mirror of
https://gitlab.com/gaelysam/mapgen_rivers.git
synced 2024-11-11 05:10:23 +01:00
121 lines
3.1 KiB
Lua
121 lines
3.1 KiB
Lua
local modpath = minetest.get_modpath(minetest.get_current_modname()) .. '/'
|
|
|
|
local make_polygons = dofile(modpath .. 'polygons.lua')
|
|
local transform_quadri = dofile(modpath .. 'geometry.lua')
|
|
|
|
local blocksize = mapgen_rivers.blocksize
|
|
local sea_level = mapgen_rivers.sea_level
|
|
local riverbed_slope = mapgen_rivers.riverbed_slope
|
|
|
|
local MAP_BOTTOM = -31000
|
|
|
|
-- 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
|
|
|
|
local function heightmaps(minp, maxp)
|
|
|
|
local polygons = make_polygons(minp, maxp)
|
|
local incr = maxp.z-minp.z+1
|
|
|
|
local terrain_height_map = {}
|
|
local lake_height_map = {}
|
|
|
|
local i = 1
|
|
for z=minp.z, maxp.z do
|
|
for x=minp.x, maxp.x do
|
|
local poly = polygons[i]
|
|
|
|
if poly then
|
|
local xf, zf = transform_quadri(poly.x, poly.z, x/blocksize, z/blocksize)
|
|
local i00, i01, i11, i10 = unpack(poly.i)
|
|
|
|
-- Load river width on 4 edges and corners
|
|
local r_west, r_north, r_east, r_south = unpack(poly.rivers)
|
|
local c_NW, c_NE, c_SE, c_SW = unpack(poly.river_corners)
|
|
|
|
-- Calculate the depth factor for each edge and corner.
|
|
-- Depth factor:
|
|
-- < 0: outside river
|
|
-- = 0: on riverbank
|
|
-- > 0: inside river
|
|
local depth_factors = {
|
|
r_west - xf,
|
|
r_north - zf,
|
|
xf - r_east,
|
|
zf - r_south,
|
|
c_NW-xf-zf,
|
|
xf-zf-c_NE,
|
|
xf+zf-c_SE,
|
|
zf-xf-c_SW,
|
|
}
|
|
|
|
-- Find the maximal depth factor and determine to which river it belongs
|
|
local depth_factor_max = 0
|
|
local imax = 0
|
|
for i=1, 8 do
|
|
if depth_factors[i] >= depth_factor_max then
|
|
depth_factor_max = depth_factors[i]
|
|
imax = i
|
|
end
|
|
end
|
|
|
|
-- 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)
|
|
if imax == 0 then
|
|
local x0 = math.max(r_west, c_NW-zf, zf-c_SW)
|
|
local x1 = math.min(r_east, c_NE+zf, c_SE-zf)
|
|
local z0 = math.max(r_north, c_NW-xf, xf-c_NE)
|
|
local z1 = math.min(r_south, c_SW+xf, c_SE-xf)
|
|
xf = (xf-x0) / (x1-x0)
|
|
zf = (zf-z0) / (z1-z0)
|
|
elseif imax == 1 then
|
|
xf = 0
|
|
elseif imax == 2 then
|
|
zf = 0
|
|
elseif imax == 3 then
|
|
xf = 1
|
|
elseif imax == 4 then
|
|
zf = 1
|
|
elseif imax == 5 then
|
|
xf, zf = 0, 0
|
|
elseif imax == 6 then
|
|
xf, zf = 1, 0
|
|
elseif imax == 7 then
|
|
xf, zf = 1, 1
|
|
elseif imax == 8 then
|
|
xf, zf = 0, 1
|
|
end
|
|
|
|
-- Determine elevation by interpolation
|
|
local vdem = poly.dem
|
|
local terrain_height = math.floor(0.5+interp(
|
|
vdem[1],
|
|
vdem[2],
|
|
vdem[3],
|
|
vdem[4],
|
|
xf, zf
|
|
))
|
|
|
|
local lake_height = math.max(math.floor(poly.lake), terrain_height)
|
|
if imax > 0 and depth_factor_max > 0 then
|
|
terrain_height = math.min(math.max(lake_height, sea_level) - math.floor(1+depth_factor_max*riverbed_slope), terrain_height)
|
|
end
|
|
|
|
terrain_height_map[i] = terrain_height
|
|
lake_height_map[i] = lake_height
|
|
else
|
|
terrain_height_map[i] = MAP_BOTTOM
|
|
lake_height_map[i] = MAP_BOTTOM
|
|
end
|
|
i = i + 1
|
|
end
|
|
end
|
|
|
|
return terrain_height_map, lake_height_map
|
|
end
|
|
|
|
return heightmaps
|