mirror of
https://gitlab.com/gaelysam/mapgen_rivers.git
synced 2024-12-29 12:20:41 +01:00
Horizontal shifting according to 3D noises:
makes slopes more irregular and natural-looking, allows overhanging. This is done by generating an intermediate 2D elevation map and, for each node in 3D, add a 2D offset vector to the position, and seek this position on the heightmap.
This commit is contained in:
Gael-de-Sailly
parent
f56857e804
commit
4edd1a946e
119
heightmap.lua
Normal file
119
heightmap.lua
Normal file
@ -0,0 +1,119 @@
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local modpath = minetest.get_modpath(minetest.get_current_modname()) .. '/'
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local make_polygons = dofile(modpath .. 'polygons.lua')
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local transform_quadri = dofile(modpath .. 'geometry.lua')
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local blocksize = mapgen_rivers.blocksize
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local sea_level = mapgen_rivers.sea_level
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local riverbed_slope = mapgen_rivers.riverbed_slope
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-- Linear interpolation
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local function interp(v00, v01, v11, v10, xf, zf)
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local v0 = v01*xf + v00*(1-xf)
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local v1 = v11*xf + v10*(1-xf)
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return v1*zf + v0*(1-zf)
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end
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local function heightmaps(minp, maxp)
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local polygons = make_polygons(minp, maxp)
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local incr = maxp.x-minp.x+1
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local i0 = (minp.z-minp.z) * incr + (minp.x-minp.x) + 1
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local terrain_height_map = {}
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local lake_height_map = {}
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local i = 1
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for x=minp.x, maxp.x do
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for z=minp.z, maxp.z do
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local poly = polygons[i]
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if poly then
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local xf, zf = transform_quadri(poly.x, poly.z, x/blocksize, z/blocksize)
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local i00, i01, i11, i10 = unpack(poly.i)
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-- Load river width on 4 edges and corners
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local r_west, r_north, r_east, r_south = unpack(poly.rivers)
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local c_NW, c_NE, c_SE, c_SW = unpack(poly.river_corners)
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-- Calculate the depth factor for each edge and corner.
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-- Depth factor:
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-- < 0: outside river
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-- = 0: on riverbank
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-- > 0: inside river
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local depth_factors = {
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r_west - xf,
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r_north - zf,
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xf - r_east,
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zf - r_south,
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c_NW-xf-zf,
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xf-zf-c_NE,
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xf+zf-c_SE,
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zf-xf-c_SW,
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}
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-- Find the maximal depth factor and determine to which river it belongs
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local depth_factor_max = 0
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local imax = 0
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for i=1, 8 do
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if depth_factors[i] >= depth_factor_max then
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depth_factor_max = depth_factors[i]
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imax = i
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end
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end
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-- Transform the coordinates to have xf and zf = 0 or 1 in rivers (to avoid rivers having lateral slope and to accomodate the surrounding smoothly)
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if imax == 0 then
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local x0 = math.max(r_west, c_NW-zf, zf-c_SW)
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local x1 = math.min(r_east, c_NE+zf, c_SE-zf)
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local z0 = math.max(r_north, c_NW-xf, xf-c_NE)
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local z1 = math.min(r_south, c_SW+xf, c_SE-xf)
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xf = (xf-x0) / (x1-x0)
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zf = (zf-z0) / (z1-z0)
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elseif imax == 1 then
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xf = 0
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elseif imax == 2 then
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zf = 0
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elseif imax == 3 then
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xf = 1
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elseif imax == 4 then
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zf = 1
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elseif imax == 5 then
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xf, zf = 0, 0
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elseif imax == 6 then
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xf, zf = 1, 0
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elseif imax == 7 then
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xf, zf = 1, 1
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elseif imax == 8 then
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xf, zf = 0, 1
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end
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-- Determine elevation by interpolation
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local vdem = poly.dem
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local terrain_height = math.floor(0.5+interp(
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vdem[1],
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vdem[2],
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vdem[3],
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vdem[4],
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xf, zf
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))
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local lake_height = math.max(math.floor(poly.lake), terrain_height)
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if imax > 0 and depth_factor_max > 0 then
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terrain_height = math.min(math.max(lake_height, sea_level) - math.floor(1+depth_factor_max*riverbed_slope), terrain_height)
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end
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terrain_height_map[i] = terrain_height
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lake_height_map[i] = lake_height
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else
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terrain_height_map[i] = -31000
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lake_height_map[i] = -31000
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end
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i = i + 1
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end
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end
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return terrain_height_map, lake_height_map
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end
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return heightmaps
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222
init.lua
222
init.lua
@ -12,6 +12,8 @@ local make_polygons = dofile(modpath .. 'polygons.lua')
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local transform_quadri = dofile(modpath .. 'geometry.lua')
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local heightmaps = dofile(modpath .. 'heightmap.lua')
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-- Linear interpolation
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local function interp(v00, v01, v11, v10, xf, zf)
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local v0 = v01*xf + v00*(1-xf)
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@ -21,7 +23,95 @@ end
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local data = {}
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local noise_x_params = {
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offset = 0,
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scale = 1,
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seed = -4574,
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spread = {x=64, y=32, z=64},
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octaves = 3,
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persistence = 0.75,
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lacunarity = 2,
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}
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local noise_z_params = {
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offset = 0,
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scale = 1,
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seed = -7940,
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spread = {x=64, y=32, z=64},
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octaves = 3,
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persistence = 0.75,
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lacunarity = 2,
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}
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local noise_distort_params = {
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offset = 0,
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scale = 10,
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seed = 676,
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spread = {x=1024, y=1024, z=1024},
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octaves = 5,
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persistence = 0.5,
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lacunarity = 2,
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flags = "absvalue",
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}
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local noise_x_obj, noise_z_obj, noise_distort_obj
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local noise_x_map = {}
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local noise_z_map = {}
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local noise_distort_map = {}
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local mapsize
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local init = false
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local function generate(minp, maxp, seed)
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local chulens = {
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x = maxp.x-minp.x+1,
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y = maxp.y-minp.y+1,
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z = maxp.z-minp.z+1,
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}
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if not init then
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mapsize = {
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x = chulens.x,
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y = chulens.y+1,
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z = chulens.z,
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}
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noise_x_obj = minetest.get_perlin_map(noise_x_params, mapsize)
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noise_z_obj = minetest.get_perlin_map(noise_z_params, mapsize)
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noise_distort_obj = minetest.get_perlin_map(noise_distort_params, chulens)
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init = true
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end
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noise_x_obj:get_3d_map_flat(minp, noise_x_map)
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noise_z_obj:get_3d_map_flat(minp, noise_z_map)
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noise_distort_obj:get_2d_map_flat(minp, noise_distort_map)
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local xmin, xmax, zmin, zmax = minp.x, maxp.x, minp.z, maxp.z
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local i = 0
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local i2d = 0
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for z=minp.z, maxp.z do
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for y=minp.y, maxp.y+1 do
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for x=minp.x, maxp.x do
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i = i+1
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i2d = i2d+1
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local distort = noise_distort_map[i2d]
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local xv = noise_x_map[i]*distort + x
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if xv < xmin then xmin = xv end
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if xv > xmax then xmax = xv end
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noise_x_map[i] = xv
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local zv = noise_z_map[i]*distort + z
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if zv < zmin then zmin = zv end
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if zv > zmax then zmax = zv end
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noise_z_map[i] = zv
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end
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i2d = i2d-chulens.x
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end
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end
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local pminp = {x=math.floor(xmin), z=math.floor(zmin)}
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local pmaxp = {x=math.floor(xmax)+1, z=math.floor(zmax)+1}
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local incr = pmaxp.z-pminp.z+1
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local i_origin = 1 - pminp.x*incr - pminp.z
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local terrain_map, lake_map = heightmaps(pminp, pmaxp)
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local c_stone = minetest.get_content_id("default:stone")
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local c_dirt = minetest.get_content_id("default:dirt")
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local c_lawn = minetest.get_content_id("default:dirt_with_grass")
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@ -35,119 +125,55 @@ local function generate(minp, maxp, seed)
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local a = VoxelArea:new({MinEdge = emin, MaxEdge = emax})
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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.
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local polygons = make_polygons(minp, maxp)
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local nid = mapsize.x*(mapsize.y-1) + 1
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local incrY = -mapsize.x
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local incrX = 1 - mapsize.y*incrY
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local incrZ = mapsize.x*mapsize.y - mapsize.x*incrX - mapsize.x*mapsize.y*incrY
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local i = 1
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for x = minp.x, maxp.x do
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for z = minp.z, maxp.z do
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local poly = polygons[i]
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if poly then
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local xf, zf = transform_quadri(poly.x, poly.z, x/blocksize, z/blocksize)
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local i00, i01, i11, i10 = unpack(poly.i)
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for x = minp.x, maxp.x do
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local ivm = a:index(x, minp.y, z)
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local ground_above = false
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for y = maxp.y+1, minp.y, -1 do
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local xn = noise_x_map[nid]
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local zn = noise_z_map[nid]
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local x0 = math.floor(xn)
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local z0 = math.floor(zn)
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-- Load river width on 4 edges and corners
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local r_west, r_north, r_east, r_south = unpack(poly.rivers)
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local c_NW, c_NE, c_SE, c_SW = unpack(poly.river_corners)
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local i0 = i_origin + x0*incr + z0
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local i1 = i0+incr
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local i2 = i1+1
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local i3 = i0+1
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-- Calculate the depth factor for each edge and corner.
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-- Depth factor:
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-- < 0: outside river
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-- = 0: on riverbank
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-- > 0: inside river
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local depth_factors = {
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r_west - xf,
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r_north - zf,
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xf - r_east,
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zf - r_south,
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c_NW-xf-zf,
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xf-zf-c_NE,
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xf+zf-c_SE,
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zf-xf-c_SW,
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}
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local terrain = interp(terrain_map[i0], terrain_map[i1], terrain_map[i2], terrain_map[i3], xn-x0, zn-z0)
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if y <= maxp.y then
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local lake = math.min(lake_map[i0], lake_map[i1], lake_map[i2], lake_map[i3])
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-- Find the maximal depth factor and determine to which river it belongs
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local depth_factor_max = 0
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local imax = 0
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for i=1, 8 do
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if depth_factors[i] >= depth_factor_max then
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depth_factor_max = depth_factors[i]
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imax = i
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end
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end
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-- Transform the coordinates to have xf and zf = 0 or 1 in rivers (to avoid rivers having lateral slope and to accomodate the surrounding smoothly)
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if imax == 0 then
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local x0 = math.max(r_west, c_NW-zf, zf-c_SW)
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local x1 = math.min(r_east, c_NE+zf, c_SE-zf)
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local z0 = math.max(r_north, c_NW-xf, xf-c_NE)
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local z1 = math.min(r_south, c_SW+xf, c_SE-xf)
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xf = (xf-x0) / (x1-x0)
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zf = (zf-z0) / (z1-z0)
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elseif imax == 1 then
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xf = 0
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elseif imax == 2 then
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zf = 0
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elseif imax == 3 then
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xf = 1
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elseif imax == 4 then
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zf = 1
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elseif imax == 5 then
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xf, zf = 0, 0
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elseif imax == 6 then
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xf, zf = 1, 0
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elseif imax == 7 then
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xf, zf = 1, 1
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elseif imax == 8 then
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xf, zf = 0, 1
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end
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-- Determine elevation by interpolation
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local vdem = poly.dem
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local terrain_height = math.floor(0.5+interp(
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vdem[1],
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vdem[2],
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vdem[3],
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vdem[4],
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xf, zf
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))
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local lake_height = math.max(math.floor(poly.lake), terrain_height)
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if imax > 0 and depth_factor_max > 0 then
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terrain_height = math.min(math.max(lake_height, sea_level) - math.floor(1+depth_factor_max*riverbed_slope), terrain_height)
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end
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local is_lake = lake_height > terrain_height
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local ivm = a:index(x, minp.y-1, z)
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if terrain_height >= minp.y then
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for y=minp.y, math.min(maxp.y, terrain_height) do
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if y == terrain_height then
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if is_lake or y <= sea_level then
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local is_lake = lake > terrain
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local ivm = a:index(x, y, z)
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if y <= terrain then
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if y <= terrain-1 or ground_above then
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data[ivm] = c_stone
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elseif is_lake then
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data[ivm] = c_sand
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else
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data[ivm] = c_lawn
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end
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else
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data[ivm] = c_stone
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end
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ivm = ivm + ystride
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elseif y <= lake and lake > sea_level then
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data[ivm] = c_rwater
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elseif y <= sea_level then
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data[ivm] = c_water
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end
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end
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if lake_height > sea_level then
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if is_lake and lake_height >= minp.y then
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for y=math.max(minp.y, terrain_height+1), math.min(maxp.y, lake_height) do
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data[ivm] = c_rwater
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ground_above = y <= terrain
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ivm = ivm + ystride
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nid = nid + incrY
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end
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nid = nid + incrX
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end
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else
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for y=math.max(minp.y, terrain_height+1), math.min(maxp.y, sea_level) do
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data[ivm] = c_water
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ivm = ivm + ystride
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end
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end
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end
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i = i + 1
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end
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nid = nid + incrZ
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end
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vm:set_data(data)
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