Unity DOTS: Creating an Entity 

I was looking for this very answer on every possible forum about ECS in Unity, but unsuccessfully. You saved me stranger, thank you!

This comment needs to be GOATed.

@@hellsbuster RIght. One of the greatest videos and useful follow-up post!

I'm not getting entity and hybrid renderer packages, I'm using 2021.3.5f1

unitylist.com/p/zro/Unity-DOTS-Following-Along

Yeah I think that came with Entities 0.6

Yes, you are correct, it should be SetComponentData if the Entity already has the Component.

Found it. In Package Manager click "advanced," then "show preview packages." Then both packages will show up.

Caleb Whitehead Yes that is a good way to make sure the versions are compatible.

current version of Unity 2019 does not include hybrid renderer

Unity have hidden these packages. I just found out myself. You have to go to the Package manager click the + button at the top and select "Add package from git URL" and paste in "com.unity.entities" and after 5-10 seconds of nothing happening the package will install. Repeat again for "com.unity.rendering.hybrid". forum.unity.com/threads/visibility-changes-for-preview-packages-in-2020-1.910880/ for more info

From the Package Manager window: Advanced > Show Preview Packages

@@MrKraignos I did that and it didn't work....Tried it under the 2020 and 2019 versions and couldn't find it

Andorf The White Yes, if you wanted robust physics, DOTS and the new Unity Physics framework (or Havok framework) is what you want to use.

@@GameAcademySchool Thanks for the quick reply!

A lot of things have pretty sparse documentation at the moment. You can find the latest documentation about the HybridRenderer here: docs.unity3d.com/Packages/com.unity.rendering.hybrid@0.4/manual/index.html If you go to the Scripting API pages, you can find specific descriptions: docs.unity3d.com/Packages/com.unity.rendering.hybrid@0.4/api/Unity.Rendering.RenderBounds.html But again these are pretty bare at the moment.

In Unity 2020, the DOTS preview packages are hidden. You have to add them either by URL (plus icon in top left) using the GitHub URL. Or just edit the manifest.json with the URL and version number; it will reload the package once that updates. Just add the HybridRenderer; the rest of the packages will come automatically because of the dependencies.

@@GameAcademySchool Ah alright thanks, I'm interested to see it in action.

I don't think that works with the Hybrid Renderer. This thread may be helpful: forum.unity.com/threads/project-available-hybrid-renderer-sandbox.681142/

Sorry, you don’t need to create Entities manually. Keep going in this series and you’ll see an easier way...

@@GameAcademySchool Ohhh Sweet! ~ Of course I need to watch the entire thing! this got me as this is the first video I see about the system. Thank you!

Check if you conflicting versions of the necessary packages. Look at the dependencies next to Entities and Hybrid Renderer

@@GameAcademySchool Thank You! One of them was on a newer version, and it also doesn't help that visual studio code doesn't recognize it :P!

Draké Martinéz Yes, you definitely need some C# experience before learning DOTS. However, the advantage of starting out with it is that you don’t have to unlearn a lot of stuff. DOTS drops a lot of the object-oriented practices traditionally associated with game development in Unity

@@GameAcademySchool Thank you for your reply...🙂

The newer workflow allows you to work with your GameObjects in the Editor and then automatically convert them to Entities at runtime. The benefits extend beyond just spawning a lot of Entities. We do that just so you can see a concrete, measurable difference in FPS. But even if you only have a few objects onscreen, the more efficient DOTS way translates into less power usage (longer battery life if you're building a mobile game, for example). Yes, it would suck if you had to script everything manually every time you make an Entity. You don't. The Editor is getting workflow improvements to make following this new architecture easier. Probably I should have started with the easier/UI way to make an Entity and show the manual, scripted way a supplementary video.

​@@GameAcademySchool​is the UI way the next video in the series or is that elsewhere? also does converting a large scene of objects to entities at run-time cause extra load at run? also i imagine if you have a scene so large you need ECS then it would be hard on the editor anyway because you still have objects before run, would be great if you could cut out the middle make and interact with entities directly in editor

We cover one way using the ConvertToEntity utility in the Editor but that is the “older” way. There is something called SubScenes you can use that is more interactive. You can work with GameObjects/Entities in the Editor. You can split scenes into smaller SubScenes and work on one piece of the scene at a time. This allows for much more complex environments with more objects/Entities in your scene.

Agreed. It used to be World.Active. But as the ConversionWorkflow was added, I think the term became inaccurate. Technically I think “DefaultGameObjectInjectionWorld” is more accurate if terrible to type. It refers to that default intermediate world used for conversion.

An archetype is created to indicate which components the entity will have. If the archetype is not created, how can you add any component?

radenzito sorry I should have showed you guys the SubScene Conversion first. Much easier. This is for folks who want the specific steps. Anybody can convert a GameObject to Entity using the UI...

You're right. You can get by just fine in Unity without DOTS. It's actually quite hard to build a complete game in DOTS right now. But the industry has sort of been moving this direction for a while, so the hardware can be used more efficiently. Though it's kind of painful to go through all of these steps to do basic stuff for the moment, eventually there will be a payoff in a couple of years when the UI and feature set catches up with the underlying architecture. People are obsessed with it, because it's a bit of learning curve and we need to get ready...

@@GameAcademySchool Totally agree with you both on this. It is a PITA! It is like going back 40 years to Assembly on a 80286. DATA in one part. Code in another. Efficient. Kind of fun in a geeky way but really not an efficient or maintainable way to code. I play with it now and then (like watching this video) but assume most of this will get "wrapped" and we can use the higher-level way to code with components and still some OO. @Sparrowhawk I think when it comes to performance it is quite amazing and fits some of the paradigms the old console programmers like. PS: Thanks @Game Academy.school for making this. @Sparrowhawk thanks for speaking up about the (cute but big) "elephant in the room." :-)

Mike Croswell I think I should have started with the Conversion Workflow video. Day-to-day usage is quite a lot less work. You only need to do this “Pure ECS” approach when you need some custom tweaking.

@@GameAcademySchool Okay. I'll go check out your other video. Thanks much. For "fun", I''ll likely finish this tutorial first. FYI: I used this stuff with Zenject (sp?) last summer with a team. I did not like it at all. It reminds me of some of the old Microsoft COM OLE and even DirectX stuff where you are not actually learning science but someone's loosely collected bunch of code. It's like Unity had this shoved down their throats by someone and they don't seem to have a controlled access point. LIke 100 people were all working on creating these technologies and someone (mostly through luck!) was able to string it altogether. I mean, just look at how obfuscated it is just to create an entity. The paradigm should match Unity's normal one. You'd use attributes to mark the the data you want to parallelize like this; [DATA COMPONENT] and then do the same for the code, eg, [CODE SYSTEM]. For creating entities, they could have EntityManager have access to the World and so you should be able to just say EntityManager.CreateEntity instead of asking the World via the default mess. Really odd. Anyway, thanks for letting us bitch. :-)

@@MikeCroswell Yeah there are definitely a lot of people working on DOTS now. My guess is that they took a hard look at what they have and they have no other way forward to stay competitive. Their original architecture, while easy for users, is ultimately holding them back. It will be a painful transition that will take a couple more years I think before the new one is attractive enough to replace the "classic" one. But we'll see. I've been trying to keep an open mind about it. It's way way easier than it was a year or two ago.

All developers care about efficiency. You don't NEED to use DOTS or ECS if your game isn't high performance. But even for a simple game, efficiency means less stress on the hardware; for example, a comparable DOTS game will use less battery life on a mobile platform.