Chunks! Where Unity ECS Data is Stored - Unity DOTS 2022

💬 Join our Discord community: tmg.dev/Discord 💬
💻 My Game Development Setup: tmg.dev/GameDevPC 💻
📸 My Camera Gear: tmg.dev/CameraGear 📸
🎮 Let me know what other topics you want to learn about 🎮
⌚ Time stamps for key topics ⌚
- 0:00 - Archetype Chunks
- 0:42 - Definition
- 1:30 - Chunk Memory Structure
- 2:56 - Preallocation
- 6:08 - Parallel Arrays
- 6:51- Things to Keep in Mind
- 7:23 - Chunk Utilization
- 8:26 - Wrap-up and Final Thoughts
🌐 Find Me Online! 🌐
📄 Blog: tmg.dev
👨‍💻 GitHub: github.com/JohnnyTurbo
🎮 Games: johnnyturbo.itch.io/
🦅 Twitter: / turbomakesgames
📺 Twitch: / turbomakesgames
🎵 Music by: Joakim Karud / joakimkarud
#️⃣ #GameDevelopment #UnityECS #Chunks

[@zurrutikGames]

sooooo much better than the official Unity documentation. Outstanding job!!

[@TurboMakesGames]

Glad to hear this was helpful, cheers 😊

[@Wbjpen]

Thanks a bunch. You're one of the few sources for introducing and interpreting DOTS and I couldn't be more appreciative. No doubt that good things will come to you for all of your hard work.

[@TurboMakesGames]

Appreciate the kind words, glad to hear the videos have been helpful to you 😊

[@simulation3120]

Agreed. Above and beyond the best resource for something so powerful and with very little coverage. DOTS is truly the way forward and Turbo has given early adopters such an easy introduction.

[@adamodimattia]

The best DOTS channel, came back to this video for a quick review :)

[@TurboMakesGames]

Hehe, I definitely rewatch some of my own videos to jog my memory from time to time 😁

[@adamodimattia]

@@TurboMakesGames they can serve as really good notes!

[@wlsmdltn]

Deeply thank you that you make for concept of ecs serise. Very Very Thank you!

[@TurboMakesGames]

You're welcome, glad they've been helpful to you!!

[@4rcant]

Awesome video Johnny!

[@TurboMakesGames]

Thanks Antonio, glad you enjoyed!!

[@Dominik-K]

Thanks for the video, is very interesting to see how Unity actually implements ECS under the hood

[@TurboMakesGames]

Thanks for stopping by! Glad to hear you found this interesting 😊

[@LukeClemens]

Great info! I've heard many times that creating entities is fast and that there's no need to pool. It now makes perfect sense after seeing the diagram at 5:33. I guess I'm a little fuzzy on how deleting an entity could be fast (I'm not even sure if it is). I doubt Unity set it up so that deleting leaves "holes" in the arrays. My best guess is that they swap the last entity into the deleted spot, which would be fast, but it would require changing the index of the last entity (which I guess in this case would just be Entity.Index ?)

[@TurboMakesGames]

Cool glad this helped! Deleting entities is interesting and it's something I'd like to pick apart a bit more. I say it's interesting because if you watch the entity debugger when adding and removing entities, you'll see that there is one "active" chunk that new entities are added to until it is filled up. Even if you delete an entity from a previously full chunk, new entities get added to that active chunk until it is full, then it goes back and fills the other partially full chunks before allocation a new one

[@LukeClemens]

@@TurboMakesGames wow I never would have guessed it would work like that!

[@hhgnehcom7672]

entities 0.50 finally lets go

[@TurboMakesGames]

😀😀😀

[@watercat1248]

I understand what those chunk's don't what I do understand if use different components like for example let's I use one entity the have health and 1 entity the have damage those 2 are completely different entity's with different components what i will happen on that case with the chunk's system ?

[@TurboMakesGames]

If two entities are built of different components, they'll be associated with different archetypes, therefore the data will live in separate chunks

[@watercat1248]

@@TurboMakesGamesokay

[@triplebog]

Whats the interaction between chunks and Dynamic buffers?

[@TurboMakesGames]

Good question - so when you define a dynamic buffer, there is an optional attribute you can set called "Internal Buffer Capacity." In there, you define how many elements of that type should be stored in the chunk. When an entity with that dynamic buffer is instantiated, it allocates for the max allowed elements in the dynamic buffer. If you end up adding more elements to the buffer than are allocated for in the chunk, all data in the buffer is moved out of the chunk and into the heap - there is now a reference pointing to the memory location of where the data was moved to. Ideally you want to set this number so that most of the time data is being stored in the chunk for the fastest access, but no so big that you end up having wasted space in the chunk. Hope that clears things up for you! (Nice Journey profile pic btw 😊)

[@yevhenii3562]

16 KiB not 16 kb

[@TurboMakesGames]

I use KB as it is the generally accepted notation for kilobyte. Thanks for stopping by!

[@yevhenii3562]

@@TurboMakesGames The only difference that i noticed) Good work. Im waiting for more ecs