States componentes setup question

[Darth-Carrotpie]

States componentes setup question

[tertle]

It'll be easier for me to walk through an example if you jumped on discord but let me try answer some stuff.

So yeah, you need to register all of the possibly states via StateAPI.Register and this needs to be done in OnCreate so they exist before your GridCellStateSystem OnStartRunning triggers.

If you're using StateModel which is adding/removing state components - you shouldn't be baking these components on your entity. Only the GridCellVisualState and GridCellVisualState Previous components should be added.

As for changing states, one of the ideas of this state system is that you can write changes to the state component without having to use ECB - you should just be able to write directly to GridCellVisualState and when the system runs it will fix up your states, otherwise you risk it being delayed.

[tertle]

StateAPI.Register adds a component StateInstance to the system.
If you call it more than once per system it'll just override the previous ones meaning only the last will be actually registered.
I've just added an error now if you try to do this.

The idea of this is that each system has it's own state component and the system won't run unless the state component exists.

If you need to have 1 system register multiple states, you need to create a new entity with StateInstance instead of assigning it to the system.

[tertle]

I've never had a single system responsible for multiple states. I always map 1 system to 1 state. But you'd just do something like this

var stateTypeIndex = TypeManager.GetTypeIndex<GridCellVisualState>();

var e0 = state.EntityManager.CreateEntity(typeof(StateInstance));
e.SetComponentData(e0, new StateInstance
    {
        State = stateTypeIndex,
        StateKey = (byte)GridCellVisualStates.Arena,
        StateInstanceComponent = TypeManager.GetTypeIndex<ArenaGridCellVisualState>(),
    });

var e1 = state.EntityManager.CreateEntity(typeof(StateInstance));
e.SetComponentData(e1, new StateInstance
{
    State = stateTypeIndex,
    StateKey = (byte)GridCellVisualStates.Workshop,
    StateInstanceComponent = TypeManager.GetTypeIndex<WorkshopGridCellVisualState>(),
});

[Darth-Carrotpie]

Thank you for response, cleared up a few things. Hadn't time to sit on this problem until now.

So after a bit of testing around, it seems to me that I can register only a ginel state component. I am actually trying to register 5, instead only the last one gets applied. My example OnCreate:

    public void OnCreate(ref SystemState state)
    {
        //Registering injects a query filter to the system State. This can act similar to RequireForUpdate if argument is true
        StateAPI.Register<GridCellVisualState, ArenaGridCellVisualState>(ref state, (byte)GridCellVisualStates.Arena, false);
        StateAPI.Register<GridCellVisualState, WorkshopGridCellVisualState>(ref state, (byte)GridCellVisualStates.Workshop, false);
        StateAPI.Register<GridCellVisualState, BarracksGridCellVisualState>(ref state, (byte)GridCellVisualStates.Barracks, false);
        StateAPI.Register<GridCellVisualState, KitchenGridCellVisualState>(ref state, (byte)GridCellVisualStates.Kitchen, false);
        StateAPI.Register<GridCellVisualState, ClearGridCellVisualState>(ref state, (byte)GridCellVisualStates.Clear, false);
    }

Then I am applying the state within an Update like so:

            byte newState = BuildingToCellState(building.buildingType);
            ecb.SetComponent(gridCellEntity, new GridCellVisualState { Value = newState });

If I switch around the order at which I run StateAPI.Register, I get a different result, i.e. if I make StateAPI.Register<GridCellVisualState, KitchenGridCellVisualState> as the last one from the all 5, then as a consequence I get only KitchenGridCellVisualState component applied by State Manager onto the gridCellEntity.

[Darth-Carrotpie]

I just noticed I'm getting a warning (had them turned off heh):

State 252 not setup
UnityEngine.Debug:LogWarning (object)
BovineLabs.Core.States.StateModel/StateJob:Execute (Unity.Entities.ArchetypeChunk&,int,bool,Unity.Burst.Intrinsics.v128&) (at ./Library/PackageCache/[email protected]/BovineLabs.Core/States/StateModel.cs:118)

Probably actually indicates that setup was wrong. No clue how though..

[Darth-Carrotpie]

Could you give a simple example of how to handle multiple states within a system? In current example there's just a single state for camera, but for a state machine it kind of makes sense to have at least a few...

[Darth-Carrotpie]

Thank you for quick and informative replies! I will try out the approach as soon as I get the chance.
Prolly my approach being different and not-as-intended suggests that I might be not understanding a best practice of using states in this case, but oh well, not the first 🥲
(but if it's fine, I can paste working code after testing, to add to the examples)

Moving from event-based OOP paradigm via which we made our previous game to DOTS is kind of mind boggling by it's own 🤯
But I feel like "this is the way" 🚀