Skip to content

Bind a hardware knob to any parameter (MIDI-learn)

Goal: drive any Gloopy parameter — a fader, a filter cutoff, a reverb's wet level — from a hardware knob, a MIDI CC, or an OSC source, with your own range. This is the controller map (MIDI-learn) system.

A map connects a source to a target, scaled to a range:

  • source — cc:<n> (a MIDI CC number), osc:<name> (a named OSC source), or any string you feed by hand.
  • target — a parameter id, e.g. track/5/volume, track/5/pan, or effect/6/0/Wet.
  • lo / hi — the output range the source's 0–1 maps onto. Set lo > hi to invert.

Bind it explicitly

If you know the CC number and target, map them directly:

from gloopy import Gloopy

with Gloopy() as g:
    # CC 74 drives track 5's filter cutoff, over the top half of its range
    g.add_controller_map("cc:74", "track/5/synth/cutoff", lo=0.5, hi=1.0)
    g.list_controller_maps()          # [{'source': 'cc:74', 'target': ..., 'lo': .5, 'hi': 1.0, ...}]

Or learn it by moving the knob

Don't know the CC number? Arm learn on the target, then wiggle the control — the next source that arrives binds to it:

g.midi_learn("effect/6/0/Wet")   # arm; next controller move binds here ('' cancels)
# now move the hardware knob

On the desktop this is the same thing: right-click a mixer fader/knob → MIDI Learn, then move your controller. Manage the resulting bindings in the Maps window (bypass, re-range, invert, remove).

Feed it (and test without hardware)

A real MIDI CC or an OSC message (/gloopy/track/5/cc) feeds the map. You can also feed a source by hand — handy for testing or for a software controller:

g.set_controller("cc:74", 0.0)    # -> cutoff = 0.5  (lo)
g.set_controller("cc:74", 1.0)    # -> cutoff = 1.0  (hi)

Manage bindings

g.set_controller_bypass("cc:74", "track/5/synth/cutoff", True)   # disable, keep it
g.remove_controller_map("cc:74")                                  # remove

MIDI-learn vs. automation vs. modulation

Controller maps are for performing a parameter live. For a fixed drawn shape use automation; for hands-off cyclic movement use modulation (set_modulation). See What to use for what.

See also