Starter Game Shard Template

This is a sample game shard built using Cardinal and Nakama as the account abstraction and transaction relayer.

Prerequisites

Mage Check

A mage target exists that will check for some common pre-requisites. Run the check with:

mage check

Docker Compose

Docker and docker compose are required for running Nakama and both can be installed with Docker Desktop.

Installation instructions for Docker Desktop

Mage

Mage is a cross-platform Make-like build tool.

git clone https://github.com/magefile/mage
cd mage
go run bootstrap.go

Running the Server

To start Nakama and Cardinal:

mage start

To start ONLY Cardinal in dev mode (compatible with the Retool dashboard):

mage dev

To restart ONLY Cardinal:

mage restart

To stop Nakama and Cardinal:

mage stop

Alternatively, killing the mage start process will also stop Nakama and Cardinal

Note, for now, if any Cardinal endpoints have been added or removed Nakama must be relaunched (via mage stop and mage start). We will add a future to hot reload this in the future.

Verify Nakama is Running

Visit localhost:7351 in a web browser to access the Nakama console. For local development, use admin:password as your login credentials.

The Account tab on the left will give you access to a valid account ID.

The API Explorer tab on the left will allow you to make requests to Cardinal.

Nakama Console

You can verify the Nakama server is running by visiting localhost:7351 in a web browser. For local development, use admin:password as our login credentials.

API Explorer

The API Explorer (on the sidebar) allows you to make requests to both Nakama and your Cardinal server.

Creating a User ID

Before using any endpoints, you need to populate the User ID field (between the endpoint dropdown and the submit button). The user ID 00000000-0000-0000-0000-000000000000 is a special admin user ID that will always be defined. Alternatively, a new user can be created by selecting the Authenticate Device endpoint from the dropdown. Populate the request boy with a payload like:

{
  "account": {
    "id": "123456789123456789"
  },
  "create": true,
  "username": "some-username"
}

And hit Submit no. User ID is required for this endpoint.

To get the User ID of your newly created account, click the Accounts item in the sidebar. Copy the relevant User ID and paste it into the User ID field on the API Explorer to hit other endpoints.

Claiming a Persona Tag

A persona tag is essentially a cardinal based user. To create a persona tag in your cardinal game, select the nakama/claim-persona endpoint from the dropdown. Make sure to paste in a valid User ID into the User ID field. Set the request body to:

{
  "persona_tag": "some-persona-tag"
}

and hit Submit. You should see a response like:

{
  "persona_tag": "some-persona-tag",
  "status": "pending",
  "tick": 2567,
  "tx_hash": "0x6bc26694dee4c4163335e4fe01d73eab2da071f38b991ae8424fa52de330c228"
}

This means cardinal received the request, and the request is pending. Change your endpoint to nakama/show-persona and hit Submit (no request body needed) to verify the claim-persona operation was successful. The response body should be similar to the nakama/claim-persona response, except "status" should now say "accepted".

This mean both Nakama and Cardinal are aware of your Nakama user and the related Persona Tag.

Custom Transactions

Once your persona tag has been set up, you send transactions to your custom cardinal transaction endpoints. If you set up a transaction like this:

package main

import (
	"pkg.world.dev/world-engine/cardinal/ecs"
	"pkg.world.dev/world-engine/cardinal/ecs/inmem"
)

type MoveMsg struct {
	Dx, Dy int
}

type MoveReply struct {
	FinalX, FinalY int
}

var MoveTx = ecs.NewTransactionType[MoveMsg, MoveReply]("move")

func main() {
	world := inmem.NewECSWorld()
	world.RegisterTransaction(MoveTx)
}

The dropdown will contain an entry with tx-move. The request body for that transaction could be:

{
	"Dx": 100,
	"Dy": 200,
}

Hit submit, and the transaction will be sent to your cardinal implementation. What your game does with the transaction depends on what Systems you've defined.

Storage

The Storage item in the sidebar allows you to view Nakama user data. Storage objects with a key name of persona_tag describe which persona tag has been associated with user ID.

Cardinal Editor

The Cardinal Editor is a web-based companion app that makes game development of Cardinal easier. It allows you to inspect the state of Cardinal in real-time without any additional code.

To work with the Cardinal Editor, you must first start the Cardinal server in dev mode:

mage dev

Then, open the Cardinal Editor in a web browser.

smsunarto/starter-game-template