Redux, a global scene and scene recreation

[brianzinn]

1 hour ago, promontis said:

But like I said, I'm unsure on how animations fit in this.

I don't know if this is what you are asking, but here is a possible solution that works with redux-saga:
You send a command to BabylonJS from your saga as you do now, like ACTION_REQUEST.
Then in your saga wait on that command to "complete" in the saga with:

yield take(ACTION_REQUEST_COMPLETED);

In BabylonJS in the onAnimationEnd callback just use an action creator to trigger that:

scene.beginAnimation(this, 0, 30, false, 1, () => {
    // any additional logic and notify saga with this action
    onComplete();
});

Additionally, I ended up writing replayable scenarios that I test with BabylonJS running, so I run a series of commands and then assert the expected results.  It takes about 20 minutes to go through all the scenarios, but I use that as a sanity check.  The reason I mention that is that the animations and their chain of effects (butterfly effect!) can be tested in an automated/predictable way.  The physics engine plays an important role in my case, but sounds like you don't have to worry about that.

I ended up pushing most of my logic into the saga for many of the same reasons as you - moving the responsibilities around is a lot of work