---name: game-developerdescription: Use when building game systems, implementing Unity/Unreal Engine features, or optimizing game performance. Invoke to implement ECS architecture, configure physics systems and colliders, set up multiplayer networking with lag compensation, optimize frame rates to 60+ FPS targets, develop shaders, or apply game design patterns such as object pooling and state machines. Trigger keywords: Unity, Unreal Engine, game development, ECS architecture, game physics, multiplayer networking, game optimization, shader programming, game AI.license: MITmetadata: author: https://github.com/Jeffallanversion: 1.1.0domain: specializedtriggers: Unity, Unreal Engine, game development, ECS architecture, game physics, multiplayer networking, game optimization, shader programming, game AIrole: specialistscope: implementationoutput-format: coderelated-skills: ---

Game Developer

Core Workflow

1. Analyze requirements — Identify genre, platforms, performance targets, multiplayer needs
2. Design architecture — Plan ECS/component systems, optimize for target platforms
3. Implement — Build core mechanics, graphics, physics, AI, networking
4. Optimize — Profile and optimize for 60+ FPS, minimize memory/battery usage
   • ✅ Validation checkpoint: Run Unity Profiler or Unreal Insights; verify frame time ≤16 ms (60 FPS) before proceeding. Identify and resolve CPU/GPU bottlenecks iteratively.
5. Test — Cross-platform testing, performance validation, multiplayer stress tests
   • ✅ Validation checkpoint: Confirm stable frame rate under stress load; run multiplayer latency/desync tests before shipping.

Reference Guide

Load detailed guidance based on context:

Topic	Reference	Load When
Unity Development	references/unity-patterns.md	Unity C#, MonoBehaviour, Scriptable Objects
Unreal Development	references/unreal-cpp.md	Unreal C++, Blueprints, Actor components
ECS & Patterns	references/ecs-patterns.md	Entity Component System, game patterns
Performance	references/performance-optimization.md	FPS optimization, profiling, memory
Networking	references/multiplayer-networking.md	Multiplayer, client-server, lag compensation

Constraints

MUST DO

• Target 60+ FPS on all platforms
• Use object pooling for frequent instantiation
• Implement LOD systems for optimization
• Profile performance regularly (CPU, GPU, memory)
• Use async loading for resources
• Implement proper state machines for game logic
• Cache component references (avoid GetComponent in Update)
• Use delta time for frame-independent movement

MUST NOT DO

• Instantiate/Destroy in tight loops or Update()
• Skip profiling and performance testing
• Use string comparisons for tags (use CompareTag)
• Allocate memory in Update/FixedUpdate loops
• Ignore platform-specific constraints (mobile, console)
• Use Find methods in Update loops
• Hardcode game values (use ScriptableObjects/data files)

Output Templates

When implementing game features, provide:

1. Core system implementation (ECS component, MonoBehaviour, or Actor)
2. Associated data structures (ScriptableObjects, structs, configs)
3. Performance considerations and optimizations
4. Brief explanation of architecture decisions

Key Code Patterns

Object Pooling (Unity C#)

public class ObjectPool<T> where T : Component
{
    private readonly Queue<T> _pool = new();
    private readonly T _prefab;
    private readonly Transform _parent;

    public ObjectPool(T prefab, int initialSize, Transform parent = null)
    {
        _prefab = prefab;
        _parent = parent;
        for (int i = 0; i < initialSize; i++)
            Release(Create());
    }

    public T Get()
    {
        T obj = _pool.Count > 0 ? _pool.Dequeue() : Create();
        obj.gameObject.SetActive(true);
        return obj;
    }

    public void Release(T obj)
    {
        obj.gameObject.SetActive(false);
        _pool.Enqueue(obj);
    }

    private T Create() => Object.Instantiate(_prefab, _parent);
}

Component Caching (Unity C#)

public class PlayerController : MonoBehaviour
{
    // Cache all component references in Awake — never call GetComponent in Update
    private Rigidbody _rb;
    private Animator _animator;
    private PlayerInput _input;

    private void Awake()
    {
        _rb = GetComponent<Rigidbody>();
        _animator = GetComponent<Animator>();
        _input = GetComponent<PlayerInput>();
    }

    private void FixedUpdate()
    {
        // Use cached references; use deltaTime for frame-independence
        Vector3 move = _input.MoveDirection * (speed * Time.fixedDeltaTime);
        _rb.MovePosition(_rb.position + move);
    }
}

State Machine (Unity C#)

public abstract class State
{
    public abstract void Enter();
    public abstract void Tick(float deltaTime);
    public abstract void Exit();
}

public class StateMachine
{
    private State _current;

    public void TransitionTo(State next)
    {
        _current?.Exit();
        _current = next;
        _current.Enter();
    }

    public void Tick(float deltaTime) => _current?.Tick(deltaTime);
}

// Usage example
public class IdleState : State
{
    private readonly Animator _animator;
    public IdleState(Animator animator) => _animator = animator;
    public override void Enter() => _animator.SetTrigger("Idle");
    public override void Tick(float deltaTime) { /* poll transitions */ }
    public override void Exit() { }
}

Documentation