fix: revert lazy scene-init - eager pin creation reserves pin-spacing so scenes no longer float over the next section; drop decode-gate that stalled with loading=lazy (kept intrinsic dims, will-change lifecycle, textContent legends)

pilot/arc.tpl.html

@@ -921,17 +921,17 @@ body:not(.fx) .slab{display:none}
     units.push({ sec, man, scene, flat, legend });
   });
 
-  // Reduced motion: leave the flat exploded hero in place (it IS the end state), no slabs, no scrub.
+  // Reduced motion / no GSAP: leave the flat exploded hero in place (it IS the end state).
   if (RM || !window.gsap || !window.ScrollTrigger) return;
   document.body.classList.add("fx");
   gsap.registerPlugin(ScrollTrigger);
 
-  const wc = (u, on) => u.slabs && u.slabs.forEach(el => el.style.willChange = on ? "transform" : "auto");
+  const wc = (u, on) => u.slabs.forEach(el => el.style.willChange = on ? "transform" : "auto");
 
-  // Build a scene's slabs lazily, just before it approaches the viewport. The flat image stays the
-  // fallback until the slabs are appended, so a scene that never initialises still reads correctly.
-  const initScene = u => {
-    if (u.slabs) return;
+  // Build every scene's slabs up front so pinned ScrollTriggers reserve their pin-spacing in the
+  // document flow from the start. Creating pins lazily reflows the page and floats a scene over the
+  // following section. The flat hero stays the fallback until its slabs exist.
+  units.forEach(u => {
     u.slabs = u.man.parts.map(p => {
       const d = document.createElement("div");
       d.className = "slab";
@@ -941,6 +941,7 @@ body:not(.fx) .slab{display:none}
       u.scene.appendChild(d);
       return d;
     });
+    u.flat.style.visibility = "hidden";
     const lis = u.legend ? [...u.legend.children] : [];
     const n = lis.length;
     u.apply = t => {
@@ -954,42 +955,37 @@ body:not(.fx) .slab{display:none}
       u.scene.style.transform = "scale(" + (0.95 + 0.05 * t).toFixed(4) + ")";
       if (n) lis.forEach((li, i) => li.classList.toggle("lit", t >= 0.9 * ((i + 0.5) / n)));
     };
-    u.flat.style.visibility = "hidden";
-
-    const desktop = document.documentElement.scrollHeight - innerHeight > 200 &&
-                    matchMedia("(min-width: 901px)").matches;
-    if (desktop) {
-      u.mode = "pin+scrub";
-      ScrollTrigger.create({
-        trigger: u.sec.querySelector(".pin"),
-        start: "top top", end: "+=1800", pin: true, scrub: 0.6,
-        onToggle: self => wc(u, self.isActive),
-        onUpdate: self => u.apply(self.progress),
-        onRefreshInit: () => u.apply(0)
-      });
-      u.apply(0);
-    } else {
-      u.mode = "assemble";
-      u.sec.querySelector(".pin").style.minHeight = "0";
-      u.apply(0); wc(u, true);
-      gsap.to({ v: 0 }, { v: 1, duration: 1.6, ease: "power3.out",
-        onUpdate: function () { u.apply(this.targets()[0].v); },
-        onComplete: () => wc(u, false) });
-    }
-    ScrollTrigger.refresh();
-  };
+  });
 
   const boot = () => {
-    // initialise each scene shortly before it reaches the viewport; keep the flat image until then
-    const near = new IntersectionObserver((es, obs) => {
-      es.forEach(e => {
-        if (!e.isIntersecting) return;
-        const u = units.find(x => x.sec === e.target);
-        if (u) initScene(u);
-        obs.unobserve(e.target);
-      });
-    }, { rootMargin: "400px 0px 400px 0px" });
-    units.forEach(u => near.observe(u.sec));
+    const desktop = document.documentElement.scrollHeight - innerHeight > 200 &&
+                    matchMedia("(min-width: 901px)").matches;
+    units.forEach(u => {
+      if (desktop) {
+        u.mode = "pin+scrub";
+        ScrollTrigger.create({
+          trigger: u.sec.querySelector(".pin"),
+          start: "top top", end: "+=1800", pin: true, scrub: 0.6,
+          onToggle: self => wc(u, self.isActive),
+          onUpdate: self => u.apply(self.progress),
+          onRefreshInit: () => u.apply(0)
+        });
+        u.apply(0);
+      } else {
+        u.mode = "assemble";
+        u.sec.querySelector(".pin").style.minHeight = "0";
+        u.apply(0);
+        // assemble once, when the scene scrolls in; keep will-change only for the tween's life
+        ScrollTrigger.create({
+          trigger: u.scene, start: "top 80%", once: true,
+          onEnter: () => { wc(u, true); gsap.to({ v: 0 }, {
+            v: 1, duration: 1.6, ease: "power3.out",
+            onUpdate: function () { u.apply(this.targets()[0].v); },
+            onComplete: () => wc(u, false) }); }
+        });
+      }
+    });
+    ScrollTrigger.refresh();
   };
   // the aperitif terminal types its transcript once, when it first enters view
   document.querySelectorAll(".crt").forEach(crt => {
@@ -1002,7 +998,7 @@ body:not(.fx) .slab{display:none}
     io.observe(crt);
   });
 
-  Promise.all(units.map(u => u.flat.decode ? u.flat.decode().catch(() => {}) : Promise.resolve()))
-    .then(() => requestAnimationFrame(() => requestAnimationFrame(boot)));
+  // boot on the next frame; do not gate on decoding lazy images (that stalls with loading=lazy)
+  requestAnimationFrame(() => requestAnimationFrame(boot));
 })();
 </script>