Setup Entitas and Unity in different projects

This is originally some notes I wrote for myself, I rewrote them here in case in can help some people.

The idea is to have most of the code in a C# only project and only have code in the Unity project that is for the game client (aka: the view). This allow us to have our simulation code independent of the game client.

Create a new c# ClassLibrary project

(keep solution and project in separate folder)

So the solution folder would be ~/projects/MyProject, and the project folder would be ~/projects/MyProject/MyProject

Initialize a Git repo in the solution folder

Create a Unity project, place it in the solution folder

Then import Entitas from the Asset Store to your assets.

I like to move the Entitas folder to my solution folder, and keep only the Entitas/Editor/Images folder in Unity (otherwise the images aren't loaded, looks like the tags from the .meta files aren't imported with a package or something), I then create a package.json file in <solution_folder>/Entitas to be able to import it as a package in Unity (using Unity 2018 package manager)

Create another C# project for the Tests

Create a ConsoleApplication project in <solution_root>/MyProject.Tests

Using Nuget, import NSubstitute, Shouldly and Nspec

Inspired by the instructions in https://youtu.be/DZpvUnj2dGI?t=289

Move Jenny to solution folder

Extract Jenny.zip and move the "Jenny" folder to the solution root

Execute the Jenny-Auto-Import script from your solution folder. Note: keep Roslyn generator

Move the Jenny-Auto-Import, Jenny-Server and preferences.properties files to the project root

Edit the Jenny-Auto-Import and Jenny-Server files to reference the correct paths (example: "..\Jenny\Jenny.exe server" instead of ".\Jenny\Jenny.exe server")

Edit the generated preferences.properties to make sure that the Jenny.SearchPaths key reference the correct directory

    Jenny.SearchPaths = ..\Jenny\Plugins\DesperateDevs, \
                        ..\Jenny\Plugins\Entitas, \
                        ..\Jenny\Plugins\Entitas.Roslyn

that the ProjectPath is correct

DesperateDevs.CodeGeneration.Plugins.ProjectPath = MyProject.csproj

that your contexts are defined correctly

Entitas.CodeGeneration.Plugins.Contexts = Game, Input, Meta

that you ignore namespaces (optional)

Entitas.CodeGeneration.Plugins.IgnoreNamespaces = true

fix the TargetDirectory since we're outside of Unity

DesperateDevs.CodeGeneration.Plugins.TargetDirectory = ./

You should now be able to launch the Jenny-Server from the project folder. (Or run jenny doctor to check for errors)

In Rider, I also like to create a run Configuration to quickly generate Entitas code

Menu: Run -> Edit Configuration...
Create a new ".NET Executable"
Name: Jenny Client Gen
Exe Path: <whatever>\Acme\Acme.MyProject\Jenny\Jenny.exe
Program arguments: client gen
Working directory: <whatever>\Acme\Acme.MyProject\Acme.MyProject
you can later uncheck "Activate tool window" once you know everything works well

Running it should create the "Generated" folder in your project with the generated contexts.

Create you first component

// Sources\Components\LogMessageComponent.cs
using Entitas;

namespace Acme.MyProject.Sources.Components
{
    [Game]
    public class LogMessageComponent: IComponent
    {
        public string value;
    }
}

Test that everything works by running "Jenny Client Gen" again and make sure you have the file generated in Source\Generated\Game\Components\GameLogMessageComponent.cs

Overview

Folder structure should look like:

projects\
--MyProject\                   <-- Solution root, .sln file, 
----MyProject\                 <-- Components, Systems, Services, etc.
----MyProject.Tests\           <-- The tests, NSpec, Nsubstitute, Shouldy
----MyProject.UnityClient\     <-- The unity project
----Jenny\                     <-- The generator, needs to be outside of the Entitas folder to avoid errors in Unity
----Entitas\                   <-- The Entitas asset moved to the solution root