digtron/pointset.lua

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Lua
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-- A simple special-purpose class, this is used for building up sets of three-dimensional points
-- I only added features to it as I needed them so may not be highly useful outside of this mod's context.
Pointset = {}
Pointset.__index = Pointset
function Pointset.create()
local set = {}
setmetatable(set,Pointset)
set.points = {}
return set
end
function Pointset:set(x, y, z, value)
-- sets a value in the 3D array "points".
if self.points[x] == nil then
self.points[x] = {}
end
if self.points[x][y] == nil then
self.points[x][y] = {}
end
self.points[x][y][z] = value
end
function Pointset:set_if_not_in(excluded, x, y, z, value)
-- If a value is not already set for this point in the 3D array "excluded", set it in "points"
if excluded:get(x, y, z) ~= nil then
return
end
self:set(x, y, z, value)
end
function Pointset:get(x, y, z)
-- return a value from the 3D array "points"
if self.points[x] == nil or self.points[x][y] == nil then
return nil
end
return self.points[x][y][z]
end
function Pointset:pop()
-- returns a point that's in the 3D array, and then removes it.
local pos = {}
local ytable
local ztable
local val
local count = 0
for _ in pairs(self.points) do count = count + 1 end
if count == 0 then
return nil
end
pos.x, ytable = next(self.points)
pos.y, ztable = next(ytable)
pos.z, val = next(ztable)
self.points[pos.x][pos.y][pos.z] = nil
count = 0
for _ in pairs(self.points[pos.x][pos.y]) do count = count + 1 end
if count == 0 then
self.points[pos.x][pos.y] = nil
end
count = 0
for _ in pairs(self.points[pos.x]) do count = count + 1 end
if count == 0 then
self.points[pos.x] = nil
end
return pos, val
end