The layer loaded two GeoJsonDataSources and a CustomDataSource: 6,459
entities. Every enable rebuilt them (a 100-250 ms task or three and
about 1 GB of heap that stayed until the next collection), every disable
removed them in a 130-150 ms task, and each horizon sweep that showed a
landing marker made Cesium create its billboard again and read the
terrain height under it once more.
The layer now makes the primitives Cesium built from those entities
itself: one GroundPolylinePrimitive for every line, one
BillboardCollection for the point markers, one PointPrimitiveCollection
for the reference tips and one static polyline Primitive for the stems
in view, rebuilt in a worker when a sweep moves a tip. A disable hides
them and an enable shows them again, so only the first enable builds
anything. A marker is clamped to the ground once, 48 per frame as
before; after that Cesium follows the terrain within its own time budget
and hiding or showing the marker reads nothing. A map-stack change
re-classifies the lines in place.
Lines keep the distance-display attribute the entity display gave them:
with a float attribute present Cesium keeps the 2.5 px width, and
without one it is stored as a byte and drawn 2 px.
Co-Authored-By: Claude Fable 5.2 <[email protected]>
