Rarity Achievement System: update and release date

I have already introduced the project some days ago with the previous blog post “Proof of Concept of an Achievement System for Rarity”.

In the last couple of days, I’ve dedicated my spare time to refactor the whole project changing some strong requirements I had hardcoded with it.

So let’s view what has changed, how other smart contract developers or web3 developers can integrate with it, and when I’ll release the contract.

But first, just a TL;DR on what’s this project about!

TL;DR: What’s the project about?

Rarity Achievement is a smart contract to create a decentralized achievement system for Rarity by Andre Cronje. The concept of the project can be adapted and adopted by other crypto games in the ecosystem.

For the summoner

  • Track the total amount of achievement points earned by the summoner while playing the game
  • Track the list of achievements earned

For the other contracts/web developers

  • Enable a way to unlock achievements when the user interacts with a contract
  • Enable to unlock content if the user has reached a certain amount of achievements points or has unlocked a specific achievement

What does this enable for the ecosystem?

  • Players are more engaged to play the game to earn achievements
  • Contract with achievements will be used more
  • The overall longevity of the Rarity game is extended
  • Other contracts / dApp could enable some content only if the user has reached a minimum level of achievements points
  • Achievements points (that’s just an idea) could be “burned” to purchase specific items payable with achievements points instead of golds
  • More concepts to come

What has changed since the last time?

First of all, I would like to thanks all the people that have given me feedback from Twitter and Discord. A special mention to @Newti from the Rarity Discord, he has helped me a lot giving me feedback and suggestions on some specific mechanics I should adopt.

Remove all the source and achievement whitelisting process

In the first version of the smart contract, I implement a whitelisting process to only accept legit smart contracts to be able to register achievements.

It was the perfect green garden but the process was too complex and the adoption of the project was doomed by the start. It could have been fine for a PoC but not for a real-world use case or at least not for the current state of the blockchain ecosystem.

So now every smart contract (even if it’s not from the Rarity ecosystem) can register achievement metadata and can award achievements to a summoner.

So you will be asking me

Aren’t you afraid that malicious users could create achievements and spam/send junk achievements to summoners?

Yup. That was the reason why I originally structured the logic to force smart contract developers to be whitelisted in order to register achievement metadata.

But as Newti suggested to me, that’s not the correct solution. The correct solution is to allow anyone to do whatever they want but allow frontend dev or other smart contract developers to be able to filter the list of achievements owned by the summoner.

Filter awarded achievements and achievement points

The second big part of the refactor was on the getters for both achievements and achievement points.

I needed to allow other developers to only get achievements from the whitelisted or recommended list of smart contracts.

So now you can specify a list of contract addresses on the getAchievements and getPoints.

How to interact with the contract?

For smart contract developers that want to register and award achievements

If you want to see an example of a contract that integrate with RarityAchievement you can look at RarityBlockSandbox.sol

What your contract needs to do is

First of all, you need to import both the RarityAchievement interface and Model

import “../interfaces/AchievementInterface.sol”;
import “../data/AchievementModel.sol”;

Save a reference to the RarityAchievement contract like this

AchievementContractInterface _ac;

Declare the Achievement Metadata ID used by your contract

uint256 private mobAchievement;
uint256 private miniBossAchievement;
uint256 private bossAchievement;

Register your achievement metadata calling _ac.registerAchievement(achievementMetadata); for each of your contract’s achievements.

registerAchievement takes a metadata as input and return the metadataID you need to send the contract when you want to award an achievement to a summoner.

The model of the metadata is like this:

AchievementModel.AchievementMetadata metadata = AchievementModel.AchievementMetadata({
id: 0, // ID here is not important, will be replaced by the AchievementContract
source: address(this), // source is not important, will be replaced by the AchievementContract
source_name: "The nightmare dungeon!",
difficulty: AchievementModel.Difficulty.Uncommon,
title: "Defeated first miniboss",
description: "You have been brave enough to defeat the Eruptus, the mini boss of 'The Fantom Dungeon'",
points: 10

I’ll explain each of those

- idis the ID of the metadata. You can pass `0` because it will be replaced by the RarityAchievement contract when you call the registration process
- source is your contract’s address
- source_name is the name of your contract. For example The Fantom Dungeon, it will be used by web apps to know from which contract the achievement comes.
- difficulty is how difficult is to get this achievement. It goes from Common to Legendary
- titleis the title of the achievement
- description is the description of the achievement
- points are the number of achievement points that the summoner will receive when awarded the achievement. Try to be fair otherwise, your contract will not be used by other web apps/contracts!

id and source are optional, they will be replaced by the RarityAchievement contract, other properties are required, otherwise, the transaction will revert!

When you have registered all your achievement you just need to award those achievements when the summoner has done some specific action like for example

  • Beaten a difficult boss
  • Crafted 100 swords
  • Collected 100.000 gold
  • Reached level 10
  • Defeated 10 times a dungeon

To award an achievement to a summoner you need to call _ac.awardAchievement(summonerId, achievementMetadataId);.

Please be aware that:

  1. You can award only achievement that your contract owns
  2. You cannot award multiple time the same achievement to the same summoner

If you want to be sure that a summoner already owns an achievement you can call _ac.hasAchievement(summonerId, achievementMetadataId);

For web3 developers / other integration

If you want to build a frontend to list the summoner’s achievement you are in the right place. These functions could also be used by other smart contract developers to create derivative contracts.

For example, you could allow a summoner to craft the ultimate sword only if he owns the achievement unlocked after crafting 100 swords. Or you can allow accessing the final dungeon only if the summoner owns all the achievements from previous dungeons and so on. Just use your imagination!

Back to web3 devs. You have 3 utility functions you can call:

hasAchievement(uint256 summonerId, uint256 metadataId) will return a bool. It will be true if the summoner owns a specific achievement.

getPoints(uint256 summonerId, address[] memory sources) it will return the total amount of achievement points owned by the summoner.

The `sources` is an array of whitelisted contracts from which you want to filter the achievements from. For example, you want to get only points gained by `ContractA` and `ContractB` contracts, you just need to pass those addresses as an array.

If you don’t want to filter at all, just pass an empty array like this []

function getAchievements(uint256 summonerId, address[] memory sources, uint256 offset, uint256 limit) will return the list of Achievements owned by the summoner. The sources parameter is used for the same reason: get only the achievement awarded from those contract addresses. The offset and limit parameters are used to paginate the results (because of RPC limitations). Use them only if you get some errors while querying the contract otherwise just pass 0 as the offset and 9999999999 (or any big number) as the limit.

When will it be released?

I’m planning to take the weekend to apply some final touch to the code, release it on testnet and as soon as I’m satisfied with the result I’ll release it on the main net. So at max a couple of days more!

Feedback, help, new ideas?

I’m open to discussion and feedback, if you have any please DM me on Twitter @StErMi or open a GitHub issue/PR!




Full-stack engineer at @Soplaya with a lot of love for everything around technology https://ericci.dev

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Full-stack engineer at @Soplaya with a lot of love for everything around technology https://ericci.dev

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