Minetest-WorldEditAdditions/worldeditadditions/lib/floodfill.lua

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--- Flood-fill command for complex lakes etc.
-- @module worldeditadditions.floodfill
-------------------------------------------------------------------------------
--- A Queue implementation, taken & adapted from https://www.lua.org/pil/11.4.html
-- @submodule worldeditadditions.utils.queue
local Queue = {}
function Queue.new()
return { first = 0, last = -1 }
end
function Queue.enqueue(queue, value)
local new_last = queue.last + 1
queue.last = new_last
queue[new_last] = value
end
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function Queue.contains(queue, value)
for i=queue.first,queue.last do
if queue[i] == value then
return true
end
end
return false
end
function Queue.is_empty(queue)
return queue.first > queue.last
end
function Queue.dequeue(queue)
local first = queue.first
if Queue.is_empty(queue) then
error("Error: The queue is empty!")
end
local value = queue[first]
queue[first] = nil -- Help the garbage collector out
queue.first = first + 1
return value
end
-------------------------------------------------------------------------------
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function worldeditadditions.floodfill(start_pos, radius, replace_node)
-- Calculate the area we want to modify
local pos1 = vector.add(start_pos, { x = radius, y = 0, z = radius })
local pos2 = vector.subtract(start_pos, { x = radius, y = radius, z = radius })
pos1, pos2 = worldedit.sort_pos(pos1, pos2)
-- pos2 will always have the highest co-ordinates now
-- Fetch the nodes in the specified area
local manip, area = worldedit.manip_helpers.init(pos1, pos2)
local data = manip:get_data()
-- Setup for the floodfill operation itself
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local start_pos_index = area:index(start_pos.x, start_pos.y, start_pos.z)
local search_id = data[start_pos_index]
local replace_id = minetest.get_content_id(replace_node)
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local radius_sq = radius*radius
if search_id == replace_id then
return false
end
local count = 0
local remaining_nodes = Queue.new()
Queue.enqueue(remaining_nodes, start_pos_index)
-- Do the floodfill
while Queue.is_empty(remaining_nodes) == false do
local cur = Queue.dequeue(remaining_nodes)
-- Replace this node
data[cur] = replace_id
count = count + 1
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-- Check all the nearby nodes
-- We don't need to go upwards here, since we're filling in lake-style
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local xplus = cur + 1 -- +X
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if data[xplus] == search_id and
worldeditadditions.vector.lengthsquared(vector.subtract(area:position(xplus), start_pos)) < radius_sq and
not Queue.contains(remaining_nodes, xplus) then
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-- minetest.log("action", "[floodfill] [+X] index " .. xplus .. " is a " .. data[xplus] .. ", searching for a " .. search_id)
Queue.enqueue(remaining_nodes, xplus)
end
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local xminus = cur - 1 -- -X
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if data[xminus] == search_id and
worldeditadditions.vector.lengthsquared(vector.subtract(area:position(xminus), start_pos)) < radius_sq and
not Queue.contains(remaining_nodes, xminus) then
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-- minetest.log("action", "[floodfill] [-X] index " .. xminus .. " is a " .. data[xminus] .. ", searching for a " .. search_id)
Queue.enqueue(remaining_nodes, xminus)
end
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local zplus = cur + area.zstride -- +Z
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if data[zplus] == search_id and
worldeditadditions.vector.lengthsquared(vector.subtract(area:position(zplus), start_pos)) < radius_sq and
not Queue.contains(remaining_nodes, zplus) then
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-- minetest.log("action", "[floodfill] [+Z] index " .. zplus .. " is a " .. data[zplus] .. ", searching for a " .. search_id)
Queue.enqueue(remaining_nodes, zplus)
end
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local zminus = cur - area.zstride -- -Z
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if data[zminus] == search_id and
worldeditadditions.vector.lengthsquared(vector.subtract(area:position(zminus), start_pos)) < radius_sq and
not Queue.contains(remaining_nodes, zminus) then
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-- minetest.log("action", "[floodfill] [-Z] index " .. zminus .. " is a " .. data[zminus] .. ", searching for a " .. search_id)
Queue.enqueue(remaining_nodes, zminus)
end
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local yminus = cur - area.ystride -- -Y
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if data[yminus] == search_id and
worldeditadditions.vector.lengthsquared(vector.subtract(area:position(yminus), start_pos)) < radius_sq and
not Queue.contains(remaining_nodes, yminus) then
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-- minetest.log("action", "[floodfill] [-Y] index " .. yminus .. " is a " .. data[yminus] .. ", searching for a " .. search_id)
Queue.enqueue(remaining_nodes, yminus)
end
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count = count + 1
end
-- Save the modified nodes back to disk & return
worldedit.manip_helpers.finish(manip, data)
return count
end