Rewritten part of code to calculate river depth
Fixes bathymetry problems on turns or confluences, as well as abrupt riverbanks.
This commit is contained in:
Gaël de Sailly
parent
cd4b517585
commit
b429b302e1
96
init.lua
96
init.lua
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@ -45,55 +45,63 @@ local function generate(minp, maxp, seed)
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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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-- Test the 4 edges to see whether we are in a river or not
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local is_river = false
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local depth_factor = 0
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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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if xf > r_east then
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is_river = true
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depth_factor = xf-r_east
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xf = 1
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elseif xf < r_west then
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is_river = true
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depth_factor = r_west-xf
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xf = 0
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end
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if zf > r_south then
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is_river = true
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depth_factor = zf-r_south
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zf = 1
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elseif zf < r_north then
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is_river = true
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depth_factor = r_north-zf
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zf = 0
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end
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local c_NW, c_NE, c_SE, c_SW = unpack(poly.river_corners)
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if not is_river then -- Test corners also
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local c_NW, c_NE, c_SE, c_SW = unpack(poly.river_corners)
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if xf+zf < c_NW then
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is_river = true
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depth_factor = c_NW-xf-zf
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xf, zf = 0, 0
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elseif 1-xf+zf < c_NE then
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is_river = true
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depth_factor = c_NE-1+xf-zf
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xf, zf = 1, 0
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elseif 2-xf-zf < c_SE then
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is_river = true
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depth_factor = c_SE-2+xf+zf
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xf, zf = 1, 1
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elseif xf+1-zf < c_SW then
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is_river = true
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depth_factor = c_SW-xf-1+zf
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xf, zf = 0, 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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c_NE+xf-zf-1,
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c_SE+xf+zf-2,
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c_SW-xf+zf-1,
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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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if not is_river then -- Redefine indicesto have 0/1 on the riverbanks (avoids ugly edge cuts, at least for small rivers)
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xf = (xf-r_west) / (r_east-r_west)
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zf = (zf-r_north) / (r_south-r_north)
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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, c_SW+zf-1)
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local x1 = math.min(r_east, 1-c_NE+zf, 2-c_SE-zf)
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local z0 = math.max(r_north, c_NW-xf, c_NE+xf-1)
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local z1 = math.min(r_south, 1-c_SW+xf, 2-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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@ -104,8 +112,8 @@ local function generate(minp, maxp, seed)
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))
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local lake_height = math.max(math.floor(poly.lake), terrain_height)
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if is_river then
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terrain_height = math.min(math.max(lake_height, sea_level) - math.floor(1+depth_factor*riverbed_slope), 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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11
polygons.lua
11
polygons.lua
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@ -153,17 +153,6 @@ local function make_polygons(minp, maxp)
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local river_east = 1 - (dirB==1 and riverB or 0) - (dirC==3 and riverC or 0)
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local river_south = 1 - (dirD==2 and riverD or 0) - (dirC==4 and riverC or 0)
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-- Only if opposite rivers overlap (should be rare)
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if river_west > river_east then
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local mean = (river_west + river_east) / 2
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river_west = mean
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river_east = mean
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end
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if river_north > river_south then
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local mean = (river_north + river_south) / 2
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river_north = mean
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river_south = mean
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end
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polygon.rivers = {river_west, river_north, river_east, river_south}
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end
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end
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