Add gallery loading indicators and recover from WebGL context loss.

- Show loading markers while the catalog, portrait thumbnails, and 3D
  halls load so users know loading is still in progress.
- Recover the 3D hall from a lost WebGL context by remounting the canvas
  with a fresh context instead of leaving a permanent dark window, and
  guard the HDR environment map behind an error boundary.
- Show movement streams whose span overlaps the view even when their
  artists lived outside the visible time range.

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/components/GalleryLoadingMarker.css

@@ -0,0 +1,61 @@
+.gallery-loading-marker {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  gap: 14px;
+  color: rgba(232, 213, 181, 0.92);
+  font-family: Georgia, serif;
+  font-size: 15px;
+  text-align: center;
+  pointer-events: none;
+}
+
+.gallery-loading-marker p {
+  margin: 0;
+}
+
+.gallery-loading-marker-spinner {
+  width: 36px;
+  height: 36px;
+  border-radius: 50%;
+  border: 3px solid rgba(201, 169, 110, 0.22);
+  border-top-color: #c9a96e;
+  animation: gallery-loading-spin 0.85s linear infinite;
+}
+
+.gallery-loading-marker-overlay {
+  position: absolute;
+  inset: 0;
+  z-index: 20;
+  background: rgba(10, 10, 20, 0.72);
+  backdrop-filter: blur(2px);
+}
+
+.gallery-loading-marker-banner {
+  position: absolute;
+  left: 50%;
+  bottom: 12px;
+  transform: translateX(-50%);
+  z-index: 12;
+  flex-direction: row;
+  gap: 10px;
+  padding: 8px 16px;
+  border-radius: 999px;
+  background: rgba(15, 15, 26, 0.88);
+  border: 1px solid rgba(201, 169, 110, 0.35);
+  font-size: 13px;
+  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.35);
+}
+
+.gallery-loading-marker-banner .gallery-loading-marker-spinner {
+  width: 18px;
+  height: 18px;
+  border-width: 2px;
+}
+
+@keyframes gallery-loading-spin {
+  to {
+    transform: rotate(360deg);
+  }
+}

client/src/components/GalleryLoadingMarker.tsx

@@ -0,0 +1,35 @@
+import './GalleryLoadingMarker.css';
+
+interface Props {
+  message?: string;
+  /** Full-area overlay (dims background). */
+  overlay?: boolean;
+  /** Compact strip along the bottom — does not block interaction. */
+  banner?: boolean;
+  className?: string;
+}
+
+export default function GalleryLoadingMarker({
+  message = 'Loading…',
+  overlay = false,
+  banner = false,
+  className = '',
+}: Props) {
+  const modeClass = overlay
+    ? ' gallery-loading-marker-overlay'
+    : banner
+      ? ' gallery-loading-marker-banner'
+      : '';
+
+  return (
+    <div
+      className={`gallery-loading-marker${modeClass}${className ? ` ${className}` : ''}`}
+      role="status"
+      aria-live="polite"
+      aria-busy="true"
+    >
+      <div className="gallery-loading-marker-spinner" aria-hidden />
+      <p>{message}</p>
+    </div>
+  );
+}

client/src/components/MovementBands.tsx

@@ -18,6 +18,7 @@ interface Props {
   onArtistClick: (artistId: number) => void;
   onMovementClick?: (movementId: number) => void;
   onArtistHover?: (info: { birthYear: number; deathYear: number; color: string } | null) => void;
+  onPortraitsLoadingChange?: (loading: boolean) => void;
 }
 
 interface MovementLayout {
@@ -660,6 +661,7 @@ const MovementArtistPortrait = memo(function MovementArtistPortrait({
   onArtistHover,
   onHoverStart,
   onHoverEnd,
+  onPortraitLoadChange,
 }: {
   artist: Artist;
   portraitRevision?: number;
@@ -680,9 +682,29 @@ const MovementArtistPortrait = memo(function MovementArtistPortrait({
   onArtistHover?: (lifespan: { birthYear: number; deathYear: number; color: string } | null) => void;
   onHoverStart: () => void;
   onHoverEnd: () => void;
+  onPortraitLoadChange?: (delta: number) => void;
 }) {
   const thumbSrc = portraitThumbUrl(artist, portraitRevision);
   const queuedSrc = useQueuedImageSrc(thumbSrc);
+  const portraitPendingRef = useRef(false);
+
+  const settlePortraitLoad = useCallback(() => {
+    if (!portraitPendingRef.current) return;
+    portraitPendingRef.current = false;
+    onPortraitLoadChange?.(-1);
+  }, [onPortraitLoadChange]);
+
+  useEffect(() => {
+    if (!thumbSrc) return;
+    portraitPendingRef.current = true;
+    onPortraitLoadChange?.(1);
+    return () => {
+      if (portraitPendingRef.current) {
+        portraitPendingRef.current = false;
+        onPortraitLoadChange?.(-1);
+      }
+    };
+  }, [thumbSrc, onPortraitLoadChange]);
 
   return (
     <div className={`artist-on-band${isHovered ? ' artist-on-band-active' : ''}`}>
@@ -729,12 +751,19 @@ const MovementArtistPortrait = memo(function MovementArtistPortrait({
             alt={artist.name}
             loading="lazy"
             decoding="async"
+            onLoad={settlePortraitLoad}
             onError={(e) => {
+              settlePortraitLoad();
               (e.target as HTMLImageElement).src = '/placeholder-portrait.svg';
             }}
           />
         ) : (
-          <img src="/placeholder-portrait.svg" alt="" aria-hidden />
+          <img
+            src="/placeholder-portrait.svg"
+            alt=""
+            aria-hidden
+            onLoad={settlePortraitLoad}
+          />
         )}
         <span className="artist-name">{artist.name}</span>
       </button>
@@ -754,8 +783,11 @@ export default function MovementBands({
   onArtistClick,
   onMovementClick,
   onArtistHover,
+  onPortraitsLoadingChange,
 }: Props) {
   const canvasRef = useRef<HTMLDivElement>(null);
+  const pendingPortraitsRef = useRef(0);
+  const [portraitsLoading, setPortraitsLoading] = useState(false);
   const [panning, setPanning] = useState(false);
   const [interacting, setInteracting] = useState(false);
   const [canvasHeight, setCanvasHeight] = useState(DEFAULT_CANVAS_HEIGHT);
@@ -769,6 +801,15 @@ export default function MovementBands({
   viewRef.current = { viewStart, viewEnd };
   onViewChangeRef.current = onViewChange;
 
+  const handlePortraitLoadChange = useCallback((delta: number) => {
+    pendingPortraitsRef.current += delta;
+    setPortraitsLoading(pendingPortraitsRef.current > 0);
+  }, []);
+
+  useEffect(() => {
+    onPortraitsLoadingChange?.(portraitsLoading);
+  }, [portraitsLoading, onPortraitsLoadingChange]);
+
   const markInteracting = useCallback(() => {
     setInteracting(true);
     if (interactionTimer.current != null) {
@@ -860,15 +901,23 @@ export default function MovementBands({
     return map;
   }, [artists, viewStart, viewEnd]);
 
+  const movementsWithArtists = useMemo(() => {
+    const set = new Set<number>();
+    for (const artist of artists) {
+      if (artist.movement_id) set.add(artist.movement_id);
+    }
+    return set;
+  }, [artists]);
+
   const visibleMovements = useMemo(
     () =>
       movements.filter(
         (m) =>
           m.end_year >= viewStart &&
           m.start_year <= viewEnd &&
-          (artistsByMovement.get(m.id)?.length ?? 0) > 0
+          movementsWithArtists.has(m.id)
       ),
-    [movements, viewStart, viewEnd, artistsByMovement]
+    [movements, viewStart, viewEnd, movementsWithArtists]
   );
 
   useLayoutEffect(() => {
@@ -1342,6 +1391,7 @@ export default function MovementBands({
                 onArtistHover={onArtistHover}
                 onHoverStart={() => setHoveredArtistKey(artistKey)}
                 onHoverEnd={() => setHoveredArtistKey(null)}
+                onPortraitLoadChange={handlePortraitLoadChange}
               />
             );
           })}

client/src/components/VirtualGallery.tsx

@@ -1,4 +1,5 @@
-import { useRef, useState, useEffect, useMemo, Suspense, useCallback } from 'react';
+import { useRef, useState, useEffect, useMemo, Suspense, useCallback, createContext, useContext, Component } from 'react';
+import type { ReactNode } from 'react';
 import { Canvas, useFrame, useThree } from '@react-three/fiber';
 import { Text, Environment } from '@react-three/drei';
 import * as THREE from 'three';
@@ -11,7 +12,6 @@ import type {
   MovementArtistGroup,
 } from '../types';
 import { galleryImageUrlWithRevision, imageUrl, api } from '../api/client';
-import { loadTextureQueued } from '../utils/textureLoadQueue';
 import { comparePaintingsChronological, paintingHasInfluenceLinks, paintingWallCaption } from '../utils/paintingUtils';
 import { cloneSurfaceTexture, getSurfaceTexture } from '../utils/galleryProceduralTextures';
 import { resolveMovementInteriorStyle, type MovementInteriorStyle, type GalleryWindowSpec } from '../data/movement-interior-styles';
@@ -25,6 +25,36 @@ import {
   type MovementHallLayout,
 } from '../utils/movementHallLayout';
 import './VirtualGallery.css';
+import GalleryLoadingMarker from './GalleryLoadingMarker';
+
+const GalleryTextureLoadContext = createContext<{
+  begin: () => void;
+  end: () => void;
+} | null>(null);
+
+/**
+ * Keeps a single failing subtree (e.g. the network-loaded HDR environment map)
+ * from unmounting the whole 3D scene and leaving a dark window.
+ */
+class SceneErrorBoundary extends Component<
+  { children: ReactNode; fallback?: ReactNode },
+  { hasError: boolean }
+> {
+  state = { hasError: false };
+
+  static getDerivedStateFromError() {
+    return { hasError: true };
+  }
+
+  componentDidCatch(error: unknown) {
+    console.warn('Gallery scene subtree failed, continuing without it.', error);
+  }
+
+  render() {
+    if (this.state.hasError) return this.props.fallback ?? null;
+    return this.props.children;
+  }
+}
 
 interface BaseGalleryProps {
   imageRevisions?: Record<number, number>;
@@ -551,6 +581,7 @@ function CanvasCover({
 function usePaintingTexture(url: string | null) {
   const [texture, setTexture] = useState<THREE.Texture | null>(null);
   const [failed, setFailed] = useState(!url);
+  const textureLoad = useContext(GalleryTextureLoadContext);
 
   useEffect(() => {
     if (!url) {
@@ -562,9 +593,21 @@ function usePaintingTexture(url: string | null) {
     setFailed(false);
     let disposed = false;
     let loaded: THREE.Texture | null = null;
+    let settled = false;
+    const loader = new THREE.TextureLoader();
+    loader.setCrossOrigin('anonymous');
 
-    loadTextureQueued(url)
+    const finish = () => {
-      .then((tex) => {
+      if (settled) return;
+      settled = true;
+      textureLoad?.end();
+    };
+
+    textureLoad?.begin();
+    loader.load(
+      url,
+      (tex) => {
+        finish();
         if (disposed) {
           tex.dispose();
           return;
@@ -579,17 +622,21 @@ function usePaintingTexture(url: string | null) {
         tex.colorSpace = THREE.SRGBColorSpace;
         tex.anisotropy = 4;
         setTexture(tex);
-      })
+      },
-      .catch(() => {
+      undefined,
+      () => {
+        finish();
         if (!disposed) setFailed(true);
-      });
+      }
+    );
 
     return () => {
       disposed = true;
+      finish();
       loaded?.dispose();
       setTexture(null);
     };
-  }, [url]);
+  }, [url, textureLoad]);
 
   return { texture, failed };
 }
@@ -1485,6 +1532,14 @@ function levelHorizontalView(pos: THREE.Vector3, target: THREE.Vector3) {
   target.y = EYE_HEIGHT;
 }
 
+function FrameloopSync({ active }: { active: boolean }) {
+  const { invalidate } = useThree();
+  useEffect(() => {
+    if (active) invalidate();
+  }, [active, invalidate]);
+  return null;
+}
+
 function CameraController({
   position,
   target,
@@ -1643,7 +1698,7 @@ export default function VirtualGallery(props: Props) {
       return [...props.data.paintings].sort(comparePaintingsChronological);
     }
     return props.data.paintings;
-  }, [props]);
+  }, [props.mode, props.mode === 'movement' ? props.data.movement.id : props.data.artist.id, props.data.paintings]);
   const initialPeriods = isMovement ? [] : props.data.periods;
 
   const [paintings, setPaintings] = useState(initialPaintings);
@@ -1655,6 +1710,46 @@ export default function VirtualGallery(props: Props) {
   const [nearExit, setNearExit] = useState(false);
   const [nearPassage, setNearPassage] = useState(false);
   const [isLooking, setIsLooking] = useState(false);
+  const [texturesPending, setTexturesPending] = useState(0);
+  const [glEpoch, setGlEpoch] = useState(0);
+  const [glLost, setGlLost] = useState(false);
+
+  const textureLoad = useMemo(
+    () => ({
+      begin: () => setTexturesPending((n) => n + 1),
+      end: () => setTexturesPending((n) => Math.max(0, n - 1)),
+    }),
+    []
+  );
+
+  useEffect(() => {
+    setTexturesPending(0);
+  }, [hallKey, glEpoch]);
+
+  const handleCanvasCreated = useCallback((state: { gl: THREE.WebGLRenderer }) => {
+    const canvas = state.gl.domElement;
+    // A freshly created canvas has a healthy context, so clear any lingering
+    // "restoring" state from a previous loss/remount.
+    setGlLost(false);
+    const onLost = (event: Event) => {
+      // Prevent the default so the browser can restore the context, and
+      // force a clean remount to obtain a fresh WebGL context if it does not.
+      event.preventDefault();
+      setGlLost(true);
+      window.setTimeout(() => {
+        setGlLost((stillLost) => {
+          if (stillLost) setGlEpoch((n) => n + 1);
+          return stillLost;
+        });
+      }, 600);
+    };
+    const onRestored = () => {
+      setGlLost(false);
+      setGlEpoch((n) => n + 1);
+    };
+    canvas.addEventListener('webglcontextlost', onLost as EventListener, false);
+    canvas.addEventListener('webglcontextrestored', onRestored as EventListener, false);
+  }, []);
 
   useEffect(() => {
     setPaintings(initialPaintings);
@@ -1974,7 +2069,10 @@ export default function VirtualGallery(props: Props) {
         onPointerLeave={endCanvasDrag}
         onPointerCancel={endCanvasDrag}
       >
-        {syncStatus && (
+        {active && texturesPending > 0 && (
+          <GalleryLoadingMarker overlay message="Loading paintings…" />
+        )}
+        {syncStatus && texturesPending === 0 && (
           <div className="gallery-loading-overlay gallery-sync-badge">
             <p>{syncStatus}</p>
           </div>
@@ -1982,11 +2080,18 @@ export default function VirtualGallery(props: Props) {
         {!showExitNav && (
           <div className="gallery-exit-hint">{exitHint}</div>
         )}
+        {glLost && (
+          <GalleryLoadingMarker overlay message="Restoring gallery…" />
+        )}
         <Canvas
+          key={`${hallKey}-${glEpoch}`}
           shadows
           frameloop={active ? 'always' : 'never'}
+          gl={{ preserveDrawingBuffer: true, powerPreference: 'high-performance' }}
           camera={{ fov: 58, position: [0, EYE_HEIGHT, 2], near: 0.1, far: 80 }}
+          onCreated={handleCanvasCreated}
         >
+          <FrameloopSync active={active} />
           <color attach="background" args={[sceneBackground]} />
           <fog attach="fog" args={[sceneFog, 18, fogFar]} />
           <ambientLight intensity={ambientIntensity} />
@@ -1997,12 +2102,15 @@ export default function VirtualGallery(props: Props) {
             castShadow
             shadow-mapSize={[1024, 1024]}
           />
+          <SceneErrorBoundary fallback={null}>
             <Suspense fallback={null}>
               <Environment
                 preset={interiorStyle?.details === 'modern' || interiorStyle?.details === 'industrial' ? 'city' : 'warehouse'}
                 environmentIntensity={interiorStyle ? 0.35 : 0.15}
               />
             </Suspense>
+          </SceneErrorBoundary>
+          <GalleryTextureLoadContext.Provider value={textureLoad}>
             <ArtistHall
             layout={layout}
             hallTitle={hallTitle}
@@ -2020,6 +2128,7 @@ export default function VirtualGallery(props: Props) {
             onNextHall={goToNextHall}
             nearPassage={nearPassage}
           />
+          </GalleryTextureLoadContext.Provider>
           <CameraController position={camPos} target={camTarget} />
         </Canvas>
       </div>

client/src/pages/HomePage.tsx

@@ -1,12 +1,13 @@
-import { useState, useEffect, useCallback, useMemo, useRef, lazy, Suspense } from 'react';
+import { useState, useEffect, useCallback, useMemo, useRef } from 'react';
 import Timeline from '../components/Timeline';
 import TimelineEventGuides from '../components/TimelineEventGuides';
 import MovementBands from '../components/MovementBands';
-const VirtualGallery = lazy(() => import('../components/VirtualGallery'));
+import VirtualGallery from '../components/VirtualGallery';
 import PaintingDetailView from '../components/PaintingDetail';
 import ArtistBio from '../components/ArtistBio';
 import CheckupPage from '../pages/CheckupPage';
 import CuratorLoginModal from '../components/CuratorLoginModal';
+import GalleryLoadingMarker from '../components/GalleryLoadingMarker';
 import '../components/CuratorLoginModal.css';
 import { useAuth } from '../context/AuthContext';
 import { api, type FixPaintingImageResult, type FixArtistPortraitResult } from '../api/client';
@@ -108,6 +109,8 @@ export default function HomePage() {
   const [timelineData, setTimelineData] = useState<TimelineData>({ eras: [], movements: [] });
   const [artists, setArtists] = useState<Artist[]>([]);
   const [loading, setLoading] = useState(true);
+  const [portraitsLoading, setPortraitsLoading] = useState(false);
+  const [galleryEntryLoading, setGalleryEntryLoading] = useState<string | null>(null);
   const [error, setError] = useState<string | null>(null);
   const [detailArtistPaintings, setDetailArtistPaintings] = useState<Painting[]>([]);
   const [imageRevisions, setImageRevisions] = useState<Record<number, number>>({});
@@ -399,21 +402,27 @@ export default function HomePage() {
   }, []);
 
   const handleArtistClick = async (artistId: number) => {
+    setGalleryEntryLoading('Opening artist gallery…');
     try {
       await api.preloadArtistImages(artistId).catch(() => undefined);
       const data = await api.getArtist(artistId);
       openArtistGallery(artistId, data);
     } catch {
       setError('Failed to load artist gallery.');
+    } finally {
+      setGalleryEntryLoading(null);
     }
   };
 
   const handleMovementClick = async (movementId: number) => {
+    setGalleryEntryLoading('Opening movement gallery…');
     try {
       const data = await api.getMovementGallery(movementId);
       openMovementGallery(movementId, data);
     } catch {
       setError('Failed to load movement gallery.');
+    } finally {
+      setGalleryEntryLoading(null);
     }
   };
 
@@ -599,9 +608,8 @@ export default function HomePage() {
           aria-hidden={!galleryActive}
         >
           {displayGallery.kind === 'artist' ? (
-            <Suspense fallback={null}>
             <VirtualGallery
-              key={`artist-${displayGallery.artistId}-${galleryRevision}-${galleryActive ? 'live' : 'parked'}`}
+              key={`artist-${displayGallery.artistId}-${galleryRevision}`}
               mode="artist"
               data={displayGallery.data}
               imageRevisions={imageRevisions}
@@ -617,11 +625,9 @@ export default function HomePage() {
                 })
               }
             />
-            </Suspense>
           ) : (
-            <Suspense fallback={null}>
             <VirtualGallery
-              key={`movement-${displayGallery.movementId}-${galleryRevision}-${galleryActive ? 'live' : 'parked'}`}
+              key={`movement-${displayGallery.movementId}-${galleryRevision}`}
               mode="movement"
               data={displayGallery.data}
               imageRevisions={imageRevisions}
@@ -629,7 +635,6 @@ export default function HomePage() {
               onPaintingClick={handlePaintingClick}
               onBack={() => setView({ type: 'timeline' })}
             />
-            </Suspense>
           )}
         </div>
       )}
@@ -787,6 +792,16 @@ export default function HomePage() {
           </header>
 
           <div className="home-timeline-stack">
+            {loading && (
+              <GalleryLoadingMarker overlay message="Loading art history…" />
+            )}
+            {galleryEntryLoading && (
+              <GalleryLoadingMarker overlay message={galleryEntryLoading} />
+            )}
+            {portraitsLoading && !loading && !galleryEntryLoading && (
+              <GalleryLoadingMarker banner message="Loading portraits…" />
+            )}
+
             <Timeline
               eras={timelineData.eras}
               viewStart={viewStart}
@@ -799,9 +814,7 @@ export default function HomePage() {
 
             {error && <div className="error-banner">{error}</div>}
 
-            {loading && timelineData.movements.length === 0 ? (
+            {!loading && (
-              <div className="loading home-movements-section">Loading art history...</div>
-            ) : (
               <>
                 <TimelineEventGuides viewStart={viewStart} viewEnd={viewEnd} />
                 <div className="home-movements-section">
@@ -817,6 +830,7 @@ export default function HomePage() {
                     onArtistClick={handleArtistClick}
                     onMovementClick={handleMovementClick}
                     onArtistHover={setHoveredLifespan}
+                    onPortraitsLoadingChange={setPortraitsLoading}
                   />
                 </div>
               </>