generic MIDI: if a CC is bound to a toggled controllable, toggle the controllable...

See comment in code for more details

diff --git a/libs/surfaces/generic_midi/midicontrollable.cc b/libs/surfaces/generic_midi/midicontrollable.cc
index b036a9d30f81e9f72491686be4276052852b6bed..3a1aea592faa0c5c87b82870a5e2f7500ea34cf5 100644 (file)
--- a/libs/surfaces/generic_midi/midicontrollable.cc
+++ b/libs/surfaces/generic_midi/midicontrollable.cc
@@ -374,12 +374,26 @@ MIDIControllable::midi_sense_controller (Parser &, EventTwoBytes *msg)
 
                        }
                } else {
-                       if ( msg->value > 0x40 ) {
-                               controllable->set_value (1, Controllable::NoGroup);
+
+                       /* toggle control: make the toggle flip only if the
+                        * incoming control value exceeds 0.5 (0x40), so that
+                        * the typical button which sends "CC N=0x7f" on press
+                        * and "CC N=0x0" on release can be used to drive
+                        * toggles on press.
+                        *
+                        * No other arrangement really makes sense for a toggle
+                        * controllable. Acting on the press+release makes the
+                        * action momentary, which is almost never
+                        * desirable. If the physical button only sends a
+                        * message on press (or release), then it will be
+                        * expected to send a controller value >= 0.5
+                        * (0x40). It is hard to imagine why anyone would make
+                        * a MIDI controller button that sent 0x0 when pressed.
+                        */
+
+                       if (msg->value >= 0x40) {
+                               controllable->set_value (controllable->get_value() >= 0.5 ? 0.0 : 1.0, Controllable::NoGroup);
                                DEBUG_TRACE (DEBUG::GenericMidi, string_compose ("Midi CC %1 value 1  %2\n", (int) msg->controller_number, current_uri()));
-                       } else {
-                               controllable->set_value (0, Controllable::NoGroup);
-                               DEBUG_TRACE (DEBUG::GenericMidi, string_compose ("Midi CC %1 value 0  %2\n", (int) msg->controller_number, current_uri()));
                        }
                }