Added midi continue support

I really think this should be handled by `clock.transport`. It already handles start and stop messages from midi devices. I'm not really happy about splitting transport responsibilities between `clock` and handling them manually in my script. Because of this, I'm implementing this in the least invasive way I can think of.

Added new params for midi continue device and mode
Device is the midi device to listen for "continue" messages from
Mode is whether a "continue" message always plays or toggles playback (like a play/pause button)
Updated readme with release notes

README.md

@@ -21,6 +21,15 @@ The size determines how long the sound will last. Larger circles will sound out
 
 There are also a few parameters to adjust under the _KEY 1_ parameters page. Play around with those.
 
+### v1.6.1
+
+Minor update to add midi continue support.
+
+- Added two new params; midi continue device and midi continue mode
+     - Midi continue device lets you choose which device to listen for "continue" messages from; This allows you to choose a different midi device for "continue" messages than the device you're sending midi out messages to
+     - Midi continue mode lets you choose if new "continue" messages always start playback or toggle so you can use it as a play/pause button
+- Grouped new params in "midi continue" group
+
 ### v1.6
 
 This is a pretty major update under the hood. Because of that I took this as an opportunity to update some of the param IDs. This means that existing PSETs will probably result in unexpected behavior.

circles.lua

@@ -1,5 +1,5 @@
 -- oO ( circles ) Oo
--- v1.6 @jakecarter
+-- v1.6.1 @jakecarter
 -- llllllll.co/t/22951
 -- 
 -- ENC 2 & 3 move cursor
@@ -34,10 +34,13 @@ local isRunning = true
 -- enums
 local outputs = { audio = 1, midi = 2, crow = 3, crow_jf = 4 }
 local radius_affects = { release = 1, amp = 2 }
+local midi_continue_modes = { always_play = 1, toggle= 2 }
 
 local midi_devices
 local midi_out_device
 local midi_out_channel
+local midi_continue_device
+local midi_continue_mode
 function build_midi_device_list()
   midi_devices = {}
   for i = 1,#midi.vports do
@@ -100,6 +103,19 @@ function setupParams()
     action = function() build_scale_notes() end
   })
 
+  -- midi continue
+  params:add_group("midi continue", 2)
+  params:add({type = "option", id = "midi_continue_device", name = "device",
+    options = midi_devices, default = 1,
+    action = function(value)
+      midi_continue_device = midi.connect(value)
+    end
+  })
+  params:add_option("midi_continue_mode", "mode", { "always play", "toggle" })
+  params:set_action("midi_continue_mode", function(value)
+    midi_continue_mode = value
+  end)
+
   -- libCircles
   params:add_option("keep_on_screen", "keep on screen", { "no", "yes" })
   params:set_action("keep_on_screen", function(value)
@@ -134,6 +150,7 @@ function init()
   build_midi_device_list()
 
   setupParams()
+  midi_continue_device.event = midi_continue_device_event
 
   clock.run(step)
 end
@@ -169,6 +186,18 @@ function clock.transport.stop()
   isRunning = false
 end
 
+function midi_continue_device_event(data)
+  msg = midi.to_msg(data)
+
+  if msg.type == "continue" then
+    if midi_continue_mode == midi_continue_modes.always_play then
+      isRunning = true
+    elseif midi_continue_mode == midi_continue_modes.toggle then
+      isRunning = not isRunning
+    end
+  end 
+end
+
 function noteForCircle(circle)
   local noteIndex = math.floor(math_helpers.scale(circle.x, 0, 128, 1, #scale_notes))
   local note = scale_notes[noteIndex]