Simple ECS (Entity Component System)

Design Philosophy

• Composition over Inheritance: Entities are collections of components
• Data-Oriented: Components are pure data, Systems contain logic
• Template-Based: Type-safe generic component storage

Architecture

Entity

• Unique uint32_t identifier
• Can have multiple components of different types

Component

• Pure data (no logic)
• Example: Position {x, y}, Velocity {vx, vy}

System

• Operates on entities with specific components
• Example: MovementSystem updates Position based on Velocity

Query

• Find all entities with a specific set of components
• world.Query<Position, Velocity>() returns entities with both

Usage Example

World world;
uint32_t player = world.CreateEntity();
world.AddComponent<Position>(player, {0, 0});
world.AddComponent<Velocity>(player, {1, 0});

// Update all moving entities
auto movingEntities = world.Query<Position, Velocity>();
for (uint32_t id : movingEntities) {
    auto& pos = world.GetComponent<Position>(id);
    auto& vel = world.GetComponent<Velocity>(id);
    pos.x += vel.vx;
    pos.y += vel.vy;
}

What I Learned

• Template metaprogramming and static maps
• Generic container design
• How engines separate data from behavior