Samples

A progressive tutorial series plus full game samples. Each builds on the previous.

Tutorial series (Trecs 101)

#	Sample	Concepts
01	Hello Entity	Components, tags, templates, systems, world setup
02	Spawn & Destroy	Entity lifecycle, dynamic spawning, timed destruction
03	Aspects	Bundled component access for clean iteration
04	Predator Prey	Cross-entity references, template inheritance, event cleanup
05	Job System	Burst compilation, parallel jobs, WrapAsJob
06	Partitions	Template partitions, partition transitions, partition-filtered iteration
07	Feeding Frenzy	Complex simulation, visual smoothing, multiple interacting systems
08	Sets	Dynamic entity subsets, overlapping membership
09	Interpolation	Fixed-to-variable timestep interpolation
10	Dynamic Collections	Five trail-storage strategies: UniquePtr Queue, FixedArray, FixedList, TrecsList, TrecsArray
13	Aspect Interfaces	Shared aspect contracts via partial interface for reusable cross-species helpers
14	Blob Seed Pattern	Content-pipeline-stable BlobIds for shared immutable assets on the heap
15	Reactive Events	OnAdded / OnRemoved observers for cleanup and stat tracking
16	Multiple Worlds	Two independent World instances ticking side-by-side
17	Heightmap Blobs	Content-derived BlobIds via UniqueHashGenerator, plus a NativeSharedPtr Burst-job variant

Game samples

#	Sample	Description
11	Snake	Complete grid-based game with input handling and recording/playback
12	Feeding Frenzy Benchmark	Performance benchmark comparing partition approaches and iteration styles

Running the samples

Open Assets/Samples/Core/Main.unity in Unity 6000.3+ and press Play. A SampleCycler lets you switch between samples at runtime. Each sample has its own composition root.

Sample architecture: Bootstrap & CompositionRoot

Each sample uses a two-class pattern:

• Bootstrap — MonoBehaviour driving the Unity lifecycle. Awake() calls CompositionRoot.Construct() and runs the initializers; Update() / LateUpdate() invoke tickables and late tickables; OnDestroy() runs disposables.
• CompositionRootBase — abstract MonoBehaviour each sample subclasses. Construct() builds the WorldBuilder, creates systems, and returns four List<Action> callbacks (init, tick, late tick, dispose).

// Simplified — each sample's composition root looks roughly like this:
public class MyCompositionRoot : CompositionRootBase
{
    public override void Construct(
        out List<Action> initializables,
        out List<Action> tickables,
        out List<Action> lateTickables,
        out List<Action> disposables)
    {
        var world = new WorldBuilder()
            .AddTemplate(MyEntity.Template)
            .Build();

        world.AddSystems(new ISystem[] { new MySystem() });

        initializables = new() { world.Initialize };
        tickables = new() { world.Tick };
        lateTickables = new() { world.LateTick };
        disposables = new() { world.Dispose };
    }
}

Note

This pattern is a convenience for the samples. Trecs is unopinionated about application structure — it doesn't register MonoBehaviours, manage singletons, or hook into Unity's update loop. Use a DI framework (Reflex, Zenject, VContainer), plain MonoBehaviours, ScriptableObjects, or anything else. Trecs only requires that your code calls world.Tick(), world.LateTick(), and world.Dispose() at the right times.

Shared utilities

Common/ contains helpers shared across samples (sample code — not part of Trecs itself):

• RenderableGameObjectManager — pools and spawns Unity GameObjects for entities carrying PrefabId + GameObjectId, driven by OnAdded / OnRemoved observers
• IndirectRenderer — GPU-instanced indirect rendering for high entity counts (samples using IndirectRenderable)
• Bootstrap / CompositionRootBase — the lifecycle wiring above
• SampleUtil — primitive / material helpers
• DisposeCollection — IDisposable aggregator
• Common components and templates (Position, Rotation, UniformScale, ColorComponent, PrefabId, GameObjectId, CommonTemplates.IndirectRenderable, CommonTemplates.RenderableGameObject, etc.)

If you copy code from a sample, also copy its Common/ dependencies.