Script for use with VCV Rack ModScript to map a Launchpad X to a virtual monome grid64

launchpadx-grid64.lua

-- Lua script for the ModScript module (https://github.com/Simon-L/ModScript)
-- to use a Launchpad X to control a virtual monome grid64 (https://dewb.github.io/monome-rack/modules/grids/)

config.frameDivider = 128
config.bufferSize = 8

grid = Module(0x12eff0454d674b)

leds = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}

function process(block)

  -- convert incoming MIDI note input to param changes
  for i=1,block.midiInputSize do
    msg = Message(block.midiInput[i])
    if msg.type == NOTE_ON or msg.type == NOTE_OFF then
      if msg.note >= 11 and msg.note <= 88 then
        local y = math.floor((88 - msg.note)/10.0)
        local x = (msg.note % 10) - 1
        local n = (y * 8 + x) * 2 -- x2 because every button has two params
        if n >= 0 and n < 128 then
          -- launchpad X sends note offs as note on with velocity zero
          if msg.type == NOTE_ON and msg.value > 0 then
            grid:setParam(n, 1.0) 
          else 
            grid:setParam(n, 0.0)
          end
        end
      end
    end
  end

  -- send light changes out as MIDI messages
  for x=0,7 do
    for y=0,7 do
      local n = y * 8 + x
      local value = grid:getLight(n)
      if leds[n] ~= value then
        local color = math.floor(value * 7)
        local note = 81 - (10 * y) + x
        sendMidiMessage(NOTE_ON, note, color)
        leds[n] = value
      end
    end
  end
end