gods-eye-view/docs/DIRECTOR.md

Director: reusable scene playback

Director is the scene playback system. Ordered shot execution, authored timing and playback clocks are separated from the scene editor and application rendering. This document records implemented camera directions, data packs, declarative interactions and file sharing, along with the remaining extensions.

Implemented boundary

src/director/playback.js, exported as gods-eye-view/director, provides:

• buildPlaybackQueue(scenes, startSceneId, { single }): ordered scenes/shots, retaining the existing round-robin behavior.
• playSceneQueue(queue, { token, adapter, previousScene, releaseOnFinish }): sequential execution, cancellation checks and scene release.

The runner imports no renderer, UI, storage, recipe or dataset. An adapter supplies these phases, in order: selectShot, applyVisual, applyLayers, travel, settle, hold, completeShot. Each receives { scene, shot, index, total, token }. It also supplies releaseScene(scene, token?) and optionally complete(). Callbacks may return promises. Each playback invocation requires its own adapter state and token; the caller owns camera arbitration and concurrent-run refusal.

The runner checks cancellation after each phase. Adapters must also pass the abort signal or liveness predicate into pending work: a check between phases cannot stop a camera flight or network request already in progress. Cleanup between scenes and on preview exit runs without an aborted token. A refused initial handoff starts no shot. Final cleanup runs on completion, Stop or failure; releaseOnFinish: false retains the final scene for ordinary playback. Exceptions propagate so the caller can restore its controls. Empty/already-cancelled queues acquire no resources. This low-level API expects normalized scene objects; untrusted file validation belongs at the import boundary.

src/scenes/playbackAdapter.js connects this runner to the existing SceneDirector. The latter still owns editor state, saved-project import/export, camera ownership and asynchronous load/seek arbitration. Pure seek calculations live in src/director/timeline.js; src/director/clock.js owns the run/load/shot tickers, hold deadlines, snapshots and clock subscriptions. Stop settles pending holds immediately, and revoked tick callbacks cannot affect a replacement clock. getPlaybackTimingState() exposes copied snapshots and an active-timer count for lifecycle diagnostics without exposing timer handles.

The director export also provides sceneTimingForShot, sceneSeekState, cameraAtProgress and createPlaybackClock. Timeline functions receive duration and hold resolvers; the clock receives timing, running-state and progress callbacks. They import no renderer, storage, recipe or dataset.

src/scenes/shotPresentation.js prepares layer/seek context and resolves holds and map preferences through a scene-pack registry. The scenes export provides createScenePackRegistry({ recipes, adapters }); pass the result as scenePacks in the SceneDirector constructor options. Trusted adapters can supply minimumHoldSec(states), resolveVisual(shot, visual, isMapStackAvailable) and cancelMotion(getLayerModule). Default composition registers the existing Nepal presentation rules. These are code-level composition hooks, not executable modules imported from scene files. Existing media-owner waits remain bounded.

All authored scenes, assets, IDs, source links, attribution and existing JSON projects are preserved. The Nepal sequence remains the contribution introduced by @manjunath22466 in #590. Its clips use source links/embeds; comparison images and river coordinates are bundled. See the event pack provenance.

Next changes, in order

1. Timeline and content separation — implemented. Pure duration/seek calculations, an owned clock and registered presentation rules preserve existing recipes and content. Tests cover direct load, forward/backward seek, replay, bounded media waits and cancellation at pending transitions.
2. Versioned scene document — implemented for existing camera-pose shots. The scene document preserves version-1/2/3 imports. Bounded validation rejects malformed files before replacing current state; legacy migration preserves IDs, pack bindings and visual edits. Unreadable saved files are protected from fallback writes. Camera anchors, pack manifests and actions receive stable IDs with their respective later format extensions.
3. Camera directions — implemented for pose-to-pose moves. Version 4 adds scene-local geographic anchors, explicit start/destination poses, easing, duration and holds. Playback and seek share the same sampler. Ellipsoidal heights are explicit; terrain-relative input is rejected. Existing shots retain ordinary flights. Basic anchor/move authoring is available through EDIT DETAILS; curved paths and look-at targets remain later extensions.
4. Data packs and placement — implemented for bounded assets. Version 5 defines a pack manifest with format/version, source, attribution/license and optional integrity/size metadata. It distinguishes registered asset directories from geographic coordinates, image bounds and media anchors. GeoJSON, PNG and native media adapters load with byte/time limits and explicit ellipsoid heights. Stop and replacement release resources. Paths resolve against a trusted directory base; missing/offline assets fail explicitly. File bundles are available; transforms and terrain-relative placement remain future extensions. Scene files carry no credentials or executable modules.
5. Declarative interactions — implemented. Version 6 connects selected feature IDs to accessible text/source cards, anchor focus, shot seek and admitted layer changes. References are validated and pending actions cancel on Stop, replacement or teardown. Scene files contain no JavaScript or arbitrary HTML; actions require explicit user input.
6. Sharing and basic authoring — implemented. Authoring and sharing adds import preview, missing-source/layer diagnostics, validated scene/shot drafts and selected-scene JSON or explicit-file bundles. Pack attribution is preserved. Bundle bytes last for the session and must be reimported after a reload. A future node graph can author the same document without becoming a playback or format requirement.

Each step must preserve existing scene editing, keyboard playback, camera arbitration, layer cleanup, media timing and provider fallback. Acceptance includes portable runner tests, existing Director regressions and browser playback with Stop/seek/replay, plus tracking and voice checks. Use reproducible local fixtures for failures and cancellation, alongside live visual checks for actual content.

Declarative actions are implemented in version 6; see scene actions for supported targets, execution and reset semantics.