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Entitas - The Entity Component System Framework for C# and Unity

Entitas is the most popular open-source Entity Component System Framework (ECS) and is specifically made for C# and Unity. Several design decisions have been made to work optimal in a garbage collected environment and to go easy on the garbage collector. Entitas comes with an optional code generator which radically reduces the amount of code you have to write and makes your code read like well written prose.

Why Entitas

#1 open-source ECS on GitHub
100% open-source under the MIT License
great and helpful community on Discord
easy to learn and easy to use
works great in pure C# standalone projects without Unity
comes with great Unity integration called Visual Debugging
battle-tested at companies like Popcore (Rollic / Zynga / Take Two), Gram Games, Wooga, Plarium, Storm Chaser and many more

Video Tutorials and Unity Unite Talks

Video	Title	Resources
	Entitas ECS Unity Tutorial - Git & Unit Tests
	Entitas ECS Unity Tutorial - Setup & Basics
	Unite Europe 2016: ECS architecture with Unity by example	SlideShare: Unite Europe 2016
	Unite Europe 2015: Entity system architecture with Unity	SlideShare: Unite Europe 2015

First glimpse

The optional code generator lets you write code that is super fast, safe and literally screams its intent.

var entity = context.CreateEntity();
entity.AddPosition(Vector3.zero);
entity.AddVelocity(Vector3.forward);
entity.AddAsset("Player");

using static GameMatcher;

public sealed class MoveSystem : IExecuteSystem
{
    readonly IGroup<GameEntity> _group;

    public MoveSystem(GameContext context)
    {
        _group = context.GetGroup(AllOf(Position, Velocity));
    }

    public void Execute()
    {
        foreach (var e in _group.GetEntities())
            e.ReplacePosition(e.position.value + e.velocity.value);
    }
}

Overview

Entitas is fast, light and gets rid of unnecessary complexity. There are less than a handful classes you have to know to rocket start your game or application:

Context
Entity
Component
Group

Entitas ECS

+-----------------+
|     Context     |
|-----------------|
|    e       e    |      +-----------+
|       e      e--|----> |  Entity   |
|  e        e     |      |-----------|
|     e  e     e  |      | Component |
| e          e    |      |           |      +-----------+
|    e     e      |      | Component-|----> | Component |
|  e    e    e    |      |           |      |-----------|
|    e    e     e |      | Component |      |   Data    |
+-----------------+      +-----------+      +-----------+
  |
  |
  |     +-------------+  Groups:
  |     |      e      |  Subsets of entities in the context
  |     |   e     e   |  for blazing fast querying
  +---> |        +------------+
        |     e  |    |       |
        |  e     | e  |  e    |
        +--------|----+    e  |
                 |     e      |
                 |  e     e   |
                 +------------+

Code Generator

The Code Generator generates classes and methods for you, so you can focus on getting the job done. It radically reduces the amount of code you have to write and improves readability by a huge magnitude. It makes your code less error-prone while ensuring best performance.

Unity integration

The optional Unity module "Visual Debugging" integrates Entitas nicely into Unity and provides powerful editor extensions to inspect and debug contexts, groups, entities, components and systems.

Entitas deep dive

Read the wiki or checkout the example projects to see Entitas in action. These example projects illustrate how systems, groups, collectors and entities all play together seamlessly.

Download and setup Entitas

GitHub releases (recommended)

Show releases

Unity package manager

Coming soon

NuGet

Entitas and all dependencies are available as NuGet packages. More detailed explanation coming soon.

Unity Asset Store (deprecated)

Entitas on the Unity Asset Store is deprecated and will not be updated anymore. The last version available on the Asset Store is 1.12.3 and is free to download. Please see discussion Entitas turns 7 - and is FREE now

Thanks to

Big shout out to @mzaks, @cloudjubei and @devboy for endless hours of discussion and helping making Entitas awesome!

Maintainers

@sschmid | @s_schmid | @entitas_csharp

Different language?

Entitas is available in

botrosg/Entitas