# ECSx

[![Hex Version](](

ECSx is an Entity-Component-System (ECS) framework for Elixir. ECS is an architecture for building real-time games and simulations, wherein data about Entities is stored in small fragments called Components, which are then read and updated by Systems.

## Setup

- Add `:ecsx` to the list of dependencies in `mix.exs`:

def deps do
    {:ecsx, "~> 0.5"}

- Run `mix deps.get`
- Run `mix ecsx.setup`

## Upgrading

While ECSx is pre-v1.0, minor version updates will contain breaking changes.  If you are upgrading an application from ECSx 0.4.x or earlier, please refer to our [upgrade guide](upgrade_guide.html).

## Tutorial Project

[Building a ship combat engine with ECSx in a Phoenix app](  
Note: This tutorial project is a work-in-progress

## Usage

### Entities and Components

Everything in your application is an Entity, but in ECS you won't work with these Entities directly - instead you will work with the individual attributes that an Entity might have. These attributes are given to an Entity by creating a Component, which holds, at minimum, the Entity's unique ID, but also can store a value. For example:

- You're running a 2-dimensional simulation of cars on a highway
- Each car gets its own `entity_id` e.g. `123`
- If the car with ID `123` is blue, we give it a `Color` Component with value `"blue"`
- If the same car is moving west at 60mph, we might model this with a `Direction` Component with value `"west"` and a `Speed` Component with value `60`
- The car would also have Components such as `XCoordinate` and `YCoordinate` to locate it on the map

### Systems

Once your Entities are modeled using Components, you'll create Systems to operate on them. For example:

- Entities with `Speed` Components should have their locations regularly updated according to the speed and direction
- We can create a `Move` System which reads the `Speed` and `Direction` Components, calculates how far the car has moved since the last server tick, and updates the Entity's `XCoordinate` and/or `YCoordinate` Component accordingly.
- The System will run every tick, only considering Entities which have a `Speed` Component

### Generators

ECSx comes with generators to quickly create new Components or Systems:

- `mix ecsx.gen.component`
- `mix ecsx.gen.system`

### Manager

Every ECSx application requires a Manager module, where valid Component types and Systems are declared, as well as the setup to spawn world objects before any players join. This module is created for you during `mix ecsx.setup` and will be automatically updated by the other generators.

It is especially important to consider the order of your Systems list. The manager will run each System one at a time, in order.

### Persistence

Components are not persisted by default. To persist an entity, use the `persist: true` option when adding the component. The default adapter for persistence is the [ECSx.Persistence.FileAdapter](lib/ecsx/persistence/file_adapter.ex), which stores the components in a binary file. The adapter can be changed using the `persistence_adapter` application variable:

config :ecsx,
  persistence_adapter: ...

Currently available Persistence Adapters (see links for installation/configuration instructions):

- [ECSx.Persistence.Ecto](

## License

Copyright (C) 2022 Andrew P Berrien

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the [GNU General Public License]( for more details.