136 lines
4.4 KiB
Lua
136 lines
4.4 KiB
Lua
-- Set the 3D noise parameters for the terrain.
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local np_terrain = {
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offset = 0,
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scale = 1,
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spread = {x = 384, y = 192, z = 384},
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seed = 5900033,
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octaves = 5,
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persist = 0.63,
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lacunarity = 2.0,
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--flags = ""
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}
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-- Set singlenode mapgen (air nodes only).
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-- Disable the engine lighting calculation since that will be done for a
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-- mapchunk of air nodes and will be incorrect after we place nodes.
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minetest.set_mapgen_params({mgname = "singlenode", flags = "nolight"})
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-- Get the content IDs for the nodes used.
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local c_sandstone = minetest.get_content_id("default:sandstone")
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local c_water = minetest.get_content_id("default:water_source")
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-- Initialize noise object to nil. It will be created once only during the
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-- generation of the first mapchunk, to minimise memory use.
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local nobj_terrain = nil
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-- Localise noise buffer table outside the loop, to be re-used for all
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-- mapchunks, therefore minimising memory use.
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local nvals_terrain = {}
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-- Localise data buffer table outside the loop, to be re-used for all
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-- mapchunks, therefore minimising memory use.
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local data = {}
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-- On generated function.
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-- 'minp' and 'maxp' are the minimum and maximum positions of the mapchunk that
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-- define the 3D volume.
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minetest.register_on_generated(function(minp, maxp, seed)
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-- Start time of mapchunk generation.
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local t0 = os.clock()
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-- Noise stuff.
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-- Side length of mapchunk.
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local sidelen = maxp.x - minp.x + 1
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-- Required dimensions of the 3D noise perlin map.
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local permapdims3d = {x = sidelen, y = sidelen, z = sidelen}
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-- Create the perlin map noise object once only, during the generation of
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-- the first mapchunk when 'nobj_terrain' is 'nil'.
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nobj_terrain = nobj_terrain or
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minetest.get_perlin_map(np_terrain, permapdims3d)
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-- Create a flat array of noise values from the perlin map, with the
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-- minimum point being 'minp'.
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-- Set the buffer parameter to use and reuse 'nvals_terrain' for this.
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nobj_terrain:get3dMap_flat(minp, nvals_terrain)
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-- Voxelmanip stuff.
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-- Load the voxelmanip with the result of engine mapgen. Since 'singlenode'
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-- mapgen is used this will be a mapchunk of air nodes.
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local vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
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-- 'area' is used later to get the voxelmanip indexes for positions.
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local area = VoxelArea:new{MinEdge = emin, MaxEdge = emax}
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-- Get the content ID data from the voxelmanip in the form of a flat array.
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-- Set the buffer parameter to use and reuse 'data' for this.
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vm:get_data(data)
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-- Generation loop.
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-- Noise index for the flat array of noise values.
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local ni = 1
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-- Process the content IDs in 'data'.
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-- The most useful order is a ZYX loop because:
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-- 1. This matches the order of the 3D noise flat array.
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-- 2. This allows a simple +1 incrementing of the voxelmanip index along x
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-- rows.
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for z = minp.z, maxp.z do
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for y = minp.y, maxp.y do
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-- Voxelmanip index for the flat array of content IDs.
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-- Initialise to first node in this x row.
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local vi = area:index(minp.x, y, z)
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for x = minp.x, maxp.x do
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-- Consider a 'solidness' value for each node,
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-- let's call it 'density', where
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-- density = density noise + density gradient.
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local density_noise = nvals_terrain[ni]
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-- Density gradient is a value that is 0 at water level (y = 1)
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-- and falls in value with increasing y. This is necessary to
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-- create a 'world surface' with only solid nodes deep underground
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-- and only air high above water level.
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-- Here '128' determines the typical maximum height of the terrain.
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local density_gradient = (1 - y) / 128
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-- Place solid nodes when 'density' > 0.
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if density_noise + density_gradient > 0 then
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data[vi] = c_sandstone
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-- Otherwise if at or below water level place water.
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elseif y <= 1 then
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data[vi] = c_water
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end
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-- Increment noise index.
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ni = ni + 1
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-- Increment voxelmanip index along x row.
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-- The voxelmanip index increases by 1 when
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-- moving by 1 node in the +x direction.
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vi = vi + 1
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end
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end
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end
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-- After processing, write content ID data back to the voxelmanip.
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vm:set_data(data)
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-- Calculate lighting for what has been created.
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vm:calc_lighting()
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-- Write what has been created to the world.
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vm:write_to_map()
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-- Liquid nodes were placed so set them flowing.
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vm:update_liquids()
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-- Print generation time of this mapchunk.
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local chugent = math.ceil((os.clock() - t0) * 1000)
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print ("[lvm_example] Mapchunk generation time " .. chugent .. " ms")
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end)
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