5.8 KiB
Roadmap
Phase 0 — Baseline
Inspect repository/toolchain, verify Makefile and minimal executable, document dependencies. No system changes without permission.
Baseline implementation: headless startup/shutdown executable, core tests, separate debug build, optional FLTK shell build, and header dependencies. See BUILD.md for toolchain, commands, licensing and limitations.
Phase 1 — C core and offline processing
Graph data structures, validation, cycle detection, topological ordering, preallocated buffers, test oscillator, gain and offline render tests.
Implemented: mono ports, transactional cycle rejection, independent compiled plans, precomputed input routing, oscillator/gain/meter/output, deterministic variable-block tests and lifecycle/error coverage. See AUDIO_ENGINE.md for API limits and compatibility behavior.
Phase 2 — Real-time backend
Choose and implement a Linux backend. Document callback semantics, start/stop, device errors, shutdown, and safe graph publication.
Implemented: optional JACK-compatible mono backend, explicit audio port routing, format/xrun/loss status, start/stop/reopen, and bounded pending/retired plan handoff using lock-free atomics. Hardware-independent failure/concurrency tests and a 30-second software-loopback run pass. See decision 0004 and AUDIO_ENGINE.md. Physical hardware playback/endurance and live server-loss recovery remain unverified; GUI engine controls are implemented in Phase 3.
Phase 3 — FLTK shell
Main window, transport controls, view switching, backend status, clean startup and shutdown through the C API.
Implemented: dark FLTK shell, Play/Stop/Reconnect, view/menu shortcuts, backend state/format/xrun/process status, persistent command errors, timer-based refresh and retirement collection, and callback-safe close/retry. Mock-backend GUI tests and live GUI/JACK start/stop/reconnect/close tests pass under Xvfb. Sequencer, mixer and project-file actions remain placeholders; initial graph is silent. See GUI.md.
Phase 4 — Modular editor
Draw nodes/ports/edges; create, move and connect nodes; reject invalid edges; safely submit edits to the C core.
Implemented: scrollable node/port/wire canvas; add/select/move/delete nodes; drag connections, select/delete wires, and show invalid-edit feedback. C owns stable IDs, read-only snapshots and transactional edits. Exact accepted graph snapshots are submitted to the backend; prepared/queued/active state is exposed through revision acknowledgements. Core/render, GUI rollback, mouse smoke and live adoption tests pass. See GUI.md and AUDIO_ENGINE.md. Preset parameters, mono-only processing, fixed canvas and no persistence/undo/zoom remain limits.
Phase 5 — Project and sequencer
Versioned persistence, stable IDs, tracks, clips, timeline, selection, zoom, scrolling, and transport synchronization.
Implemented: bounded version-1 project persistence with transactional loads and temporary-file/fsync/rename saves; stable track/clip/node IDs; silent regions; track and region creation/deletion, selection, move/trim, timeline zoom/scroll; sample-counted playhead, pause/resume and stopped seek. Project/graph arrangement roundtrips, malformed-input, GUI rollback/gesture and live transport tests pass. See PROJECT_FORMAT.md and GUI.md. Constant tempo/4/4, silent metadata regions, no undo, asset playback, MIDI or persisted GUI layout are explicit limits.
Phase 6 — Audio clips and recording
Audio import/playback, recording through bounded buffers, missing-asset handling, no file I/O in callbacks.
Implemented: bounded PCM16/24/32 and float32 WAV import (mono/stereo downmix), preloaded overlap-summed clip plans with linear rate conversion, and an audio source node using ordinary graph routing. A lock-free SPSC ring transfers JACK input to a control-thread WAV writer; Stop finalizes and adds successful takes. Version 2 metadata stores external asset references and reads v1. Missing assets remain silent with reporting and manual relinking. Core, callback, GUI and live software record/save/reopen/play acceptance tests pass. See AUDIO_FILES.md for memory/format limits, overflow recovery and deferred physical-device validation. No new dependency or callback I/O was introduced.
Phase 7 — MIDI and instrument
MIDI input/events/clips, simple internal instrument, note-off/panic handling, then a basic piano roll.
Implemented: bounded source-relative note events with stable IDs; sample-offset JACK MIDI input; a velocity-scaled sine instrument and separate graph source; panic, note-off, stop and seek handling; and a piano roll for drawing, moving, resizing and deleting notes. Version 3 saves notes and reads v1/v2 projects. Core, fault-injection, GUI and live software MIDI/save/reopen/play tests pass. Acceptance uses drawn notes; MIDI recording and SMF import are deferred. See MIDI.md for capacities, immediate note-off, routing and hardware limits.
Phase 8 — Mixer and editing
Gain/pan, meters, mute/solo, automation, undo/redo, keyboard workflow.
Implemented: selectable per-track channel strips with gain/pan and mute/solo; stereo graph/JACK output and output peak meters; editable gain/pan automation lanes with sample interpolation; bounded 32-edit C snapshot undo/redo and mixer keyboard controls. Format v4 persists mixing/automation and reads v1–v3. Core, GUI rollback/gesture/history and live stereo software playback tests pass. See MIXER.md for routing, mono compatibility, pan law, history behavior and limits. Track inserts/sends, live fader adoption, MIDI capture, per-track meters and advanced automation remain deferred. No project-file editing is needed for the implemented composition/mixing workflow.
Phase 9 — Extensibility and release
Native node API, evaluate plugin hosting, licensing review, packaging, installation tests, performance and recovery tests.
Do not skip phases without documenting why and preserving acceptance criteria.