fix: polish pass for traffic, nav, icons, contact email reveal and dashcam robustness

src/scene/world/environment.ts

@@ -149,7 +149,7 @@ export async function createProceduralSceneGeneration(
   const sun = createSun(context.resources);
   const horizonAir = createHorizonAir(context.resources);
   const skyline = createSkyline(context.resources);
-  const traffic = createTraffic(context.resources, quality);
+  const traffic = createTraffic(context.resources, quality, scene.fog.color);
   // Phones and the low tier get the decimated car; it is about 200 px wide
   // there and seen from behind.
   const liteCar =
@@ -214,6 +214,7 @@ export async function createProceduralSceneGeneration(
   let underpassShade = 0;
   let underpassKey = '';
   let underpassAttr = false;
+  let underpassSince = -1;
   scene.add(
     underpass.group,
     relay.group,
@@ -786,7 +787,13 @@ export async function createProceduralSceneGeneration(
         },
       );
       underpassShade = passage.shade;
-      const under = shadeDepth(passage.shade) > 0.2;
+      // The HUD tint follows the shade, but only once it has held for
+      // UNDERPASS_ATTR_HOLD_MS: an approach walk can graze the threshold for a
+      // frame or three before the real pass. Leaving is immediate.
+      const shaded = shadeDepth(passage.shade) > 0.2;
+      if (!shaded) underpassSince = -1;
+      else if (underpassSince < 0) underpassSince = now;
+      const under = shaded && now - underpassSince >= UNDERPASS_ATTR_HOLD_MS;
       if (under !== underpassAttr) {
         underpassAttr = under;
         if (under) document.documentElement.dataset.underpass = 'under';
@@ -934,6 +941,8 @@ export async function createProceduralSceneGeneration(
   };
 }
 
+/** html[data-underpass] waits for the shade to hold this long (ms). */
+const UNDERPASS_ATTR_HOLD_MS = 120;
 const INTRO_SECONDS = 4.2;
 /** Long enough for the dawn to read: the sun clears the skyline near 3.8 s. */
 const OUTRO_SECONDS = 7.0;