midi_keyswitch.lua

ardour {
    ["type"]    = "Session",
    name        = "Midi Keyswitch",
    category    = "MIDI Controls",
    license     = "MIT",
    author      = "Mostly Ardour devs",
    description = [[Switch preset on key]]
  }
  
  function factory ()
    return function (n_samples)
      -- iterate over all MIDI ports
      _, t = Session:engine():get_ports(ARDOUR.DataType.midi (), ARDOUR.PortList())
      local routes = Session:get_routes():table()
      local proc = routes[1]:nth_plugin (0)
      if proc:isnil () then 
        print("Proc is nil")
        return
      else
        -- print(proc:display_name())
      end
      local plug = proc:to_insert():plugin(0)
      for p in t[2]:iter () do
        -- skip output ports
        if not p:receives_input () then goto next end
  
        local midiport = p:to_midiport ()
        -- and skip async event ports
        if midiport:isnil () then goto next end
    
        local mb = midiport:get_midi_buffer(n_samples) -- get the midi-data buffers
        local events = mb:table() -- copy event list into lua table
  
        for _,e in pairs (events) do -- iterate over all events in the midi-buffer
          if (e:buffer():array()[1] & 0xf0) == 0x90 then -- note on
            print("Note on")
            local record = plug:preset_by_label("Test 2")
            if plug:load_preset(record) then
              print("Loaded")
            else
              print("Error")
            end
          end
        end
        ::next::
      end
    end
  end