Fix first load flash and black screen: no pow() of a negative base in the intro sweep shader (NaN on real GPUs, spread by bloom), guarded normal and rim terms, service worker serves exact ?v= matches only (older copies are the offline fallback), cache bust nan1

CHANGELOG.md

@@ -16,6 +16,7 @@ The 0.9.x entries below are the pre-release series that led up to 1.0.0. Version
 ## 1.2.0 (2026-10-16)
 
 - **Lower resolution while dragging**: the 3D view draws at 0.75x or 0.5x pixel ratio while the camera moves and returns to full sharpness when it settles. Settings and Performance panel control, `unrollView.dragRes`, `?dragRes=off|light|strong`. See docs/CT_VIEW.md.
+- **Fix first load on real GPUs**: the intro scan line squared a negative number with `pow()`, which GPUs return as NaN; the bloom pass spread it into colour flashes and a black view. It is now squared by hand, and the normal and rim terms are guarded the same way. The service worker no longer answers a new `?v=` asset with an older cached copy (that copy is now only the offline fallback).
 
 ## 1.1.0 (2026-10-16)
 

app.js

@@ -394,7 +394,8 @@ void main() {
   // soaked papyrus softens and sags
   // soaked charcoal swells a little and slumps where it turns to mush; it does not sag like wet paper
   if (uDmgOn > 0.5) { float wv = texture2D(uDmg, aLocal).a; p.z += wv * 0.35; p.y -= wv * wv * 0.35; }
-  vN = normalize(mix(nc, vec3(0.0, 0.0, 1.0), e));
+  vec3 nm = mix(nc, vec3(0.0, 0.0, 1.0), e);
+  vN = dot(nm, nm) > 1e-8 ? normalize(nm) : vec3(0.0, 0.0, 1.0);   // a zero normal would normalize to NaN
   vLocal = aLocal;
   vE = e;
   vec4 w = modelMatrix * vec4(p, 1.0);
@@ -422,7 +423,7 @@ void main() {
   vec3 v = normalize(cameraPosition - vW);
   float ndl = abs(dot(n, normalize(vec3(-0.35, 0.75, 0.55))));
   float ndv = abs(dot(n, v));
-  float rim = pow(1.0 - ndv, 3.0);
+  float rim = pow(max(1.0 - ndv, 0.0), 3.0);
   float diff = 0.28 + 0.72 * ndl;
 
   // X-ray: the CT intensity on the surface, cool and clinical
@@ -451,7 +452,10 @@ void main() {
   float revealed = smoothstep(uSweep - 1.5, uSweep + 1.5, vW.y);
   float layer = uLayer * revealed;
   vec3 col = mix(xray, inked, layer);
-  float line = exp(-pow((vW.y - uSweep) / 0.35, 2.0));
+  // pow() with a negative base is undefined in GLSL: real GPUs return NaN there, which the bloom pass smears over the
+  // whole frame (colour flashes, then black) during the intro sweep. Square it by hand.
+  float sd = (vW.y - uSweep) / 0.35;
+  float line = exp(-sd * sd);
   col += vec3(1.0, 0.7, 0.35) * line * 1.6;
   col += vec3(1.0, 0.6, 0.25) * uHi * 0.12;
   gl_FragColor = vec4(col, 1.0);

index.html

@@ -63,7 +63,7 @@ if (!/(^|[#&])s=/.test(location.hash)) ['scrolls/index.json', 'scrolls/PHerc0139
   "./lib/apispec.js": "./lib/apispec.js?v=20261016vol3",
   "./lib/embed.js": "./lib/embed.js?v=20261016vol3",
   "./lib/version.js": "./lib/version.js?v=20261016vol3",
-  "./tear.js": "./tear.js?v=20261016vol3",
+  "./tear.js": "./tear.js?v=20261016vol3nan",
   "./damage.js": "./damage.js?v=20261016vol3"
 } }
 </script>
@@ -251,7 +251,7 @@ if (!/(^|[#&])s=/.test(location.hash)) ['scrolls/index.json', 'scrolls/PHerc0139
   </div>
 </section>
 
-<script type="module" src="app.js?v=20261016vol3"></script>
+<script type="module" src="app.js?v=20261016vol3nan"></script>
 <script type="module" src="polish.js?v=20261016vol3"></script>
 <script type="module" src="lib/bench.js?v=20261016vol3"></script>
 <script type="module" src="ui.js?v=20261016vol3"></script>

sw.js

@@ -57,9 +57,12 @@ self.addEventListener('message', (e) => { if (e.data === 'version') e.source?.po
 
 const isData = (url) => /\/(data|scrolls)\//.test(url.pathname);
 async function fromCache(req) {
-  // assets are requested as file.js?v=..., so fall back to a match that ignores the query string
-  return (await caches.match(req)) || (await caches.match(req, { ignoreSearch: true }));
+  // exact match only: a new release asks for file.js?v=<new>, and answering that with the old file.js?v=<old> mixes
+  // versions on the first load after an update (an old app.js against a new index.html)
+  return caches.match(req);
 }
+// offline fallback: any cached copy of the same path, whatever its ?v=
+const anyCopy = (req) => caches.match(req, { ignoreSearch: true });
 
 self.addEventListener('fetch', (e) => {
   const req = e.request;
@@ -80,7 +83,7 @@ self.addEventListener('fetch', (e) => {
     e.respondWith(fromCache(req).then((hit) => hit || fetch(req).then((r) => {
       if (r.ok && r.status === 200) { const copy = r.clone(); caches.open(url.pathname.includes('/data/hi/') || !DATA_FILES.some((f) => url.pathname.endsWith(f)) ? RUNTIME : DATA).then((c) => c.put(req, copy)); }
       return r;
-    })));
+    }).catch(async () => (await anyCopy(req)) || Response.error())));
     return;
   }
   // shell, three.js and fonts: stale while revalidate
@@ -88,7 +91,7 @@ self.addEventListener('fetch', (e) => {
     const net = fetch(req).then((r) => {
       if (r.ok || r.type === 'opaque') { const copy = r.clone(); caches.open(same ? SHELL : RUNTIME).then((c) => c.put(req, copy)); }
       return r;
-    }).catch(() => hit || Response.error());
+    }).catch(async () => hit || (await anyCopy(req)) || Response.error());
     if (hit) { e.waitUntil(net.catch(() => {})); return hit; }
     return net;
   }));

tear.js

@@ -1169,7 +1169,7 @@ ${DMG_EDGE_T}
         // black carbon with a faint glassy sheen on fresh fracture faces
         float spec = pow(max(dot(reflect(-l, n), v), 0.0), 24.0) * 0.38;
         vec3 base = mix(vec3(0.035, 0.026, 0.019), vec3(0.17, 0.12, 0.085), vTone);
-        diff += 0.25 * pow(1.0 - abs(dot(n, v)), 2.0);   // rim light so dark flakes read against the dark floor
+        diff += 0.25 * pow(max(1.0 - abs(dot(n, v)), 0.0), 2.0);   // rim light so dark flakes read against the dark floor
         gl_FragColor = vec4(base * diff + spec, 1.0);
       }`,
   });

version.json

@@ -2,7 +2,7 @@
   "name": "unroll",
   "version": "1.4.0",
   "date": "2026-10-16",
-  "sha": "ce6b88b",
+  "sha": "bf9ab42",
   "license": "Apache-2.0",
   "data_license": "CC-BY-NC-4.0",
   "shaNote": "Short SHA of the commit this build was stamped on (its parent, since a commit cannot contain its own hash). Run node tools/stamp_version.mjs patch before each push.",