DragonECS-ClassicThreads/README.md

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# Classic C# Threads for [DragonECS](https://github.com/DCFApixels/DragonECS)

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    <td colspan="3">Readme Languages:</td>
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        <span>Русский</span>
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Support for processing entities in multiple threads, based on classic C# threads implementation. Inspired by a similar extension for [LeoEcs Lite](https://github.com/Leopotam/ecslite-threads).

> [!WARNING]
> The project is a work in progress, API may change.  
>
> The most current version of the README is in [Russian version](https://github.com/DCFApixels/DragonECS-ClassicThreads/blob/main/README-RU.md).

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# Installation
Versioning semantics - [Open](https://gist.github.com/DCFApixels/e53281d4628b19fe5278f3e77a7da9e8#file-dcfapixels_versioning_ru-md)
## Environment
Requirements:
+ Dependency: [DragonECS](https://github.com/DCFApixels/DragonECS)
+ Minimum version of C# 7.3;
  
Optional:
+ Support for NativeAOT
+ Game engines with C#: Unity, Godot, MonoGame, etc.
  
Tested with:
+ **Unity:** Minimum version 2020.1.0;

## Unity Installation
* ### Unity Package
The package can be installed as a Unity package by adding the Git URL [in the PackageManager](https://docs.unity3d.com/2023.2/Documentation/Manual/upm-ui-giturl.html) or manually adding it to `Packages/manifest.json`: 
```
https://github.com/DCFApixels/DragonECS-ClassicThreads.git
```
* ### Source Code
The package can also be added to the project as source code.

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# Parallel iteration
``` csharp
EcsThreadHandler _handler;
public void Run(EcsPipeline pipeline)
{
    // Getting the Aspect and entities for iteration.
    var group = _world.Where(out Aspect a);

    void Handler(ReadOnlySpan<int> entities)
    {
        foreach (var e in entities)
        {
            // Computations in a separate thread.
            a.poses.Get(e).position += a.velocities.Read(e).value * _time.DeltaTime;
        }
    }

    // Starts parallel iteration over entities,
    // entities will be split into parts with a minimum size of 1000.
    group.IterateParallel(_handler ??= Handler, 1000);
}
```
> The smaller the minimum size of the group part when dividing, the more threads can be utilized. In some situations, too many threads can negatively impact performance.

> Inside the handler, creating/deleting entities, adding/removing components on entities is prohibited. Only modification of data within components is allowed.