[screen] compositor: shipments drive THE SCREEN

Eased param pressure so shipments land as waves, log escalation over the
first ~100 items, cross-modulated wobble above 0.8 so a mature factory looks
alive, brownout seize, and a one-frame white awakening on the first ship ever.

Measured 0.004-0.013ms/frame CPU against a 2ms budget.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

fktry/src/screen/index.ts

@@ -1,21 +1,139 @@
-/** LANE-SCREEN territory. Stub — replace per lanes/LANE-SCREEN.md. */
+/**
+ * LANE-SCREEN — THE SCREEN compositor.
+ *
+ * The sky-display everything ships to. Starts sterile, ends deranged. Shipped items
+ * feed a corruption ledger (corruptionMap.ts) whose blend drives the 8 tuned glitch
+ * params of the ported GLYTCH shader stack (glitchStack.ts).
+ *
+ * Design contract with the player: WHAT you ship decides WHICH artifact; HOW MUCH you
+ * have ever shipped decides the intensity. Shipments arrive as waves, not switches —
+ * every param eases toward its target.
+ */
 import type { GameData, ScreenFX, SimEvent } from '../contracts';
+import { createBaseFeed } from './baseTexture';
+import { createGlitchStack, type GlitchStack } from './glitchStack';
+import { resolveLedger, unmappedItems, ESCALATION_ITEMS } from './corruptionMap';
+import { PARAMS, ease, zeroParams, type ParamSet } from './params';
+
+/** Seconds for a param to travel ~63% toward its target. Shipments feel like waves. */
+const EASE_TAU = 1.2;
+/** Brownouts hit fast and lift fast — the factory's pain should be legible immediately. */
+const BROWNOUT_TAU = 0.12;
+/** Above this total corruption, params start cross-modulating so a mature SCREEN looks alive. */
+const WOBBLE_THRESHOLD = 0.8;
+const WOBBLE_DEPTH = 0.12;
+/** Distinct slow rates per param so the wobble never reads as one global pulse. */
+const WOBBLE_RATE = [0.13, 0.19, 0.11, 0.23, 0.17, 0.29, 0.31, 0.07];
 
 export function createScreenFX(): ScreenFX {
-  let ctx: CanvasRenderingContext2D | null = null;
+  let stack: GlitchStack | null = null;
+  const tally = new Map<string, number>();
+  const eased: ParamSet = zeroParams();
+  const out: ParamSet = zeroParams();
+
+  let targets: ParamSet = zeroParams();
+  let total = 0;
+  let units = 0;
+  let ledgerDirty = false;
+
+  let brownout = 0;
+  let brownoutTarget = 0;
+  let pendingFlash = false;
+  let hasShipped = false;
+
+  let lastMs = 0;
+  let frameCost = 0; // rolling avg ms of this module's CPU work
+
+  function recompute() {
+    const r = resolveLedger(tally);
+    targets = r.targets;
+    total = r.total;
+    units = r.units;
+    ledgerDirty = false;
+  }
+
+  function ship(item: string, count: number) {
+    if (count <= 0) return;
+    tally.set(item, (tally.get(item) ?? 0) + count);
+    ledgerDirty = true;
+    if (!hasShipped) {
+      hasShipped = true;
+      pendingFlash = true; // the awakening
+    }
+  }
+
   return {
-    init(canvas: HTMLCanvasElement, _data: GameData) {
-      ctx = canvas.getContext('2d');
+    init(canvas: HTMLCanvasElement, data: GameData) {
+      const base = createBaseFeed();
+      stack = createGlitchStack(canvas, base);
+
+      const unmapped = unmappedItems(data);
+      if (unmapped.length) {
+        console.info(
+          `[screen] ${unmapped.length} item(s) have no corruption profile, using generic noise: ${unmapped.join(', ')}`,
+        );
+      }
+
+      // Debug/authoring hook — LANE-SIM does not ship yet, so THE SCREEN must be
+      // drivable by hand. Console: __fktryScreen.ship('melt', 40)
+      (window as any).__fktryScreen = {
+        ship,
+        brownout: (on: boolean) => (brownoutTarget = on ? 1 : 0),
+        reset: () => {
+          tally.clear();
+          ledgerDirty = true;
+          hasShipped = false;
+          for (const p of PARAMS) eased[p] = 0;
+        },
+        stats: () => ({
+          units: +units.toFixed(2),
+          total: +total.toFixed(3),
+          idle: !hasShipped,
+          brownout: +brownout.toFixed(2),
+          msPerFrame: +frameCost.toFixed(3),
+          tally: Object.fromEntries(tally),
+          params: Object.fromEntries(PARAMS.map((p) => [p, +out[p].toFixed(3)])),
+        }),
+        escalationItems: ESCALATION_ITEMS,
+      };
     },
-    onEvents(_events: SimEvent[]) {},
+
+    onEvents(events: SimEvent[]) {
+      for (const e of events) {
+        if (e.kind === 'shipped') ship(e.item, e.count);
+        else if (e.kind === 'brownout') brownoutTarget = e.on ? 1 : 0;
+      }
+    },
+
     frame(timeMs: number) {
-      if (!ctx) return;
-      // placeholder: sterile clean playback awaiting corruption
-      ctx.fillStyle = '#101018';
-      ctx.fillRect(0, 0, 640, 360);
-      ctx.fillStyle = '#2a2440';
-      ctx.font = '20px monospace';
-      ctx.fillText('THE SCREEN  ·  0 corruption', 140, 180 + Math.sin(timeMs / 800) * 4);
+      if (!stack) return;
+      const t0 = performance.now();
+      const dt = lastMs === 0 ? 1 / 60 : Math.min(0.1, (timeMs - lastMs) / 1000);
+      lastMs = timeMs;
+
+      if (ledgerDirty) recompute();
+      brownout = ease(brownout, brownoutTarget, dt, BROWNOUT_TAU);
+
+      const timeSec = timeMs / 1000;
+      const wobble =
+        total > WOBBLE_THRESHOLD ? (total - WOBBLE_THRESHOLD) / (1 - WOBBLE_THRESHOLD) : 0;
+
+      for (let i = 0; i < PARAMS.length; i++) {
+        const p = PARAMS[i];
+        eased[p] = ease(eased[p], targets[p], dt, EASE_TAU);
+        // Wobble rides on top of the eased value; it never feeds back into the ledger.
+        const w =
+          wobble > 0
+            ? Math.sin(timeSec * WOBBLE_RATE[i] * Math.PI * 2 + i) * WOBBLE_DEPTH * wobble
+            : 0;
+        out[p] = Math.min(1, Math.max(0, eased[p] + w));
+      }
+
+      const flash = pendingFlash ? 1 : 0;
+      stack.draw({ params: out, timeSec, drift: 1, brownout, flash, idle: !hasShipped });
+      pendingFlash = false;
+
+      frameCost = frameCost * 0.95 + (performance.now() - t0) * 0.05;
     },
   };
 }