Minetest-WorldEditAdditions/worldeditadditions/utils/terrain/make_heightmap.lua

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local wea = worldeditadditions
local Vector3 = wea.Vector3
--- Given a manip object and associates, generates a 2D x/z heightmap.
-- Note that pos1 and pos2 should have already been pushed through
-- worldedit.sort_pos(pos1, pos2) before passing them to this function.
-- @param pos1 Vector Position 1 of the region to operate on
-- @param pos2 Vector Position 2 of the region to operate on
-- @param manip VoxelManip The VoxelManip object.
-- @param area area The associated area object.
-- @param data table The associated data object.
-- @return table,table The ZERO-indexed heightmap data (as 1 single flat array), followed by the size of the heightmap in the form { z = size_z, x = size_x }.
local function make_heightmap(pos1, pos2, manip, area, data)
-- z y x (in reverse for little-endian machines) is the preferred loop order, but that isn't really possible here
local heightmap = {}
local hi = 0
local changes = { updated = 0, skipped_columns = 0 }
for z = pos1.z, pos2.z, 1 do
for x = pos1.x, pos2.x, 1 do
local found_node = false
-- Scan each column top to bottom
for y = pos2.y+1, pos1.y, -1 do
local i = area:index(x, y, z)
if not (wea.is_airlike(data[i]) or wea.is_liquidlike(data[i])) then
-- It's the first non-airlike node in this column
-- Start heightmap values from 1 (i.e. there's at least 1 node in the column)
heightmap[hi] = (y - pos1.y) + 1
found_node = true
break
end
end
if not found_node then heightmap[hi] = -1 end
hi = hi + 1
end
end
local heightmap_size = Vector3.new(
(pos2.x - pos1.x) + 1, -- x
0, -- y
(pos2.z - pos1.z) + 1 -- z
)
return heightmap, heightmap_size
end
return make_heightmap