fix(navara): invalidate cached glyphs after context loss

Clear the display-resource signature used by static sprite reuse when the WebGL context is lost or restored. Cover both events and verify that caching resumes after the redraw.

src/globe/navara/overlayPass.js

@@ -48,12 +48,14 @@ void main(){vec4 bg=texture2D(image,vUv);vec4 glyph=texture2D(glyphs,vUv);if(gly
   });
   const quad = new FullScreenQuad(composite);
   const canvas = renderer.domElement;
+  const display = { target, composite, quad, canvas, signature: null };
   const invalidate = () => {
-    target.signature = null;
+    display.signature = null;
   };
   canvas?.addEventListener('webglcontextlost', invalidate);
   canvas?.addEventListener('webglcontextrestored', invalidate);
-  return { target, composite, quad, canvas, invalidate };
+  display.invalidate = invalidate;
+  return display;
 }
 
 function staticSpriteSignature(scene, camera, renderer, width, height) {

src/globe/navara/overlayPass.test.mjs

@@ -30,6 +30,7 @@ function harness() {
     pass = new GevOverlayPass(scene, new PerspectiveCamera(), overlay),
     draws = [];
   const renderer = {
+    domElement: new EventTarget(),
     autoClear: true,
     outputColorSpace: SRGBColorSpace,
     getPixelRatio: () => 1,
@@ -190,6 +191,21 @@ test('static sprite glyphs reuse their target until instance data changes', () =
   h.pass.camera.updateMatrixWorld();
   h.pass.render(h.renderer, input, output);
   assert.equal(h.draws.filter((draw) => draw.object === h.scene).length, 3);
+  for (const type of ['webglcontextlost', 'webglcontextrestored']) {
+    h.renderer.domElement.dispatchEvent(new Event(type));
+    const before = h.draws.filter((draw) => draw.object === h.scene).length;
+    h.pass.render(h.renderer, input, output);
+    assert.equal(
+      h.draws.filter((draw) => draw.object === h.scene).length,
+      before + 1,
+      `${type} invalidates the cached GPU pixels`,
+    );
+    h.pass.render(h.renderer, input, output);
+    assert.equal(
+      h.draws.filter((draw) => draw.object === h.scene).length,
+      before + 1,
+    );
+  }
   h.pass.dispose();
   texture.dispose();
   mesh.geometry.dispose();