export function getOSMTileIndices()

in modules/geo-layers/src/tile-layer/tile-2d-traversal.js [92:137]

• 35 lines of code
• 12 McCabe index (conditional complexity)

export function getOSMTileIndices(viewport, maxZ, zRange) {
  // Get the culling volume of the current camera
  const planes = Object.values(viewport.getFrustumPlanes()).map(
    ({normal, distance}) => new Plane(normal.clone().negate(), distance)
  );
  const cullingVolume = new CullingVolume(planes);

  // Project zRange from meters to common space
  const unitsPerMeter = viewport.distanceScales.unitsPerMeter[2];
  const elevationMin = (zRange && zRange[0] * unitsPerMeter) || 0;
  const elevationMax = (zRange && zRange[1] * unitsPerMeter) || 0;

  // Always load at the current zoom level if pitch is small
  const minZ = viewport.pitch <= 60 ? maxZ : 0;

  const root = new OSMNode(0, 0, 0);
  const traversalParams = {
    viewport,
    cullingVolume,
    elevationBounds: [elevationMin, elevationMax],
    minZ,
    maxZ,
    // num. of worlds from the center. For repeated maps
    offset: 0
  };

  root.update(traversalParams);

  if (viewport.subViewports && viewport.subViewports.length > 1) {
    // Check worlds in repeated maps
    traversalParams.offset = -1;
    while (root.update(traversalParams)) {
      if (--traversalParams.offset < -MAX_MAPS) {
        break;
      }
    }
    traversalParams.offset = 1;
    while (root.update(traversalParams)) {
      if (++traversalParams.offset > MAX_MAPS) {
        break;
      }
    }
  }

  return root.getSelected();
}