CONTINUOUS FIELD SPEC

Continuous Field Specification

A persistent gallery behind the reading: imagery that never fades to black, crossfading slowly among a pool, swapping smoothly at each pericope boundary.

Status: IMPLEMENTED in src/visuals/continuous-field.js, wired through the visual cortex. Rulings by the creator are marked ✦; open questions are marked ⁇.

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1. The problem this solves

Behind-stream interlocution today is the flash economy shown beneath text: each visual is a full enter→hold→exit presentation that fades the cortex container to opacity 0 between flashes (visual-cortex.js _presentAsset). At the Chapel's long presence (~1.4s) with a shallow pericope pool, this reads exactly as the creator observed — choppy, fading to black, the same few works returning. The flash economy is built to interrupt; behind glassmorphism the reader wants the opposite: a continuous presence.

The precedent already exists in the codebase. Genesis is a continuous field — a Klee composition that grows around the token stream with no flashes, no fade-to-black, the text on a glass tile (Chamber.js initializeGenesis). The Continuous Field is Genesis's structure applied to sourced imagery: instead of a growing drawing, a slowly crossfading wall of the reading's own works.

2. What it is

✦ A new presentation mode, beside behind-stream — never replacing it. (Creator's ruling: additive, no regression to the flash economy for those who want it.) Selected in the visual panel as a distinct choice; behind-stream's frequency-gated flashes remain untouched.

The field:

• Never fades to black. At least one image is always present behind the text (once the pool has warmed). Transitions are crossfades between works, not fade-out/fade-in through nothing.
• Holds the pool. It draws from the same source pool the reading provides (a museum category, or a pericope cue's collection), crossfading among its works on a slow, gentle cadence.
• Composes with the pericope schedule. When the reading carries a visual program (a Gospel chapter), the field's pool IS the current episode's pool; at a pericope boundary it crossfades to the new episode's works — the same continuity, now the gallery wall changing scene.
• Sits behind the text on glass, exactly as Genesis and behind-stream do (the presentation-behind-stream surface, glass-tile on the atom display).

3. Architecture: a dual-layer crossfade, driven by a clock, not the flash economy

The flash economy (VisualFlashGate, hazard rolls, the presentation clock) is fundamentally about discrete interrupts at frequency. The Continuous Field is a steady process, so it must NOT route through flash() / _presentAsset at all. It is its own presenter.

3.1 Two image layers

container.presentation-continuous
  ├─ layer A  (an <img>, opacity transitions)
  └─ layer B  (an <img>, opacity transitions)

A crossfade is: the incoming work is set on the hidden layer, that layer fades to 1 while the other fades to 0 over crossfadeMs; the now-hidden layer becomes the next incoming target. Two layers so a transition never passes through black — the outgoing image is still at full opacity as the incoming rises. (This is the standard double-buffer crossfade; it structurally cannot fade to black between works, which is the entire point.)

3.2 The advance clock

A single interval (requestAnimationFrame-paced, wall-time gated) advances the field:

every dwellMs:  pick next work from the pool → crossfade to it over crossfadeMs

• dwellMs — how long a work holds before the next crossfade begins (default long: this is contemplative, ~8–12s).
• crossfadeMs — the transition length (default ~2s, gentle).
• The clock is independent of the reading clock — the field breathes at its own contemplative pace, not the atom rate. (Like soundscapes, which are ambient and clock-independent — Shuttle spec §5.)

3.3 Pool consumption

The field draws works through the same provider pools the cortex already resolves — it does not fetch differently. It holds a small ShuffleBag over the active pool's works (the same no-repeat discipline as the flash economy) and advances through it. When the pool grows (streaming pin resolution) or changes (a pericope cue), the field picks up the new works on its next advance — no reset, no black.

✦ Selection within the pool: pure ShuffleBag order (creator's ruling), matching the flash economy's fairness — every work shown before any repeats. Semantic-aware ordering is a possible future refinement, explicitly deferred.

4. Interaction with the pericope schedule

The field is a cue consumer, exactly like the flash economy — applyCue already sets activeTypes to the current episode's collection (PERICOPE-IMAGERY-SPEC §6). So:

• ✦ A pericope boundary is a pool change, and the field crossfades across it — the last work of before-pilate gently dissolves into the first work of flagellation. No special case: the field reads the active pool each advance, and a cue swapped the pool.
• A cue to a works-less episode (stillness) fades the field to nothing gracefully (the one sanctioned fade-to-black — the episode genuinely has no imagery, and stillness outranks substitution). The field resumes at the next imaged episode.
• The generation token the cue system already advances protects the field's async work identically: a work resolving after a cue change verifies its generation before it may enter a layer.

5. Safety — the field has NO flash rate

This is the key safety distinction and it must be stated precisely.

✦ The Continuous Field is not a flash source. A flash is a rapid appearance/disappearance; the VisualFlashGate exists to bound flash rate (min interval, burst, duty ceiling — visual-safety.js). The field has none of that: it holds each work for many seconds and transitions over seconds. Its effective "flash rate" is a fraction of a hertz — orders of magnitude below any photosensitivity concern, in the same regime as a slow film dissolve.

Therefore:

• The field does not consult the VisualFlashGate (it is not gated because it cannot burst).
• Photosensitivity mode still suppresses it — not because it flashes, but because the mode's contract is "no non-essential moving imagery," and a crossfading field is moving imagery. Under photosensitivity mode the field is still (holds one work with no transitions, or suspends entirely — §6 ruling).
• prefers-reduced-motion: the field holds a single work with crossfades disabled (a still gallery — one image, no motion), matching how Rosa Mystica and the attractor honor reduced motion.

6. Reduced motion & photosensitivity rulings

✦ Reduced motion → the field shows ONE work, no crossfades, no advance clock. A still image behind the text. (The imagery's value survives; only the motion is removed.)

✦ Photosensitivity mode → the field suspends entirely (no imagery behind the text — the mode is a hard safety override, and the reader who set it wants stillness, not a held image competing with the text). Consistent with how photosensitivity mode suppresses the flash economy wholesale.

7. The Shuttle (LATERAL-TRAVERSAL-SPEC)

The field is ambient imagery, clock-independent — like soundscapes it persists at any shuttle velocity, holding the current work. It does not accelerate its crossfades at 4×; it simply keeps showing the field. (Contrast the flash economy, which suspends off home velocity because its flash rate would multiply — the field has no rate to multiply.) At a shuttle boundary crossing that changes the pericope pool, the field crossfades to the new episode on its own next advance, whichever direction the head moved.

8. Degradation

• Cold pool (no works resolved yet): the field shows nothing (transparent, the text's own field behind it) until the first work resolves, then fades it in. Never a broken image, never a placeholder — the reverent-degradation contract (SacredImage's decode-before-reveal applies: a work is decoded before it enters a layer).
• A work fails to load: skipped silently, the field holds its current work and advances to the next. A single miss costs one crossfade, never the field.
• An empty pool mid-session (all works failed): the field fades to nothing and waits; the pin-recovery backoff may refill it.

9. Controls (the visual panel)

A new presentation option in the interlocution section, beside "Behind stream":

• ✦ Gallery (creator's ruling). Selecting it sets interlocution.presentation = 'continuous'. The user-facing label is "Gallery"; the config value is 'continuous'.
• Cadence (optional, deferred): dwell/crossfade timing could be exposed, but sensible contemplative defaults (dwell ~10s, crossfade ~2s) ship first. A single "slower / faster" control is the likely future surface, not raw milliseconds.
• The glass tile behind the text is on by default (the field needs the text legible over imagery), reusing the existing streamGlass control.

10. What this spec deliberately excludes

• No effect on the flash economy. Behind-stream and full-frame interlocution are untouched; this is a third presentation, selected explicitly.
• No new provider or pool machinery. The field consumes the pools the cortex already resolves; it is a new presenter, not a new source.
• No Ken Burns / pan-zoom (deferred). The first field is a pure crossfade — motion is the dissolve alone. Slow pan/zoom is a clean future layer if wanted, but it introduces its own motion-safety questions and is out of scope here.
• No per-work timing authoring. The field's cadence is uniform; it is a wall, not a slideshow with per-slide durations.

11. Build order

1. The presenter (ContinuousField in visual-cortex, or a small sibling module): the two-layer element pair, the advance clock, the crossfade, the ShuffleBag over the active pool. Pure of the flash economy. Unit-testable with a fake pool + fake clock.
2. Cortex wiring: a presentation === 'continuous' branch that starts/stops the field instead of the flash loop; the field reads activeTypes' resolved pool and re-reads it on applyCue.
3. Chamber surface: initializeContinuousField beside initializeStreamPresentation / initializeGenesis — the glass tile, the layer host.
4. Panel control: the "Field" presentation option; presentation: 'continuous' flows through the same config path as behind-stream.
5. Safety: reduced-motion (one still work) and photosensitivity (suspend) paths, each tested.
6. Compose with pericopes: verify a Gospel chapter's field crossfades at each episode boundary and stills on a works-less episode.

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The frame is the creator's: behind glassmorphism, a continuous presence rather than a flashing interrupt — a gallery wall the text floats over, changing scene with the reading. Built as a distinct presenter beside the flash economy, with no flash rate and therefore no gate, honoring reduced motion and photosensitivity as stillness.

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Published from docs/specs/CONTINUOUS-FIELD-SPEC.md. Edits made here are overwritten on the next push to main.