Github https://github.com/Winteradio/ECS-with-Scene-and-Node

Github https://github.com/Winteradio/Log

Github https://github.com/Winteradio/MemoryPool

Summary

• Rebuilding ECS (Entity Component System)

🛠️ Technology Stack and Libraries

• Language
  • C++
• Libraries
  • Log Project
  • Memory Project
  • Rpc (UUID)

📝 Concept Explanation

What is ECS (Entity Component System)?

• A DOTS-based system under development in Unity.
• DOTS vs OOP
  • What is DOTS?
    • Data-Oriented Technology Stack.
    • A data-centric programming approach.
  • How is it different from OOP?
    • Data-centric
      • Focuses on optimizing performance and accessing data directly.
    • Continuous memory accessibility
      • Unlike OOP objects, stores data of the same type in contiguous memory.
      • Optimizes memory access patterns to increase cache hit probability.
    • Ease of parallel processing
      • Allows independent construction of methods (or systems) for different data types.
      • Systems operate on data, not objects (entities), enabling separation of objects and systems.
• Entity Component System (ECS)
  • What is an Entity?
    • An abstraction representing individual objects such as game objects or characters.
    • Serves as a simple identifier (naming) and does not directly hold data.
    • Example:
      • Entity ID: "John Doe"
        • "Abilities" Component - "John Doe"
        • "Skills" Component - "John Doe"
        • "Weapon" Component - "John Doe"
      • In this example, the Entity serves as an identifier for the components.
  • What is a Component?
    • Represents actual data used by entities.
    • Identified by Entity ID when attached to an entity.
    • Components of the same type should be stored in contiguous memory.
  • What is a System?
    • Logic that processes and manipulates components.
    • Each system has access rights to the components it requires.
    • Systems can be processed in parallel, but dependencies between them must be considered.
    • Example:
      • System: "Render"
        • Uses "Render Component"
      • System: "Move"
        • Uses "Move Component"

Types of ECS: Sparse Set vs. Archetype

• Sparse Set
  • A method of linking Entity IDs with each component.
  • Uses a Dense Set to store Entity IDs and a Sparse Set for components.
  • Allows rapid access to components in contiguous memory using the Entity ID.
  • Related Site: Entt Library on Github
• Archetype
  • Groups of entities with similar component compositions.
  • Each archetype has a unique component composition.
  • Unlike Sparse Set, it doesn't store components in contiguous memory but stores similar types of archetypes in contiguous memory.
  • Related Site: Unity's ECS Archetype

Why Implement ECS in C++, an OOP Language?

• Understanding Game Engine Structure
  • Need for a continuously usable library.
  • Lack of understanding of how the engine's internals work.
    • How project files are structured.
    • How play, pause, and building within the engine work.
    • Whether the engine and the game are developed separately.
  • Difficulty in implementing information from UML diagrams of other engines.
• Implementation of Independent Systems
  • Need for a basic engine to implement functionality like collision and fluid simulation.
• Different Approach to ECS
  • Issues with Sparse Set:
    • Limited to accessing only one component via the Entity ID.
    • Not all systems can use just one component.
  • Issues with Archetype:
    • Even if you want to add just one or two components to a specific archetype, you need to create a new archetype by duplicating data.
    • Example:
      • When you want to create objects that emit light and render, you need a new "Light Render Archetype."
      • This would require duplicating the required components and removing them from the existing archetype.
  • Introduction of the "Node" Concept

📝 Development Details