Building an Entity Component System

Mar 08, 2022

Today's goal: Build the foundation of an "Entity Component System" for the game engine!

Updates

Texture rendering is now working!
Reorganized and renamed code in the game engine

Developing a component-based engine

Today we'll be sketching out the initial design of an Entity Component System written in Mesche!

This is a relatively common design in modern game engines which seeks to break down monolithic game object implementations into a more composable design:

Entity: A game object comprised of behaviors split across components (really just an ID)
Component: The data for an entity that a particular "system" understands
System: The actual code that implements a behavior across a collection of one component type

What's nice about this?

Decoupling of game objects from behavior
Systems can be executed at any time, even on different threads
Enables much better performance when component data is organized appropriately (data-oriented design)

We're going to start with a simple design using the language features we have so far in Mesche and then improve it as we go!

Tasks

DONE Add new `ObjectArray` type to Mesche

DONE Create `entity` record to store `id`

DONE Create `system` record to hold system definitions (like the `update` function)

DONE Create `physical` component to hold position, size, and other physics attributes

DONE Create `renderable` component for sprite rendering

DONE Create `renderable-system` to draw all `renderable` components

Notes

The code for this stream can be found here:

Building an Entity Component System

Updates

Developing a component-based engine

Tasks

DONE Add new ObjectArray type to Mesche

DONE Create entity record to store id

DONE Create system record to hold system definitions (like the update function)

DONE Create physical component to hold position, size, and other physics attributes

DONE Create renderable component for sprite rendering

DONE Create renderable-system to draw all renderable components