feat: add cesium traffic signal countdowns

scripts/lib/traffic-signals.js

@@ -5,6 +5,32 @@ const fs = require("fs");
 const EARTH_RADIUS = 6371008.8;
 const CURB_OFFSET_METERS = 5.2;
 const MAST_REACH_METERS = 4.5;
+// This layout is serialized with the anchors so Blender's static structure and
+// Cesium's dynamic overlay cannot independently drift in size or handedness.
+// Lateral offsets use the approach travel direction: positive is the driver's
+// right. The countdown board therefore sits at +1.15m from the signal head.
+const SIGNAL_LAYOUT = Object.freeze({
+  poleHeightMeters: 6.7,
+  poleRadiusMeters: 0.13,
+  armWidthMeters: 0.21,
+  // The mast arm and the signal head share this centre elevation.
+  mastHeightMeters: 6.25,
+  headCenterHeightMeters: 6.25,
+  headWidthMeters: 0.68,
+  headDepthMeters: 0.30,
+  headBodyHeightMeters: 1.62,
+  lensRadiusMeters: 0.22,
+  lensDepthMeters: 0.07,
+  lensFaceOffsetMeters: 0.18,
+  lensVerticalOffsetsMeters: [0.49, -0.01, -0.51],
+  countdownLateralMeters: 1.15,
+  countdownFaceOffsetMeters: 0.05,
+  countdownWidthMeters: 0.82,
+  countdownDepthMeters: 0.14,
+  countdownHeightMeters: 0.56,
+  // The countdown board is fixed on the mast arm, not hung below it.
+  countdownVerticalOffsetMeters: 0.0,
+});
 
 function buildTrafficSignals(stopLines, intersections) {
   const centers = (intersections.features || []).map((feature, index) => {
@@ -37,9 +63,36 @@ function buildTrafficSignals(stopLines, intersections) {
       stopLatitude: center[1],
       headingDegrees: Math.atan2(axis[0], axis[1]) * 180 / Math.PI,
       mastReachMeters: MAST_REACH_METERS,
+      pose: buildSignalPose(point, axis, MAST_REACH_METERS),
     });
   }
-  return { version: 1, signals };
+  return { version: 3, layout: SIGNAL_LAYOUT, signals };
+}
+
+function buildSignalPose(pole, axis, mastReach) {
+  const lateral = [axis[1], -axis[0]];
+  const face = [-axis[0], -axis[1]];
+  const head = moveMeters(pole, lateral, -mastReach);
+  const faceHeadingDegrees = Math.atan2(face[0], face[1]) * 180 / Math.PI;
+  const position = (point, height) => ({ longitude: point[0], latitude: point[1], height });
+  const lensPoint = moveMeters(head, face, SIGNAL_LAYOUT.lensFaceOffsetMeters);
+  const board = moveMeters(
+    moveMeters(head, lateral, SIGNAL_LAYOUT.countdownLateralMeters),
+    face, SIGNAL_LAYOUT.countdownFaceOffsetMeters,
+  );
+  return {
+    pole: position(pole, 0),
+    arm: {
+      from: position(pole, SIGNAL_LAYOUT.mastHeightMeters),
+      to: position(head, SIGNAL_LAYOUT.mastHeightMeters),
+    },
+    head: { ...position(head, SIGNAL_LAYOUT.headCenterHeightMeters), faceHeadingDegrees },
+    lenses: ["red", "yellow", "green"].map((state, index) => ({
+      state,
+      ...position(lensPoint, SIGNAL_LAYOUT.headCenterHeightMeters + SIGNAL_LAYOUT.lensVerticalOffsetsMeters[index]),
+    })),
+    countdown: { ...position(board, SIGNAL_LAYOUT.mastHeightMeters), faceHeadingDegrees },
+  };
 }
 
 function readTrafficSignals(stopLinePath, intersectionPath) {
@@ -90,4 +143,4 @@ function moveMeters(point, vector, meters) {
   return [point[0] + vector[0] * meters * scale / Math.cos(point[1] * Math.PI / 180), point[1] + vector[1] * meters * scale];
 }
 
-module.exports = { buildTrafficSignals, readTrafficSignals };
+module.exports = { SIGNAL_LAYOUT, buildTrafficSignals, readTrafficSignals };