reactor_mon.lua

local monitor = peripheral.find("monitor")
local reactor = peripheral.find("BigReactors-Reactor")

local rodSize = 4

function clear()
    term.clear()
    term.setBackgroundColor(colors.black)
    term.setCursorPos(1,1)
end

function drawRods(sx, sy)

    local controlRods = reactor.getNumberOfControlRods()

    for i=1,controlRods do
        term.setCursorPos(1,1)
        local percent = reactor.getControlRodLevel(i-1)/100.0

        local h = math.floor(percent*rodSize)

        if percent == 1 then
            h = rodSize-1
        end

        local left = (rodSize-h)-1
        local x = sx+i*2
        local y = sy

        if i > 10 then
            y = y + rodSize+1
            x = sx + (i-10)*2
        end

        --write(tostring(i)..' '..tostring(h))
        --x,y,width,height
        paintutils.drawFilledBox(x, y, x, y+h, colours.green)

        if percent < 1 then
          paintutils.drawFilledBox(x, y+h, x, (y+h)+left, colours.red)
        end
    end

    term.setBackgroundColor(colours.black)
end

function drawHeader()
    local activeText = "Active"

    if not reactor.getActive() then
        activeText = "Disabled"
    end

    write("Reactor"..activeText.."\n")
end

term.redirect(monitor)
monitor.setTextScale(0.5)

while true do
    clear()
    drawHeader()
    drawRods(1, 4)
    sleep(5)
end