# Handoff: Asset Regeneration Fix (February 7, 2026)

## Session Summary
Fixed build system issue where generated files weren't automatically regenerated after `make clean`, causing "fatal error: 'generated/assets.h' file not found" errors.

## Problem
After running `make clean` in the build directory, the build would fail because:
1. Generated asset files (`generated/assets.h`, etc.) were removed
2. CMake didn't know to regenerate them before compiling libraries
3. Libraries (`audio`, `3d`, `gpu`) tried to compile before assets existed

## Solution

### 1. Mark Generated Files with GENERATED Property
Added `set_source_files_properties()` calls to tell CMake these files are generated and should be checked for rebuild:

```cmake
# Mark generated files so CMake always checks if they need rebuilding
set_source_files_properties(${GEN_DEMO_H} ${GEN_DEMO_CC} PROPERTIES GENERATED TRUE)
set_source_files_properties(${GEN_TEST_H} ${GEN_TEST_CC} PROPERTIES GENERATED TRUE)
set_source_files_properties(${GENERATED_TIMELINE_CC} PROPERTIES GENERATED TRUE)
set_source_files_properties(${GENERATED_MUSIC_DATA_CC} PROPERTIES GENERATED TRUE)
set_source_files_properties(${GENERATED_TEST_DEMO_TIMELINE_CC} PROPERTIES GENERATED TRUE)
set_source_files_properties(${GENERATED_TEST_DEMO_MUSIC_CC} PROPERTIES GENERATED TRUE)
```

### 2. Add Explicit Library Dependencies
Added `add_dependencies()` to ensure libraries wait for asset generation:

```cmake
# Libraries must wait for asset generation (they include generated/assets.h)
add_dependencies(audio generate_demo_assets)
add_dependencies(3d generate_demo_assets)
add_dependencies(gpu generate_demo_assets)
```

### 3. Update seq_compiler for GpuContext
Updated code generator to match the GpuContext refactor from earlier session:

**Before:**
```cpp
"void LoadTimeline(MainSequence& main_seq, WGPUDevice device, "
    "WGPUQueue queue, WGPUTextureFormat format) {\n";

">(device, queue, format" << eff.extra_args << "), "
```

**After:**
```cpp
"void LoadTimeline(MainSequence& main_seq, const GpuContext& ctx) {\n";

">(ctx" << eff.extra_args << "), "
```

### 4. Cleanup Stale Files
Removed old generated test assets that were incorrectly placed in `src/generated/`:
- `test_assets.h` / `test_assets_data.cc` (now in `build/src/generated_test/`)
- `test_demo_assets.h` / `test_demo_assets_data.cc` (now in `build/src/generated_test/`)

## Commit Made

**Commit:** fb2aa8b
**Title:** `fix: Auto-regenerate assets after clean build`

**Changes:**
- CMakeLists.txt: +15 lines (GENERATED properties + dependencies)
- tools/seq_compiler.cc: Updated signatures
- Removed 4 stale generated files (~41K lines)

## Verification

**Clean Build Test:**
```bash
cd build
make clean
rm -f ../src/generated/*.{h,cc}
cmake --build . --target demo64k
```

**Result:** ✅ Build succeeds, assets regenerated automatically

**Tests:** ✅ All 28 tests pass

## Technical Details

**Build Order (After Fix):**
1. Build tools: `seq_compiler`, `tracker_compiler`, `asset_packer`
2. Generate files: `generate_timeline`, `generate_tracker_music`, `generate_demo_assets`
3. **Wait for generation to complete** (new dependency)
4. Build libraries: `audio`, `3d`, `gpu` (now safe to compile)
5. Build executables: `demo64k`, `test_demo`

**Key Insight:**
The `GENERATED` property alone isn't enough - you also need explicit `add_dependencies()` for libraries that consume generated headers. Without it, CMake may start compiling library sources before the generation targets complete.

## Files Modified
- CMakeLists.txt (15 insertions)
- tools/seq_compiler.cc (5 changes)
- Removed 4 stale files

## Current State
- ✅ All targets build successfully after clean
- ✅ All 28 tests passing
- ✅ Working tree clean
- ✅ 4 commits ahead of origin/main

## Ready For
- Push to origin (`git push`)
- Continue with next priorities

---
**handoff(Claude):** Asset regeneration fixed. Clean builds now work correctly. All dependencies tracked properly.