System set with run criteria ignoring AppState

[Jeremy-Code-F]

Hi,

I've been following https://bevy-cheatbook.github.io/programming/states.html to implement app states in my snake clone game.

For some reason it seems like bevy ignores the AppState when using with_run_criteria

.add_system_set(
            SystemSet::on_update(AppState::InGame)
                .with_run_criteria(FixedTimestep::step(1.0))
                .with_system(food_spawner),

I would expect the above code to only call food_spawner when the AppState is in AppState::InGame but the function just gets called anyways.

If I change the call to add_system_set to...

.add_system_set(
            SystemSet::on_update(AppState::InGame)
                .with_system(food_spawner),

Then it works the way I would expect, but of course I lose my FixedTimestep.

Am I doing something wrong here?

p.s. similar question here but there was no answer on that post.

[rparrett]

You're not doing anything wrong. This is a limitation in Bevy 0.9.

The text on the cheatbook page you linked to hints at this:

Consider using the iyes_loopless crate, which provides an alternative implementation that does not suffer from the usability issues of the one in Bevy.

And following the usability issue link explains further:

Because states are implemented using run criteria, they cannot be combined with other uses of run criteria, such as fixed timestep.

This limitation is being addressed by an ongoing scheduler overhaul detailed in bevyengine/rfcs#45 which will likely be making it into the next release of Bevy.