holo-set.lua

local component = require("component")
local hologram = component.hologram

function setVoxel(x, y, z, value)
  local current = hologram.get(x, z)
  local positiveMask = bit32.lshift(1, y - 1)
  if value then
    hologram.set(x, z, bit32.bor(current, positiveMask))
  else
    local negativeMask = bit32.bnot(positiveMask)
    hologram.set(x, z, bit32.band(current, negativeMask))
  end
end

local args = {...}
setVoxel(tonumber(args[1]), tonumber(args[2]), tonumber(args[3]), args[4] == "true" or args[4] == "on")