How to detect change in orbit?

[Xyphos]

I'm working on a partmodule and I want it to detect when the vessel's orbit changes

eg, Ap/Pe modified, inclination changed, and SOI changed

not sure how to implement such a thing

[Shadowmage]

6 hours ago, Xyphos said:

I'm working on a partmodule and I want it to detect when the vessel's orbit changes

eg, Ap/Pe modified, inclination changed, and SOI changed

not sure how to implement such a thing

If you are looking for an event-driven architecture... start with the GameEvents class and see what it offers.  Might well be an easy event you can subscribe to, that will call an event-handler/callback whenever the orbit changes.

If you are looking for a polling-driven architecture -- simply cache the current values into your partmodule, and examine the values from the vessel every frame/update.  When they no longer match, you know the orbit has changed.  There are 6 or 7 parameters you'll need to cache, as every one is used to determine the unique orbit: https://en.wikipedia.org/wiki/Orbital_elements

(might be named slightly different in KSP)

Edited February 14, 2020 by Shadowmage

[Morse]

That's gonna be hard, since while the vessel is off-rails it basically constantly changes its orbit. The "orbit" itself is just a prediction, which is strictly followed only when the vessel is on-rails. As soon as physics kicks in - all bets are off where exactly the vessel will fly.