rill-patchbay

Automation and control system — LFOs, envelopes, sequencers, sensors, servos, and event mapping for the Rill audio graph.

Architecture

Two-thread design. Automata run on the control thread (green threads via tokio) and communicate with the audio thread through lock-free MpscQueue<ParameterCommand>.

Control thread (tokio):
  Automaton ── mpsc<f64> ──→ PortCombiner ── MpscQueue ──→ Audio thread
  UI/MIDI    ── mpsc<UiCmd> → PortCombiner ── MpscQueue ──→ Audio thread
  Sequencer  ◀── crossbeam<Telemetry> ◀──────────────────── Audio thread

Key components

Automata — LfoAutomaton, EnvelopeAutomaton, RandomWalkAutomaton, SequencerAutomaton, FunctionAutomaton, CellularAutomaton
PortCombiner — sits between automaton and audio thread. Resolves conflicts between automaton output and UI/MIDI/OSC input using ControlStrategy (Absolute / Modulation) and ConflictStrategy.
Sequencer — SnapshotSequencer driven by clock ticks from the audio thread via crossbeam channel. SequencerHandle for start/stop/reset.
Servos — apply automaton signals to graph node parameters via ParameterMapping (Linear, Exponential, Logarithmic, Inverted, Custom).
Sensors — acoustic (pitch, envelope follower), physical (knobs, buttons), MIDI, CV.
Event mapping — MIDI CC → parameter, OSC address → parameter, with transforms.
Engine — centralised API for adding automata, servos, mappings, green threads, and port combiners (fka PatchbayControl).
Manager — high-level coordinator with per-port cancellation domains.

Usage

use rill_core_actor::ActorRef;
use rill_patchbay::prelude::*;

let (actor_ref, _mailbox) = ActorRef::new_pair();
let mut engine = Engine::new(actor_ref);

engine.add_lfo(
    "vibrato", 5.0, 0.5, 0.0, LfoWaveform::Sine,
    osc_node_id, "frequency", 400.0, 480.0,
);

engine.add_envelope(
    "amp", 0.01, 0.1, 0.7, 0.2,
    vca_node_id, "gain", 0.0, 1.0,
);

engine.update(1.0 / 60.0);

Feature flags

Feature	Description
`serde`	Serialization support (JSON/CBOR)
`json`	`serde` + JSON serialization
`cbor`	`serde` + CBOR serialization
`serialization`	`json` + `cbor`

Dependencies

rill-core — node traits, queues, types
crossbeam-channel, parking_lot, tokio — green thread infrastructure