Adding an ISystem explicitly

[ornate yew]

I cannot find a world.AddSystem that accepts an ISystem implementation. What am I missing? CreateSystem doesn't seem to work either

I don't see how the fact that are struct may affect this logic

[ornate yew]

Adding an ISystem explicitly

[kindred flax]

World.GetOrCreateSystemsAndLogException

is how DefaultWorldInitialization creates its systems

i'm pretty sure World.CreateSystem(type)

will let you create ISystems

        public SystemHandle CreateSystem(Type type)
        {
            CheckGetOrCreateSystem();

            if (typeof(ComponentSystemBase).IsAssignableFrom(type))
                return CreateSystemInternal(type).SystemHandle;

            return Unmanaged.GetOrCreateUnmanagedSystem(type);
        }

they all check if type is managed otherwise create an unmanaged system

[ornate yew]

It doesn't return the struct itself

I guess it makes sense under dots point of view, a sort of protection mechanism

However this means no easy way to inject external dependencies

[kindred flax]

you can't (shouldn't) access isystem structs

you'd only be using a copy of it

isystems are strongly designed to not be accessed ever

[ornate yew]

Yep I see why. I wonder how this works out in real life

[kindred flax]

and instead using the entity it generates to pass data in/out

[kindred flax]

very well?

isystems are amazing

[ornate yew]

Did you make complete games with them already?

But yes on paper it is how it should be

[kindred flax]

95% of my systems are isystem

none of my systems ever interact

even when they were all systembase

i never had references to systems

[ornate yew]

Obviously

But if you need to make somehow your system interact with 3rd party libraries is going to be challenging but very possible

[kindred flax]

the whole ecs pattern is about systems reacting to data

[ornate yew]

Yes did your make full product with it? Many fundamental part of what is needed for a game is not converted to ecs yet

Often you need to mix and match

[kindred flax]

yes

[ornate yew]

Starting from the ui?

[kindred flax]

i work for a company with a published game

that was written in entities

my libraries are used in at least 3 other companies games

[ornate yew]

So how do you make the ui interact with entities?

[kindred flax]

my systems control the UI

(i should say work project is still and will forever be on 0.51)

(my personal UI library is for 1.0 though)

i have a whole UI management system

using UI toolkit

[ornate yew]

So you made an ecs based ui framework?

[kindred flax]

not really

each panel is owned by a system that's all

[ornate yew]

ISystem?

[kindred flax]

no

UI is managed

[ornate yew]

Ok makes more sense

[kindred flax]

UI is pretty much the only SystemBase in my project

and input reading

i don't inject anything into this system though

[ornate yew]

Ok that makes sense

[kindred flax]

        protected override void OnStartRunning()
        {
            if (this.panelElement == null)
            {
                var assets = this.EntityManager.GetComponentObject<UIAssets>(SystemAPI.ManagedAPI.GetSingletonEntity<UIAssets>());
                var asset = assets.Assets[this.stateKey];

                Assert.IsNotNull(asset, $"No UI asset set for {this.StateName}");

                this.panelElement = asset.CloneTree();
                this.panelElement.name = this.StateInstanceComponent.ToString();
                this.panelElement.pickingMode = PickingMode.Ignore;
                this.panelElement.AddToClassList(RootClassName);
                this.OnLoad(this.panelElement);

                this.localization = new UILocalization(ref this.CheckedStateRef, new LocalizedStringTable(assets.StringLocalization), this.panelElement);
            }

            this.OnShow(this.panelElement);
            this.AddToParent(this.documentSystem, this.panelElement, this.Priority);
        }```

all my VisualTreeAsset are baked in subscenes

[ornate yew]

Yeah ok now I can see it
The ui problem can be solved in many ways

[kindred flax]

(I think UI toolkit fundamentally works better with entities than ugui)

[ornate yew]

The point is that atm not everything can be done with ISystem

[ornate yew]

@kindred flax last question for the day, time to go to sleep:

between burstified entitymanager setcomponent with iteration of native array like we discussed and component lookup like in this example:

https://github.com/Unity-Technologies/EntityComponentSystemSamples/blob/master/EntitiesSamples/Boids/Assets/Scripts/Systems/BoidSchoolSpawnSystem.cs

which one do you think is faster?

the example has the benefit to go in parallel

[kindred flax]

kind of do different things

the boids one lets you do it off thread which is nice

if you can there's no real harm in doing it in a job

[ornate yew]

yes both solve my problem tho

[kindred flax]

instead of EM.setcomponent

it depends how many you have anyway

[ornate yew]

that's true

[kindred flax]

if you only have a small set then you may as well just do it main thread

cost of scheduling etc going to be higher

[ornate yew]

didn't schedule parallel revert to schedule if the set is small?

[kindred flax]

no

[ornate yew]

I may add an if myself then

[kindred flax]

but there's not a huge difference in scheduling performance anyway

[ornate yew]

if they were running on the main thread ,you think EM would be faster?

[kindred flax]

than what?

[ornate yew]

than the dictionary lookup

[kindred flax]

component lookup is just doing the same thing under the hood as EM

it accesses the same component store

[ornate yew]

ah ok makes sense