From 645b396ef9509257a896f0df5610e846f54b79a5 Mon Sep 17 00:00:00 2001 From: skal Date: Wed, 4 Feb 2026 13:42:21 +0100 Subject: docs: Milestone state snapshot - Audio system robustness complete Documented completion of major audio system improvements: - Task #51: Tracker timing verification (0.000ms sync confirmed) - Variable tempo system (6 tests, all passing) - Zero production size impact (all test code under !STRIP_ALL) Key achievements: - Perfect audio synchronization verified - Dynamic tempo control ready (music_time abstraction) - Comprehensive test coverage (16/16 tests passing) - Mathematical precision verified for reset tricks Updated: - PROJECT_CONTEXT.md: Added milestone section - HANDOFF_2026-02-04.md: Complete state snapshot for handoff System ready for: - Dynamic tempo animation - Physics & collision (Task #49) - 3D scene pipeline (Task #18) handoff(Claude): Audio milestone complete, state saved Co-Authored-By: Claude Sonnet 4.5 --- HANDOFF_2026-02-04.md | 219 ++++++++++++++++++++++++++++++++++++++++++++++++++ PROJECT_CONTEXT.md | 6 ++ 2 files changed, 225 insertions(+) create mode 100644 HANDOFF_2026-02-04.md diff --git a/HANDOFF_2026-02-04.md b/HANDOFF_2026-02-04.md new file mode 100644 index 0000000..f38e5be --- /dev/null +++ b/HANDOFF_2026-02-04.md @@ -0,0 +1,219 @@ +# Handoff: Audio System Milestone (February 4, 2026) + +## Summary +Completed comprehensive audio system robustness improvements including tracker timing verification and variable tempo implementation. + +## What Was Accomplished + +### Task #51: Tracker Timing Verification System +**Goal**: Create robust testing infrastructure to verify audio synchronization. + +**Implementation**: +- Created `AudioBackend` interface (`src/audio/audio_backend.h`) separating synthesis from output +- Implemented `MiniaudioBackend` for production use +- Implemented `MockAudioBackend` for testing with event recording +- Added time tracking to `synth.cc` (32kHz sample rate precision) +- Created comprehensive test suite (`test_tracker_timing.cc`) + +**Key Finding**: ✅ Simultaneous pattern triggers have **0.000ms delta** (perfect sync verified) + +**Files**: +- `src/audio/audio_backend.h` (interface) +- `src/audio/miniaudio_backend.{h,cc}` (production backend) +- `src/audio/mock_audio_backend.{h,cc}` (test backend, under `!STRIP_ALL`) +- `src/audio/audio.cc` (refactored to use backends) +- `src/audio/synth.cc` (added time tracking hooks) +- `src/tests/test_audio_backend.cc` (3 tests) +- `src/tests/test_mock_backend.cc` (6 tests) +- `src/tests/test_tracker_timing.cc` (7 tests) + +**Test Results**: 13 → 16 tests passing (100% success rate) + +### Variable Tempo System +**Goal**: Enable dynamic tempo changes without pitch shifting or BPM dependencies. + +**Design Philosophy**: +- Don't modify spectrograms or synthesis engine +- Only change WHEN patterns trigger (not HOW they sound) +- Simple: `music_time += dt * tempo_scale` + +**Implementation**: +- Added `g_music_time`, `g_tempo_scale`, `g_last_physical_time` to `main.cc` +- Modified `update_game_logic` to calculate delta time and advance music_time +- Changed `tracker_update((float)t)` → `tracker_update(g_music_time)` +- Created test suite (`test_variable_tempo.cc`) with 6 scenarios + +**Test Coverage**: +1. Basic tempo scaling (1.0x, 2.0x, 0.5x) ✅ +2. 2x speed-up reset trick (accelerate to 2.0x, reset to 1.0x) ✅ +3. 2x slow-down reset trick (decelerate to 0.5x, reset to 1.0x) ✅ +4. Pattern density swap at reset points ✅ +5. Continuous acceleration (0.5x to 2.0x over 10s) ✅ +6. Oscillating tempo (sine wave modulation) ✅ + +**Key Results**: +- After 5s physical at 2.0x tempo: `music_time=7.550s` (expected ~7.5s) ✅ +- Reset to 1.0x, advance 2s: `music_time delta=2.000s` (expected ~2.0s) ✅ +- All mathematical predictions verified with <0.1s tolerance + +**Files**: +- `src/main.cc` (~15 lines added) +- `src/tests/test_variable_tempo.cc` (376 lines, 6 tests) +- `ANALYSIS_VARIABLE_TEMPO.md` (original complex approach) +- `ANALYSIS_VARIABLE_TEMPO_V2.md` (simplified approach - implemented) + +## Current State + +### Build Status +- ✅ All 16 tests passing (100% success rate) +- ✅ Clean build with no warnings +- ✅ Zero size impact on stripped builds (`STRIP_ALL`) + +### Audio System +- ✅ Backend abstraction layer working +- ✅ Mock backend for deterministic testing +- ✅ Perfect audio synchronization verified (0.000ms delta) +- ✅ Variable tempo ready for dynamic control +- ✅ No pitch shifting artifacts + +### Ready for Next Steps +The audio system is now robust and ready for: +- Dynamic tempo control during playback (animate `g_tempo_scale`) +- "Reset trick" implementation (accelerate/slow + pattern density swap) +- Tempo curves (linear, exponential, oscillating, manual) +- Integration with visual sync and beat detection + +## Technical Details + +### Music Time Formula +```cpp +// Physical time → Music time +float dt = current_time - last_time; +music_time += dt * tempo_scale; + +// Examples: +// tempo_scale=1.0 → music_time advances at normal rate +// tempo_scale=2.0 → music_time advances 2x faster (patterns trigger sooner) +// tempo_scale=0.5 → music_time advances 2x slower (patterns trigger later) +``` + +### Reset Trick Pattern +```cpp +// Phase 1: Accelerate +tempo_scale = 1.0f + (time / 5.0f); // Linear acceleration +if (tempo_scale >= 2.0f) tempo_scale = 2.0f; + +// Phase 2: Reset +if (tempo_scale >= 2.0f) { + tempo_scale = 1.0f; // Reset to normal + // Switch to 2x denser pattern to maintain perceived tempo +} +``` + +### MockAudioBackend API +```cpp +// Record events +void on_voice_triggered(float timestamp, int spectrogram_id, + float volume, float pan) override; + +// Time management +void on_frames_rendered(int num_frames) override; +float get_current_time() const; + +// Test queries +const std::vector& get_events() const; +void clear_events(); +``` + +## Commits Made + +1. `c4888be` - feat(audio): Audio backend abstraction layer (Task #51.1) +2. `bb49daa` - feat(audio): Mock audio backend for testing (Task #51.2) +3. `215a4d8` - feat(audio): Tracker timing test suite (Tasks #51.3 & #51.4) +4. `a09e36b` - docs: Variable tempo architecture analysis +5. `829e211` - docs: Simplified variable tempo approach (V2) +6. `25d7e4e` - feat(audio): Variable tempo system with music time abstraction + +## Documentation Updated +- ✅ `TODO.md` - Marked Task #51 complete, added variable tempo section +- ✅ `PROJECT_CONTEXT.md` - Added milestone to "Recently Completed" +- ✅ `ANALYSIS_VARIABLE_TEMPO.md` - Original complex analysis +- ✅ `ANALYSIS_VARIABLE_TEMPO_V2.md` - Simplified approach (implemented) +- ✅ `HANDOFF_2026-02-04.md` - This document + +## Next Steps (Recommendations) + +### Immediate (Optional) +- Add tempo control API (`set_tempo_scale()`, `get_tempo_scale()`, `get_music_time()`) +- Expose tempo control to demo sequence system +- Test with actual demo playback + +### Priority 1: Physics & Collision (Task #49) +- Implement CPU-side SDF library +- Build BVH for acceleration +- Create physics loop with collision resolution + +### Priority 2: 3D System Enhancements (Task #18) +- Blender exporter script +- Asset ingestion for 3D scenes +- Runtime scene loader + +## Notes for Next Developer + +### Testing Strategy +- All audio tests use `MockAudioBackend` for deterministic verification +- Use `audio_set_backend(&mock)` before tests +- Check `get_events()` for voice trigger timing +- Compare timestamps with expected values (<1ms tolerance) + +### Variable Tempo Usage +```cpp +// In main loop or sequence system +extern float g_tempo_scale; // Declared in main.cc +g_tempo_scale = 1.5f; // 1.5x faster playback + +// For gradual acceleration +g_tempo_scale = 1.0f + (time / 10.0f); // Accelerate over 10s + +// For reset trick +if (g_tempo_scale >= 2.0f) { + g_tempo_scale = 1.0f; + trigger_denser_pattern(); +} +``` + +### Code Philosophy +- Keep spectrograms unchanged (size optimization) +- All timing in "music time" space +- Physical time only for delta calculation +- Zero production overhead (`!STRIP_ALL` guards) + +## Verification Commands + +```bash +# Build and test +cmake --build build +cd build && ctest + +# Coverage report +./scripts/gen_coverage_report.sh src/audio + +# Size check (stripped build) +cmake -S . -B build_strip -DDEMO_STRIP_ALL=ON +cmake --build build_strip +ls -lh build_strip/demo64k* +``` + +## Status: MILESTONE COMPLETE ✅ + +All objectives achieved: +- ✅ Audio synchronization verified (0.000ms delta) +- ✅ Variable tempo system implemented and tested +- ✅ Zero production size impact +- ✅ 100% test pass rate +- ✅ Documentation complete +- ✅ Ready for next phase + +--- +*Generated: February 4, 2026* +*Claude Sonnet 4.5* diff --git a/PROJECT_CONTEXT.md b/PROJECT_CONTEXT.md index 4c308c9..ba66bf4 100644 --- a/PROJECT_CONTEXT.md +++ b/PROJECT_CONTEXT.md @@ -28,6 +28,12 @@ Style: ## Project Roadmap ### Recently Completed + +#### Milestone: Audio System Robustness & Variable Tempo (February 4, 2026) +- **Variable Tempo System**: Implemented unified music time abstraction in `main.cc` that decouples tracker timing from physical time. Music time advances at configurable `tempo_scale` rate (default 1.0), enabling dynamic tempo changes without pitch shifting. Created comprehensive test suite (`test_variable_tempo.cc`) verifying 2x speed-up and 2x slow-down "reset tricks" work perfectly. All 6 test scenarios pass with mathematical precision. System ready for expressive tempo control in demo with zero size impact. + +- **Task #51: Tracker Timing Verification System**: Created robust audio testing infrastructure with mock backend abstraction. Implemented `AudioBackend` interface separating synthesis from output, `MiniaudioBackend` for production, and `MockAudioBackend` for testing. Added event recording with precise timestamp tracking (32kHz sample rate). Created comprehensive test suite (`test_tracker_timing.cc`) that **verified simultaneous pattern triggers have 0.000ms delta** (perfect synchronization). All test infrastructure under `#if !defined(STRIP_ALL)` for zero production impact. 16/16 tests passing. + - **Task #50: WGSL Modularization**: Updated `ShaderComposer` to support recursive `#include` directives, refactored the entire shader library into granular snippets (shapes, utils, lighting), and updated the 3D renderer to use this modular system. This resolved macOS shader compilation issues and significantly improved shader maintainability. - **Task #48: Improve Audio Coverage**: Achieved 93% coverage for `src/audio/` by adding dedicated tests for DCT transforms, procedural generation, and synthesis rendering. - **Task #47: Improve Asset Manager Coverage**: Increased `asset_manager.cc` coverage to 88% by testing runtime error paths (unknown functions, generation failure). -- cgit v1.2.3