steemhunt / dixel-contract

Dixel

A single NFT canvas where users overwrite the previous edition with price-compounded pixels.

1. There is an universal art canvas with 16x16 pixels that anyone can overwrite
2. Whenever a user overwrites a pixel, the price of the pixel increases by 0.1% (Initial pixel price: 0.001 DIXEL)
3. A new NFT edition with the current canvas state will be minted to the updater (image data is encoded as SVG, 100% on-chain)
4. Total cost that user paid to overwrite pixels goes to:
   • 10% -> all contributors proportional to their contribution count (total pixel count a user has updated so far)
   • 90% -> reserve for refund when the NFT gets burned
5. If a user burn a NFT they own, reserve amount (DIXEL tokens) gets refunded to the user (90% of total minting cost)

Run Tests

npx hardhat test

Contracts

BSC Production

• DIXEL token: 0xA4CB7f8c6659576F50A893C18F28765018f34E12
• DixelClub: 0x5d6FB69Bf26090aDc60e1567f05947c486773f57
• DixelArt NFT: 0x9F2659b0D2baD4C1D57819df58787cDFd391E3dF
• DixelAirdrop: 0x0f56Bd665b1Df1eafab97D0A2393acC1dEA47a21
• DixelTip: 0x7388d9AC06a49A2e52B3fB34374C83f4C1df1081

BSC Testnet

• Test token: 0x62c01AF8F8Ab997Acec06C3a71DC18594726ba24
• TestTokenFaucet: 0x0d5B2E37FB21A784FE26fD8d89Ea3Ce8F8BDc54d
• DixelClub: 0x3b7bd4FCcc630f025584f1F7e4874adB1f324AcE
• DixelArt NFT: 0x46cc5a12A3F58A837475C9BFe52C0C02274C0C0c
• DixelAirdrop: 0x7Fcb48b7AF75E47af89B328f99B681aCa93A7d10
• DixelTip: 0x37F6692763d388902f7413Fd560A15491927Fe0D

Deploy

npx hardhat compile

HARDHAT_NETWORK=bscmain node scripts/deploy.js

# Verify source code on Etherscan
npx hardhat verify --network bscmain {contract address} "parameter 1" "parameter 2"

Gas Consumption

·----------------------------------------------------|---------------------------|--------------|-----------------------------·
|                Solc version: 0.8.10                ·  Optimizer enabled: true  ·  Runs: 1500  ·  Block limit: 60000000 gas  │
·····················································|···························|··············|······························
|  Methods                                           ·                1 gwei/gas                ·       2607.30 usd/eth       │
····························|························|·············|·············|··············|···············|··············
|  Contract                 ·  Method                ·  Min        ·  Max        ·  Avg         ·  # calls      ·  usd (avg)  │
····························|························|·············|·············|··············|···············|··············
|  DixelAirdrop             ·  claim                 ·          -  ·          -  ·       69988  ·            8  ·       0.18  │
····························|························|·············|·············|··············|···············|··············
|  DixelAirdrop             ·  closeAirdrop          ·          -  ·          -  ·       78915  ·            3  ·       0.21  │
····························|························|·············|·············|··············|···············|··············
|  DixelAirdrop             ·  whitelist             ·          -  ·          -  ·       95119  ·           22  ·       0.25  │
····························|························|·············|·············|··············|···············|··············
|  DixelArt                 ·  approve               ·          -  ·          -  ·       48721  ·            5  ·       0.13  │
····························|························|·············|·············|··············|···············|··············
|  DixelArt                 ·  burn                  ·          -  ·          -  ·       68181  ·            7  ·       0.18  │
····························|························|·············|·············|··············|···············|··············
|  DixelArt                 ·  transferOwnership     ·      28630  ·      28642  ·       28641  ·          102  ·       0.07  │
····························|························|·············|·············|··············|···············|··············
|  DixelMock                ·  claimReward           ·      55953  ·      73053  ·       57268  ·           52  ·       0.15  │
····························|························|·············|·············|··············|···············|··············
|  DixelMock                ·  updatePixels          ·    1157496  ·    1292627  ·     1243279  ·          214  ·       3.24  │
····························|························|·············|·············|··············|···············|··············
|  DixelMock                ·  updatePixelsNoChecks  ·          -  ·          -  ·     3008326  ·            1  ·       7.84  │
····························|························|·············|·············|··············|···············|··············
|  DixelMock                ·  updatePixelsOriginal  ·          -  ·          -  ·     3258586  ·            1  ·       8.50  │
····························|························|·············|·············|··············|···············|··············
|  DixelTip                 ·  burnAndRefundTips     ·          -  ·          -  ·       91497  ·            4  ·       0.24  │
····························|························|·············|·············|··············|···············|··············
|  DixelTip                 ·  tip                   ·          -  ·          -  ·       98370  ·            9  ·       0.26  │
····························|························|·············|·············|··············|···············|··············
|  ERC20PresetMinterPauser  ·  approve               ·      46608  ·      46620  ·       46619  ·          203  ·       0.12  │
····························|························|·············|·············|··············|···············|··············
|  ERC20PresetMinterPauser  ·  mint                  ·      55830  ·      72954  ·       62554  ·          316  ·       0.16  │
····························|························|·············|·············|··············|···············|··············
|  Deployments                                       ·                                          ·  % of limit   ·             │
·····················································|·············|·············|··············|···············|··············
|  ColorUtilsMock                                    ·          -  ·          -  ·      298677  ·        0.5 %  ·       0.78  │
·····················································|·············|·············|··············|···············|··············
|  DixelAirdrop                                      ·     794659  ·     794671  ·      794670  ·        1.3 %  ·       2.07  │
·····················································|·············|·············|··············|···············|··············
|  DixelArt                                          ·    2927148  ·    2927172  ·     2927171  ·        4.9 %  ·       7.63  │
·····················································|·············|·············|··············|···············|··············
|  DixelMock                                         ·    8076080  ·    8096016  ·     8076295  ·       13.5 %  ·      21.06  │
·····················································|·············|·············|··············|···············|··············
|  DixelTip                                          ·     823384  ·     823396  ·      823395  ·        1.4 %  ·       2.15  │
·····················································|·············|·············|··············|···············|··············
|  ERC20PresetMinterPauser                           ·          -  ·          -  ·     1951544  ·        3.3 %  ·       5.09  │
·----------------------------------------------------|-------------|-------------|--------------|---------------|-------------·

dixel-contract's Issues

Consider removing usage of _msgSender()

OpenZeppelin's Context.sol and _msgSender() are needed only if you plan to use meta-transactions, in which you'll pay for the user's gas fees. (reference)

Since most projects don't do that, I'm guessing that you won't do it either.

If that is so, you can consider removing Context.sol and replace all _msgSender()s with msg.sender. This will save a tiny bit of gas and perhaps be more clean.

After burning token, original minter continues to receive rewards

Just checking - is this intended behavior?

Reward distribution for community audits 💸

Overall, we had 6 devs who participated in our community driven audit event.

@Nipol @junomonster @Jinmo @cryptocorgie @inmarelibero @assafom

I really appreciate everyone who participated in reviewing the code, and we successfully improved our contract in many ways:

• 1 critical issue on reward calculation
• 2 medium level issues on parameter edge cases
• 2 minor issues on edge cases
• optimizations on gas consumption

We discussed about the fair reward distribution for the contributions considering the importance of the contribution and amount of work put into the reviewing process.

I hope you guys are okay with this distribution table below:

If you have any concerns or opinion on the distribution, please comment down here so we can discuss together.
I will distribute the reward (total $10,000 USDT) to the wallet address by the end of tomorrow if there are no issues brought up.

We were very satisfied with the result of this event, and we may have other bounty programs later on.
Let's keep in touch and hope to see you guys again soon! ❤️

playerWallets can contain duplicate values

address[] public playerWallets; in https://github.com/Steemhunt/dixel-contract/blob/main/contracts/Dixel.sol#L69 can accept multiple times the same wallet, because of use of playerWallets.push

if so, require(playerWallets.length < 0xffffffff, "MAX_USER_REACHED"); in https://github.com/Steemhunt/dixel-contract/blob/main/contracts/Dixel.sol#L95 behaves incorrectly, because playerWallets.length would reach the limit also if it would contain 0xffffffff times the same address

why don't use https://docs.openzeppelin.com/contracts/3.x/api/utils#EnumerableMap for address[] public playerWallets?

Reward calculation issue when the same player update in a row

When the same user updates the pixels twice, the reward doesn't get accumulated.

Prevent updating pixel with the same color

It causes a minting of a new edition of exactly the same pixels with the previous edition

• Add checks on updatePixels if it has the same color data with the previous pixel
• Check gas consumption increase by this check

gas saving

not really an issue, opening just for discussion because I made a review on a closed PR and I wasn't sure it got viewed: #2 (review)

Reward calculation error - lost rewards

Consider the following scenario:

• Alice updates 2 pixels and sends reward to Dixel: rewrad amount X
• Bob updates 2 pixels and sends reward to Dixel: reward amount Y
• Alice updates 2 pixels and sends reward to Dixel: reward amount Z

Now let's say Alice and Bob claim their rewards.
Per my understanding, amount X will be lost in the contract (per design), but all of amounts Y+Z should get sent to Alice and Bob, as they are the only ones who minted so far.

However, when testing this scenario - after Alice and Bob claim their rewards - I see that there are more tokens in Dixel than amount X. These are tokens that are unclaimable as Alice and Bob, the only players, have already claimed their rewards, and they should have gotten all the rewards.

So this leads me to think that there is a fundamental error in the reward calculation, unless I'm missing something.
Here is a test file that will simulate this scenario and print Dixel's baseToken balance, so you can see there are more rewards than should be there.

Tomorrow I will try looking at this further and understand what's the root cause.

Prevent duplicated pixel params

#3 ensures updating pixel parameters are sorted ([0][0], [0][1], [0][2], [0][3] ... [15][15]) so it can prevent updating the same pixel multiple times in one transaction.

Let's check how much gas fee is added by this check when a user update all 256 pixels, and decide whether we allow this by design or not.

• Add test case updating all 256 pixels and compare the gas consumption between dup-checks and non dup-checks

If we're going to add duplication checking,

• Front-end should sort pixel updating params

airdrop reopening

supposing that airdrop will be run only one tine, once closed it should not be reopenable

suggestion: add bool public airdropEnded toDixelAirdrop.sol, and a check before

dixel-contract/contracts/DixelAirdrop.sol

Line 60 in 07a6805

canClaim = true;

Running all tests not working any more

Looks like running npx hardhat test doesn't run all the tests anymore, but just one -

Contract: DixelArt
    generate NFT
      ✓ should revert tokenURI in JSON format generation if tokenId has not been minted yet

Dunno if I'm missing something. Running Dixel.test.js manually is working, but running DixelArt.test.js manually or just general hardhat test just runs that one test. So far I haven't found the cause for the problem.