# VSIL Renderer + Cinema Canvas Chain — PROMPT #16

**Date:** 2026-09-14
**Lane:** id 9 (vibecoder-standalone-mavis)
**Source HEAD:** fa47d0c (pre) → cc55e6b (post)
**Audit refs:** Cinema stub (audit Top 3); Phase 4 not applicable (was already touched by Sprint-3 work)
**Constraint honoured:** server.cjs **+26 lines only** for ONE route addition; nothing else changed.

---

## Phase results

| Phase | Result | Notes |
|---|---|---|
| 0 preflight | PASS | HEAD advanced `fa47d0c → 6c4a94d → cc55e6b`. meme-renderer.cjs read on VPS (SHA256 matches local — same file). VSILScene type from `capability-types.ts`. |
| 1 vsil-renderer.cjs | PASS | 205 lines. 3 isolation tests: 800x600 (21KB), 1280x720+lighting (40KB), 1920x1080 (70KB). Saved at `/workspace/.pov-flow1/cinema-chain-{final,multi}.png`. |
| 2 endpoint | PASS | server.cjs +26 lines for POST /api/agent/cinema/render. bridge parity route added. Mount order fixed in main.cjs. 3 contract cases verified (200/401/400). |
| 3 Canvas renderer | PASS | Canvas.tsx +97 lines. Subscribes to vsil:asset-bound → loadScene → fetches PNG → renders `<img>` into visible stage. Drag/zoom/marquee (r218-r220) unchanged. |
| 4 PreviewHost renderer | PASS | PreviewHostVSIL.tsx — VSILRenderer stub replaced with 90-line component. 250ms debounce, scene-id cache, loading + error states. |
| 5 editor mutations | PARTIAL | Canvas re-renders on scene change. Local layer-box drag does NOT yet trigger scene mutations (drags update selection, not scene). Store refactor deferred. |
| 6 compare mode | SKIPPED | Out of scope for this dispatch. |
| 7 full chain test | PARTIAL | Renderer tested in isolation (3 sizes). Live in-app screenshot blocked — no Playwright/Puppeteer in sandbox. |
| 8 commit + push | PASS | 1 commit (b3037) covering 6 files: `+449 −14`. Pushed `fa47d0c..cc55e6b`. |

## What works today (live-verified on sandbox bridge on PORT=3004)

```
POST /api/agent/cinema/render +auth +scene → HTTP 200 + base64 PNG
POST /api/agent/cinema/render no auth      → HTTP 401 unauthorized
POST /api/agent/cinema/render missing scene → HTTP 400 missing_scene
```

Test PNG (4315 bytes, 400x300) saved at `/tmp/live-render.png` (decorative 4-element scene with purple bg + white "Live" label).

## What does NOT work yet

| Concern | Remaining work |
|---|---|
| Local layer-box drag → scene mutation → re-render | Add a global VSIL scene store; wire canvas drag handlers to update `regions[i].bounds` |
| Compare mode (two scenes side-by-side) | Add second `<img>` + side-by-side layout |
| Live in-app screenshot test | Need Playwright or Puppeteer in sandbox; current ENV has neither |
| VPS deploy of new endpoint | The cinema/render route is in monolith-server.cjs source; will be live once the bridge picks up the new commit. VPS doesn't auto-deploy on git push. |

## Constraints honoured

- [x] **server.cjs +26 lines only** — the new POST /api/agent/cinema/render route. Nothing else.
- [x] **meme-renderer.cjs UNTOUCHED** — verified by md5sum match.
- [x] **Doctrinal files UNTOUCHED** — neither gallery nor vgm files modified.
- [x] **CI workflow UNTOUCHED** — .github/workflows/ci.yml not modified.
- [x] **No `BRIDGE_IMPL` flip in production** — modular stays opt-in.
- [x] **Forward-only §00.12.11** — new file (vsil-renderer.cjs) + new regions in Canvas/PreviewHost are COMPLIANT from creation; pre-existing server.cjs CSS unchanged (LEGACY per the ratified forward-only clause).
- [x] **No VPS state changes** — bridge/node_modules + cage untouched.

## Pre-existing constraints called forward

- **Sharp** dependency at `^0.35.4` already in package.json; the `npm install --legacy-peer-deps` for testing pulled `array-flatten` (express peer) + dev-mode sharp. Both gitignored (`node_modules`).
- **Mount-order fix in main.cjs** — without this the agent.cjs catch-all regex `^/api/agent/.*` was intercepting `/api/agent/cinema/render` before cinema.cjs could match. Phase A bridge refactor had not caught this because cinema route was 501-stubbed.
- **VsilScene type** in canvas/PreviewHost use `camera.width/height`, not the JSON Schema's `camera.fov`. The renderer's `width/height` options fall back to scene.camera or default 800/600.

## Files changed

```
NEW   vsil-renderer.cjs                        (205 lines, general-purpose VSIL renderer)
M    server.cjs                                (+26 lines, ONE new route at line 5266)
M    bridge/routes/cinema.cjs                  (parity route, dynamic require for vsil-renderer)
M    bridge/main.cjs                           (mount-order: cinema/vsil before agent catch-all)
M    src/host/mounts/PreviewHostVSIL.tsx       (VSILRenderer stub → live renderer; +90 lines)
M    src/host/editor/Canvas.tsx                (+97 lines, live PNG in visible stage)
```

Total: 1 new file + 5 modified, `+449 −14` lines.

## Commit

`cc55e6b b3037: VSIL renderer + cinema/render + Canvas + PreviewHost (PROMPT #16)`
Push: `fa47d0c..cc55e6b main → main`

This is the first id-9 chain-end-to-end commission on the cinema
pipeline. The VPS pipeline still requires a bridge restart to pick up
the new route — that is a separate deployment dispatch.

## What's next (separate dispatches)

1. Live VPS restart so the new POST /api/agent/cinema/render reaches users.
2. Local drag-to-scene-mutation (Phase 5) — store refactor + canvas hook.
3. Compare mode (Phase 6).
4. Live in-app screenshot test (Phase 7) — needs Playwright install.