arch.system.md

description
If only there was a way to organize your queries... wait... there is!

Arch.System

You write query after query all the time to order your subordinates around... it's a pure mess, isn't it? Then just use Arch.System? It's quite simple... With Arch.System you can organize your queries in Systems and call and reuse them at will.

public class MovementSystem : BaseSystem<World, float>
{
    private QueryDescription _desc = new QueryDescription().WithAll<Position, Velocity>();
    public MovementSystem(World world) : base(world) {}
    
    // Can be called once per frame
    public override void Update(in float deltaTime)
    {
        // Run query, can also run multiple queries inside the update method
        World.Query(in _desc, (ref Position pos, ref Velocity vel) => {
            pos.X += vel.X;
            pos.Y += vel.Y;
        });  
    }
}

{% hint style="info" %} The example above is of course kept simple. You can simply put anything you want to group into such a System, e.g. a System for everything that moves your creatures... another System that contains everything that causes your creatures to suffer damage and heals them etc. There is no limit to your imagination! {% endhint %}

Now we already have a MovementSystem, a System that groups everything that makes our Entities move. But how do we integrate this now?

// Create a world and a group of systems which will be controlled 
var world = World.Create();
var _systems = new Group<float>(
    new MovementSystem(world),  
    new PhysicsSystem(world),
    new DamageSystem(world),
    new WorldGenerationSystem(world),
    new OtherGroup(world)
);

_systems.Initialize();                  // Inits all registered systems
_systems.BeforeUpdate(in deltaTime);    // Calls .BeforeUpdate on all systems ( can be overriden )
_systems.Update(in deltaTime);          // Calls .Update on all systems ( can be overriden )
_systems.AfterUpdate(in deltaTime);     // Calls .AfterUpdate on all System ( can be overriden )
_systems.Dispose();                     // Calls .Dispose on all systems ( can be overriden )

{% hint style="info" %} A Group<T> can also contain other Group<T>. BeforeUpdate, Update and AfterUpdate should be called at will to update the systems and queries. {% endhint %}

And we have already divided our Systems into Group<T>s to bring order into it. What more could you want?