- Implement saveScene: captures full mixer state via getStateJson(),
stores in ~/op-pedal/default_config/scenes.json with auto-incrementing ID
- Implement loadScene: manual JSON walk to restore channel/bus state
from saved scene JSON, routes skipped for safety
- Implement listScenes: returns JSON array of {id, name}
- Implement deleteScene: remove by ID from scenes file
- Add WS handlers: mixerSaveScene, mixerLoadScene, mixerGetScenes
registered in PiPedalSocket.cpp message dispatcher
- Uses project's JSON_MAP/raw_json_string for file persistence
- Compiles cleanly against existing build
New files:
- MixerApi.hpp/cpp: Model-level API bridging WebSocket messages to
MixerEngine control (channel volume/pan/mute/solo/hpf, bus control,
routing, state queries)
- 15 new WebSocket message handlers in PiPedalSocket.cpp for full
mixer control surface
Integration:
- MixerEngine member added to PiPedalModel with Get/Set accessors
- SetMixerEngine propagates to AudioHost rt processing pipeline
- Socket handler auto-wires MixerEngine to MixerApi on connect
Messages implemented:
mixerSetChannelVolume, mixerSetChannelPan, mixerSetChannelMute,
mixerSetChannelSolo, mixerSetChannelLabel, mixerSetChannelHpf,
mixerGetState, mixerAddChannel, mixerRemoveChannel,
mixerSetBusVolume, mixerSetBusMute, mixerAddBus, mixerRemoveBus,
mixerRouteChannelToBus
When SetMixerEngine() is called with a MixerEngine instance, the
audio processing thread routes all device input/output channels
through the mixer (channel strips → buses → master) instead of
the legacy Lv2Pedalboard. Falls back when no mixer engine is set.
- Thread-safe via mutex + realtime raw pointer swap (same pattern
as existing SetPedalboard)
- Preserves existing pedalboard processing — both modes coexist
- New ProcessLv2Pedalboard() path when realtimeActiveMixerEngine
is non-null uses device buffers directly for multi-channel I/O
MixerEngine architecture:
- MixerChannelStrip: per-input FX chain (Lv2Pedalboard reuse),
volume, pan, mute, solo, HPF, aux sends, VU metering
- MixerBus: accumulation bus with volume, mute, VU. Supports
master, subgroup, aux, and FX-return bus types
- MixerEngine: orchestrator managing channel→bus routing graph,
bus→bus routing, solo override, and the full real-time audio
processing cycle
All new code compiles cleanly with the existing C++20 build and
follows the existing PiPedal codebase conventions (namespaces,
error handling, buffer patterns). CPU-efficient real-time thread
processing with atomic control surface interaction.
- Horizontal lockup: OP Labs icon + 'OP' (silver) + 'PEDAL' (blue)
- Square stack: icon above 'OP PEDAL' text
- Place in artifacts/ and vite/public/img/ for UI use
- OP Labs icon SVG as default app icon + favicon (SVG + ICO fallback)
- 192x192 and 512x512 PWA icons generated from OP Labs logo
- Updated manifest.json with SVG favicon + maskable icon support
- Updated index.html with SVG favicon link
- Replaced old ic_logo.svg with OP Labs icon mark
- Stored OP Labs logo assets (icon, horizontal, square) in artifacts/
- Removed old PiPedal20Thumb.jpg
Reset midiEventMemoryIndex in AlsaDriver.cpp when starting MIDI processing and when clearing midiEventCount to avoid stale index/state issues while using expression pedals.
shawn
Robin Davies