Reuse aircraft render times and extrapolation frames

src/layers/flights/rendering.js

@@ -32,6 +32,7 @@ import {
   TRACKED_MODEL_MIN_PX,
   TRACKED_MODEL_MAX_PX,
   FLEET_DR_INTERVAL_MS,
+  RENDER_DELAY_SEC,
   COURSE_SLEW_DT_MAX_SEC,
   ROTATION_REFRESH_MS,
   COURSE_MAX_DPS,
@@ -854,6 +855,12 @@ export function createRendering({
         )
       : 0.08;
     flightState._lastFleetTickMs = nowMs;
+    // Every contact in this pass shares the same delayed display instant.
+    const renderTime = Cesium.JulianDate.addSeconds(
+      Cesium.JulianDate.now(flightState._scratchFleetRenderTime),
+      -RENDER_DELAY_SEC,
+      flightState._scratchFleetRenderTime,
+    );
 
     _drainIrReloadQueue(); // bounded per-tick slice of any pending boost-flip reload
     if (flightState._cockpitContactMode)
@@ -957,7 +964,11 @@ export function createRendering({
 
       const info = flightState.records.data.get(icao24);
 
-      const dr = parts.motion._deadReckon(icao24, flightState._scratchFleetPos);
+      const dr = parts.motion._deadReckon(
+        icao24,
+        flightState._scratchFleetPos,
+        renderTime,
+      );
       // The dead-reckoned point drifts away from the fix whose cell supplied the
       // height, so a grounded contact's sprite ends up under the mesh it taxied
       // (or coasted) over. Re-floor at the DISPLAYED coordinate — read-only, and