zForTime method
🌐 zForTime(time)
Gives a Z position adjusted for our time Z is always between (0 .. 1) We subtract time from this, and take the fraction. So a star at 0.5, after 10 seconds would be at -9.5. We then take the fraction and it's back at -0.5;
Implementation
double zForTime(double time) => (z - (time / kStarTravelTime)).fraction();