Epic 5 Phase 0 — actors have bodies; the stage has depth

ActorGenerator is the cast with bodies: generateActor{mpl} takes
{summary,rng,archetype,personality,identity} and returns a serialisable
ActorSpec — same audio-tilts-centre / seed-picks-within rule as
Personality/Identity, forked rng so adding an actor never shifts later
decisions. Five archetypes (monolith/swarm/walker/vehicle/structure),
per-track actor set on look.actors, HUD helper included. Stage C will
grow as a library on this without infra changes.

Mesh twin of Identity.form: actors/meshes.js builds BufferGeometry from
the same assembly (cast SDF → Shape → ExtrudeGeometry, box/capsule/
torus/sphere primitives, symmetry folding radial/mirror/stack). Shared
with the shader impostor path — one character, two projectors.

Renderer depth targets: createDepthTarget / createTarget{depthTexture}
for WebGL DepthTexture plumbing.

Compositor shared rig: one PerspectiveCamera + DepthTexture so a ground
mesh can occlude a subject mesh from another layer. 4/scale dolly,
Personality.camera drift/sway/spin, framing shift — matches particles.js
and shader epilogue behaviour. ModelLayer (kind:model) with
build/update(actorSpec) and sharedCamera injection; createLayer dispatches
on model. Shader contract gains MODEL_PREAMBLE.

LookGenerator now derives actors before scenes; ArcDriver._actorFor +
_layerFor wires ActorSpec into ModelLayer; schema validates kind:model
and actor archetype; lint determinism gate covers actors/.

Gate: lint 107 files clean, 70 shader literals, 68 scenes green; vite
build 294 modules; ActorGenerator determinism + mesh smoke tests pass.

Co-Authored-By: Claude <noreply@anthropic.com>

flow-state/src/look/ArcDriver.js

@@ -221,20 +221,32 @@ export class ArcDriver {
         return stack[slot] || null;
     }
 
+    /** Resolve the ActorSpec for a layer, if the module requests one. */
+    _actorFor(module) {
+        const actors = this.look.actors;
+        if (!actors || !module || !module.actor) return null;
+        return actors[module.actor] || null;
+    }
+
     /** One Layer per (section, variant, layer slot), built lazily and kept. */
     _layerFor(sectionIndex, variant, slot = 0) {
         const key = `${sectionIndex}:${variant}:${slot}`;
         let layer = this.layerCache.get(key);
         if (!layer) {
             const spec = this._specFor(sectionIndex, variant, slot);
+            const actorSpec = this._actorFor(spec.module);
             layer = createLayer(spec.module, {
                 params: spec.params,
                 seed: spec.seed,
                 opacity: spec.opacity,
                 blend: spec.blend,
+                actorSpec,
             });
             layer.setPalette(this.look.palette);
             layer.setPersonality(this.look.personality);
+            // ModelLayers can have their actor swapped without being rebuilt — the
+            // mesh is imposter-free so the geometry can be re-bound live.
+            if (actorSpec && layer.setActor) layer.setActor(actorSpec);
             this.layerCache.set(key, layer);
         }
         return layer;

flow-state/src/look/LookGenerator.js

@@ -25,6 +25,7 @@ import { derivePaletteArc, describePaletteArc } from './paletteArc.js';
 import { deriveFramingStyle, describeFraming } from './framing.js';
 import { deriveCamera, describeCamera } from './Camera.js';
 import { deriveStory, storyForSection, NEUTRAL_STATE } from './Story.js';
+import { generateActorSet, describeActorSet } from '../actors/ActorGenerator.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
@@ -816,6 +817,10 @@ export function generateLook(track, {
     // toward one camera the way it leans toward one family per kind, and the
     // seed decides — see look/Camera.js.
     const camera = deriveCamera(director, summary, rng.fork('camera'));
+    // The cast with bodies — one ActorSpec per archetype, seeded so a later
+    // library of actors (Stage C) grows without changing the infra. See
+    // src/actors/ActorGenerator.js — audio tilts the centre, seed picks within.
+    const actors = generateActorSet(summary, rng.fork('actors'), personality, personality.identity);
     const { post, feedback } = derivePost(summary, rng.fork('post'), grain);
 
     // Scenes eligible to be composited OVER a background. Same casting rule as
@@ -887,6 +892,7 @@ export function generateLook(track, {
         paletteArc,
         framing,
         camera,
+        actors,
         grain,
         post,
         feedback,