honk_piano.lua

util.require_natives("2944b")

local cur_note = nil
util.create_tick_handler(function()
    PAD.DISABLE_CONTROL_ACTION(0, 0, true) -- Disable INPUT_NEXT_CAMERA (V)
    PAD.DISABLE_CONTROL_ACTION(0, 79, true) -- Disable INPUT_VEH_LOOK_BEHIND (C)

    local note = nil
    if util.is_key_down('Z') then -- C4
        note = 16
    elseif util.is_key_down('X') then -- D4
        note = 17
    elseif util.is_key_down('C') then -- E4
        note = 18
    elseif util.is_key_down('V') then -- F4
        note = 19
    elseif util.is_key_down('B') then -- G4
        note = 20
    elseif util.is_key_down('N') then -- A4
        note = 21
    elseif util.is_key_down('M') then -- B4
        note = 22
    elseif util.is_key_down(0xBC) then -- C5
        note = 23
    end

    if cur_note and note ~= cur_note then
        cur_note = nil
    elseif note ~= nil then
        cur_note = note
        VEHICLE.SET_VEHICLE_MOD(entities.get_user_vehicle_as_handle(), 14, note)
        PAD.SET_CONTROL_VALUE_NEXT_FRAME(0, 86, 1)
    end
end)

Inspired by https://github.com/hexarobi/stand-lua-hornsongs