fix(traffic): hold rendering only for animated content

src/layers/traffic/animation.js

@@ -20,6 +20,20 @@ export function createAnimation({
   parts,
   source,
 }) {
+  function syncRenderDemand() {
+    const needed = Boolean(
+      layerState._enabled &&
+      (layerState._dots.length || layerState._heatJamPrim),
+    );
+    if (needed === Boolean(layerState._renderHeld)) return;
+    layerState._renderHeld = needed;
+    if (needed) {
+      layerState._lastAnimTime = 0;
+      services.render.holdContinuousRender('traffic');
+      layerState._viewer?.scene?.requestRender?.();
+    } else services.render.releaseContinuousRender('traffic');
+  }
+
   /**
    * Spawn animated dot primitives along a single road.
    *
@@ -188,6 +202,7 @@ export function createAnimation({
             : null,
       });
     }
+    syncRenderDemand();
   }
 
   /**
@@ -206,6 +221,8 @@ export function createAnimation({
    */
 
   function animate() {
+    syncRenderDemand();
+    if (!layerState._renderHeld) return;
     const now = Date.now();
     // Delta time in seconds, capped to avoid jumps when returning from background tab
     const dt = layerState._lastAnimTime
@@ -339,6 +356,13 @@ export function createAnimation({
     layerState._count = 0;
     layerState._bucketCounts = { free: 0, slow: 0, jam: 0, sim: 0 };
     layerState._closedRoads = 0;
+    syncRenderDemand();
   }
-  return { spawnDotsForRoad, animate, maybeStopLight, clearDots };
+  return {
+    spawnDotsForRoad,
+    animate,
+    maybeStopLight,
+    clearDots,
+    syncRenderDemand,
+  };
 }