feat: add audio track support with WAV/MP3 playback and looping

Introduce KGAudioTrack and KGAudioRegion as new track/region types
alongside existing MIDI tracks. Users can import WAV, MP3, OGG, FLAC,
and AAC files into audio tracks with full playback, looping, and
solo/mute/volume support.

New core models:
- KGAudioTrack (extends KGTrack with TrackType.Wave)
- KGAudioRegion (extends KGRegion with audio file reference)
- KGAudioPlayerBus (Tone.Gain + ToneBufferSource-based playback)
- KGAudioFileStorage (OPFS media/ directory for binary audio files)

New commands:
- AddAudioTrackCommand (create audio track with player bus)
- ImportAudioCommand (import audio file, create region at playhead,
auto-expand maxBars)

Playback features:
- Audio regions scheduled via Tone.Transport alongside MIDI events
- Loop support with duration capping at loop boundaries
- Resume safety offset to prevent ToneBufferSource timing misses
- Cross-track buffer copy when moving audio regions between tracks
- Proper buffer cleanup on track deletion and project switch

UI changes:
- Separate "+ MIDI" and "+ Audio" buttons in top-left spacer
- Audio track shows upload button instead of instrument selector
- FileImportModal reused for audio file drag-and-drop upload
- Real waveform rendering on audio region canvas
- Green color scheme for audio regions (vs blue for MIDI)
- Pencil icon and resize handles hidden for audio regions
- Cross-type region moves blocked (MIDI ↔ Audio)
- Piano roll blocked for audio regions
- Audio region deletion support

Infrastructure:
- Project structure version bumped to 4 (no-op migration)
- class-transformer discriminators updated for new subtypes
- RemoveTrackCommand updated to clean up audio player buses

This commit is contained in:

Xiaohan-Tian

2026-04-09 21:54:54 -07:00

parent de2979178e

commit fc84edfc59

23 changed files with 1406 additions and 100 deletions

									
										src/components/MainContent.css
									
		+2
		
												View File
												
				@@ -25,6 +25,8 @@

				  border-bottom: 1px solid #3a3a3a;

				  border-right: 1px solid #3a3a3a;

				  z-index: 1002; /* Higher than other elements to ensure it's always visible */

				  display: flex;

				  flex-direction: row;

				}

				/* Offset spacer when instrument selection panel is visible on the left */