# Handoff: GpuContext Refactor (February 7, 2026)

## Session Summary
Completed two-phase refactor to improve GPU context management in Effect system.

## Commits Made

### Commit 1: bd939ac
**Title:** `refactor: Bundle GPU context into GpuContext struct`

**Changes:**
- Created `GpuContext` struct bundling device/queue/format
- Updated Effect/PostProcessEffect constructors to take `const GpuContext&`
- Updated all 19 effect implementations
- Updated MainSequence.init() and LoadTimeline() signatures
- Added `gpu_get_context()` accessor
- Fixed test_mesh.cc compilation error (g_device/g_queue/g_format conflicts)

**Files:** 35 changed, 470 insertions(+), 248 deletions(-)

### Commit 2: 8c9815a
**Title:** `refactor: Store const GpuContext& in Effect base class`

**Rationale:** User suggested storing `const GpuContext& ctx_` instead of splitting into individual members.

**Changes:**
- Effect now stores `const GpuContext& ctx_` instead of `device_`, `queue_`, `format_`
- Simplified constructor: `ctx_(ctx)` vs `device_(ctx.device), queue_(ctx.queue), format_(ctx.format)`
- Updated all effects to use `ctx_.device`, `ctx_.queue`, `ctx_.format`

**Lifetime Safety:** Reference points to static global `g_gpu_context` from `gpu_get_context()`, which outlives all effects.

**Files:** 16 changed, 58 insertions(+), 60 deletions(-)

## Build Status
- ✅ All targets build successfully (demo64k, test_demo, all tests)
- ✅ All 28 tests pass (100% success rate)
- ✅ Working tree clean
- ✅ 3 commits ahead of origin/main

## Technical Notes

**GpuContext Lifetime:**
```cpp
// Safe reference chain:
static GpuContext g_gpu_context = {};  // Static global
gpu_get_context() → &g_gpu_context     // Returns pointer to static
*gpu_ctx                                // Dereference
LoadTimeline(..., *gpu_ctx)             // Pass by reference
Effect::ctx_                            // Store reference to static
```

**Effect Access Pattern:**
```cpp
class Effect {
 protected:
  const GpuContext& ctx_;
  // Effects access: ctx_.device, ctx_.queue, ctx_.format
};
```

## Files Modified (Total: 51 files across both commits)

**Core:**
- src/gpu/gpu.{h,cc}
- src/gpu/effect.{h,cc}
- src/gpu/demo_effects.h

**Effects (19 files):**
- All effects in src/gpu/effects/*.cc

**Generated:**
- src/generated/timeline.cc
- src/generated/test_demo_timeline.cc

**Tests (all test files updated to use fixture.ctx())**

## Ready For
- Push to origin (`git push`)
- Continue with Task #5 (Spectral Brush Editor) or other priorities

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**handoff(Claude):** GpuContext refactor complete. Effect base class now stores const GpuContext& reference. All 28 tests pass.