Epic 2.5.1: basis for framing layer

flow-state/src/look/ArcDriver.js

@@ -3,6 +3,7 @@ import { Rng } from '../engine/rng.js';
 import { clampValue } from '../params/schema.js';
 import { paletteShiftAt } from './paletteArc.js';
 import { shiftPalette } from './palette.js';
+import { frameShot, neutralFraming } from './framing.js';
 
 /**
  * Drives the look across the song.
@@ -39,9 +40,35 @@ export class ArcDriver {
         this.driftPlans = new Map();
         this.activeLayers = [];
         this.cues = this._buildCues();
+        this.framingStyle = (look.framing && look.framing.mode !== 'locked')
+            ? look.framing : null;
+        this._planFraming();
         this.state = { sectionIndex: 0, shotIndex: 0, crossfade: 0, incoming: null };
     }
 
+    /**
+     * Give every cue the framing its shot will be played with.
+     *
+     * Framing is the one device that lives at the SHOT level — a wide answered
+     * by a close is the whole point of it, and both belong to the same scene.
+     * Planned here, once, walking the cues in order, so the whole video gets a
+     * consistent hand and a seek always finds the same framing as playback.
+     * A track that decided to stay locked-off (or a hand-built look with no
+     * framing) gets the neutral, unframed read everywhere.
+     */
+    _planFraming() {
+        if (!this.framingStyle) return;
+        const rng = new Rng((this.look.seed ^ 0x517cc1b7) >>> 0);
+        let previous = null;
+        for (const cue of this.cues) {
+            const section = this.look.sections[cue.sectionIndex];
+            const energy = (section.bias && section.bias.energy) || 0;
+            const framing = frameShot(this.framingStyle, previous, energy, rng);
+            cue.framing = framing;
+            previous = framing;
+        }
+    }
+
     dispose() {
         for (const layer of this.layerCache.values()) layer.dispose();
         this.layerCache.clear();
@@ -386,6 +413,12 @@ export class ArcDriver {
         const t = fading ? framesIntoCue / cue.fadeFrames : 1;
         const eased = t * t * (3 - 2 * t);
 
+        // The shot being played INTO carries its own framing; the shot fading
+        // out keeps the framing it was filmed with, so a cut changes the size
+        // exactly when the cut changes the image rather than half a beat after.
+        const framing = cue.framing || neutralFraming();
+        const outgoingFraming = previous ? (previous.framing || neutralFraming()) : framing;
+
         const layers = [];
 
         if (fading) {
@@ -409,6 +442,7 @@ export class ArcDriver {
                 layer.blend = slot === 0 ? 'normal' : spec.blend;
                 layer.setPalette(palette);
                 layer.setPersonality(this.look.personality);
+                layer.setFraming(outgoingFraming);
                 layers.push(layer);
             }
         }
@@ -421,6 +455,7 @@ export class ArcDriver {
             layer.blend = slot === 0 ? 'normal' : spec.blend;
             layer.setPalette(palette);
             layer.setPersonality(this.look.personality);
+            layer.setFraming(framing);
             layers.push(layer);
         }
 
@@ -462,6 +497,7 @@ export class ArcDriver {
         }
         // A reroll re-plans the section's shots, so the cue list is stale too.
         this.cues = this._buildCues();
+        this._planFraming();
         this._slopeCache = null;
     }
 
@@ -469,6 +505,7 @@ export class ArcDriver {
         this.dispose();
         this.driftPlans.clear();
         this.cues = this._buildCues();
+        this._planFraming();
         this._slopeCache = null;
     }
 

flow-state/src/look/LookGenerator.js

@@ -13,6 +13,7 @@ import { generatePersonality, sceneHonours, describePersonality } from './Person
 import { deriveGrain, describeGrain, applyGrainToPost } from './grain.js';
 import { pickDirector, directorByName } from './directors.js';
 import { derivePaletteArc, describePaletteArc } from './paletteArc.js';
+import { deriveFramingStyle, describeFraming } from './framing.js';
 
 // Which families suit which section kind now comes from the track's DIRECTOR
 // (look/directors.js) rather than from a constant here. The coupling it
@@ -292,6 +293,8 @@ export function generateLook(track, { seed = null, samples = null, overrides = n
     const grain = deriveGrain(summary, rng.fork('grain'));
     // How the palette MOVES over the track. See look/paletteArc.js.
     const paletteArc = derivePaletteArc(summary, rng.fork('paletteArc'));
+    // Whether shots change SIZE at the cut, and how boldly. See look/framing.js.
+    const framing = deriveFramingStyle(summary, rng.fork('framing'));
     const { post, feedback } = derivePost(summary, rng.fork('post'), grain);
 
     // Scenes that declare role 'accent' composite over a background rather than
@@ -348,6 +351,7 @@ export function generateLook(track, { seed = null, samples = null, overrides = n
         paletteScheme: paletteSource.lastScheme,
         director: director.name,
         paletteArc,
+        framing,
         grain,
         post,
         feedback,
@@ -427,7 +431,7 @@ export function describeLook(look) {
     const kinds = look.sections.map((s) => `${s.kind}:${s.layers[0].module.name}`);
     return `seed ${look.seed.toString(16)} · ${look.director} · ${look.paletteScheme} · ` +
            `${describePersonality(look.personality)} · ${describeGrain(look.grain)} · ` +
-           `${describePaletteArc(look.paletteArc)} · ` +
+           `${describePaletteArc(look.paletteArc)} · ${describeFraming(look.framing)} · ` +
            `${[...new Set(kinds)].join(', ')}`;
 }
 

flow-state/src/look/Personality.js

@@ -205,6 +205,11 @@ export function signatureUniforms(personality, module = null) {
         u_sigSoft: style.softness,
         u_sigTexture: style.texture * textureAffinity,
         u_sigFold: style.symmetry,
+
+        // Framing is per shot, not per track: the arc driver overwrites these
+        // every frame. Neutral here so a layer built without one is unframed.
+        u_sigFrameScale: 1,
+        u_sigFrameShift: [0, 0],
     };
 }
 
@@ -225,6 +230,8 @@ export const NEUTRAL_UNIFORMS = {
     u_sigSoft: 0.5,
     u_sigTexture: 0,
     u_sigFold: 1,
+    u_sigFrameScale: 1,
+    u_sigFrameShift: [0, 0],
 };
 
 const SHAPE_NAMES = { 0: 'round', 3: 'triangular', 4: 'square', 5: 'pentagonal', 6: 'hexagonal', 8: 'octagonal' };

flow-state/src/look/framing.js

@@ -0,0 +1,114 @@
+// How a shot is FRAMED, as opposed to what it contains.
+//
+// Every scene in the library is a locked-off, full-frame wide, and always has
+// been. That is one shot type, held for the length of a song. Cutting between
+// two scenes therefore changes the subject and never the framing — and framing
+// is at least half of how a real edit holds attention. A wide answered by a
+// close reads as two shots of one thing; two wides read as two things.
+//
+// So a shot now carries a scale and a recentre, applied in SCENE coordinates
+// inside sigCamera. That distinction matters: a close-up is rendered close
+// rather than being a magnified 720p frame, which is why this is a coordinate
+// transform and not a post pass. It is also why it costs nothing at 4K.
+//
+// Framing is per shot and constant within it. A zoom that moves during a shot
+// is a different device — one that would fight the drift LFO and the slow axis,
+// both of which already own continuous motion.
+
+/**
+ * The shot sizes, as multipliers on the scene's coordinate scale.
+ *
+ * Bounded much more tightly than a real camera would be. Past about 2.2 most
+ * scenes in this library run out of detail and a close-up is just a blurry
+ * wide; below about 0.55 the subject is a speck in an empty frame. Both were
+ * measured by pushing until the image stopped being worth looking at.
+ */
+export const SHOT_SIZES = {
+    wide:   { scale: 0.62, drift: 0.06 },
+    normal: { scale: 1.0,  drift: 0.05 },
+    close:  { scale: 1.7,  drift: 0.10 },
+};
+
+export const SHOT_SIZE_NAMES = Object.keys(SHOT_SIZES);
+
+/**
+ * Whether this track uses framing at all, and how boldly.
+ *
+ * A track that never changes size is a legitimate look — locked-off is a style,
+ * and it is the one the whole library was built in — so it stays reachable.
+ * What is not acceptable is it being the only option, which is what it was.
+ */
+export function deriveFramingStyle(summary, rng) {
+    const mode = rng.pickWeighted(['locked', 'gentle', 'edited'], [1, 2.5, 3]);
+    return {
+        mode,
+        // How far from `normal` this track is willing to go.
+        range: mode === 'locked' ? 0 : mode === 'gentle' ? 0.45 : 1,
+        // Chance a cut also changes the shot size, rather than only the image.
+        changeChance: mode === 'locked' ? 0 : mode === 'gentle' ? 0.35 : 0.6,
+    };
+}
+
+/**
+ * Choose the framing for one shot.
+ *
+ * `previous` is the framing of the shot before it, and it is the whole point:
+ * a size only means something relative to the size before it. The rule is that
+ * a change of size must be a real change — a wide answered by a slightly less
+ * wide is not a cut, it is a mistake — so sizes step rather than slide.
+ *
+ * @param {object} style      from deriveFramingStyle
+ * @param {object|null} previous  the previous shot's framing
+ * @param {number} energy     section energy, 0..1
+ * @param {Rng} rng
+ */
+export function frameShot(style, previous, energy, rng) {
+    if (style.mode === 'locked') return neutralFraming();
+
+    const keep = previous && !rng.bool(style.changeChance);
+    if (keep) return { ...previous };
+
+    // Loud material earns the close-ups; quiet material earns the wides. This
+    // is a lean rather than a rule, so an intro can still land on a close and
+    // read as intimate instead of empty.
+    const weights = [
+        1 + (1 - energy) * 2.5,     // wide
+        2,                          // normal
+        1 + energy * 2.5,           // close
+    ];
+    let size = rng.pickWeighted(SHOT_SIZE_NAMES, weights);
+
+    // Never repeat the previous size when we have decided to change: repeating
+    // it is what "no change" already means.
+    if (previous && size === previous.size) {
+        const others = SHOT_SIZE_NAMES.filter((n) => n !== size);
+        size = rng.pick(others);
+    }
+
+    const spec = SHOT_SIZES[size];
+    // Scale toward 1 for a timid track, so `gentle` is genuinely gentle rather
+    // than the same sizes drawn less often.
+    const scale = 1 + (spec.scale - 1) * style.range;
+
+    // Recentring is what stops a close-up being a centre crop of the wide. Held
+    // small: the scenes are centred compositions and pushing far off centre
+    // finds their empty corners.
+    const angle = rng.range(0, Math.PI * 2);
+    const amount = spec.drift * style.range * rng.range(0.3, 1);
+
+    return {
+        size,
+        scale,
+        shift: [Math.cos(angle) * amount, Math.sin(angle) * amount],
+    };
+}
+
+export function neutralFraming() {
+    return { size: 'normal', scale: 1, shift: [0, 0] };
+}
+
+/** One line for the HUD and check output. */
+export function describeFraming(style) {
+    if (!style || style.mode === 'locked') return 'framing: locked off';
+    return `framing: ${style.mode}`;
+}