First commit

README.txt

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+stability 0.1.1 by paramat
+For latest stable Minetest back to 0.4.8
+Depends default
+Licenses: code WTFPL

depends.txt

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+default

init.lua

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+-- stability 0.1.1 by paramat
+-- For latest stable Minetest and back to 0.4.8
+-- Depends default
+-- License: code WTFPL
+
+-- Parameters
+
+local YMIN = 6000
+local YMAX = 8000
+local TCEN = 7000
+local WATY = 7000 -- approximate water y, is rounded down to near base of chunk
+local GRAD = 128
+local STOT = 0.04
+
+-- 3D noise for terrain
+
+local np_terrain = {
+	offset = 0,
+	scale = 1,
+	spread = {x=256, y=192, z=256},
+	seed = 5900033,
+	octaves = 5,
+	persist = 0.67
+}
+
+-- Stuff
+
+stability = {}
+
+waty = (80 * math.floor((WATY + 32) / 80)) - 32 + 12
+
+-- On generated function
+
+minetest.register_on_generated(function(minp, maxp, seed)
+	if minp.y < YMIN or maxp.y > YMAX then
+		return
+	end
+
+	local t1 = os.clock()
+	local x1 = maxp.x
+	local y1 = maxp.y
+	local z1 = maxp.z
+	local x0 = minp.x
+	local y0 = minp.y
+	local z0 = minp.z
+	
+	print ("[stability] chunk minp ("..x0.." "..y0.." "..z0..")")
+	
+	local vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
+	local area = VoxelArea:new{MinEdge=emin, MaxEdge=emax}
+	local data = vm:get_data()
+	
+	local c_air = minetest.get_content_id("air")
+	local c_stone = minetest.get_content_id("default:stone")
+	local c_sand = minetest.get_content_id("default:sand")
+	local c_water = minetest.get_content_id("default:water_source")
+	
+	local sidelen = x1 - x0 + 1
+	local chulens = {x=sidelen, y=sidelen, z=sidelen}
+	local minpos = {x=x0, y=y0, z=z0}
+	
+	local nvals_terrain = minetest.get_perlin_map(np_terrain, chulens):get3dMap_flat(minpos)
+	
+	local ni = 1
+	local stable = {} -- stability table, a true/false entry for the top node in each vertical column of xy plane
+	for z = z0, z1 do -- for each xy plane progressing northwards
+		for x = x0, x1 do -- set initial values of stability table by scanning top x row of chunk below
+			local si = x - x0 + 1 -- stability table index starts from 1 not 0
+			local nodename = minetest.get_node({x=x,y=y0-1,z=z}).name
+			if nodename == "air"
+			or nodename == "default:water_source" then
+				stable[si] = false
+			else -- solid nodes
+				stable[si] = true -- assume "ignore" in ungenerated chunks is solid
+			end
+		end
+		
+		for y = y0, y1 do -- for each x row progressing upwards
+			local vi = area:index(x0, y, z) -- get voxel index for first node in x row
+			for x = x0, x1 do -- for each node do
+				local si = x - x0 + 1
+				local grad = (TCEN - y) / GRAD
+				local density = nvals_terrain[ni] + grad
+				if density >= STOT then
+					data[vi] = c_stone
+					stable[si] = true -- only stone can reset an unstable column to stable
+				elseif density >= 0 and density < STOT and stable[si] then -- only add if node is stable
+					data[vi] = c_sand
+				elseif y <= waty then
+					data[vi] = c_water
+					stable[si] = false -- set to unstable
+				else
+					data[vi] = c_air
+					stable[si] = false -- set to unstable
+				end
+				ni = ni + 1 -- increment perlinmap noise index
+				vi = vi + 1 -- increment voxel index along x row
+			end
+		end
+	end
+	
+	vm:set_data(data)
+	vm:set_lighting({day=0, night=0})
+	vm:calc_lighting()
+	vm:write_to_map(data)
+	local chugent = math.ceil((os.clock() - t1) * 1000)
+	print ("[stability] "..chugent.." ms")
+end)

license.txt

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+            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
+                    Version 2, December 2004
+
+ Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
+
+ Everyone is permitted to copy and distribute verbatim or modified
+ copies of this license document, and changing it is allowed as long
+ as the name is changed.
+
+            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+  0. You just DO WHAT THE FUCK YOU WANT TO.
+