Angular-Momentum-Transfer when creating new PosVels

[lumi-a]

When I set the bullet-release-speed to 0 and shoot bullets, and make the player-ship spin fast, I would expect that bullets are launched at high velocities, because they carried over some of the ship's angular momentum (the bullets, after all, are not launched at the center of the ship, but at the gunbarrel's end). However, the bullets remain stationary and don't carry over any of the angular momentum.

Based on the title of #99, I would have expected that PR to address that, but that's not the case. Should we fix that?

More generally, should this behavior always happen when spawning new PosVels? I.e., if I have a PosVel with angular momentum (e.g. a large, rotating planet), and spawn another PosVel relative to it (e.g. a tree growing on said planet), I would expect the tree to have the same velocity as the planet's surface-rotation, so that it doesn't scrape against the surface immediately after spawning in.

On the other hand, we need to worry about conservation of energy: When a high-angular-momentum ship shoots bullets, and those bullets carry over some of the ship's angular-momentum into their (non-angular) momentum, that should result in the ship's angular-momentum being reduced. However, that has the unintuitive consequence: If we spawn in an enemy relative to the player and far away from the player, that enemy will immediately drain all the player's angular-momentum, which definitely is unexpected behaviour, too. (In fact, it violates the nice property that, when you spawn in a new PosVel a relative to an existing PosVel b, that b should not be mutated by that spawn-call).

[Tim2othy]

Oh I totally didn't think of that. #99 was just about the acceleration the rockets and missiles do. I'll probably just implement that for bullets. For any other PosVels this doesn't seem relevant.