Avoid allocation caused by the ForEachEntity() delegate

[MaansenV]

@friflo edit - renamed title. Was: "MonoGame Render GarbageCollection"; format code as C#; typo

Im generation Garbage every frame because of the Delegate Allocation here. Any idea how to do it better?

using App2;
using App2.Components;
using Friflo.Engine.ECS;
using Friflo.Engine.ECS.Systems;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;

public class RenderSystem : QuerySystem<Position2D, Sprite>
{
    private SpriteBatch _spriteBatch;
    private TextureManager _textureManager;

    public RenderSystem(SpriteBatch spriteBatch, TextureManager textureManager)
    {
        _spriteBatch = spriteBatch;
        _textureManager = textureManager;
    }

    protected override void OnUpdate()
    {
        _spriteBatch.Begin();

        Query.ForEachEntity((ref Position2D position, ref Sprite sprite, Entity entity) =>
        {
            var texture = _textureManager.GetTexture(sprite.TextureId);
                _spriteBatch.Draw(
                    texture,
                    new Vector2(position.Value.X, position.Value.Y),
                    null,
                    sprite.Color,
                    0f,
                    new Vector2(texture.Width / 2, texture.Height / 2),
                    sprite.Scale,
                    SpriteEffects.None,
                    0f
                );
        });

        _spriteBatch.End();
    }
}

[friflo]

To avoid the allocation caused by the delegate you can use the approach explained in the Wiki - Enumerate Query Chunks

This approach replaces Query.ForEachEntity(...) by two loops. This approach is allocation free.

foreach (var (positions, sprites, entities) in Query.Chunks)
{
    for (int n = 0; n < positions.Length; n++) {
        var position = positions[n];
        var sprite   = sprites[n];
        var texture = _textureManager.GetTexture(sprite.TextureId);
        _spriteBatch.Draw(...)
    }
}

If you like you can extract the inner block to a method.

foreach (var (positions, sprites, entities) in Query.Chunks)
{
    for (int n = 0; n < positions.Length; n++) {
        Draw(position[n], sprites[n]);
    }
}

void Draw(Position2D position, Sprite sprite) {
    ...
}