minp.y, z)

			local terr = get_height(dx, dz, biome, index)
			local in_cave = false

			for y = minp.y, maxp.y do
				local dy = y - minp.y
				if pod then
					if math.min(dx, csize.x - dx) + math.min(dy, csize.y - dy) + math.min(dz, csize.z - dz) < 40 then
						data[ivm] = node("air")
						--lightmap[ivm] = 0
						in_cave = false
					elseif math.min(dx, csize.x - dx) + math.min(dy, csize.y - dy) + math.min(dz, csize.z - dz) < 41 then
						if dy < terr + 40 then
							data[ivm] = node("loud_walking:scrith")
							lightmap[ivm] = 0
						else
							data[ivm] = node("default:glass")
						end
						in_cave = false
						write = true
					elseif (dx == 0 or dx == csize.x - 1) or (dz == 0 or dz == csize.z - 1) or (dy == 0 or dy == csize.y - 1) then
						if math.abs(dy - 42) < 2 and (dz == 40 or dx == 40) then
							data[ivm] = node("air")
						else
							if dy < terr + 40 then
								data[ivm] = node("loud_walking:scrith")
								lightmap[ivm] = 0
							else
								data[ivm] = node("default:glass")
							end
							write = true
						end
						in_cave = false
					elseif dy > terr + 40 then
						data[ivm] = node("air")
						in_cave = false
					elseif cave[index3d] ^ 2 > 0.1 + dy / 40 then
						if terr + 40 >= dy and not in_cave and dy > terr + 30 then
							data[ivm] = node("default:dirt")
						else
							data[ivm] = node("air")
						end
						in_cave = true
						lightmap[ivm] = 0
					elseif dy > terr + 39 then
						data[ivm] = top
						lightmap[ivm] = 0
						in_cave = false
						write = true
					elseif dy > terr + 37 then
						data[ivm] = node("default:dirt")
						lightmap[ivm] = 0
						in_cave = false
						write = true
					else
						data[ivm] = node("default:stone")
						lightmap[ivm] = 0
						in_cave = false
						write = true
					end
				elseif connection and dy == 40 and ((dx == 40 and connection % 4 == 0) or (dz == 40 and connection % 2 == 1)) then
					data[ivm] = node("default:stone")
					lightmap[ivm] = 0
					write = true
				end

				ivm = ivm + a.ystride
				index3d = index3d + csize.x
			end
		end
	end

	if pod then
		for dz = 0, 75, 5 do
			for dx = 0, 75, 5 do
				if math.random(2) == 1 then
					local x = minp.x + dx + math.random(0, 4)
					local z = minp.z + dz + math.random(0, 4)
					local y = minp.y + get_height(x - minp.x, z - minp.z, biome) + 40

					local ivm = a:index(x, y, z)
					if data[ivm + a.ystride] == node("air") and (data[ivm] == node("default:dirt") or data[ivm] == node("default:dirt_with_grass") or data[ivm] == node("default:dirt_with_snow")) then
						if tree_biomes[biome] then
							local tree_type = tree_biomes[biome][math.random(#tree_biomes[biome])]
							local schem = loud_walking.schematics[tree_type][math.random(#loud_walking.schematics[tree_type])]
							local pos = {x=x, y=y, z=z}
							-- The minetest schematic functions don't seem very accurate.
							place_schematic(pos, schem, true)
						end
					end
				end
			end
		end
	end

	if write then
		vm:set_data(data)
		minetest.generate_ores(vm, minp, maxp)
		minetest.generate_decorations(vm, minp, maxp)
		--vm:set_param2_data(p2data)
		--vm:set_lighting({day = 15, night = 0})
		vm:set_light_data(lightmap)
		vm:calc_lighting(minp, maxp, false)
		vm:update_liquids()
		vm:write_to_map()
	end

	vm, a, heightmap, biomemap = nil, nil, nil, nil
end

function loud_walking.respawn(player)
	local success = false
	while not success do
		local px = math.random(-10, 10) * 2
		local pz = math.random(-10, 10) * 2
		-- How do we get csize before generation?
		local dx = math.random(80) - 1
		local dz = math.random(80) - 1
		local x = (dx - 32) + 80 * px
		local z = (dz - 32) + 80 * pz
		local y = get_height(x, z, get_biome(px, pz), true) + 8

		local pos = {x=x,y=y,z=z}
		local node = minetest.get_node(pos)
		if node.name ~= "air" then
			player:setpos(pos)
			success = true
		end
		--print(node.name)
	end
end