• Advertisement
Sign in to follow this  

Unity Unity's ECS: how to handle scripting systems?

This topic is 1471 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

One of the things that intrigues me in Unity is it's Entity-Component system and how it handles scripting. When you create a C# or Javascript and attach to a GameObject in Unity, several methods from that script are called. onUpdate, onAwake, onLateUpdate, etc. 

 

Does anyone have any ideas on the possible implementation of that in a custom ECS? Is there a ScriptingSystem, which pre-interprets all scripts on boot, and then calls those methods on each frame? The ScriptingSystem has several calls from the game loop, for each event (method attached) on those scripts (update, late update, awake, etc.)?

Share this post


Link to post
Share on other sites
Advertisement

One of the things that intrigues me in Unity is it's Entity-Component system


Unity is not an ECS. There are _many_ types of component-based designs and ECS is a subset of those (of which Unity does not fall into). It does not use the entity-system architecture (where a component is just data managed by a system object).

Share this post


Link to post
Share on other sites

 

One of the things that intrigues me in Unity is it's Entity-Component system


Unity is not an ECS. There are _many_ types of component-based designs and ECS is a subset of those (of which Unity does not fall into). It does not use the entity-system architecture (where a component is just data managed by a system object).

 

 

You're wrong here.  An ECS isn't a defined system where Components only have data.  An ECS is simply a collection of components that make up an entity, instead of using OO to build entities.

 

An ECS can be a system where components have both data and logic.

Share this post


Link to post
Share on other sites

Without formally knowing the details of Unity, an ECS at its root is just a list of behaviors and information. It's likely that Unity defines a number of components as "default" which are run as long as they are present on an entity. I imagine there's some scripted way to enable/disable components as well. If the component is defined as a script, there's probably just a small trampoline function that calls the script.

 

ECSs aren't magic; back in the day before it was a buzzword, I was working on a game for one of my college classes and one of the other programmers started implementing a deep hierarchy of entities where each kind of enemy was its own class. Since this was bad, I convinced the team that a better way to go would be a much shallower hierarchy, where instead of a virtual function defining behavior, the common entity just had a function pointer instead, and the pointed-to function implemented the behavior (had I known better at the time, this could have been a functor object instead of a pointer-to-function). We did the same for some other events, like taking damage. This was a type of ECS, although I didn't know it at the time, and modern ECSs tend to operate differently.

Share this post


Link to post
Share on other sites

Unity uses the Mono runtime to run the scripts. I don't know the internals either but I'd figure the C++ engine runtime will call into the Mono runtime to get each relevant script object to execute its Start(), Update() etc. functions when needed.

 

Due to it integrating several 3rd party SDKs it doesn't have complete say into how it implements its ECS / scene model internally. The PhysX physics for example could be thought as its own "system" which each frame simulates all the rigidbodies in the scene, but the PhysX objects aren't just bare data containers, so SeanMiddleditch is right that it doesn't implement the ECS according to that strict definition.

Edited by AgentC

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
  • Advertisement
  • Popular Tags

  • Advertisement
  • Popular Now

  • Similar Content

    • By BTO_Dev
      Hi Guys, I am developing an Online Multiplayer game and I am creating devlogs every few weeks and it will be great if you could subscribe! I also upload other videos that I assume could help you too  
       
      THANKS FOR READING!
    • By 3dmodelerguy
      So I am building a turn based rogue-like (think CDDA). The game is going to have a very large map (up to 1000's x 1000's) however to alleviate most of that I obviously can't render everything so there will just be render a certain radius around the player and just load in and out data as the player moves.
      The next major system I am prototyping is making interactive tiles destructible and pretty much everything will be destructible besides basic landscape (cars, doors, windows, structures, etc. will be destructible)
      While I am only rendering a certain amount of tiles around the player, I want to keep the amount of colliders active at one time to be as small as possible for performance and currently the tilemap tool I use automatically merges colliders together.
      So instead of creating a separate colliders for each of these tiles and having the destructible behavior tied to that object (which my tilemap tool would allow me to do) I was thinking that I would store an array of all the X and Y locations for the interactive tilemap layer and let the tilemap manage the colliders. 
      Then when I hit a collider on the interactive tilemap layer, instead of of getting the behavior for how to deal with the destruction for that tile from that game object, I would pull it from the array I mentioned earlier based on the tile I attempt to interact with which I already have.
      Does this sound like a good approach? Any other recommendations would be welcomed.
    • By NDraskovic
      Hey guys,
      I have a really weird problem. I'm trying to get some data from a REST service. I'm using the following code:
       
      private void GetTheScores() { UnityWebRequest GetCommand = UnityWebRequest.Get(url); UnityWebRequestAsyncOperation operation = GetCommand.SendWebRequest(); if (!operation.webRequest.isNetworkError) { ResultsContainer rez = JsonUtility.FromJson<ResultsContainer>(operation.webRequest.downloadHandler.text); Debug.Log("Text: " + operation.webRequest.downloadHandler.text); } } The problem is that when I'm in Unity's editor, the request doesn't return anything (operation.webRequest.downloadHandler.text is empty, the Debug.Log command just prints "Text: "), but when I enter the debug mode and insert a breakpoint on that line, then it returns the text properly. Does anyone have an idea why is this happening?
      The real problem I'm trying to solve is that when I receive the text, I can't get the data from the JSON. The markup is really simple:
      [{"id":1,"name":"Player1"},{"id":2,"name":"Player2"}] and I have an object that should accept that data:
      [System.Serializable] public class ResultScript { public int id; public string name; } There is also a class that should accept the array of these objects (which the JSON is returning):
      [System.Serializable] public class ResultsContainer { public ResultScript[] results; } But when I run the code (in the debug mode, to get any result) I get an error: ArgumentException: JSON must represent an object type. I've googled it but none of the proposed solutions work for me.
      Also (regardless if I'm in the debug mode or not) when I try to do some string operations like removing or adding characters to the GET result, the functions return an empty string as a result
      Can you help me with any of these problems?
      Thank you
    • By nihitori
      The Emotional Music Vol. I pack focuses on beautiful and esoteric orchestral music, capable of creating truly emotive and intimate moods. It features detailed chamber strings, cello and piano as the main instruments, resulting in a subtle and elegant sound never before heard in video game royalty-free music assets.

      The pack includes 5 original tracks, as well as a total of 47 loops based on these tracks (long loops for simple use and short loops for custom / complex music layering).

      Unity Asset Store link: https://www.assetstore.unity3d.com/en/#!/content/107032
      Unreal Engine Marketplace link: https://www.unrealengine.com/marketplace/emotional-music-vol-i

      A 15 seconds preview of each main track is available on Soundcloud:
       
    • By RoKabium Games
      Another one of our new UI for #screenshotsaturday. This is the inventory screen for showing what animal fossils you have collected so far. #gamedev #indiedev #sama
  • Advertisement