Away from live, a launch shows from its lift-off on: its marker, label,
paths and orbit stay hidden while the world time is before it, so scrubbing
or playing brings the launches up in the order they flew. The selected
mission stays whenever it flies, and live shows every launch as before.
Play on the timeline runs the whole track in about a minute, from its start
when at live, and runs the clock itself past weather's own replay. It goes
live when it reaches now, or holds at an end that lies ahead of now. Going
live puts the rate back to 1.
Core told time eight ways: Date.now() in most layers, JulianDate.now() for
flights and military, Cesium's clock frozen at page load for the sky, the
weather clock for observed imagery. They now read one clock,
src/time/worldClock.js, exported as ./time.
Live is a mode, not a timestamp: while live the clock is the wall clock,
so every layer draws as before. Away from live only the layers that follow
the clock move with it. The weather products follow it, as they followed
the weather transport; a host opts others in with follow(id).
- The weather clock takes its time from the world clock and drives its
replay, stepping its frames as before.
- Satellites, launches, flights and military (still 30 s and 15 s behind),
transit, GNSS, Recent Imagery, street level, the HUD and the celestial
ring read worldTimeFor(id). Cadences stay on the wall clock.
- Cesium's sky (stars, sun, moon, atmosphere, lighting) draws at the world
time each frame instead of the moment the page loaded.
- Weather frames and satellites declare coverage() for a host's timeline.
Sameh Khamis